Update release notes for v4.1.7

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.dockerignore

@@ -0,0 +1,52 @@
+# Git
+.git
+.gitignore
+
+# Python
+__pycache__
+*.py[cod]
+*.egg-info
+.eggs
+venv/
+.venv/
+
+# Instance data (user creates fresh)
+frontends/web/instance/
+frontends/web/certs/
+instance/
+
+# Test data
+test_data/
+tests/
+
+# Pi-specific
+rpi/
+*.img
+*.img.xz
+*.img.zst
+*.img.zst.zip
+
+# Docs
+*.md
+docs/
+
+# IDE
+.vscode/
+.idea/
+
+# Misc
+*.log
+*.tmp
+.DS_Store
+
+# Dev scripts and old files
+scripts/
+old_files/
+*_old
+*_old.*
+*.bak
+*.orig
+
+# Temp files
+frontends/web/temp_files/
+*.db

.github/CI_CD_PRIMER.md

@@ -0,0 +1,228 @@
+# CI/CD Primer for Stegasoo
+
+## What is CI/CD?
+
+**CI** = Continuous Integration
+**CD** = Continuous Deployment
+
+Think of it as a robot assistant that automatically:
+1. **Tests your code** every time you push
+2. **Checks formatting** so code stays consistent
+3. **Publishes releases** when you tag a version
+
+```
+You push code → GitHub runs workflows → You get ✓ or ✗
+```
+
+---
+
+## How It Works
+
+### The Trigger
+
+When you `git push` or create a Pull Request, GitHub looks for workflow files in:
+```
+.github/workflows/*.yml
+```
+
+Each `.yml` file defines a workflow - a series of steps to run.
+
+### The Runners
+
+GitHub provides free Linux/Mac/Windows VMs that:
+1. Clone your repo
+2. Set up Python
+3. Run your commands
+4. Report success/failure
+
+You don't manage servers - GitHub does.
+
+---
+
+## Your Workflows
+
+### 1. `test.yml` - Run Tests on Every Push
+
+**When it runs:** Every push, every PR
+
+**What it does:**
+```
+1. Spins up Ubuntu VM
+2. Installs Python 3.10, 3.11, 3.12
+3. Installs your package + dependencies
+4. Runs pytest
+5. Reports pass/fail
+```
+
+**You'll see:** Green ✓ or red ✗ on your commits
+
+### 2. `lint.yml` - Check Code Style
+
+**When it runs:** Every push, every PR
+
+**What it does:**
+```
+1. Runs ruff (fast Python linter)
+2. Checks black formatting
+3. Fails if code isn't formatted
+```
+
+**Why:** Keeps code consistent, catches common bugs
+
+### 3. `release.yml` - Publish to PyPI
+
+**When it runs:** Only when you create a version tag
+
+**What it does:**
+```
+1. Builds the package (wheel + sdist)
+2. Uploads to PyPI
+```
+
+**You trigger it by:**
+```bash
+git tag v2.2.0
+git push origin v2.2.0
+```
+
+---
+
+## Day-to-Day Usage
+
+### Normal Development
+
+```bash
+# Make changes
+git add .
+git commit -m "Add new feature"
+git push
+```
+
+Then check GitHub → Actions tab → See if tests pass.
+
+### If Tests Fail
+
+1. Click the failed workflow
+2. Click the failed job
+3. Read the error log
+4. Fix locally, push again
+
+### Making a Release
+
+```bash
+# 1. Update version in pyproject.toml and constants.py
+# 2. Commit the version bump
+git add .
+git commit -m "Bump version to 2.2.1"
+git push
+
+# 3. Create and push a tag
+git tag v2.2.1
+git push origin v2.2.1
+
+# 4. GitHub automatically publishes to PyPI
+```
+
+---
+
+## Reading the GitHub UI
+
+### Actions Tab
+
+```
+Repository → Actions → [List of workflow runs]
+```
+
+Each run shows:
+- ✓ Green checkmark = passed
+- ✗ Red X = failed
+- 🟡 Yellow dot = running
+
+### Pull Request Checks
+
+When you open a PR, you'll see:
+```
+┌─────────────────────────────────────────┐
+│ All checks have passed                  │
+│ ✓ test (3.10) — 45s                     │
+│ ✓ test (3.11) — 42s                     │
+│ ✓ test (3.12) — 44s                     │
+│ ✓ lint — 12s                            │
+└─────────────────────────────────────────┘
+```
+
+---
+
+## Setting Up PyPI Publishing
+
+For `release.yml` to work, you need to add a PyPI API token:
+
+### One-Time Setup
+
+1. **Create PyPI account** at https://pypi.org/account/register/
+
+2. **Generate API token:**
+   - PyPI → Account Settings → API tokens
+   - Create token (scope: entire account or just stegasoo)
+   - Copy the token (starts with `pypi-`)
+
+3. **Add to GitHub:**
+   - GitHub repo → Settings → Secrets and variables → Actions
+   - New repository secret
+   - Name: `PYPI_API_TOKEN`
+   - Value: paste the token
+
+Now `release.yml` can publish automatically.
+
+---
+
+## Common Scenarios
+
+### "Tests pass locally but fail in CI"
+
+Usually means:
+- Missing dependency in `pyproject.toml`
+- Hardcoded path that doesn't exist in CI
+- Test relies on local file
+
+### "Lint is failing"
+
+Run locally to see/fix:
+```bash
+# Check issues
+ruff check src/
+
+# Auto-fix what's possible
+ruff check --fix src/
+
+# Format code
+black src/
+```
+
+### "I want to skip CI for a commit"
+
+Add `[skip ci]` to commit message:
+```bash
+git commit -m "Update README [skip ci]"
+```
+
+---
+
+## Costs
+
+GitHub Actions is **free** for public repos.
+
+For private repos: 2,000 minutes/month free, then paid.
+
+---
+
+## Summary
+
+| Action | What Happens |
+|--------|--------------|
+| `git push` | Tests + lint run automatically |
+| Open PR | Tests must pass before merge |
+| `git tag v*` | Publishes to PyPI |
+| Check results | GitHub → Actions tab |
+
+That's it! Push code, check for green checkmarks.

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,98 @@
+name: Bug Report
+description: Report a bug or unexpected behavior
+title: "[Bug]: "
+labels: ["bug", "triage"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for taking the time to report a bug! Please fill out the form below.
+
+  - type: textarea
+    id: description
+    attributes:
+      label: Bug Description
+      description: A clear and concise description of what the bug is.
+      placeholder: Describe the bug...
+    validations:
+      required: true
+
+  - type: textarea
+    id: reproduction
+    attributes:
+      label: Steps to Reproduce
+      description: Steps to reproduce the behavior.
+      placeholder: |
+        1. Run command '...'
+        2. Upload image '...'
+        3. See error
+    validations:
+      required: true
+
+  - type: textarea
+    id: expected
+    attributes:
+      label: Expected Behavior
+      description: What did you expect to happen?
+    validations:
+      required: true
+
+  - type: textarea
+    id: actual
+    attributes:
+      label: Actual Behavior
+      description: What actually happened?
+    validations:
+      required: true
+
+  - type: dropdown
+    id: interface
+    attributes:
+      label: Interface
+      description: Which interface are you using?
+      options:
+        - CLI
+        - Web UI
+        - REST API
+        - Python Library
+    validations:
+      required: true
+
+  - type: input
+    id: version
+    attributes:
+      label: Stegasoo Version
+      description: Run `stegasoo --version` or check the web UI footer
+      placeholder: "4.0.1"
+    validations:
+      required: true
+
+  - type: input
+    id: python-version
+    attributes:
+      label: Python Version
+      description: Run `python --version`
+      placeholder: "3.11.0"
+    validations:
+      required: true
+
+  - type: input
+    id: os
+    attributes:
+      label: Operating System
+      placeholder: "Ubuntu 22.04 / Windows 11 / macOS 14"
+    validations:
+      required: true
+
+  - type: textarea
+    id: logs
+    attributes:
+      label: Error Logs
+      description: Paste any relevant error messages or tracebacks.
+      render: shell
+
+  - type: textarea
+    id: additional
+    attributes:
+      label: Additional Context
+      description: Add any other context, screenshots, or files here.

.github/ISSUE_TEMPLATE/config.yml

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+blank_issues_enabled: true
+contact_links:
+  - name: Security Vulnerability
+    url: https://github.com/adlee-was-taken/stegasoo/security/advisories/new
+    about: Report security vulnerabilities privately
+  - name: Documentation
+    url: https://github.com/adlee-was-taken/stegasoo#readme
+    about: Check the documentation before opening an issue

.github/ISSUE_TEMPLATE/feature_request.yml

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+name: Feature Request
+description: Suggest a new feature or enhancement
+title: "[Feature]: "
+labels: ["enhancement"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for suggesting a feature! Please fill out the form below.
+
+  - type: textarea
+    id: problem
+    attributes:
+      label: Problem Statement
+      description: Is your feature request related to a problem? Describe it.
+      placeholder: I'm always frustrated when...
+    validations:
+      required: true
+
+  - type: textarea
+    id: solution
+    attributes:
+      label: Proposed Solution
+      description: Describe the solution you'd like.
+      placeholder: I would like to be able to...
+    validations:
+      required: true
+
+  - type: textarea
+    id: alternatives
+    attributes:
+      label: Alternatives Considered
+      description: Describe any alternative solutions or features you've considered.
+
+  - type: dropdown
+    id: interface
+    attributes:
+      label: Affected Interface(s)
+      description: Which interface(s) would this feature affect?
+      multiple: true
+      options:
+        - CLI
+        - Web UI
+        - REST API
+        - Python Library
+        - Core Library
+
+  - type: dropdown
+    id: priority
+    attributes:
+      label: Priority
+      description: How important is this feature to you?
+      options:
+        - Nice to have
+        - Would improve my workflow
+        - Critical for my use case
+
+  - type: textarea
+    id: context
+    attributes:
+      label: Additional Context
+      description: Add any other context, mockups, or examples here.

.github/PULL_REQUEST_TEMPLATE.md

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+## Description
+
+<!-- Describe your changes in detail -->
+
+## Type of Change
+
+<!-- Mark the relevant option with an 'x' -->
+
+- [ ] Bug fix (non-breaking change that fixes an issue)
+- [ ] New feature (non-breaking change that adds functionality)
+- [ ] Breaking change (fix or feature that would cause existing functionality to change)
+- [ ] Documentation update
+- [ ] Refactoring (no functional changes)
+- [ ] CI/CD or build changes
+
+## Related Issues
+
+<!-- Link any related issues here -->
+
+Fixes #
+
+## Testing
+
+<!-- Describe how you tested your changes -->
+
+- [ ] I have added tests that prove my fix/feature works
+- [ ] Existing tests pass locally with my changes
+- [ ] I have tested manually (describe below)
+
+### Manual Testing Steps
+
+<!-- If applicable, describe manual testing performed -->
+
+## Checklist
+
+- [ ] My code follows the project's style guidelines
+- [ ] I have performed a self-review of my code
+- [ ] I have commented my code, particularly in hard-to-understand areas
+- [ ] I have updated the documentation accordingly
+- [ ] I have updated CHANGELOG.md (if user-facing changes)
+- [ ] My changes generate no new warnings
+- [ ] Any dependent changes have been merged and published
+
+## Screenshots
+
+<!-- If applicable, add screenshots to help explain your changes -->

.github/workflows/lint.yml

@@ -0,0 +1,63 @@
+# Check code style and formatting
+name: Lint
+
+on:
+  push:
+    branches: [main, master, develop]
+  pull_request:
+    branches: [main, master, develop]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    
+    steps:
+      # 1. Get the code
+      - name: Checkout code
+        uses: actions/checkout@v4
+      
+      # 2. Set up Python
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+      
+      # 3. Install linting tools
+      - name: Install linters
+        run: |
+          python -m pip install --upgrade pip
+          pip install ruff black
+      
+      # 4. Run ruff (fast linter - catches bugs and style issues)
+      - name: Run ruff
+        run: |
+          ruff check src/ tests/ frontends/
+      
+      # 5. Check black formatting (doesn't modify, just checks)
+      - name: Check black formatting
+        run: |
+          black --check src/ tests/ frontends/
+
+  # Type checking (optional but helpful)
+  typecheck:
+    runs-on: ubuntu-latest
+    
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+      
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e ".[dev]"
+          pip install mypy
+      
+      - name: Run mypy
+        run: |
+          mypy src/stegasoo --ignore-missing-imports
+        continue-on-error: true  # Don't fail build on type errors (yet)

.github/workflows/release.yml

@@ -0,0 +1,95 @@
+# Publish to PyPI when a version tag is pushed
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'  # Triggers on v1.0.0, v2.1.0, etc.
+
+jobs:
+  # First, run tests to make sure everything works
+  test:
+    runs-on: ubuntu-latest
+    
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+      
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libzbar0
+      
+      - name: Install package
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e ".[dev]"
+      
+      - name: Run tests
+        run: pytest
+
+  # Then build and publish
+  publish:
+    needs: test  # Only run if tests pass
+    runs-on: ubuntu-latest
+    
+    # Required for PyPI trusted publishing (recommended)
+    permissions:
+      id-token: write
+    
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+      
+      - name: Install build tools
+        run: |
+          python -m pip install --upgrade pip
+          pip install build twine
+      
+      - name: Build package
+        run: python -m build
+      
+      - name: Check package
+        run: twine check dist/*
+      
+      # Option 1: Trusted Publishing (recommended, no token needed)
+      # Set this up at: https://pypi.org/manage/project/stegasoo/settings/publishing/
+      - name: Publish to PyPI (Trusted Publishing)
+        uses: pypa/gh-action-pypi-publish@release/v1
+        # No token needed if you configure trusted publishing on PyPI
+      
+      # Option 2: API Token (uncomment if not using trusted publishing)
+      # - name: Publish to PyPI (API Token)
+      #   env:
+      #     TWINE_USERNAME: __token__
+      #     TWINE_PASSWORD: ${{ secrets.PYPI_API_TOKEN }}
+      #   run: twine upload dist/*
+
+  # Create GitHub Release with changelog
+  github-release:
+    needs: publish
+    runs-on: ubuntu-latest
+    
+    permissions:
+      contents: write  # Needed to create releases
+    
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v1
+        with:
+          generate_release_notes: true
+          files: |
+            dist/*

.github/workflows/test.yml

@@ -0,0 +1,53 @@
+# Run tests on every push and pull request
+name: Tests
+
+on:
+  push:
+    branches: [main, master, develop]
+  pull_request:
+    branches: [main, master, develop]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    
+    strategy:
+      fail-fast: false  # Don't cancel other jobs if one fails
+      matrix:
+        python-version: ["3.10", "3.11", "3.12"]
+    
+    steps:
+      # 1. Get the code
+      - name: Checkout code
+        uses: actions/checkout@v4
+      
+      # 2. Set up Python
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+      
+      # 3. Install system dependencies (for pyzbar QR reading)
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libzbar0
+      
+      # 4. Install the package with all dependencies
+      - name: Install package
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e ".[dev]"
+      
+      # 5. Run tests with coverage
+      - name: Run tests
+        run: |
+          pytest --cov=stegasoo --cov-report=xml --cov-report=term-missing
+      
+      # 6. Upload coverage report (optional - integrates with codecov.io)
+      - name: Upload coverage
+        uses: codecov/codecov-action@v4
+        if: matrix.python-version == '3.11'  # Only upload once
+        with:
+          files: ./coverage.xml
+          fail_ci_if_error: false  # Don't fail if codecov is down

.gitignore

@@ -35,6 +35,12 @@ old_files/
 *.swp
 *.swo
 
+# Backup files
+*_old
+*_old.*
+*.bak
+*.orig
+
 # Testing
 .pytest_cache/
 .coverage
@@ -48,7 +54,7 @@ htmlcov/
 
 # Environment
 .env
-.env.*
+.env.local
 *.log
 
 # Distribution
@@ -56,4 +62,38 @@ htmlcov/
 *.spec
 
 # Output test files.
-*.png
+test_data/*.png
+
+# Dev scripts (local convenience scripts - except these)
+scripts/*
+!scripts/validate-release.sh
+!scripts/smoke-test.sh
+!scripts/setup-trusted-certs.sh
+!scripts/screenshots.sh
+!scripts/build.sh
+
+# Web UI auth database and SSL certs
+instance/
+frontends/web/instance/
+frontends/web/certs/
+
+# Tests (private)
+tests/
+
+# RPi image build artifacts
+*.img
+*.img.xz
+*.img.zst
+*.img.zst.zip
+rpi/tools/pishrink.sh
+
+# Temp file storage
+frontends/web/temp_files/
+rpi/config.json
+
+# Pre-built Pi tarballs and images (release assets, too large for git)
+rpi/*.tar.zst
+rpi/*.tar.zst.zip
+rpi/*.img
+rpi/*.img.zst
+rpi/*.img.zst.zip

.pre-commit-config.yaml

@@ -0,0 +1,40 @@
+# Pre-commit hooks - run formatting/linting before each commit
+# Install: pip install pre-commit && pre-commit install
+# Manual run: pre-commit run --all-files
+
+repos:
+  # Ruff - fast Python linter (replaces flake8, isort, etc.)
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.1.6
+    hooks:
+      - id: ruff
+        args: [--fix]  # Auto-fix what's possible
+      - id: ruff-format  # Ruff's formatter (alternative to black)
+
+  # Black - code formatter (comment out if using ruff-format above)
+  # - repo: https://github.com/psf/black
+  #   rev: 23.11.0
+  #   hooks:
+  #     - id: black
+
+  # Basic file hygiene
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.5.0
+    hooks:
+      - id: trailing-whitespace      # Remove trailing spaces
+      - id: end-of-file-fixer        # Ensure newline at EOF
+      - id: check-yaml               # Validate YAML
+      - id: check-toml               # Validate TOML
+      - id: check-added-large-files  # Prevent giant files
+        args: ['--maxkb=1000']
+      - id: check-merge-conflict     # No merge conflict markers
+      - id: debug-statements         # No print() or pdb left behind
+
+  # Security checks
+  - repo: https://github.com/PyCQA/bandit
+    rev: 1.7.6
+    hooks:
+      - id: bandit
+        args: ["-c", "pyproject.toml"]
+        additional_dependencies: ["bandit[toml]"]
+        exclude: tests/

.python-version

@@ -0,0 +1 @@
+3.12

API.md

@@ -0,0 +1,882 @@
+# Stegasoo REST API Documentation (v4.0.2)
+
+Complete REST API reference for Stegasoo steganography operations.
+
+## Table of Contents
+
+- [Overview](#overview)
+- [What's New in v4.0.0](#whats-new-in-v400)
+- [Installation](#installation)
+- [Base URL](#base-url)
+- [Endpoints](#endpoints)
+  - [GET /](#get--status)
+  - [GET /modes](#get-modes)
+  - [GET /channel/status](#get-channelstatus)
+  - [POST /channel/generate](#post-channelgenerate)
+  - [POST /channel/set](#post-channelset)
+  - [DELETE /channel](#delete-channel)
+  - [POST /generate](#post-generate)
+  - [POST /encode](#post-encode-json)
+  - [POST /encode/file](#post-encodefile)
+  - [POST /encode/multipart](#post-encodemultipart)
+  - [POST /decode](#post-decode-json)
+  - [POST /decode/multipart](#post-decodemultipart)
+  - [POST /compare](#post-compare)
+  - [POST /will-fit](#post-will-fit)
+  - [POST /image/info](#post-imageinfo)
+- [Channel Keys](#channel-keys)
+- [Data Models](#data-models)
+- [Error Handling](#error-handling)
+- [Code Examples](#code-examples)
+
+---
+
+## Overview
+
+The Stegasoo REST API provides programmatic access to all steganography operations:
+
+- **Generate** credentials (passphrase, PINs, RSA keys)
+- **Encode** messages or files into images (LSB or DCT mode)
+- **Decode** messages or files from images (auto-detects mode)
+- **Channel keys** for deployment/group isolation (v4.0.0)
+- **Analyze** image capacity and compare modes
+
+The API supports both JSON (base64-encoded images) and multipart form data (direct file uploads).
+
+---
+
+## What's New in v4.0.0
+
+Version 4.0.0 adds **channel key** support for deployment/group isolation:
+
+| Feature | Description |
+|---------|-------------|
+| Channel keys | 256-bit keys that isolate message groups |
+| New endpoints | `/channel/status`, `/channel/generate`, `/channel/set`, `DELETE /channel` |
+| Encode/decode param | `channel_key` parameter on all encode/decode endpoints |
+| Response headers | `X-Stegasoo-Channel-Mode` and `X-Stegasoo-Channel-Fingerprint` |
+
+**Key benefits:**
+- ✅ Isolate messages between teams, deployments, or groups
+- ✅ Same credentials can't decode messages from different channels
+- ✅ Backward compatible (public mode = no channel key)
+
+**Breaking change:** v4.0.0 messages (with channel key) cannot be decoded by v3.x installations.
+
+---
+
+## Installation
+
+### From PyPI
+
+```bash
+pip install stegasoo[api]
+```
+
+### Running the Server
+
+**Development:**
+```bash
+cd frontends/api
+python main.py
+```
+
+**Production:**
+```bash
+uvicorn main:app --host 0.0.0.0 --port 8000 --workers 4
+```
+
+**Docker with channel key:**
+```bash
+STEGASOO_CHANNEL_KEY=XXXX-XXXX-... docker-compose -f docker/docker-compose.yml up api
+```
+
+---
+
+## Base URL
+
+| Environment | URL |
+|-------------|-----|
+| Local Development | `http://localhost:8000` |
+| Docker | `http://localhost:8000` |
+| Production | Configure as needed |
+
+---
+
+## Endpoints
+
+### GET / (Status)
+
+Check API status and configuration.
+
+#### Response
+
+```json
+{
+  "version": "4.0.2",
+  "has_argon2": true,
+  "has_qrcode_read": true,
+  "has_dct": true,
+  "max_payload_kb": 500,
+  "available_modes": ["lsb", "dct"],
+  "dct_features": {
+    "output_formats": ["png", "jpeg"],
+    "color_modes": ["grayscale", "color"]
+  },
+  "channel": {
+    "mode": "private",
+    "configured": true,
+    "fingerprint": "ABCD-••••-••••-••••-••••-••••-••••-3456",
+    "source": "~/.stegasoo/channel.key"
+  },
+  "breaking_changes": {
+    "v4_channel_key": "Messages encoded with channel key require same key to decode",
+    "format_version": 5,
+    "backward_compatible": false
+  }
+}
+```
+
+---
+
+### GET /modes
+
+Get available embedding modes and channel status.
+
+#### Response
+
+```json
+{
+  "lsb": {
+    "available": true,
+    "name": "Spatial LSB",
+    "description": "Embed in pixel LSBs, outputs PNG/BMP",
+    "output_format": "PNG (color)",
+    "capacity_ratio": "100%"
+  },
+  "dct": {
+    "available": true,
+    "name": "DCT Domain",
+    "output_formats": ["png", "jpeg"],
+    "color_modes": ["grayscale", "color"],
+    "capacity_ratio": "~20% of LSB",
+    "requires": "scipy"
+  },
+  "channel": {
+    "mode": "private",
+    "configured": true,
+    "fingerprint": "ABCD-••••-••••-••••-••••-••••-••••-3456"
+  }
+}
+```
+
+---
+
+### GET /channel/status
+
+Get current channel key status. **New in v4.0.0.**
+
+#### Query Parameters
+
+| Parameter | Type | Default | Description |
+|-----------|------|---------|-------------|
+| `reveal` | boolean | `false` | Include full key in response |
+
+#### Response
+
+```json
+{
+  "mode": "private",
+  "configured": true,
+  "fingerprint": "ABCD-••••-••••-••••-••••-••••-••••-3456",
+  "source": "~/.stegasoo/channel.key",
+  "key": null
+}
+```
+
+With `reveal=true`:
+
+```json
+{
+  "mode": "private",
+  "configured": true,
+  "fingerprint": "ABCD-••••-••••-••••-••••-••••-••••-3456",
+  "source": "~/.stegasoo/channel.key",
+  "key": "ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456"
+}
+```
+
+#### cURL Example
+
+```bash
+# Show status
+curl http://localhost:8000/channel/status
+
+# Reveal full key
+curl "http://localhost:8000/channel/status?reveal=true"
+```
+
+---
+
+### POST /channel/generate
+
+Generate a new channel key. **New in v4.0.0.**
+
+#### Query Parameters
+
+| Parameter | Type | Default | Description |
+|-----------|------|---------|-------------|
+| `save` | boolean | `false` | Save to user config |
+| `save_project` | boolean | `false` | Save to project config |
+
+#### Response
+
+```json
+{
+  "key": "ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456",
+  "fingerprint": "ABCD-••••-••••-••••-••••-••••-••••-3456",
+  "saved": true,
+  "save_location": "~/.stegasoo/channel.key"
+}
+```
+
+#### cURL Examples
+
+```bash
+# Just generate (don't save)
+curl -X POST http://localhost:8000/channel/generate
+
+# Generate and save to user config
+curl -X POST "http://localhost:8000/channel/generate?save=true"
+
+# Generate and save to project config
+curl -X POST "http://localhost:8000/channel/generate?save_project=true"
+```
+
+---
+
+### POST /channel/set
+
+Set/save a channel key to config. **New in v4.0.0.**
+
+#### Request Body
+
+```json
+{
+  "key": "ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456",
+  "location": "user"
+}
+```
+
+| Field | Type | Default | Description |
+|-------|------|---------|-------------|
+| `key` | string | required | Channel key |
+| `location` | string | `"user"` | `"user"` or `"project"` |
+
+#### Response
+
+```json
+{
+  "success": true,
+  "location": "~/.stegasoo/channel.key",
+  "fingerprint": "ABCD-••••-••••-••••-••••-••••-••••-3456"
+}
+```
+
+---
+
+### DELETE /channel
+
+Clear channel key from config. **New in v4.0.0.**
+
+#### Query Parameters
+
+| Parameter | Type | Default | Description |
+|-----------|------|---------|-------------|
+| `location` | string | `"user"` | `"user"`, `"project"`, or `"all"` |
+
+#### Response
+
+```json
+{
+  "success": true,
+  "mode": "public",
+  "still_configured": false,
+  "remaining_source": null
+}
+```
+
+#### cURL Example
+
+```bash
+# Clear user config
+curl -X DELETE http://localhost:8000/channel
+
+# Clear project config
+curl -X DELETE "http://localhost:8000/channel?location=project"
+
+# Clear all
+curl -X DELETE "http://localhost:8000/channel?location=all"
+```
+
+---
+
+### POST /generate
+
+Generate credentials for encoding/decoding.
+
+#### Request Body
+
+```json
+{
+  "use_pin": true,
+  "use_rsa": false,
+  "pin_length": 6,
+  "rsa_bits": 2048,
+  "words_per_passphrase": 4
+}
+```
+
+#### Response
+
+```json
+{
+  "passphrase": "abandon ability able about",
+  "pin": "847293",
+  "rsa_key_pem": null,
+  "entropy": {
+    "passphrase": 44,
+    "pin": 19,
+    "rsa": 0,
+    "total": 63
+  }
+}
+```
+
+---
+
+### POST /encode (JSON)
+
+Encode a text message into an image.
+
+#### Request Body
+
+```json
+{
+  "message": "Secret message here",
+  "reference_photo_base64": "iVBORw0KGgo...",
+  "carrier_image_base64": "iVBORw0KGgo...",
+  "passphrase": "apple forest thunder mountain",
+  "pin": "123456",
+  "rsa_key_base64": null,
+  "rsa_password": null,
+  "channel_key": null,
+  "embed_mode": "lsb",
+  "dct_output_format": "png",
+  "dct_color_mode": "grayscale"
+}
+```
+
+#### Channel Key Parameter (v4.0.0)
+
+| Value | Effect |
+|-------|--------|
+| `null` | Auto mode - use server-configured key |
+| `""` (empty string) | Public mode - no channel isolation |
+| `"XXXX-XXXX-..."` | Explicit key - use this specific key |
+
+#### Response
+
+```json
+{
+  "stego_image_base64": "iVBORw0KGgo...",
+  "filename": "a1b2c3d4.png",
+  "capacity_used_percent": 12.4,
+  "embed_mode": "lsb",
+  "output_format": "png",
+  "color_mode": "color",
+  "channel_mode": "private",
+  "channel_fingerprint": "ABCD-••••-••••-••••-••••-••••-••••-3456"
+}
+```
+
+---
+
+### POST /encode/file
+
+Encode a file into an image (JSON with base64).
+
+Same parameters as `/encode`, plus:
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `file_data_base64` | string | ✓ | Base64-encoded file data |
+| `filename` | string | ✓ | Original filename |
+| `mime_type` | string | | MIME type |
+
+---
+
+### POST /encode/multipart
+
+Encode using multipart form data (file uploads).
+
+#### Form Fields
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `passphrase` | string | ✓ | Passphrase |
+| `reference_photo` | file | ✓ | Reference photo |
+| `carrier` | file | ✓ | Carrier image |
+| `message` | string | * | Text message |
+| `payload_file` | file | * | Binary file to embed |
+| `pin` | string | | Static PIN |
+| `rsa_key` | file | | RSA key (.pem) |
+| `rsa_key_qr` | file | | RSA key (QR code image) |
+| `rsa_password` | string | | RSA key password |
+| `channel_key` | string | | `"auto"` (default), `"none"=public`, or explicit key |
+| `embed_mode` | string | | `"lsb"` or `"dct"` |
+| `dct_output_format` | string | | `"png"` or `"jpeg"` |
+| `dct_color_mode` | string | | `"grayscale"` or `"color"` |
+
+\* Provide either `message` or `payload_file`
+
+#### Channel Key in Multipart
+
+For form data, the channel_key field uses strings:
+
+| Value | Effect |
+|-------|--------|
+| `"auto"` | Use server config (default) |
+| `"none"` | Public mode |
+| `"XXXX-XXXX-..."` | Explicit key |
+
+#### Response
+
+Returns the stego image directly with headers:
+
+```http
+HTTP/1.1 200 OK
+Content-Type: image/png
+Content-Disposition: attachment; filename=a1b2c3d4.png
+X-Stegasoo-Capacity-Percent: 12.4
+X-Stegasoo-Embed-Mode: lsb
+X-Stegasoo-Channel-Mode: private
+X-Stegasoo-Channel-Fingerprint: ABCD-••••-...-3456
+X-Stegasoo-Version: 4.0.2
+
+<binary image data>
+```
+
+#### cURL Examples
+
+```bash
+# Encode with auto channel key (default)
+curl -X POST http://localhost:8000/encode/multipart \
+  -F "passphrase=apple forest thunder mountain" \
+  -F "pin=123456" \
+  -F "message=Secret message" \
+  -F "reference_photo=@reference.jpg" \
+  -F "carrier=@carrier.png" \
+  --output stego.png
+
+# Encode with explicit channel key
+curl -X POST http://localhost:8000/encode/multipart \
+  -F "passphrase=words here" \
+  -F "pin=123456" \
+  -F "message=Team message" \
+  -F "channel_key=ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456" \
+  -F "reference_photo=@reference.jpg" \
+  -F "carrier=@carrier.png" \
+  --output stego.png
+
+# Encode in public mode (no channel isolation)
+curl -X POST http://localhost:8000/encode/multipart \
+  -F "passphrase=words here" \
+  -F "pin=123456" \
+  -F "message=Public message" \
+  -F "channel_key=none" \
+  -F "reference_photo=@reference.jpg" \
+  -F "carrier=@carrier.png" \
+  --output stego.png
+```
+
+---
+
+### POST /decode (JSON)
+
+Decode a message or file from a stego image.
+
+#### Request Body
+
+```json
+{
+  "stego_image_base64": "iVBORw0KGgo...",
+  "reference_photo_base64": "iVBORw0KGgo...",
+  "passphrase": "apple forest thunder mountain",
+  "pin": "123456",
+  "rsa_key_base64": null,
+  "rsa_password": null,
+  "channel_key": null,
+  "embed_mode": "auto"
+}
+```
+
+#### Response (Text)
+
+```json
+{
+  "payload_type": "text",
+  "message": "Secret message here",
+  "file_data_base64": null,
+  "filename": null,
+  "mime_type": null
+}
+```
+
+#### Response (File)
+
+```json
+{
+  "payload_type": "file",
+  "message": null,
+  "file_data_base64": "UEsDBBQAAAA...",
+  "filename": "document.pdf",
+  "mime_type": "application/pdf"
+}
+```
+
+---
+
+### POST /decode/multipart
+
+Decode using multipart form data.
+
+#### Form Fields
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `passphrase` | string | ✓ | Passphrase |
+| `reference_photo` | file | ✓ | Reference photo |
+| `stego_image` | file | ✓ | Stego image to decode |
+| `pin` | string | | Static PIN |
+| `rsa_key` | file | | RSA key (.pem) |
+| `rsa_key_qr` | file | | RSA key (QR code image) |
+| `rsa_password` | string | | RSA key password |
+| `channel_key` | string | | `"auto"` (default), `"none"=public`, or explicit key |
+| `embed_mode` | string | | `"auto"`, `"lsb"`, or `"dct"` |
+
+---
+
+## Channel Keys
+
+### Overview
+
+Channel keys provide **deployment/group isolation**. Messages encoded with a channel key can only be decoded with the same key.
+
+### Key Format
+
+```
+ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456
+└──┘ └──┘ └──┘ └──┘ └──┘ └──┘ └──┘ └──┘
+  8 groups of 4 alphanumeric characters (256 bits)
+```
+
+### Storage Locations
+
+Keys are checked in order:
+
+| Priority | Location | Best For |
+|----------|----------|----------|
+| 1 | `STEGASOO_CHANNEL_KEY` env var | Docker, CI/CD |
+| 2 | `./config/channel.key` | Project-specific |
+| 3 | `~/.stegasoo/channel.key` | User default |
+
+### API Parameter Values
+
+#### JSON Endpoints (`/encode`, `/decode`)
+
+| Value | Effect |
+|-------|--------|
+| `null` | Auto - use server config |
+| `""` | Public mode |
+| `"XXXX-..."` | Explicit key |
+
+#### Multipart Endpoints (`/encode/multipart`, `/decode/multipart`)
+
+| Value | Effect |
+|-------|--------|
+| `"auto"` | Use server config (default) |
+| `"none"` | Public mode |
+| `"XXXX-..."` | Explicit key |
+
+### Workflow Example
+
+```bash
+# 1. Generate a channel key for the team
+KEY=$(curl -s -X POST http://localhost:8000/channel/generate | jq -r '.key')
+echo "Team key: $KEY"
+
+# 2. Distribute to team members (securely!)
+
+# 3. Each deployment sets the key
+export STEGASOO_CHANNEL_KEY=$KEY
+
+# 4. Encode - automatically uses server key
+curl -X POST http://localhost:8000/encode/multipart \
+  -F "passphrase=team passphrase" \
+  -F "pin=123456" \
+  -F "message=Team secret" \
+  -F "reference_photo=@ref.jpg" \
+  -F "carrier=@carrier.png" \
+  --output stego.png
+
+# 5. Decode - automatically uses server key
+curl -X POST http://localhost:8000/decode/multipart \
+  -F "passphrase=team passphrase" \
+  -F "pin=123456" \
+  -F "reference_photo=@ref.jpg" \
+  -F "stego_image=@stego.png"
+```
+
+---
+
+## Data Models
+
+### ChannelStatusResponse
+
+```json
+{
+  "mode": "private",
+  "configured": true,
+  "fingerprint": "ABCD-••••-...-3456",
+  "source": "~/.stegasoo/channel.key",
+  "key": "ABCD-1234-..." 
+}
+```
+
+### EncodeResponse (v4.0.0)
+
+```json
+{
+  "stego_image_base64": "string",
+  "filename": "string",
+  "capacity_used_percent": 12.4,
+  "embed_mode": "lsb",
+  "output_format": "png",
+  "color_mode": "color",
+  "channel_mode": "private",
+  "channel_fingerprint": "ABCD-••••-...-3456"
+}
+```
+
+### DecodeResponse
+
+```json
+{
+  "payload_type": "text",
+  "message": "string",
+  "file_data_base64": null,
+  "filename": null,
+  "mime_type": null
+}
+```
+
+---
+
+## Error Handling
+
+### HTTP Status Codes
+
+| Code | Meaning | Use Case |
+|------|---------|----------|
+| 200 | OK | Successful operation |
+| 400 | Bad Request | Invalid input, capacity error, invalid channel key |
+| 401 | Unauthorized | Decryption failed, channel key mismatch |
+| 500 | Internal Error | Unexpected server error |
+| 501 | Not Implemented | Feature unavailable |
+
+### Channel Key Errors
+
+| Status | Error | Cause |
+|--------|-------|-------|
+| 400 | "Invalid channel key format" | Key doesn't match `XXXX-XXXX-...` pattern |
+| 401 | "Message encoded with channel key but none configured" | Need to provide channel key |
+| 401 | "Message encoded without channel key" | Use `channel_key=""` or `"none"` |
+
+---
+
+## Code Examples
+
+### Python
+
+```python
+import requests
+
+BASE_URL = "http://localhost:8000"
+
+# Check channel status
+status = requests.get(f"{BASE_URL}/channel/status").json()
+print(f"Channel mode: {status['mode']}")
+print(f"Fingerprint: {status.get('fingerprint', 'N/A')}")
+
+# Generate channel key
+response = requests.post(f"{BASE_URL}/channel/generate?save=true")
+key_info = response.json()
+print(f"Generated: {key_info['fingerprint']}")
+
+# Encode with channel key (auto from server)
+with open("ref.jpg", "rb") as ref, open("carrier.png", "rb") as carrier:
+    response = requests.post(f"{BASE_URL}/encode/multipart", files={
+        "reference_photo": ref,
+        "carrier": carrier,
+    }, data={
+        "message": "Team secret",
+        "passphrase": "apple forest thunder",
+        "pin": "123456",
+        # channel_key defaults to "auto" (use server config)
+    })
+    
+    with open("stego.png", "wb") as f:
+        f.write(response.content)
+    
+    print(f"Channel mode: {response.headers.get('X-Stegasoo-Channel-Mode')}")
+
+# Encode with explicit channel key
+with open("ref.jpg", "rb") as ref, open("carrier.png", "rb") as carrier:
+    response = requests.post(f"{BASE_URL}/encode/multipart", files={
+        "reference_photo": ref,
+        "carrier": carrier,
+    }, data={
+        "message": "Using explicit key",
+        "passphrase": "words here",
+        "pin": "123456",
+        "channel_key": "ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456",
+    })
+
+# Decode
+with open("ref.jpg", "rb") as ref, open("stego.png", "rb") as stego:
+    response = requests.post(f"{BASE_URL}/decode/multipart", files={
+        "reference_photo": ref,
+        "stego_image": stego,
+    }, data={
+        "passphrase": "apple forest thunder",
+        "pin": "123456",
+        # channel_key defaults to "auto"
+    })
+    
+    result = response.json()
+    print(f"Decoded: {result.get('message')}")
+```
+
+### JavaScript
+
+```javascript
+const axios = require('axios');
+const FormData = require('form-data');
+const fs = require('fs');
+
+const BASE_URL = 'http://localhost:8000';
+
+async function main() {
+    // Check channel status
+    const status = await axios.get(`${BASE_URL}/channel/status`);
+    console.log('Channel:', status.data.mode);
+    
+    // Encode with auto channel key
+    const form = new FormData();
+    form.append('passphrase', 'apple forest thunder');
+    form.append('pin', '123456');
+    form.append('message', 'Secret');
+    form.append('reference_photo', fs.createReadStream('ref.jpg'));
+    form.append('carrier', fs.createReadStream('carrier.png'));
+    // channel_key defaults to "auto" (use server config)
+    
+    const response = await axios.post(`${BASE_URL}/encode/multipart`, form, {
+        headers: form.getHeaders(),
+        responseType: 'arraybuffer'
+    });
+    
+    fs.writeFileSync('stego.png', response.data);
+    console.log('Channel mode:', response.headers['x-stegasoo-channel-mode']);
+}
+
+main();
+```
+
+### cURL / Bash
+
+```bash
+#!/bin/bash
+
+BASE_URL="http://localhost:8000"
+
+# Check channel status
+echo "Channel status:"
+curl -s "$BASE_URL/channel/status" | jq .
+
+# Generate and save channel key
+echo "Generating channel key..."
+curl -s -X POST "$BASE_URL/channel/generate?save=true" | jq .
+
+# Encode (channel_key defaults to "auto")
+echo "Encoding..."
+curl -s -X POST "$BASE_URL/encode/multipart" \
+  -F "passphrase=apple forest thunder" \
+  -F "pin=123456" \
+  -F "message=Secret message" \
+  -F "reference_photo=@ref.jpg" \
+  -F "carrier=@carrier.png" \
+  --output stego.png
+
+echo "Encoded to stego.png"
+
+# Decode
+echo "Decoding..."
+curl -s -X POST "$BASE_URL/decode/multipart" \
+  -F "passphrase=apple forest thunder" \
+  -F "pin=123456" \
+  -F "reference_photo=@ref.jpg" \
+  -F "stego_image=@stego.png" | jq .
+```
+
+---
+
+## Docker Configuration
+
+### docker/docker-compose.yml
+
+```yaml
+x-common-env: &common-env
+  STEGASOO_CHANNEL_KEY: ${STEGASOO_CHANNEL_KEY:-}
+
+services:
+  api:
+    build:
+      context: .
+      target: api
+    ports:
+      - "8000:8000"
+    environment:
+      <<: *common-env
+```
+
+### .env (gitignored)
+
+```bash
+STEGASOO_CHANNEL_KEY=ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456
+```
+
+### Generate key for .env
+
+```bash
+curl -s -X POST http://localhost:8000/channel/generate | \
+  jq -r '"STEGASOO_CHANNEL_KEY=\(.key)"' >> .env
+```
+
+---
+
+## See Also
+
+- [CLI Documentation](CLI.md) - Command-line interface
+- [Web UI Documentation](WEB_UI.md) - Browser interface
+- [README](../README.md) - Project overview

CHANGELOG.md

@@ -0,0 +1,214 @@
+# Changelog
+
+All notable changes to Stegasoo will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org).
+
+## [4.1.5] - 2026-01-07
+
+### Added
+- **Developer Documentation**: Educational comments throughout core modules
+  - DCT module: zig-zag diagrams, QIM explanation, Reed-Solomon deep dive
+  - LSB module: visual bit embedding examples, ChaCha20 pixel selection
+  - Crypto module: multi-factor KDF flow diagrams, Argon2id reasoning
+  - CLI module: Click patterns (groups, JSON output, secure input)
+  - Web UI module: Flask architecture, subprocess isolation, async jobs
+- **Pi Test Automation**: `rpi/kickoff-pi-test.sh` script
+  - One command to flash, wait for boot, setup, and smoke test
+  - Self-contained (no dotfile dependencies)
+- **v4.2 Wishlist**: `WISHLIST-4.2.md` for blue-sky ideas (GPU acceleration)
+
+### Changed
+- **Pi MOTD Improvements**:
+  - Dynamic temperature emoji (ice/cool/fire based on temp)
+  - Rocket emoji for service status, globe emoji for URL
+  - Shortened Debian boilerplate message
+  - Fixed escaped variable syntax in heredoc
+
+## [4.1.3] - 2026-01-05
+
+### Added
+- **Docker Deployment**: Production-ready containerization
+  - `docker-compose.yml` for Web UI (port 5000) and REST API (port 8000)
+  - Multi-stage builds with base image for faster rebuilds
+  - Health checks, resource limits (768MB), and volume persistence
+  - Comprehensive `DOCKER.md` documentation
+- **Raspberry Pi First-Boot Wizard**: Interactive TUI setup experience
+  - `gum` TUI toolkit for styled prompts and spinners
+  - WiFi configuration, HTTPS setup, channel key generation
+  - Overclock presets (Pi 5: 2.8/3.0 GHz with cooling recommendations)
+  - Port 443 redirect option for clean HTTPS URLs
+  - Styled banners with purple→blue gradient and gold logo
+- **Pi Image Distribution**: Scripts for SD card imaging
+  - `sanitize-for-image.sh` removes credentials, SSH keys, user data
+  - Soft reset mode for testing without clearing WiFi
+  - Auto-validates sanitization before imaging
+- **Unit Tests**: Comprehensive pytest test suite
+  - Tests for encode/decode, LSB/DCT modes, channel keys
+  - Validation, generation, compression, edge cases
+  - 29 tests covering core library functionality
+- **Release Validation**: `scripts/validate-release.sh` for pre-release checks
+- **Custom SSL Documentation**: Guide for replacing certs, Let's Encrypt setup
+
+### Changed
+- Pi MOTD shows CPU speed and temperature when overclocked
+- Mobile UI polish and responsive improvements
+- Standardized ASCII banners across all Pi scripts
+- Setup script uses pyenv for Python 3.12 (Pi OS ships 3.13)
+
+### Fixed
+- **SSL certificate generation**: Wizard and setup now generate certs when HTTPS enabled
+- DCT decode reliability improvements
+- Fixed `gum --inline` flag compatibility (not supported in all versions)
+- Wizard banner alignment and spacing issues
+- Better error handling in app.py for SSL failures
+
+## [4.1.0] - 2026-01-04
+
+### Added
+- **Admin Recovery System**: Password reset for locked-out admins
+  - Recovery key generated during setup (32-char alphanumeric)
+  - Multiple backup options: text file, QR code, stego image
+  - QR codes obfuscated (XOR'd with magic header hash)
+  - Stego backups hide key in an image using Stegasoo itself
+  - CLI: `stegasoo admin recover --db path/to/db`
+- **EXIF Editor**: Full metadata editing in Tools page
+  - View all EXIF fields from uploaded image
+  - Inline editing of individual fields
+  - Clear all metadata with one click
+  - Download cleaned image
+  - CLI: `stegasoo tools exif image.jpg [--clear] [--set Field=Value]`
+- **Multi-User Support**: Admin can create up to 16 additional users
+  - Role-based access control (admin/user)
+  - Admin user management page
+  - Temp password generation for new users
+- **Saved Channel Keys**: Users can save/manage channel keys in account page
+
+### Changed
+- **Architecture**: Consolidated `resolve_channel_key()` to library layer
+  - Single source of truth in `src/stegasoo/channel.py`
+  - CLI, API, WebUI now use thin wrappers
+- **DCT Pre-Check**: Fail fast with helpful error before expensive encoding
+- **Toast Notifications**: Auto-dismiss after 20 seconds with fade animation
+- `RECOVERY_OBFUSCATION_KEY` constant added to `constants.py`
+
+### Fixed
+- DCT payload size error now caught early with clear message
+
+## [4.0.2] - 2026-01-02
+
+### Added
+- **Web UI Authentication**: Single-admin login with SQLite3 user storage
+  - First-run setup wizard for admin account creation
+  - Account management page for password changes
+  - `@login_required` decorator protects encode/decode/generate routes
+  - Argon2id password hashing (lighter 64MB for fast login)
+- **Optional HTTPS**: Auto-generated self-signed certificates for home network deployment
+  - Configurable via `STEGASOO_HTTPS_ENABLED` environment variable
+  - Certificates stored in `frontends/web/certs/`
+- New environment variables: `STEGASOO_AUTH_ENABLED`, `STEGASOO_HTTPS_ENABLED`, `STEGASOO_HOSTNAME`
+
+### Changed
+- PIN entry column widened in encode/decode forms (col-md-4 → col-md-6)
+- Channel options column narrowed (col-md-8 → col-md-6)
+- QR preview panels enlarged for better text readability
+- Consistent font sizing across all preview panel banners (0.7rem filename, 0.6rem data, 0.65rem badges)
+
+### Fixed
+- QR preview text too small to read in encode/decode templates
+- Inconsistent label sizes between reference/carrier/stego panels
+
+## [4.0.1] - 2025-01-02
+
+### Fixed
+- Fixed numpy binary incompatibility on Python 3.10 (jpegio/scipy)
+- Fixed BatchCredentials test failures with missing `reference_photo` parameter
+- Graceful handling when DCT dependencies have version mismatches
+
+### Changed
+- Applied `ruff` linter fixes across entire codebase (~400 issues)
+- Applied `black` formatter to all Python files
+- Modernized type hints: `Optional[X]` → `X | None`
+- Updated ruff config to use `[tool.ruff.lint]` section
+- Moved documentation files to repository root
+
+### Removed
+- Removed obsolete debug/diagnostic scripts
+- Cleaned up backup files and dev scripts
+
+## [4.0.0] - 2024-12-29
+
+### Added
+- Refreshed Web UI with modern, snazzy interface
+- Improved user experience across all pages
+
+### Changed
+- Major version bump for breaking API changes
+- Simplified passphrase handling (single passphrase instead of day-based)
+- Removed date_str parameter from encoding
+
+### Fixed
+- Various bug fixes for Web UI
+- CLI updates and improvements
+
+## [3.2.0] - 2024-12-28
+
+### Added
+- Big revamp of the encoding system
+- Home and about page improvements
+- UNDER_THE_HOOD.md documentation
+
+### Changed
+- Renamed `phrase` → `passphrase` in API
+- Updated Web UI styling
+
+## [3.0.2] - 2024-12-27
+
+### Added
+- Full experimental DCT steganography support
+- jpegio integration for better JPEG manipulation
+- DCT/LSB mode selector in Web UI
+
+## [3.0.0] - 2024-12-25
+
+### Added
+- DCT (Discrete Cosine Transform) steganography mode
+- Support for JPEG carriers without quality loss
+- Channel key feature for private messaging
+
+### Changed
+- Complete rewrite of steganography engine
+- New hybrid authentication system
+
+## [2.0.0] - 2024-12-20
+
+### Added
+- Web UI frontend
+- REST API (FastAPI)
+- Batch processing support
+- RSA key authentication option
+
+### Changed
+- Migrated to hybrid photo + passphrase + PIN authentication
+
+## [1.0.0] - 2024-12-15
+
+### Added
+- Initial release
+- LSB steganography
+- AES-256-GCM encryption
+- CLI interface
+- Basic PIN authentication
+
+[4.1.5]: https://github.com/adlee-was-taken/stegasoo/compare/v4.1.3...v4.1.5
+[4.1.3]: https://github.com/adlee-was-taken/stegasoo/compare/v4.1.0...v4.1.3
+[4.1.0]: https://github.com/adlee-was-taken/stegasoo/compare/v4.0.2...v4.1.0
+[4.0.2]: https://github.com/adlee-was-taken/stegasoo/compare/v4.0.1...v4.0.2
+[4.0.1]: https://github.com/adlee-was-taken/stegasoo/compare/v4.0.0...v4.0.1
+[4.0.0]: https://github.com/adlee-was-taken/stegasoo/compare/v3.2.0...v4.0.0
+[3.2.0]: https://github.com/adlee-was-taken/stegasoo/compare/v3.0.2...v3.2.0
+[3.0.2]: https://github.com/adlee-was-taken/stegasoo/compare/v3.0.0...v3.0.2
+[3.0.0]: https://github.com/adlee-was-taken/stegasoo/compare/v2.0.0...v3.0.0
+[2.0.0]: https://github.com/adlee-was-taken/stegasoo/compare/v1.0.0...v2.0.0
+[1.0.0]: https://github.com/adlee-was-taken/stegasoo/releases/tag/v1.0.0

CLI.md

@@ -0,0 +1,921 @@
+# Stegasoo CLI Documentation (v4.1.0)
+
+Complete command-line interface reference for Stegasoo steganography operations.
+
+## Table of Contents
+
+- [Installation](#installation)
+- [What's New in v4.1.0](#whats-new-in-v410)
+- [Quick Start](#quick-start)
+- [Commands](#commands)
+  - [generate](#generate-command)
+  - [encode](#encode-command)
+  - [decode](#decode-command)
+  - [verify](#verify-command)
+  - [channel](#channel-command)
+  - [admin](#admin-command)
+  - [tools](#tools-command)
+  - [info](#info-command)
+  - [compare](#compare-command)
+  - [modes](#modes-command)
+- [Channel Keys](#channel-keys)
+- [Embedding Modes](#embedding-modes)
+- [Security Factors](#security-factors)
+- [Workflow Examples](#workflow-examples)
+- [Piping & Scripting](#piping--scripting)
+- [Error Handling](#error-handling)
+- [Exit Codes](#exit-codes)
+
+---
+
+## Installation
+
+### From PyPI
+
+```bash
+# CLI only
+pip install stegasoo[cli]
+
+# CLI with DCT support
+pip install stegasoo[cli,dct]
+
+# With all extras
+pip install stegasoo[all]
+```
+
+### From Source
+
+```bash
+git clone https://github.com/example/stegasoo.git
+cd stegasoo
+pip install -e ".[cli,dct]"
+```
+
+### Verify Installation
+
+```bash
+stegasoo --version
+stegasoo --help
+
+# Check DCT support
+python -c "from stegasoo import has_dct_support; print('DCT:', 'available' if has_dct_support() else 'requires scipy')"
+
+# Check channel key status
+stegasoo channel show
+```
+
+### Man Page
+
+```bash
+# Install man page
+sudo mkdir -p /usr/local/share/man/man1
+sudo cp docs/stegasoo.1 /usr/local/share/man/man1/
+sudo mandb
+
+# View
+man stegasoo
+```
+
+---
+
+## What's New in v4.1.0
+
+Version 4.1.0 adds **admin recovery** and **tools** commands:
+
+| Feature | Description |
+|---------|-------------|
+| Admin recovery | Reset admin password using recovery key |
+| EXIF tools | View, edit, and strip image metadata |
+| Peek tool | Quick stego detection check |
+| Strip tool | Remove hidden data from images |
+
+**New commands:**
+- `stegasoo admin recover` - Reset admin password with recovery key
+- `stegasoo tools exif` - View/edit EXIF metadata
+- `stegasoo tools peek` - Check for hidden data
+- `stegasoo tools strip` - Remove stego data from image
+
+---
+
+## What's New in v4.0.0
+
+Version 4.0.0 added **channel key** support for deployment/group isolation:
+
+| Feature | Description |
+|---------|-------------|
+| Channel keys | 256-bit keys that isolate message groups |
+| Deployment isolation | Different deployments can't read each other's messages |
+| CLI management | New `stegasoo channel` command group |
+| Flexible override | Use server config, explicit key, or public mode |
+
+---
+
+## Quick Start
+
+```bash
+# 1. Generate credentials (do this once, memorize results)
+stegasoo generate
+
+# 2. (Optional) Set up channel key for deployment isolation
+stegasoo channel generate --save
+
+# 3. Encode a message (uses configured channel key automatically)
+stegasoo encode \
+  --ref secret_photo.jpg \
+  --carrier meme.png \
+  --passphrase "apple forest thunder mountain" \
+  --pin 123456 \
+  --message "Meet at midnight"
+
+# 4. Decode a message (uses same channel key)
+stegasoo decode \
+  --ref secret_photo.jpg \
+  --stego stego_abc123.png \
+  --passphrase "apple forest thunder mountain" \
+  --pin 123456
+
+# 5. Decode without channel key (public mode)
+stegasoo decode \
+  --ref secret_photo.jpg \
+  --stego public_stego.png \
+  --passphrase "words here now" \
+  --pin 123456 \
+  --no-channel
+```
+
+---
+
+## Commands
+
+### Generate Command
+
+Generate credentials for encoding/decoding operations.
+
+#### Synopsis
+
+```bash
+stegasoo generate [OPTIONS]
+```
+
+#### Options
+
+| Option | Short | Type | Default | Description |
+|--------|-------|------|---------|-------------|
+| `--pin/--no-pin` | | flag | `--pin` | Generate a PIN |
+| `--rsa/--no-rsa` | | flag | `--no-rsa` | Generate an RSA key |
+| `--pin-length` | | 6-9 | 6 | PIN length in digits |
+| `--rsa-bits` | | choice | 2048 | RSA key size (2048, 3072, 4096) |
+| `--words` | | 3-12 | 4 | Words in passphrase |
+| `--output` | `-o` | path | | Save RSA key to file |
+| `--password` | `-p` | string | | Password for RSA key file |
+| `--json` | | flag | | Output as JSON |
+
+#### Examples
+
+```bash
+# Basic generation with PIN (default)
+stegasoo generate
+
+# Generate with more words for higher security
+stegasoo generate --words 6
+
+# Generate with RSA key
+stegasoo generate --rsa --rsa-bits 4096
+
+# Save RSA key to encrypted file
+stegasoo generate --rsa -o mykey.pem -p "mysecretpassword"
+```
+
+---
+
+### Encode Command
+
+Encode a secret message or file into an image.
+
+#### Synopsis
+
+```bash
+stegasoo encode [OPTIONS]
+```
+
+#### Options
+
+| Option | Short | Type | Required | Default | Description |
+|--------|-------|------|----------|---------|-------------|
+| `--ref` | `-r` | path | ✓ | | Reference photo |
+| `--carrier` | `-c` | path | ✓ | | Carrier image |
+| `--passphrase` | `-p` | string | ✓ | | Passphrase |
+| `--message` | `-m` | string | | | Message to encode |
+| `--message-file` | `-f` | path | | | Read message from file |
+| `--embed-file` | `-e` | path | | | Embed a binary file |
+| `--pin` | | string | * | | Static PIN (6-9 digits) |
+| `--key` | `-k` | path | * | | RSA key file |
+| `--key-qr` | | path | * | | RSA key from QR code |
+| `--key-password` | | string | | | RSA key password |
+| `--channel` | | string | | auto | Channel key (v4.0.0) |
+| `--channel-file` | | path | | | Read channel key from file |
+| `--no-channel` | | flag | | | Force public mode |
+| `--output` | `-o` | path | | | Output filename |
+| `--mode` | | choice | | `lsb` | Embedding mode |
+| `--dct-format` | | choice | | `png` | DCT output format |
+| `--dct-color` | | choice | | `grayscale` | DCT color mode |
+| `--quiet` | `-q` | flag | | | Suppress output |
+
+\* At least one of `--pin`, `--key`, or `--key-qr` is required.
+
+#### Channel Key Options
+
+| Option | Effect |
+|--------|--------|
+| *(none)* | Use server-configured key (auto mode) |
+| `--channel KEY` | Use explicit channel key |
+| `--channel auto` | Same as no option |
+| `--channel-file F` | Read channel key from file |
+| `--no-channel` | Force public mode (no isolation) |
+
+#### Examples
+
+```bash
+# Basic encoding (uses server channel key if configured)
+stegasoo encode \
+  -r photo.jpg -c meme.png \
+  -p "correct horse battery staple" \
+  --pin 847293 \
+  -m "The package arrives Tuesday"
+
+# With explicit channel key
+stegasoo encode \
+  -r photo.jpg -c meme.png \
+  -p "correct horse battery staple" \
+  --pin 847293 \
+  -m "Secret message" \
+  --channel ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456
+
+# Public mode (no channel isolation)
+stegasoo encode \
+  -r photo.jpg -c meme.png \
+  -p "correct horse battery staple" \
+  --pin 847293 \
+  -m "Public message" \
+  --no-channel
+
+# DCT mode for social media
+stegasoo encode \
+  -r photo.jpg -c meme.png \
+  -p "words here" --pin 847293 \
+  -m "Secret" \
+  --mode dct --dct-format jpeg
+```
+
+---
+
+### Decode Command
+
+Decode a secret message or file from a stego image.
+
+#### Synopsis
+
+```bash
+stegasoo decode [OPTIONS]
+```
+
+#### Options
+
+| Option | Short | Type | Required | Default | Description |
+|--------|-------|------|----------|---------|-------------|
+| `--ref` | `-r` | path | ✓ | | Reference photo |
+| `--stego` | `-s` | path | ✓ | | Stego image |
+| `--passphrase` | `-p` | string | ✓ | | Passphrase |
+| `--pin` | | string | * | | Static PIN |
+| `--key` | `-k` | path | * | | RSA key file |
+| `--key-qr` | | path | * | | RSA key from QR code |
+| `--key-password` | | string | | | RSA key password |
+| `--channel` | | string | | auto | Channel key (v4.0.0) |
+| `--channel-file` | | path | | | Read channel key from file |
+| `--no-channel` | | flag | | | Force public mode |
+| `--output` | `-o` | path | | | Save output to file |
+| `--mode` | | choice | | `auto` | Extraction mode |
+| `--quiet` | `-q` | flag | | | Minimal output |
+| `--force` | | flag | | | Overwrite existing file |
+
+#### Examples
+
+```bash
+# Basic decoding (uses server channel key)
+stegasoo decode \
+  -r photo.jpg -s stego.png \
+  -p "correct horse battery staple" \
+  --pin 847293
+
+# With explicit channel key
+stegasoo decode \
+  -r photo.jpg -s stego.png \
+  -p "words here" --pin 847293 \
+  --channel ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456
+
+# Decode public image (no channel key was used)
+stegasoo decode \
+  -r photo.jpg -s stego.png \
+  -p "words here" --pin 847293 \
+  --no-channel
+
+# Save to file
+stegasoo decode \
+  -r photo.jpg -s stego.png \
+  -p "words" --pin 123456 \
+  -o decoded.txt
+```
+
+---
+
+### Verify Command
+
+Verify credentials without extracting the message.
+
+#### Synopsis
+
+```bash
+stegasoo verify [OPTIONS]
+```
+
+#### Options
+
+Same as `decode`, minus `--output` and `--force`. Adds `--json` for JSON output.
+
+#### Examples
+
+```bash
+# Quick verification
+stegasoo verify -r photo.jpg -s stego.png -p "phrase" --pin 123456
+
+# With explicit channel key
+stegasoo verify -r photo.jpg -s stego.png -p "phrase" --pin 123456 \
+  --channel ABCD-1234-...
+
+# JSON output
+stegasoo verify -r photo.jpg -s stego.png -p "phrase" --pin 123456 --json
+```
+
+---
+
+### Channel Command
+
+Manage channel keys for deployment/group isolation.
+
+#### Subcommands
+
+| Subcommand | Description |
+|------------|-------------|
+| `generate` | Create a new channel key |
+| `show` | Display current channel key status |
+| `set` | Save a channel key to config |
+| `clear` | Remove channel key from config |
+
+#### channel generate
+
+```bash
+stegasoo channel generate [OPTIONS]
+```
+
+| Option | Short | Description |
+|--------|-------|-------------|
+| `--save` | `-s` | Save to user config (~/.stegasoo/channel.key) |
+| `--save-project` | | Save to project config (./config/channel.key) |
+| `--env` | `-e` | Output as environment variable export |
+| `--quiet` | `-q` | Output only the key |
+
+**Examples:**
+
+```bash
+# Just display a new key
+stegasoo channel generate
+
+# Save to user config
+stegasoo channel generate --save
+
+# Add to .env file
+stegasoo channel generate --env >> .env
+
+# For scripts
+KEY=$(stegasoo channel generate -q)
+```
+
+#### channel show
+
+```bash
+stegasoo channel show [OPTIONS]
+```
+
+| Option | Short | Description |
+|--------|-------|-------------|
+| `--reveal` | `-r` | Show full key (not just fingerprint) |
+| `--json` | | Output as JSON |
+
+**Examples:**
+
+```bash
+# Show status (fingerprint only)
+stegasoo channel show
+
+# Reveal full key
+stegasoo channel show --reveal
+
+# JSON for scripts
+stegasoo channel show --json
+```
+
+**Output:**
+
+```
+─── CHANNEL KEY STATUS ───
+
+    Mode: PRIVATE
+    Fingerprint: ABCD-••••-••••-••••-••••-••••-••••-3456
+    Source: ~/.stegasoo/channel.key
+
+    Messages require this channel key to decode.
+```
+
+#### channel set
+
+```bash
+stegasoo channel set [KEY] [OPTIONS]
+```
+
+| Option | Short | Description |
+|--------|-------|-------------|
+| `--file` | `-f` | Read key from file |
+| `--project` | `-p` | Save to project config instead of user |
+
+**Examples:**
+
+```bash
+# Set from command line
+stegasoo channel set ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456
+
+# Set from file
+stegasoo channel set --file channel.key
+
+# Set in project config
+stegasoo channel set XXXX-... --project
+```
+
+#### channel clear
+
+```bash
+stegasoo channel clear [OPTIONS]
+```
+
+| Option | Short | Description |
+|--------|-------|-------------|
+| `--project` | `-p` | Clear project config |
+| `--all` | | Clear both user and project configs |
+| `--force` | `-f` | Skip confirmation |
+
+**Examples:**
+
+```bash
+# Clear user config (with confirmation)
+stegasoo channel clear
+
+# Clear project config
+stegasoo channel clear --project
+
+# Clear all configs without confirmation
+stegasoo channel clear --all --force
+```
+
+---
+
+### Info Command
+
+Show information about an image file.
+
+```bash
+stegasoo info IMAGE [OPTIONS]
+```
+
+---
+
+### Compare Command
+
+Compare embedding mode capacities for an image.
+
+```bash
+stegasoo compare IMAGE [OPTIONS]
+```
+
+---
+
+### Modes Command
+
+Show available embedding modes and their status.
+
+```bash
+stegasoo modes
+```
+
+Now also displays channel key status.
+
+---
+
+### Admin Command
+
+Manage Web UI admin accounts and recovery.
+
+#### Subcommands
+
+| Subcommand | Description |
+|------------|-------------|
+| `recover` | Reset admin password using recovery key |
+
+#### admin recover
+
+Reset the admin password for a Web UI database.
+
+```bash
+stegasoo admin recover --db PATH [OPTIONS]
+```
+
+| Option | Short | Type | Required | Description |
+|--------|-------|------|----------|-------------|
+| `--db` | `-d` | path | ✓ | Path to stegasoo.db file |
+| `--key` | `-k` | string | | Recovery key (prompted if not provided) |
+| `--password` | `-p` | string | | New password (prompted if not provided) |
+
+**Examples:**
+
+```bash
+# Interactive mode (prompts for key and password)
+stegasoo admin recover --db frontends/web/instance/stegasoo.db
+
+# Non-interactive mode
+stegasoo admin recover \
+  --db /path/to/stegasoo.db \
+  --key "XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX" \
+  --password "NewSecurePassword123"
+```
+
+**Recovery process:**
+1. The recovery key is verified against the database hash
+2. If valid, the admin password is reset
+3. User can now log in with the new password
+
+**Note:** Recovery keys are instance-bound. A key from one database won't work on another.
+
+---
+
+### Tools Command
+
+Image utilities and analysis tools.
+
+#### Subcommands
+
+| Subcommand | Description |
+|------------|-------------|
+| `exif` | View/edit EXIF metadata |
+| `peek` | Check for hidden data |
+| `strip` | Remove stego data from image |
+
+#### tools exif
+
+View and edit EXIF metadata in images.
+
+```bash
+stegasoo tools exif IMAGE [OPTIONS]
+```
+
+| Option | Type | Description |
+|--------|------|-------------|
+| `--clear` | flag | Remove all EXIF metadata |
+| `--set FIELD=VALUE` | string | Set a specific EXIF field |
+| `--output` / `-o` | path | Output filename (default: overwrites input) |
+| `--json` | flag | Output as JSON |
+
+**Examples:**
+
+```bash
+# View all EXIF data
+stegasoo tools exif photo.jpg
+
+# View as JSON
+stegasoo tools exif photo.jpg --json
+
+# Clear all metadata
+stegasoo tools exif photo.jpg --clear -o clean.jpg
+
+# Set specific fields
+stegasoo tools exif photo.jpg \
+  --set "Artist=John Doe" \
+  --set "Copyright=2026" \
+  -o tagged.jpg
+
+# Remove GPS data only
+stegasoo tools exif photo.jpg \
+  --set "GPSLatitude=" \
+  --set "GPSLongitude=" \
+  -o no-gps.jpg
+```
+
+#### tools peek
+
+Check if an image contains hidden Stegasoo data.
+
+```bash
+stegasoo tools peek IMAGE [OPTIONS]
+```
+
+| Option | Type | Description |
+|--------|------|-------------|
+| `--json` | flag | Output as JSON |
+| `--quiet` / `-q` | flag | Exit code only (0=found, 1=not found) |
+
+**Examples:**
+
+```bash
+# Check for hidden data
+stegasoo tools peek suspicious.png
+
+# Script-friendly check
+if stegasoo tools peek image.png -q; then
+  echo "Contains hidden data"
+fi
+```
+
+#### tools strip
+
+Remove hidden stego data from an image (destructive).
+
+```bash
+stegasoo tools strip IMAGE [OPTIONS]
+```
+
+| Option | Type | Description |
+|--------|------|-------------|
+| `--output` / `-o` | path | Output filename |
+| `--force` / `-f` | flag | Overwrite without confirmation |
+
+**Examples:**
+
+```bash
+# Strip and save to new file
+stegasoo tools strip stego.png -o clean.png
+
+# Strip in place (with confirmation)
+stegasoo tools strip stego.png
+```
+
+---
+
+## Channel Keys
+
+Channel keys provide **deployment/group isolation** - messages encoded with a channel key can only be decoded by systems with the same key.
+
+### Key Format
+
+```
+ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456
+└──┘ └──┘ └──┘ └──┘ └──┘ └──┘ └──┘ └──┘
+  8 groups of 4 alphanumeric characters (256 bits)
+```
+
+### Storage Locations
+
+Channel keys are checked in this order:
+
+| Priority | Location | Best For |
+|----------|----------|----------|
+| 1 | `STEGASOO_CHANNEL_KEY` env var | Docker, CI/CD |
+| 2 | `./config/channel.key` | Project-specific |
+| 3 | `~/.stegasoo/channel.key` | User default |
+
+### Modes
+
+| Mode | Description | CLI Option |
+|------|-------------|------------|
+| **Auto** | Use server-configured key | *(default)* |
+| **Explicit** | Use specific key | `--channel KEY` |
+| **Public** | No channel isolation | `--no-channel` |
+
+### Fingerprints
+
+For security, full keys aren't displayed by default. Instead, a fingerprint is shown:
+
+```
+Full key:    ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456
+Fingerprint: ABCD-••••-••••-••••-••••-••••-••••-3456
+```
+
+### Use Cases
+
+**Team isolation:**
+```bash
+# Team A
+export STEGASOO_CHANNEL_KEY=AAAA-1111-...
+
+# Team B  
+export STEGASOO_CHANNEL_KEY=BBBB-2222-...
+
+# Messages from Team A can only be decoded by Team A
+```
+
+**Development vs Production:**
+```bash
+# Development
+./config/channel.key contains DEV-KEY-...
+
+# Production
+STEGASOO_CHANNEL_KEY=PROD-KEY-... in Docker
+
+# Dev messages can't be decoded in production
+```
+
+**Public messages:**
+```bash
+# Anyone with credentials can decode
+stegasoo encode ... --no-channel
+stegasoo decode ... --no-channel
+```
+
+---
+
+## Embedding Modes
+
+### LSB Mode (Default)
+
+```bash
+stegasoo encode ... --mode lsb
+```
+
+| Aspect | Details |
+|--------|---------|
+| **Capacity** | ~375 KB for 1920×1080 |
+| **Output** | PNG only |
+| **Best For** | Maximum capacity |
+
+### DCT Mode
+
+```bash
+stegasoo encode ... --mode dct --dct-format jpeg --dct-color color
+```
+
+| Aspect | Details |
+|--------|---------|
+| **Capacity** | ~65 KB for 1920×1080 |
+| **Output** | PNG or JPEG |
+| **Best For** | Social media, stealth |
+
+---
+
+## Security Factors
+
+| Factor | Description | Entropy |
+|--------|-------------|---------|
+| Reference Photo | Shared image | ~80-256 bits |
+| Passphrase | BIP-39 words | ~44 bits (4 words) |
+| Static PIN | Numeric (6-9) | ~20 bits (6 digits) |
+| RSA Key | Shared key file | ~128 bits |
+| Channel Key (v4.0.0) | Deployment isolation | ~256 bits |
+
+---
+
+## Workflow Examples
+
+### Team Setup with Channel Key
+
+**Initial setup (team lead):**
+```bash
+# Generate team channel key
+stegasoo channel generate -q > team_channel.key
+
+# Distribute to team members securely
+# (encrypted email, secure file share, etc.)
+```
+
+**Team member setup:**
+```bash
+# Save received key
+stegasoo channel set --file team_channel.key
+
+# Verify
+stegasoo channel show
+```
+
+**Daily use:**
+```bash
+# Channel key is used automatically
+stegasoo encode -r ref.jpg -c meme.png -p "phrase" --pin 123456 -m "Team message"
+stegasoo decode -r ref.jpg -s stego.png -p "phrase" --pin 123456
+```
+
+### Docker Deployment
+
+**docker/docker-compose.yml:**
+```yaml
+x-common-env: &common-env
+  STEGASOO_CHANNEL_KEY: ${STEGASOO_CHANNEL_KEY:-}
+
+services:
+  web:
+    environment:
+      <<: *common-env
+  api:
+    environment:
+      <<: *common-env
+```
+
+**.env (gitignored):**
+```bash
+STEGASOO_CHANNEL_KEY=ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456
+```
+
+### CI/CD Pipeline
+
+```bash
+# Generate key for CI
+CHANNEL_KEY=$(stegasoo channel generate -q)
+
+# Use in pipeline
+STEGASOO_CHANNEL_KEY=$CHANNEL_KEY stegasoo encode ...
+```
+
+---
+
+## Piping & Scripting
+
+### Extract channel key for scripts
+
+```bash
+# Get just the key
+KEY=$(stegasoo channel show --json | jq -r '.key // empty')
+
+# Get fingerprint
+FINGERPRINT=$(stegasoo channel show --json | jq -r '.fingerprint // "none"')
+
+# Check if configured
+if stegasoo channel show --json | jq -e '.configured' > /dev/null; then
+  echo "Channel key is configured"
+fi
+```
+
+### Generate and use immediately
+
+```bash
+# Generate, save, and use
+stegasoo channel generate --save
+stegasoo encode -r ref.jpg -c carrier.png -p "phrase" --pin 123456 -m "message"
+```
+
+---
+
+## Error Handling
+
+### Channel Key Errors
+
+| Error | Cause | Solution |
+|-------|-------|----------|
+| "Invalid channel key format" | Key doesn't match pattern | Use `stegasoo channel generate` |
+| "Message encoded with channel key but none configured" | Missing channel key | Set key or use `--channel` |
+| "Message encoded without channel key" | Used `--no-channel` to encode | Decode with `--no-channel` |
+| "Channel key mismatch" | Wrong key | Verify correct key |
+
+### Troubleshooting
+
+```bash
+# Check current channel status
+stegasoo channel show
+
+# Try decoding with explicit key
+stegasoo decode ... --channel XXXX-XXXX-...
+
+# Try decoding without channel key
+stegasoo decode ... --no-channel
+```
+
+---
+
+## Exit Codes
+
+| Code | Meaning |
+|------|---------|
+| 0 | Success |
+| 1 | General error / decryption failed |
+| 2 | Invalid arguments/options |
+
+---
+
+## Environment Variables
+
+| Variable | Description |
+|----------|-------------|
+| `STEGASOO_CHANNEL_KEY` | Channel key for deployment isolation (v4.0.0) |
+| `PYTHONPATH` | Include `src/` for development |
+| `STEGASOO_DEBUG` | Enable debug output (set to `1`) |
+
+---
+
+## See Also
+
+- [API Documentation](API.md) - Python API reference
+- [Web UI Documentation](WEB_UI.md) - Browser interface guide
+- [README](../README.md) - Project overview and security model

CODE_OF_CONDUCT.md

@@ -0,0 +1,54 @@
+# Code of Conduct
+
+## Our Pledge
+
+We as members, contributors, and leaders pledge to make participation in our
+community a harassment-free experience for everyone, regardless of age, body
+size, visible or invisible disability, ethnicity, sex characteristics, gender
+identity and expression, level of experience, education, socio-economic status,
+nationality, personal appearance, race, religion, or sexual identity
+and orientation.
+
+We pledge to act and interact in ways that contribute to an open, welcoming,
+diverse, inclusive, and healthy community.
+
+## Our Standards
+
+Examples of behavior that contributes to a positive environment:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior:
+
+* The use of sexualized language or imagery, and sexual attention or advances
+* Trolling, insulting or derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information without explicit permission
+* Other conduct which could reasonably be considered inappropriate
+
+## Enforcement Responsibilities
+
+Project maintainers are responsible for clarifying and enforcing our standards
+of acceptable behavior and will take appropriate and fair corrective action in
+response to any behavior that they deem inappropriate, threatening, offensive,
+or harmful.
+
+## Scope
+
+This Code of Conduct applies within all community spaces, and also applies when
+an individual is officially representing the community in public spaces.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported to the project maintainers. All complaints will be reviewed and
+investigated promptly and fairly.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant](https://www.contributor-covenant.org),
+version 2.0.

CONTRIBUTING.md

@@ -0,0 +1,165 @@
+# Contributing to Stegasoo
+
+Thank you for your interest in contributing to Stegasoo! This document provides guidelines and information for contributors.
+
+## Getting Started
+
+### Prerequisites
+
+- Python 3.10 - 3.12
+- Git
+- Docker (optional, for container testing)
+
+### Development Setup
+
+1. **Clone the repository**
+   ```bash
+   git clone https://github.com/adlee-was-taken/stegasoo.git
+   cd stegasoo
+   ```
+
+2. **Create a virtual environment**
+   ```bash
+   python -m venv venv
+   source venv/bin/activate  # On Windows: venv\Scripts\activate
+   ```
+
+3. **Install development dependencies**
+   ```bash
+   pip install -e ".[dev]"
+   ```
+
+4. **Install pre-commit hooks**
+   ```bash
+   pre-commit install
+   ```
+
+## Development Workflow
+
+### Code Style
+
+We use the following tools to maintain code quality:
+
+- **Black** - Code formatting (line length: 100)
+- **Ruff** - Linting
+- **MyPy** - Type checking
+
+Run all checks before committing:
+```bash
+black src/ tests/ frontends/
+ruff check src/ tests/ frontends/
+mypy src/
+```
+
+### Running Tests
+
+```bash
+# Run all tests
+pytest
+
+# Run with coverage
+pytest --cov=stegasoo --cov-report=term-missing
+
+# Run specific test file
+pytest tests/test_stegasoo.py
+```
+
+### Type Hints
+
+All new code should include type hints:
+
+```python
+def encode_message(
+    message: str,
+    carrier_image: bytes,
+    passphrase: str,
+    pin: str = "",
+) -> EncodeResult:
+    ...
+```
+
+## Making Changes
+
+### Branch Naming
+
+- `feature/description` - New features
+- `fix/description` - Bug fixes
+- `docs/description` - Documentation updates
+- `refactor/description` - Code refactoring
+
+### Commit Messages
+
+Write clear, concise commit messages:
+
+```
+Add channel key validation for private messaging
+
+- Implement validate_channel_key() function
+- Add tests for valid/invalid key formats
+- Update CLI to support --channel-key flag
+```
+
+### Pull Request Process
+
+1. **Create a feature branch** from `main`
+2. **Make your changes** with appropriate tests
+3. **Ensure all checks pass** (tests, linting, formatting)
+4. **Submit a PR** with a clear description
+5. **Address review feedback** promptly
+
+### PR Checklist
+
+- [ ] Tests added/updated for changes
+- [ ] Documentation updated if needed
+- [ ] CHANGELOG.md updated for user-facing changes
+- [ ] All CI checks passing
+- [ ] No merge conflicts with `main`
+
+## Project Structure
+
+```
+stegasoo/
+├── src/stegasoo/       # Core library
+│   ├── crypto.py       # Encryption/decryption
+│   ├── steganography.py # LSB embedding
+│   ├── dct_steganography.py # DCT embedding
+│   └── ...
+├── frontends/
+│   ├── cli/            # Command-line interface
+│   ├── web/            # Flask web UI
+│   └── api/            # FastAPI REST API
+├── tests/              # Test suite
+└── examples/           # Usage examples
+```
+
+## Reporting Issues
+
+### Bug Reports
+
+Please include:
+- Python version and OS
+- Stegasoo version (`stegasoo --version`)
+- Minimal reproduction steps
+- Expected vs actual behavior
+- Error messages/tracebacks
+
+### Feature Requests
+
+Please include:
+- Use case description
+- Proposed solution (if any)
+- Alternatives considered
+
+## Security
+
+If you discover a security vulnerability, please see [SECURITY.md](SECURITY.md) for responsible disclosure guidelines. **Do not open a public issue for security vulnerabilities.**
+
+## License
+
+By contributing, you agree that your contributions will be licensed under the MIT License.
+
+## Questions?
+
+Feel free to open a discussion or issue if you have questions about contributing.
+
+Thank you for helping make Stegasoo better!

DOCKER.md

@@ -0,0 +1,156 @@
+# Docker Deployment
+
+Stegasoo provides Docker images for both the Web UI and REST API.
+
+## Quick Start
+
+```bash
+# Build and start all services
+docker-compose -f docker/docker-compose.yml up -d
+
+# Check status
+docker-compose -f docker/docker-compose.yml ps
+```
+
+Access:
+- **Web UI**: https://localhost:5000 (HTTPS with self-signed cert)
+- **REST API**: http://localhost:8000
+
+## Services
+
+| Service | Port | Description |
+|---------|------|-------------|
+| `web` | 5000 | Flask Web UI with authentication |
+| `api` | 8000 | FastAPI REST API |
+
+## Configuration
+
+### Environment Variables
+
+Create a `.env` file or set these variables:
+
+```bash
+# Channel key for private group communication (optional)
+STEGASOO_CHANNEL_KEY=XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX
+
+# Web UI authentication (default: enabled)
+STEGASOO_AUTH_ENABLED=true
+
+# HTTPS support (default: enabled, generates self-signed cert)
+STEGASOO_HTTPS_ENABLED=true
+STEGASOO_HOSTNAME=localhost
+
+# To disable HTTPS:
+# STEGASOO_HTTPS_ENABLED=false
+```
+
+### Volume Mounts
+
+Persistent data is stored in Docker volumes:
+
+| Volume | Purpose |
+|--------|---------|
+| `stegasoo-web-data` | User database, session data |
+| `stegasoo-web-certs` | SSL certificates (if HTTPS enabled) |
+
+## Building
+
+### Standard Build (Recommended)
+
+Uses a pre-built base image with all dependencies:
+
+```bash
+# First time only: build the base image
+docker build -f docker/Dockerfile.base -t stegasoo-base:latest .
+
+# Build services (fast - only copies app code)
+docker-compose -f docker/docker-compose.yml build
+```
+
+### Full Build (No Base Image)
+
+If you don't have the base image, the Dockerfile will build all dependencies (slower):
+
+```bash
+docker-compose -f docker/docker-compose.yml build
+```
+
+## Commands
+
+```bash
+# Start services
+docker-compose -f docker/docker-compose.yml up -d
+
+# View logs
+docker-compose -f docker/docker-compose.yml logs -f
+
+# Stop services
+docker-compose -f docker/docker-compose.yml down
+
+# Rebuild after code changes
+docker-compose -f docker/docker-compose.yml build && docker-compose -f docker/docker-compose.yml up -d
+
+# Full rebuild (no cache)
+docker-compose -f docker/docker-compose.yml build --no-cache
+```
+
+## Resource Limits
+
+Each container is configured with:
+- **Memory limit**: 768 MB
+- **Memory reservation**: 384 MB
+
+This accounts for Argon2id's 256 MB RAM requirement during key derivation.
+
+## Health Checks
+
+Both services include health checks:
+- Interval: 30 seconds
+- Timeout: 10 seconds
+- Start period: 5 seconds
+- Retries: 3
+
+Check health status:
+```bash
+docker-compose -f docker/docker-compose.yml ps
+```
+
+## Production Deployment
+
+For production, consider:
+
+1. **Enable HTTPS**:
+   ```bash
+   STEGASOO_HTTPS_ENABLED=true
+   STEGASOO_HOSTNAME=your-domain.com
+   ```
+
+2. **Use secrets for channel key**:
+   ```bash
+   # Don't commit .env files with secrets
+   export STEGASOO_CHANNEL_KEY=your-key
+   docker-compose -f docker/docker-compose.yml up -d
+   ```
+
+3. **Reverse proxy**: Put behind nginx/traefik for TLS termination
+
+4. **Backup volumes**:
+   ```bash
+   docker run --rm -v stegasoo-web-data:/data -v $(pwd):/backup \
+     alpine tar czf /backup/stegasoo-backup.tar.gz /data
+   ```
+
+## Troubleshooting
+
+### Container won't start
+```bash
+# Check logs
+docker-compose -f docker/docker-compose.yml logs web
+docker-compose -f docker/docker-compose.yml logs api
+```
+
+### Out of memory
+Increase Docker's memory allocation or reduce worker count in `docker/Dockerfile`.
+
+### Permission errors
+The containers run as non-root user `stego` (UID 1000). Ensure volume permissions match.

Dockerfile.txt

@@ -1,129 +0,0 @@
-# Stegasoo Docker Image
-# Multi-stage build for smaller image size
-
-FROM python:3.11-slim as base
-
-# Set environment variables
-ENV PYTHONDONTWRITEBYTECODE=1
-ENV PYTHONUNBUFFERED=1
-
-# Install system dependencies
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    gcc \
-    libc-dev \
-    libffi-dev \
-    && rm -rf /var/lib/apt/lists/*
-
-# ============================================================================
-# Builder stage - install Python packages
-# ============================================================================
-FROM base as builder
-
-WORKDIR /build
-
-# Copy package files (including README.md which pyproject.toml references)
-COPY pyproject.toml README.md ./
-COPY src/ src/
-COPY data/ data/
-
-# Install the package with web extras
-RUN pip install --no-cache-dir ".[web]"
-
-# ============================================================================
-# Production stage - Web UI
-# ============================================================================
-FROM base as web
-
-WORKDIR /app
-
-# Copy installed packages from builder
-COPY --from=builder /usr/local/lib/python3.11/site-packages /usr/local/lib/python3.11/site-packages
-COPY --from=builder /usr/local/bin /usr/local/bin
-
-# Copy application files
-COPY src/ src/
-COPY data/ data/
-COPY frontends/web/ frontends/web/
-
-# Create upload directory
-RUN mkdir -p /tmp/stego_uploads
-
-# Create non-root user
-RUN useradd -m -u 1000 stego && chown -R stego:stego /app /tmp/stego_uploads
-USER stego
-
-# Set Python path
-ENV PYTHONPATH=/app/src
-
-# Expose port
-EXPOSE 5000
-
-# Health check
-HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
-    CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:5000/')" || exit 1
-
-# Run with gunicorn
-WORKDIR /app/frontends/web
-CMD ["gunicorn", "--bind", "0.0.0.0:5000", "--workers", "2", "--threads", "4", "--timeout", "60", "app:app"]
-
-# ============================================================================
-# API stage - REST API
-# ============================================================================
-FROM base as api
-
-WORKDIR /app
-
-# Install API extras
-COPY pyproject.toml README.md ./
-COPY src/ src/
-COPY data/ data/
-RUN pip install --no-cache-dir ".[api]"
-
-# Copy API files
-COPY frontends/api/ frontends/api/
-
-# Create non-root user
-RUN useradd -m -u 1000 stego && chown -R stego:stego /app
-USER stego
-
-# Set Python path
-ENV PYTHONPATH=/app/src
-
-# Expose port
-EXPOSE 8000
-
-# Health check
-HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
-    CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8000/')" || exit 1
-
-# Run with uvicorn
-WORKDIR /app/frontends/api
-CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]
-
-# ============================================================================
-# CLI stage - Command line tool
-# ============================================================================
-FROM base as cli
-
-WORKDIR /app
-
-# Install CLI extras
-COPY pyproject.toml README.md ./
-COPY src/ src/
-COPY data/ data/
-RUN pip install --no-cache-dir ".[cli]"
-
-# Copy CLI files
-COPY frontends/cli/ frontends/cli/
-
-# Create non-root user
-RUN useradd -m -u 1000 stego && chown -R stego:stego /app
-USER stego
-
-# Set Python path
-ENV PYTHONPATH=/app/src
-
-# Default to help
-WORKDIR /app/frontends/cli
-ENTRYPOINT ["python", "main.py"]
-CMD ["--help"]

INSTALL.md

@@ -0,0 +1,904 @@
+# Stegasoo Installation Guide
+
+Complete installation instructions for all platforms and deployment methods.
+
+## Table of Contents
+
+- [Requirements](#requirements)
+- [Quick Install](#quick-install)
+- [Installation Methods](#installation-methods)
+  - [From Source (Development)](#from-source-development)
+  - [From PyPI](#from-pypi)
+  - [Docker](#docker)
+  - [Docker Compose](#docker-compose)
+- [Optional Dependencies](#optional-dependencies)
+- [Platform-Specific Notes](#platform-specific-notes)
+- [Verification](#verification)
+- [Troubleshooting](#troubleshooting)
+
+---
+
+## Requirements
+
+### ⚠️ Python Version Requirements
+
+| Python Version | Status | Notes |
+|----------------|--------|-------|
+| 3.10 | ✅ Supported | |
+| 3.11 | ✅ Supported | Recommended |
+| 3.12 | ✅ Supported | Recommended |
+| 3.13 | ❌ **Not Supported** | jpegio C extension incompatible |
+
+**Important:** Python 3.13 (released October 2024) is **not compatible** with jpegio due to C extension ABI changes. Use Python 3.12 or earlier.
+
+### Minimum Requirements
+
+| Requirement | Value |
+|-------------|-------|
+| Python | 3.10-3.12 |
+| RAM | 512 MB minimum (256MB for Argon2) |
+| Disk | ~100 MB |
+
+### System Dependencies
+
+**Linux (Debian/Ubuntu):**
+```bash
+sudo apt-get update
+sudo apt-get install -y \
+  python3.12 \
+  python3.12-venv \
+  python3-pip \
+  python3-dev \
+  libzbar0 \
+  libjpeg-dev \
+  build-essential
+```
+
+**Linux (Arch):**
+```bash
+# Use pyenv for Python version management
+curl https://pyenv.run | bash
+pyenv install 3.12
+pyenv local 3.12
+
+sudo pacman -S zbar libjpeg-turbo base-devel
+```
+
+**macOS:**
+```bash
+brew install python@3.12 zbar jpeg
+xcode-select --install  # For compilation
+```
+
+**Windows:**
+- Install Python 3.12 from [python.org](https://python.org)
+- Install Visual Studio Build Tools for compilation
+
+---
+
+## Quick Install
+
+```bash
+# Clone and install everything
+git clone https://github.com/adlee-was-taken/stegasoo.git
+cd stegasoo
+
+# Create venv with Python 3.12 (critical!)
+python3.12 -m venv venv
+source venv/bin/activate  # Linux/macOS
+# or: venv\Scripts\activate  # Windows
+
+# Install all dependencies
+pip install -e ".[all]"
+
+# Verify
+stegasoo --version
+python -c "from stegasoo import has_dct_support; print(f'DCT: {has_dct_support()}')"
+```
+
+---
+
+## Installation Methods
+
+### From Source (Development)
+
+Best for development or customization.
+
+```bash
+# Clone the repository
+git clone https://github.com/adlee-was-taken/stegasoo.git
+cd stegasoo
+
+# Create virtual environment with Python 3.12 (recommended)
+python3.12 -m venv venv
+source venv/bin/activate  # Linux/macOS
+# or: venv\Scripts\activate  # Windows
+
+# Verify Python version
+python -V  # Should show 3.12.x
+
+# Install core library only
+pip install -e .
+
+# Install with specific extras
+pip install -e ".[cli]"       # Command-line interface
+pip install -e ".[web]"       # Flask web UI + DCT support
+pip install -e ".[api]"       # FastAPI REST API + DCT support
+pip install -e ".[dct]"       # DCT steganography only
+pip install -e ".[compression]"  # LZ4 compression
+
+# Install everything
+pip install -e ".[all]"
+
+# Install with development tools
+pip install -e ".[dev]"
+```
+
+### From PyPI
+
+```bash
+# Core only
+pip install stegasoo
+
+# With extras
+pip install stegasoo[cli]
+pip install stegasoo[web]
+pip install stegasoo[api]
+pip install stegasoo[all]
+```
+
+### Docker
+
+Build and run individual containers.
+
+#### Build Images
+
+```bash
+# From project root - build all targets
+docker build -t stegasoo-web --target web -f docker/Dockerfile .
+docker build -t stegasoo-api --target api -f docker/Dockerfile .
+docker build -t stegasoo-cli --target cli -f docker/Dockerfile .
+```
+
+#### Run Web UI
+
+```bash
+docker run -d \
+  --name stegasoo-web \
+  -p 5000:5000 \
+  --memory=768m \
+  stegasoo-web
+
+# Visit http://localhost:5000
+```
+
+#### Run REST API
+
+```bash
+docker run -d \
+  --name stegasoo-api \
+  -p 8000:8000 \
+  --memory=768m \
+  stegasoo-api
+
+# Docs at http://localhost:8000/docs
+```
+
+#### Run CLI
+
+```bash
+# Interactive shell
+docker run -it --rm stegasoo-cli /bin/bash
+
+# Run commands directly
+docker run --rm stegasoo-cli --help
+docker run --rm stegasoo-cli generate --pin --words 4
+
+# With volume for files
+docker run --rm \
+  -v $(pwd)/images:/data \
+  stegasoo-cli encode \
+    -r /data/ref.jpg \
+    -c /data/carrier.png \
+    -p "passphrase words here more" \
+    --pin 123456 \
+    -m "Secret message" \
+    -o /data/stego.png
+```
+
+### Docker Compose
+
+The easiest way to run all services.
+
+#### Start All Services
+
+```bash
+# Start in background
+docker-compose -f docker/docker-compose.yml up -d
+
+# Start specific service
+docker-compose -f docker/docker-compose.yml up -d web
+docker-compose -f docker/docker-compose.yml up -d api
+
+# View logs
+docker-compose -f docker/docker-compose.yml logs -f
+
+# Stop all
+docker-compose -f docker/docker-compose.yml down
+```
+
+#### Authentication Configuration (v4.0.2)
+
+The Web UI supports optional authentication. Configure via environment variables:
+
+```bash
+# .env file (create in project root)
+STEGASOO_AUTH_ENABLED=true      # Enable login (default: true)
+STEGASOO_HTTPS_ENABLED=false    # Enable HTTPS (default: false)
+STEGASOO_HOSTNAME=localhost     # Hostname for SSL cert
+STEGASOO_CHANNEL_KEY=           # Optional channel key
+
+# Then run
+docker-compose -f docker/docker-compose.yml up -d web
+```
+
+On first access, you'll be prompted to create an admin account. The database and SSL certs are persisted in Docker volumes.
+
+#### Services
+
+| Service | URL | Description |
+|---------|-----|-------------|
+| `web` | http://localhost:5000 | Flask Web UI |
+| `api` | http://localhost:8000 | FastAPI REST API |
+
+#### Build and Start
+
+```bash
+# Build images and start
+docker-compose -f docker/docker-compose.yml up -d --build
+
+# Force rebuild (no cache)
+docker-compose -f docker/docker-compose.yml build --no-cache
+docker-compose -f docker/docker-compose.yml up -d
+```
+
+#### Resource Configuration
+
+The `docker/docker-compose.yml` includes resource limits:
+
+```yaml
+services:
+  web:
+    deploy:
+      resources:
+        limits:
+          memory: 768M    # For Argon2 + scipy
+        reservations:
+          memory: 384M
+```
+
+Adjust based on your available RAM:
+
+| Available RAM | Recommended Limit | Workers |
+|---------------|-------------------|---------|
+| 2 GB | 768M | 2 |
+| 4 GB | 1G | 3 |
+| 8 GB+ | 1.5G | 4 |
+
+---
+
+## Optional Dependencies
+
+### DCT Steganography (scipy + jpegio)
+
+DCT mode enables JPEG-resilient steganography. It's automatically included with `[web]`, `[api]`, and `[all]` extras.
+
+#### Install via pip
+
+```bash
+# scipy is straightforward
+pip install scipy numpy
+
+# jpegio - MUST use Python 3.12 or earlier!
+pip install jpegio
+
+# If pip fails, build from source
+pip install cython numpy
+git clone https://github.com/dwgoon/jpegio.git
+cd jpegio
+python setup.py install
+```
+
+#### Linux Build Dependencies
+
+```bash
+sudo apt-get install -y \
+  build-essential \
+  python3-dev \
+  libjpeg-dev \
+  cython3
+```
+
+#### macOS Build Dependencies
+
+```bash
+brew install jpeg cython
+```
+
+#### Verify DCT Support
+
+```python
+from stegasoo import has_dct_support
+from stegasoo.dct_steganography import has_jpegio_support
+
+print(f"DCT support (scipy): {has_dct_support()}")
+print(f"JPEG native (jpegio): {has_jpegio_support()}")
+```
+
+Expected output:
+```
+DCT support (scipy): True
+JPEG native (jpegio): True
+```
+
+### Compression (lz4)
+
+Optional LZ4 compression for messages:
+
+```bash
+pip install lz4
+```
+
+---
+
+## Platform-Specific Notes
+
+### Linux
+
+Most straightforward installation. Use your package manager for system dependencies.
+
+**Ubuntu/Debian:**
+```bash
+sudo apt-get install python3.12 python3.12-venv python3-dev libzbar0 libjpeg-dev
+python3.12 -m venv venv
+source venv/bin/activate
+pip install stegasoo[all]
+```
+
+**Fedora/RHEL:**
+```bash
+sudo dnf install python3.12 python3-devel zbar libjpeg-devel
+python3.12 -m venv venv
+source venv/bin/activate
+pip install stegasoo[all]
+```
+
+**Arch (using pyenv):**
+```bash
+# Install pyenv
+curl https://pyenv.run | bash
+
+# Add to ~/.bashrc or ~/.zshrc
+export PATH="$HOME/.pyenv/bin:$PATH"
+eval "$(pyenv init -)"
+
+# Install Python 3.12
+pyenv install 3.12
+cd ~/Sources/stegasoo
+pyenv local 3.12
+
+# Create venv and install
+python -m venv venv
+source venv/bin/activate
+pip install stegasoo[all]
+```
+
+### macOS
+
+```bash
+# Install Homebrew if needed
+/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
+
+# Install dependencies
+brew install python@3.12 zbar jpeg
+
+# Create venv
+python3.12 -m venv venv
+source venv/bin/activate
+
+# Install Stegasoo
+pip install stegasoo[all]
+```
+
+**Apple Silicon (M1/M2/M3):**
+
+jpegio may need native compilation:
+```bash
+# Ensure you have native Python
+arch -arm64 brew install python@3.12
+arch -arm64 python3.12 -m venv venv
+source venv/bin/activate
+pip install jpegio
+```
+
+### Windows
+
+1. Install Python 3.12 from [python.org](https://python.org) (NOT 3.13!)
+2. Install Visual Studio Build Tools
+3. Install from pip:
+
+```powershell
+python -m venv venv
+.\venv\Scripts\activate
+pip install stegasoo[all]
+```
+
+### Raspberry Pi
+
+Stegasoo works on Raspberry Pi 4/5 (4GB+ RAM recommended for Web UI).
+
+#### Step 1: Install System Dependencies
+
+```bash
+sudo apt-get update
+sudo apt-get install -y \
+  build-essential \
+  git \
+  libssl-dev \
+  zlib1g-dev \
+  libbz2-dev \
+  libreadline-dev \
+  libsqlite3-dev \
+  libncursesw5-dev \
+  xz-utils \
+  tk-dev \
+  libxml2-dev \
+  libxmlsec1-dev \
+  libffi-dev \
+  liblzma-dev \
+  libzbar0 \
+  libjpeg-dev
+```
+
+#### Step 2: Install Python 3.12 via pyenv
+
+Raspberry Pi OS ships with Python 3.13, which is **not compatible** with jpegio. Install Python 3.12:
+
+```bash
+# Install pyenv
+curl https://pyenv.run | bash
+
+# Add to ~/.bashrc
+echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
+echo '[[ -d $PYENV_ROOT/bin ]] && export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bashrc
+echo 'eval "$(pyenv init - bash)"' >> ~/.bashrc
+source ~/.bashrc
+
+# Install Python 3.12 (takes ~10 minutes on Pi 5)
+pyenv install 3.12
+pyenv global 3.12
+```
+
+#### Step 3: Build jpegio for ARM
+
+The upstream jpegio has x86-specific build flags. Patch and build from source:
+
+```bash
+# Clone jpegio
+git clone https://github.com/dwgoon/jpegio.git
+cd jpegio
+
+# Patch for ARM (removes x86-specific -m64 flag)
+sed -i "s/cargs.append('-m64')/pass  # ARM fix/" setup.py
+
+# Build and install
+pip install .
+cd ..
+```
+
+#### Step 4: Install Stegasoo
+
+```bash
+# Clone Stegasoo
+git clone https://github.com/adlee-was-taken/stegasoo.git
+cd stegasoo
+
+# Create venv with Python 3.12
+~/.pyenv/versions/3.12.*/bin/python -m venv venv
+source venv/bin/activate
+
+# Install (jpegio already installed, skip it)
+pip install -e ".[web]" --no-deps
+pip install argon2-cffi cryptography pillow flask gunicorn scipy numpy pyzbar qrcode
+```
+
+#### Step 5: Run the Web UI
+
+```bash
+cd frontends/web
+
+# Optional: Enable authentication
+export STEGASOO_AUTH_ENABLED=true
+
+# Optional: Enable HTTPS for local network security
+export STEGASOO_HTTPS_ENABLED=true
+export STEGASOO_HOSTNAME=raspberrypi.local
+
+# Start server
+python app.py
+# Access at http://<pi-ip>:5000
+```
+
+#### Verify Installation
+
+```bash
+python -c "
+import stegasoo
+from stegasoo.dct_steganography import has_jpegio_support
+print(f'Stegasoo: {stegasoo.__version__}')
+print(f'Argon2: {stegasoo.has_argon2()}')
+print(f'DCT: {stegasoo.has_dct_support()}')
+print(f'jpegio: {has_jpegio_support()}')
+"
+# Expected: All True
+```
+
+#### Notes
+
+- **RAM**: Web UI needs ~768MB free for Argon2 + scipy operations
+- **Performance**: Argon2 operations take 3-5 seconds on Pi 5 (vs ~2s on desktop)
+- **Python 3.13**: Not supported due to jpegio C extension incompatibility
+- **First run**: Will prompt you to create an admin account
+- **HTTPS**: Generates self-signed certificate (browsers will warn)
+
+---
+
+## Custom SSL Certificates
+
+By default, Stegasoo generates a self-signed certificate for HTTPS. To use your own certificate (e.g., from Let's Encrypt or your organization's CA):
+
+### Replace Self-Signed Certificates
+
+```bash
+# Stop the service
+sudo systemctl stop stegasoo
+
+# Backup existing certs (optional)
+mv /opt/stegasoo/frontends/web/certs /opt/stegasoo/frontends/web/certs.bak
+
+# Create new certs directory
+mkdir -p /opt/stegasoo/frontends/web/certs
+
+# Copy your certificates (adjust paths as needed)
+cp /path/to/your/certificate.crt /opt/stegasoo/frontends/web/certs/server.crt
+cp /path/to/your/private.key /opt/stegasoo/frontends/web/certs/server.key
+
+# Set permissions (key must be readable by service user)
+chmod 600 /opt/stegasoo/frontends/web/certs/server.key
+chown -R $(whoami):$(whoami) /opt/stegasoo/frontends/web/certs
+
+# Start the service
+sudo systemctl start stegasoo
+```
+
+### Generate New Self-Signed Certificate
+
+If your certificate expires or you need to regenerate:
+
+```bash
+# Stop service
+sudo systemctl stop stegasoo
+
+# Generate new cert with SANs
+CERT_DIR="/opt/stegasoo/frontends/web/certs"
+LOCAL_IP=$(hostname -I | awk '{print $1}')
+HOSTNAME=$(hostname)
+
+openssl req -x509 -newkey rsa:2048 \
+  -keyout "$CERT_DIR/server.key" \
+  -out "$CERT_DIR/server.crt" \
+  -days 365 -nodes \
+  -subj "/O=Stegasoo/CN=$HOSTNAME" \
+  -addext "subjectAltName=DNS:$HOSTNAME,DNS:$HOSTNAME.local,DNS:localhost,IP:$LOCAL_IP,IP:127.0.0.1"
+
+chmod 600 "$CERT_DIR/server.key"
+
+# Start service
+sudo systemctl start stegasoo
+```
+
+### Let's Encrypt with Certbot
+
+For publicly accessible servers:
+
+```bash
+# Install certbot
+sudo apt install certbot
+
+# Get certificate (standalone mode)
+sudo certbot certonly --standalone -d yourdomain.com
+
+# Copy to Stegasoo
+sudo cp /etc/letsencrypt/live/yourdomain.com/fullchain.pem /opt/stegasoo/frontends/web/certs/server.crt
+sudo cp /etc/letsencrypt/live/yourdomain.com/privkey.pem /opt/stegasoo/frontends/web/certs/server.key
+sudo chown $(whoami):$(whoami) /opt/stegasoo/frontends/web/certs/*
+sudo chmod 600 /opt/stegasoo/frontends/web/certs/server.key
+
+# Restart
+sudo systemctl restart stegasoo
+```
+
+**Note:** Set up a cron job or systemd timer to copy renewed certificates and restart Stegasoo.
+
+---
+
+## Verification
+
+### Check Installation
+
+```bash
+# CLI version
+stegasoo --version
+
+# Python import
+python -c "import stegasoo; print(stegasoo.__version__)"
+
+# Check Python version (must be 3.10-3.12)
+python -V
+```
+
+### Check All Features
+
+```python
+#!/usr/bin/env python3
+"""Verify Stegasoo installation."""
+
+import sys
+
+def check_feature(name, check_fn):
+    try:
+        result = check_fn()
+        status = "✓" if result else "✗"
+        print(f"  {status} {name}: {result}")
+        return result
+    except Exception as e:
+        print(f"  ✗ {name}: Error - {e}")
+        return False
+
+print("Stegasoo Installation Check")
+print("=" * 40)
+
+# Python version check
+py_version = sys.version_info
+print(f"\nPython: {py_version.major}.{py_version.minor}.{py_version.micro}")
+if py_version >= (3, 13):
+    print("  ⚠️  WARNING: Python 3.13+ not supported!")
+    print("      jpegio will not work. Use Python 3.12.")
+elif py_version >= (3, 10):
+    print("  ✓ Python version OK")
+else:
+    print("  ✗ Python 3.10+ required")
+
+# Core
+import stegasoo
+print(f"\nStegasoo Version: {stegasoo.__version__}")
+
+print("\nCore Features:")
+check_feature("Argon2", lambda: stegasoo.has_argon2())
+check_feature("Pillow", lambda: True)  # Required, would fail import
+
+print("\nOptional Features:")
+check_feature("DCT (scipy)", stegasoo.has_dct_support)
+
+try:
+    from stegasoo.dct_steganography import has_jpegio_support
+    check_feature("JPEG native (jpegio)", has_jpegio_support)
+except ImportError:
+    print("  ✗ JPEG native (jpegio): Not installed")
+
+try:
+    import lz4
+    check_feature("Compression (lz4)", lambda: True)
+except ImportError:
+    print("  - Compression (lz4): Not installed (optional)")
+
+try:
+    import pyzbar
+    check_feature("QR codes (pyzbar)", lambda: True)
+except ImportError:
+    print("  - QR codes (pyzbar): Not installed (optional)")
+
+print("\nInterfaces:")
+try:
+    import click
+    check_feature("CLI", lambda: True)
+except ImportError:
+    print("  ✗ CLI: Not installed")
+
+try:
+    import flask
+    check_feature("Web UI", lambda: True)
+except ImportError:
+    print("  - Web UI: Not installed")
+
+try:
+    import fastapi
+    check_feature("REST API", lambda: True)
+except ImportError:
+    print("  - REST API: Not installed")
+
+print("\n" + "=" * 40)
+print("Installation check complete!")
+```
+
+Save as `check_install.py` and run:
+```bash
+python check_install.py
+```
+
+### Test Encoding/Decoding
+
+```bash
+# Quick test with CLI
+stegasoo generate --pin --words 4 --json > /tmp/creds.json
+
+# Create test image
+python -c "
+from PIL import Image
+img = Image.new('RGB', (256, 256), 'blue')
+img.save('/tmp/test_carrier.png')
+img.save('/tmp/test_ref.jpg')
+"
+
+# Encode
+stegasoo encode \
+  -r /tmp/test_ref.jpg \
+  -c /tmp/test_carrier.png \
+  -p "test phrase words here" \
+  --pin 123456 \
+  -m "Hello, Stegasoo!" \
+  -o /tmp/test_stego.png
+
+# Decode
+stegasoo decode \
+  -r /tmp/test_ref.jpg \
+  -s /tmp/test_stego.png \
+  -p "test phrase words here" \
+  --pin 123456
+```
+
+---
+
+## Troubleshooting
+
+### Common Issues
+
+#### "jpegio crashes" / "free(): invalid size" / Core dump
+
+**This is the #1 issue!** You're using Python 3.13.
+
+```bash
+# Check your Python version
+python -V
+
+# If it shows 3.13, you need to use 3.12
+# Option 1: Use pyenv
+pyenv install 3.12
+pyenv local 3.12
+
+# Option 2: Use system Python 3.12
+python3.12 -m venv venv
+source venv/bin/activate
+pip install -e ".[all]"
+```
+
+#### "No module named 'stegasoo'"
+
+```bash
+# Ensure you're in the right environment
+which python
+pip list | grep stegasoo
+
+# Reinstall
+pip install -e ".[all]"
+```
+
+#### "Argon2 not available"
+
+```bash
+# Install argon2-cffi
+pip install argon2-cffi
+
+# On Linux, may need:
+sudo apt-get install libffi-dev
+pip install --force-reinstall argon2-cffi
+```
+
+#### "jpegio not available" (not crash, just missing)
+
+```bash
+# Install build dependencies first
+sudo apt-get install libjpeg-dev  # Linux
+brew install jpeg                  # macOS
+
+# Then install jpegio
+pip install cython numpy
+pip install jpegio
+
+# If still fails, build from source
+git clone https://github.com/dwgoon/jpegio.git
+cd jpegio
+python setup.py install
+```
+
+#### "libzbar not found" (QR codes)
+
+```bash
+# Linux
+sudo apt-get install libzbar0
+
+# macOS
+brew install zbar
+
+# Then reinstall pyzbar
+pip install --force-reinstall pyzbar
+```
+
+#### Docker: "Cannot allocate memory"
+
+Argon2 needs 256MB per operation. Increase container memory:
+
+```bash
+# Docker run
+docker run --memory=768m ...
+
+# Docker Compose - edit docker/docker-compose.yml
+deploy:
+  resources:
+    limits:
+      memory: 768M
+```
+
+#### Slow performance
+
+- **Argon2 is intentionally slow** - This is a security feature
+- Expected encode/decode time: 2-5 seconds
+- DCT mode adds ~1-2 seconds for transforms
+- Large images (10MB+) may take 15-30 seconds
+
+#### "Carrier image too small"
+
+- LSB needs ~3 bits per pixel
+- DCT needs ~0.25 bits per pixel
+- For 50KB message: LSB needs ~136K pixels, DCT needs ~1.6M pixels
+- Use larger carrier images or shorter messages
+
+### Getting Help
+
+1. Check the documentation:
+   - [README.md](README.md)
+   - [CLI.md](CLI.md)
+   - [API.md](API.md)
+   - [WEB_UI.md](WEB_UI.md)
+
+2. Check existing issues on GitHub
+
+3. Open a new issue with:
+   - Python version (`python --version`)
+   - OS and version
+   - Installation method
+   - Full error message
+   - Steps to reproduce
+
+---
+
+## Next Steps
+
+After installation:
+
+1. **Generate credentials**: `stegasoo generate --pin --words 4`
+2. **Read the CLI docs**: [CLI.md](CLI.md)
+3. **Try the Web UI**: `cd frontends/web && python app.py`
+4. **Explore the API**: `cd frontends/api && python main.py`
+
+Happy steganography! 🦕

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024-2025 Aaron D. Lee
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

PLAN-4.1.6.md

@@ -0,0 +1,97 @@
+# Stegasoo v4.1.6 Planning
+
+## UI Tweaks
+
+### 1. Revamp Tron Lines Animation (Carrier/Stego Image)
+**Current state:**
+- 6-8 snake paths, each with 3-5 segments (~24-40 total lines)
+- 2px thick lines
+- 30-60px length per segment
+- Starting points spread across 80% of image area
+- Colors: yellow, cyan, purple, blue with glow
+
+**Target improvements:**
+- [x] Thinner lines (1px instead of 2px)
+- [x] More numerous (20-40 paths via 5x4 grid, ~60-200 segments total)
+- [x] Better distribution across entire image (grid-based seeding)
+- [x] Shorter segments (12-30px) for denser "circuit board" look
+
+**Files:**
+- `frontends/web/static/style.css` (~881-979) - `.embed-trace` styling
+- `frontends/web/static/js/stegasoo.js` (~333-390) - `generateEmbedTraces()`
+
+---
+
+## Tools Page Expansion
+
+### Analysis Tools
+- [x] **JPEG Compression Tester** - Preview image at different quality levels (10-100%), show file size delta. Useful for understanding stego survivability.
+- [ ] **LSB Plane Viewer** - Visualize least significant bit plane(s) of RGB channels. Classic stego analysis tool.
+- [ ] **Histogram Viewer** - Color distribution graph per channel. Anomalies can indicate hidden data.
+- [ ] **Image Diff** - Compare two images side-by-side with pixel difference highlighting. Great for original vs stego comparison.
+- [ ] **Noise Analysis** - Chi-square or similar statistical analysis for detecting LSB embedding.
+
+### Transform Tools
+- [x] **Rotate/Flip** - 90°/180°/270° rotation, horizontal/vertical flip
+- [ ] **Resize** - Scale with aspect ratio lock, common presets (50%, 25%, etc.)
+- [ ] **Crop** - Basic rectangular crop with preview
+- [x] **Format Convert** - PNG ↔ JPEG ↔ WebP with quality slider
+
+### Existing Tools (already done)
+- [x] Capacity Calculator
+- [x] EXIF Viewer
+- [x] EXIF Strip
+- [x] Image Peek (header analysis)
+
+### Tools UI/UX Overhaul
+
+**Final Layout: Office-style Ribbon + Two-Panel**
+```
+┌─────────────────────────────────────────────────────────────┐
+│  📏  📋  👁️  📊  ┃  ✂️  🔄  📐  🔀      Image Tools         │ ← Icon toolbar
+├────────────────────────────────────────┬────────────────────┤
+│  [Format: PNG ▼] [Quality: 85]         │                    │
+├────────────────────────────────────────┤  Capacity          │
+│                                        │  Calculator        │
+│    ┌────────────────────────────┐     │  ──────────────    │
+│    │                            │     │                    │
+│    │      Drop image here       │     │  Dimensions:       │
+│    │         or click           │     │  1920 × 1080       │
+│    │                            │     │                    │
+│    └────────────────────────────┘     │  LSB Capacity:     │
+│                                        │  245 KB            │
+│           [image.jpg]                  │                    │
+│                                        │  ──────────────    │
+│                                        │  [Clear] [Export]  │
+└────────────────────────────────────────┴────────────────────┘
+      Options + dropzone/preview             Results sidebar
+```
+
+- Top ribbon: Icon buttons grouped by category (Analyze | Transform)
+- Left panel: Tool options + dropzone/preview (INPUT)
+- Right panel: Tool name + results/metadata + actions (OUTPUT)
+- Flow: Left → Right (input → output)
+
+**Implementation Tasks:**
+- [x] Move inline CSS to style.css
+- [x] Build icon toolbar ribbon
+- [x] Build two-panel layout structure
+- [x] Migrate existing tools (Capacity, EXIF, Strip)
+- [x] Add new tools (Rotate, Compress, Convert)
+- [ ] Loading spinner on all async operations
+- [ ] Toast notifications instead of alerts
+- [ ] Consistent color coding (green=analysis, amber=transform)
+- [ ] Mobile: stack panels vertically
+
+---
+
+## CLI Improvements
+
+### (Add items here)
+
+---
+
+## Other UI Tweaks
+
+### (Add items here)
+

README.md

@@ -2,272 +2,156 @@
 
 A secure steganography system for hiding encrypted messages in images using hybrid authentication.
 
-![Python](https://img.shields.io/badge/Python-3.10+-blue)
-![License](https://img.shields.io/badge/License-MIT-green)
+[![Tests](https://github.com/adlee-was-taken/stegasoo/actions/workflows/test.yml/badge.svg)](https://github.com/adlee-was-taken/stegasoo/actions/workflows/test.yml)
+[![Lint](https://github.com/adlee-was-taken/stegasoo/actions/workflows/lint.yml/badge.svg)](https://github.com/adlee-was-taken/stegasoo/actions/workflows/lint.yml)
+![Python](https://img.shields.io/badge/Python-3.10--3.12-blue)
+[![License: MIT](https://img.shields.io/badge/License-MIT-green.svg)](LICENSE)
 ![Security](https://img.shields.io/badge/Security-AES--256--GCM-red)
 
 ## Features
 
-- 🔐 **AES-256-GCM** authenticated encryption
-- 🧠 **Argon2id** memory-hard key derivation (256MB RAM requirement)
-- 🎲 **Pseudo-random pixel selection** defeats steganalysis
-- 📅 **Daily key rotation** with BIP-39 passphrases
-- 🔑 **Multi-factor authentication**: PIN, RSA key, or both
-- 🖼️ **Reference photo** as "something you have"
-- 🌐 **Multiple interfaces**: CLI, Web UI, REST API
+- **AES-256-GCM** authenticated encryption
+- **Argon2id** memory-hard key derivation (256MB RAM requirement)
+- **Pseudo-random pixel selection** defeats steganalysis
+- **Multi-factor authentication**: Reference photo + passphrase + PIN/RSA key
+- **Multiple interfaces**: CLI, Web UI, REST API
+- **File embedding**: Hide any file type (PDF, ZIP, documents)
+- **DCT steganography**: JPEG-resilient embedding for social media
+- **Channel keys**: Private group communication channels
 
-## Installation
+## Embedding Modes
 
-### From PyPI (coming soon)
+| Mode | Capacity (1080p) | JPEG Resilient | Best For |
+|------|------------------|----------------|----------|
+| **DCT** (default) | ~150 KB | Yes | Social media, messaging apps |
+| **LSB** | ~750 KB | No | Email, direct file transfer |
 
-```bash
-# Core library only
-pip install stegasoo
+## Web UI
 
-# With CLI
-pip install stegasoo[cli]
-
-# With Web UI
-pip install stegasoo[web]
-
-# With REST API
-pip install stegasoo[api]
-
-# Everything
-pip install stegasoo[all]
-```
-
-### From Source
-
-```bash
-git clone https://github.com/example/stegasoo.git
-cd stegasoo
-
-# Install with all extras
-pip install -e ".[all]"
-```
-
-### Docker
-
-```bash
-# Web UI only
-docker-compose up web
-
-# REST API only
-docker-compose up api
-
-# Both
-docker-compose up
-```
+| Home | Encode | Decode | Generate |
+|:----:|:------:|:------:|:--------:|
+| ![Home](data/WebUI.webp) | ![Encode](data/WebUI_Encode.webp) | ![Decode](data/WebUI_Decode.webp) | ![Generate](data/WebUI_Generate.webp) |
 
 ## Quick Start
 
-### Python Library
-
-```python
-import stegasoo
+```bash
+# Install (Python 3.10-3.12)
+pip install -e ".[all]"
 
 # Generate credentials
-creds = stegasoo.generate_credentials(use_pin=True, use_rsa=False)
-print(f"Today's phrase: {creds.phrases['Monday']}")
-print(f"PIN: {creds.pin}")
+stegasoo generate --pin --words 4
 
 # Encode a message
-with open('secret_photo.jpg', 'rb') as f:
-    ref_photo = f.read()
-with open('meme.png', 'rb') as f:
-    carrier = f.read()
-
-result = stegasoo.encode(
-    message="Meet at midnight",
-    reference_photo=ref_photo,
-    carrier_image=carrier,
-    day_phrase="apple forest thunder",
-    pin="123456"
-)
-
-with open('stego.png', 'wb') as f:
-    f.write(result.stego_image)
-
-# Decode a message
-message = stegasoo.decode(
-    stego_image=result.stego_image,
-    reference_photo=ref_photo,
-    day_phrase="apple forest thunder",
-    pin="123456"
-)
-print(message)  # "Meet at midnight"
-```
-
-### CLI
-
-```bash
-# Generate credentials
-stegasoo generate --pin --words 3
-
-# With RSA key
-stegasoo generate --rsa --rsa-bits 4096 -o mykey.pem -p "secretpassword"
-
-# Encode
 stegasoo encode \
-  --ref photo.jpg \
-  --carrier meme.png \
-  --phrase "apple forest thunder" \
+  --ref my_photo.jpg \
+  --carrier meme.jpg \
+  --passphrase "apple forest thunder mountain" \
   --pin 123456 \
   --message "Secret message"
 
 # Decode
 stegasoo decode \
-  --ref photo.jpg \
-  --stego stego.png \
-  --phrase "apple forest thunder" \
+  --ref my_photo.jpg \
+  --stego stego_image.png \
+  --passphrase "apple forest thunder mountain" \
   --pin 123456
-
-# Pipe-friendly
-echo "secret" | stegasoo encode -r photo.jpg -c meme.png -p "words" --pin 123456 > stego.png
-stegasoo decode -r photo.jpg -s stego.png -p "words" --pin 123456 -q
 ```
 
-### Web UI
+## Interfaces
 
-```bash
-# Development
-cd frontends/web
-python app.py
-
-# Production
-gunicorn --bind 0.0.0.0:5000 app:app
-```
-
-Visit http://localhost:5000
-
-### REST API
-
-```bash
-# Development
-cd frontends/api
-python main.py
-
-# Production
-uvicorn main:app --host 0.0.0.0 --port 8000
-```
-
-API docs at http://localhost:8000/docs
-
-#### Example API Calls
-
-```bash
-# Generate credentials
-curl -X POST http://localhost:8000/generate \
-  -H "Content-Type: application/json" \
-  -d '{"use_pin": true, "use_rsa": false}'
-
-# Encode (multipart)
-curl -X POST http://localhost:8000/encode/multipart \
-  -F "message=Secret" \
-  -F "day_phrase=apple forest thunder" \
-  -F "pin=123456" \
-  -F "reference_photo=@photo.jpg" \
-  -F "carrier=@meme.png" \
-  --output stego.png
-
-# Decode (multipart)
-curl -X POST http://localhost:8000/decode/multipart \
-  -F "day_phrase=apple forest thunder" \
-  -F "pin=123456" \
-  -F "reference_photo=@photo.jpg" \
-  -F "stego_image=@stego.png"
-```
+| Interface | Start Command | Documentation |
+|-----------|---------------|---------------|
+| **CLI** | `stegasoo --help` | [CLI.md](CLI.md) |
+| **Web UI** | `cd frontends/web && python app.py` | [WEB_UI.md](WEB_UI.md) |
+| **REST API** | `cd frontends/api && uvicorn main:app` | [API.md](API.md) |
 
 ## Security Model
 
-| Component | Entropy | Purpose |
-|-----------|---------|---------|
-| Reference Photo | ~80-256 bits | Something you have |
-| Day Phrase (3 words) | ~33 bits | Something you know (rotates daily) |
-| PIN (6 digits) | ~20 bits | Something you know (static) |
-| RSA Key (2048-bit) | ~128 bits | Something you have |
-| **Combined** | **133-400+ bits** | **Beyond brute force** |
-
-### Attack Resistance
-
-| Attack | Protection |
-|--------|------------|
-| Brute force | 2^133+ combinations |
-| Rainbow tables | Random salt per message |
-| Steganalysis | Random pixel selection |
-| GPU cracking | Argon2id requires 256MB RAM per attempt |
-| Side-channel | Constant-time operations in crypto |
-
-## Project Structure
-
 ```
-stegasoo/
-├── src/stegasoo/           # Core library
-│   ├── __init__.py         # Public API
-│   ├── constants.py        # Configuration
-│   ├── crypto.py           # Encryption/decryption
-│   ├── steganography.py    # Image embedding
-│   ├── keygen.py           # Credential generation
-│   ├── validation.py       # Input validation
-│   ├── models.py           # Data classes
-│   ├── exceptions.py       # Custom exceptions
-│   └── utils.py            # Utilities
-│
-├── frontends/
-│   ├── web/                # Flask web UI
-│   ├── cli/                # Command-line interface
-│   └── api/                # FastAPI REST API
-│
-├── data/
-│   └── bip39-words.txt     # BIP-39 wordlist
-│
-├── pyproject.toml          # Package configuration
-├── Dockerfile              # Multi-stage Docker build
-└── docker-compose.yml      # Container orchestration
+Reference Photo ──┐
+(~80-256 bits)    │
+                  ├──► Argon2id KDF ──► AES-256-GCM Key
+Passphrase ───────┤    (256MB RAM)
+(~43-132 bits)    │
+                  │
+PIN ──────────────┤
+(~20-30 bits)     │
+                  │
+RSA Key ──────────┘
+(optional)
 ```
 
-## Configuration
+| Configuration | Entropy | Use Case |
+|--------------|---------|----------|
+| 4-word passphrase + 6-digit PIN | ~153 bits | Standard security |
+| 4-word passphrase + PIN + RSA | ~280+ bits | Maximum security |
 
-### Environment Variables
+## Requirements
 
-| Variable | Default | Description |
-|----------|---------|-------------|
-| `FLASK_ENV` | production | Flask environment |
-| `PYTHONPATH` | - | Include src/ for development |
-
-### Limits
-
-| Limit | Value |
-|-------|-------|
-| Max image size | 4 megapixels |
-| Max message size | 50 KB |
-| Max file upload | 5 MB |
-| PIN length | 6-9 digits |
-| Phrase length | 3-12 words |
-| RSA key sizes | 2048, 3072, 4096 bits |
+| Requirement | Version |
+|-------------|---------|
+| Python | 3.10-3.12 |
+| RAM | 512 MB+ |
 
 ## Development
 
 ```bash
-# Install dev dependencies
 pip install -e ".[dev]"
-
-# Run tests
 pytest
-
-# Format code
-black src/ frontends/
-ruff check src/ frontends/
-
-# Type checking
-mypy src/
+black src/ tests/ frontends/
+ruff check src/ tests/ frontends/
 ```
 
+## Docker
+
+```bash
+# Quick start (HTTPS enabled by default)
+docker-compose -f docker/docker-compose.yml up -d
+
+# Access
+# Web UI:   https://localhost:5000  (self-signed cert)
+# REST API: http://localhost:8000
+
+# Disable HTTPS if needed:
+STEGASOO_HTTPS_ENABLED=false docker-compose -f docker/docker-compose.yml up -d
+```
+
+See [DOCKER.md](DOCKER.md) and [docs/DOCKER_QUICKSTART.md](docs/DOCKER_QUICKSTART.md) for full documentation.
+
+## Raspberry Pi
+
+Pre-built SD card images available for Pi 4/5:
+
+```bash
+# Flash image (download from GitHub Releases)
+zstdcat stegasoo-rpi-*.img.zst | sudo dd of=/dev/sdX bs=4M status=progress
+
+# First boot runs interactive setup wizard:
+# - WiFi configuration
+# - HTTPS with port 443
+# - Channel key generation
+# - Optional overclocking
+```
+
+See [rpi/README.md](rpi/README.md) for manual installation.
+
+## Documentation
+
+- [INSTALL.md](INSTALL.md) - Installation guide
+- [DOCKER.md](DOCKER.md) - Docker deployment
+- [CLI.md](CLI.md) - Command-line reference
+- [API.md](API.md) - REST API documentation
+- [WEB_UI.md](WEB_UI.md) - Web interface guide
+- [SECURITY.md](SECURITY.md) - Security model details
+- [UNDER_THE_HOOD.md](UNDER_THE_HOOD.md) - Technical deep-dive
+- [CHANGELOG.md](CHANGELOG.md) - Version history
+- [CONTRIBUTING.md](CONTRIBUTING.md) - Contributor guide
+- `man stegasoo` - Man page (install: `sudo cp docs/stegasoo.1 /usr/local/share/man/man1/ && sudo mandb`)
+
 ## License
 
-MIT License - Use responsibly.
+MIT License - see [LICENSE](LICENSE). Use responsibly.
 
-## ⚠️ Disclaimer
+---
 
-This tool is for educational and legitimate privacy purposes only. Users are responsible for complying with applicable laws in their jurisdiction.
+*This tool is for educational and legitimate privacy purposes. Users are responsible for complying with applicable laws.*

RELEASE_CHECKLIST.md

@@ -0,0 +1,44 @@
+# Stegasoo Release Checklist
+
+Pre-release validation checklist. Complete all items before tagging a release.
+
+## Code Quality
+
+- [ ] All tests pass: `./venv/bin/pytest tests/ -v`
+- [ ] No lint errors: `./venv/bin/ruff check src/`
+- [ ] Version bumped in `pyproject.toml`
+- [ ] CHANGELOG.md updated
+
+## Pi Image Validation
+
+- [ ] Fresh Pi OS install with setup.sh works
+- [ ] First-boot wizard completes successfully
+- [ ] MOTD shows correct URL on SSH login
+- [ ] Smoke test passes: `./rpi/smoke-test.sh --443 <PI_IP>`
+- [ ] Encode/decode works on large image (10MB+)
+- [ ] Sanitize script runs cleanly
+- [ ] Image created and compressed
+
+## Docker Validation
+
+- [ ] Base image builds: `docker build -f docker/Dockerfile.base -t stegasoo-base:latest .`
+- [ ] Web image builds: `docker-compose -f docker/docker-compose.yml build web`
+- [ ] Container starts: `docker-compose -f docker/docker-compose.yml up -d web`
+- [ ] Web UI accessible at http://localhost:5000
+- [ ] Encode/decode works in container
+- [ ] Container stops cleanly: `docker-compose -f docker/docker-compose.yml down`
+
+## Release Process
+
+- [ ] Merge feature branch to main
+- [ ] Create annotated tag: `git tag -a vX.Y.Z -m "message"`
+- [ ] Push tag: `git push origin vX.Y.Z`
+- [ ] Create GitHub Release with release notes
+- [ ] Upload Pi image (.img.zst.zip)
+- [ ] Verify download links work
+
+## Post-Release
+
+- [ ] Delete old/obsolete releases if needed
+- [ ] Update any external documentation
+- [ ] Announce release (if applicable)

RELEASE_NOTES.md

@@ -0,0 +1,52 @@
+## Stegasoo v4.1.7
+
+### Mobile UI Polish
+- **PIN Entry**: Shrunk digit boxes for 9-digit PIN support on mobile
+- **Mode Selectors**: DCT/LSB buttons now use consistent button-group styling with icons
+- **Navbar**: Left-aligned collapsed menu, shortened channel fingerprint display (`ABCD-••••-3456`)
+- **Text Wrapping**: Fixed button text wrapping issues on narrow screens
+
+### Docker Improvements
+- **Reorganized**: Docker files moved to `docker/` directory
+  - `docker/Dockerfile`
+  - `docker/Dockerfile.base`
+  - `docker/docker-compose.yml`
+- **DCT Fix**: Added Reed-Solomon (`reedsolo`) to Docker images - fixes DCT decode failures
+- **Quick Start**: New `docs/DOCKER_QUICKSTART.md` guide
+
+```bash
+# Build and run
+docker build -f docker/Dockerfile.base -t stegasoo-base:latest .
+docker-compose -f docker/docker-compose.yml up -d
+```
+
+### Raspberry Pi
+- **First-Boot Wizard**: Can now load existing channel key (for joining team deployments)
+- **Project Cleanup**: Moved `pishrink.sh` to `rpi/tools/`
+
+### UI Copy
+- Changed "Undetectable" to "Covertly Embedded" on encode page (more accurate)
+
+### Raspberry Pi Image
+Download `stegasoo-rpi-4.1.7.img.zst.zip` from Releases.
+
+```bash
+# Flash (auto-detects SD card)
+sudo ./rpi/flash-image.sh stegasoo-rpi-4.1.7.img.zst.zip
+
+# Or manual
+unzip -p stegasoo-rpi-4.1.7.img.zst.zip | zstdcat | sudo dd of=/dev/sdX bs=4M status=progress
+```
+
+Default login: `admin` / `stegasoo`
+
+First boot runs the setup wizard for WiFi, HTTPS, and channel key configuration.
+
+### Docker
+```bash
+docker-compose -f docker/docker-compose.yml up -d web  # Web UI on :5000
+docker-compose -f docker/docker-compose.yml up -d api  # REST API on :8000
+```
+
+### Full Changelog
+See [CHANGELOG.md](CHANGELOG.md) for complete version history.

SECURITY.md

@@ -0,0 +1,274 @@
+# Security Policy
+
+## Supported Versions
+
+| Version | Supported          | Notes |
+| ------- | ------------------ | ----- |
+| 4.1.x   | Current Version | What you SHOULD be using. |
+| 4.x.x   | ⚠️ Security fixes only | Upgrade (EOL soon) |
+| <= 3.x.x   | ❌ End of life | |
+
+
+## Reporting a Vulnerability
+
+**Please do not report security vulnerabilities through public GitHub issues.**
+
+Instead, please email: **adlee-was-taken@proton.me**
+
+Include:
+- Description of the vulnerability
+- Steps to reproduce
+- Potential impact
+- Any suggested fixes
+
+You should receive a response within 48 hours. We'll work with you to understand and address the issue.
+
+---
+
+# Threat Model
+
+## What Stegasoo Protects
+
+Stegasoo is designed to hide the **existence** of a secret message within an ordinary-looking image, protected by multi-factor authentication.
+
+### Protection Goals
+
+| Goal | How It's Achieved |
+|------|-------------------|
+| **Confidentiality** | AES-256-GCM encryption with Argon2id key derivation |
+| **Steganography** | LSB/DCT embedding with pseudo-random pixel/coefficient selection |
+| **Authentication** | Multi-factor: reference photo + passphrase + PIN (or RSA key) |
+| **Integrity** | GCM authentication tag detects tampering |
+
+### Security Factors
+
+Stegasoo combines multiple authentication factors:
+
+```
+┌─────────────────────────────────────────────────────────────────┐
+│                     Key Derivation                              │
+│                                                                 │
+│  Reference Photo ───────┐                                       │
+│  (something you have)   │                                       │
+│                         ├──► Argon2id ──► AES-256 Key           │
+│  Passphrase ────────────┤    (256MB RAM)                        │
+│  (something you know)   │                                       │
+│                         │                                       │
+│  PIN or RSA Key ────────┘                                       │
+│  (second factor)                                                │
+└─────────────────────────────────────────────────────────────────┘
+```
+
+## Changes in v4.0
+
+### Removed: Date-Based Key Rotation
+
+**Previous versions (v3.x and earlier):**
+- Required a date parameter for encode/decode
+- Keys rotated daily based on "day phrase"
+- Users had to remember which date they used
+
+**Version 4.0:**
+- No date dependency
+- Single passphrase (no rotation)
+- Simpler but slightly reduced entropy per-message
+
+**Security Impact:** 
+- Minimal - the date only added ~10 bits of entropy
+- Passphrase default increased from 3 to 4 words to compensate (+11 bits)
+- Overall entropy remains similar or higher with 4-word default
+
+### Renamed: day_phrase → passphrase
+
+Terminology change only. No security impact.
+
+## What Stegasoo Does NOT Protect Against
+
+### 1. Statistical Steganalysis
+
+**Risk:** Advanced analysis can detect that an image contains hidden data.
+
+**Reality:** LSB steganography is detectable by:
+- Chi-square analysis
+- RS analysis
+- Machine learning classifiers
+
+**DCT mode is more resilient** but not undetectable.
+
+**Mitigation:** Stegasoo uses pseudo-random pixel/coefficient selection, which helps but doesn't eliminate detectability.
+
+**Recommendation:** Don't rely on Stegasoo if your adversary has:
+- Access to the original carrier image
+- Sophisticated forensic tools
+- Motivation to analyze your specific images
+
+### 2. Compromised Endpoints
+
+**Risk:** If your device is compromised, the attacker can capture credentials.
+
+**Not protected:**
+- Keyloggers capturing your PIN/passphrase
+- Screen capture of decoded messages
+- Memory scraping during encode/decode
+- Malware on sender or receiver device
+
+**Recommendation:** Use on trusted devices only.
+
+### 3. Reference Photo Exposure
+
+**Risk:** The reference photo is a critical secret.
+
+**If leaked:** Attacker only needs to guess/brute-force the passphrase + PIN.
+
+**Recommendation:**
+- Never share the reference photo
+- Use a unique photo (not posted online)
+- Store securely (encrypted drive, password manager)
+
+### 4. Weak Credentials
+
+**Risk:** Short PINs or common passphrases can be brute-forced.
+
+| PIN Length | Combinations | Time to Brute Force* |
+|------------|--------------|----------------------|
+| 4 digits   | 10,000       | Seconds              |
+| 6 digits   | 1,000,000    | Minutes              |
+| 8 digits   | 100,000,000  | Hours                |
+| 9 digits   | 1,000,000,000| Days                 |
+
+*With Argon2 (256MB RAM, 4 iterations), each attempt takes ~1 second, making brute force slow but not impossible for short PINs.
+
+**Recommendation:**
+- Use 8+ digit PINs
+- Use 4+ word passphrases (v4.0 default)
+- Consider RSA keys for high-security use cases
+
+### 5. Image Modification
+
+**Risk:** Lossy compression destroys hidden data.
+
+**LSB mode - data is destroyed by:**
+- JPEG compression
+- Resizing
+- Filters/effects
+- Screenshots
+- Social media upload
+
+**DCT mode - more resilient but not immune:**
+- Survives moderate JPEG recompression
+- May fail with aggressive compression (quality < 70)
+- Still destroyed by resizing, filters, screenshots
+
+**Recommendation:** 
+- LSB: Always use lossless formats (PNG, BMP), direct transfer
+- DCT: Use for social media, but test with your specific platform
+
+### 6. Metadata Leakage
+
+**Risk:** The stego image itself may reveal information.
+
+**Potential leaks:**
+- File creation timestamp
+- Camera EXIF data (if carrier has it)
+- File size changes
+
+**Mitigation:** Stegasoo strips EXIF on output, but timestamps remain.
+
+### 7. Traffic Analysis
+
+**Risk:** The act of sending an image may be suspicious.
+
+**Not protected:**
+- Network observers seeing you send image files
+- Email metadata showing sender/receiver
+- Frequency analysis of communications
+
+**Recommendation:** Use alongside normal image-sharing behavior.
+
+## Cryptographic Details
+
+### Encryption
+
+| Component | Algorithm | Parameters |
+|-----------|-----------|------------|
+| Key Derivation | Argon2id | 256MB RAM, 4 iterations, 4 parallelism |
+| Fallback KDF | PBKDF2-SHA256 | 600,000 iterations |
+| Encryption | AES-256-GCM | 12-byte IV, 16-byte tag |
+| Photo Hash | SHA-256 | Full image bytes |
+
+### Pixel/Coefficient Selection
+
+Selection key is derived from:
+```
+selection_key = SHA256(photo_hash || passphrase || pin/rsa_signature)
+```
+
+This prevents:
+- Sequential embedding patterns
+- Statistical detection of modified regions
+
+### Message Format (v4.0)
+
+```
+┌──────────────────────────────────────────────────────────────────┐
+│ Magic (4B) │ Version (1B) │ Salt (32B) │ IV (12B)                │
+├──────────────────────────────────────────────────────────────────┤
+│ Encrypted Payload (AES-256-GCM)                                  │
+│ ├── Type (1B): 0x01=text, 0x02=file                              │
+│ ├── Length (4B)                                                  │
+│ ├── Data (variable)                                              │
+│ └── [Filename if file] (variable)                                │
+├──────────────────────────────────────────────────────────────────┤
+│ GCM Auth Tag (16B)                                               │
+└──────────────────────────────────────────────────────────────────┘
+```
+
+**Note:** v4.0 removed the date field from the header, reducing overhead by 10 bytes.
+
+## Best Practices
+
+### For Maximum Security
+
+1. **Use RSA keys** instead of PINs for authentication
+2. **Use unique reference photos** not available online
+3. **Use long passphrases** (4+ random words, recommend 6+)
+4. **Transfer via secure channels** (Signal, encrypted email)
+5. **Delete stego images** after message is read
+6. **Keep software updated** for security fixes
+7. **Use DCT mode** for social media sharing
+
+### For Casual Privacy
+
+1. **6-digit PIN** is sufficient for non-adversarial use
+2. **4-word passphrase** provides reasonable security (v4.0 default)
+3. **PNG format** for LSB mode output
+4. **Direct file transfer** (email attachment, AirDrop)
+
+## Known Limitations
+
+| Limitation | Impact | Status |
+|------------|--------|--------|
+| LSB is detectable | Statistical analysis can detect hidden data | By design (tradeoff for capacity) |
+| No forward secrecy | Compromised key decrypts all messages | Use different keys per message for high security |
+| No deniability | Single password = single message | Future: plausible deniability layers |
+| Python 3.13 incompatible | jpegio C extension crashes | Use Python 3.12 or earlier |
+
+## Security Audit Status
+
+This software has **not** been professionally audited. Use at your own risk for sensitive applications.
+
+If you're a security researcher interested in auditing Stegasoo, please reach out.
+
+---
+
+## Version History (Security Relevant)
+
+| Version | Security Changes |
+|---------|------------------|
+| 4.0.0   | Removed date dependency, increased default passphrase to 4 words, added JPEG normalization |
+| 3.2.0   | DCT color mode added |
+| 3.0.0   | Added DCT steganography mode |
+| 2.2.0   | Added compression (no security impact) |
+| 2.1.0   | Upgraded to Argon2id, increased iterations |
+| 2.0.0   | Added RSA key support |
+| 1.0.0   | Initial release |

SECURITY_AUDIT_PLAN.md

@@ -0,0 +1,284 @@
+# Stegasoo Security Audit Plan
+
+> **Target Audience**: Developers, security reviewers, and deployment administrators
+> **Scope**: Web UI, REST API, CLI, and cryptographic core
+> **Deployment Model**: Air-gapped / private LAN (primary), Internet-facing (secondary)
+
+---
+
+## Overview
+
+Stegasoo is a steganography tool designed for **air-gapped deployments** on private networks. While the primary threat model assumes a trusted local network, this audit plan covers security best practices for both isolated and potentially exposed deployments.
+
+### Known Limitations (By Design)
+
+- **Self-signed certificates**: HTTPS uses self-signed certs; users must add exceptions or deploy their own CA
+- **No rate limiting**: Assumes trusted users on private network
+- **Single-node**: No distributed session store; sessions are per-instance
+- **Air-gap focus**: External security (firewalls, network isolation) is user's responsibility
+
+---
+
+## 1. Authentication & Authorization
+
+### 1.1 Password Security
+- [ ] Passwords hashed with Argon2id (preferred) or PBKDF2 fallback
+- [ ] Minimum password length enforced (8+ characters)
+- [ ] Password not logged or exposed in error messages
+- [ ] Password change requires current password verification
+- [ ] Admin re-authentication required for sensitive operations (channel key export)
+
+### 1.2 Session Management
+- [ ] Session tokens are cryptographically random
+- [ ] Session cookies have `HttpOnly` flag
+- [ ] Session cookies have `Secure` flag (when HTTPS enabled)
+- [ ] Session cookies have `SameSite` attribute
+- [ ] Sessions invalidated on logout
+- [ ] Sessions invalidated on password change
+- [ ] Session timeout configured appropriately
+
+### 1.3 Authorization
+- [ ] Admin-only routes protected by `@admin_required` decorator
+- [ ] User-only routes protected by `@login_required` decorator
+- [ ] Users cannot access other users' saved channel keys
+- [ ] Users cannot modify other users' accounts
+- [ ] Role escalation not possible through API manipulation
+
+---
+
+## 2. Cryptographic Implementation
+
+### 2.1 Key Derivation
+- [ ] KDF uses Argon2id with appropriate parameters (memory, iterations, parallelism)
+- [ ] PBKDF2 fallback uses sufficient iterations (600,000+)
+- [ ] Salt is cryptographically random and unique per operation
+- [ ] PIN/passphrase combined securely before KDF
+
+### 2.2 Encryption
+- [ ] AES-256-GCM used for payload encryption
+- [ ] Nonce/IV is unique per encryption operation
+- [ ] Authentication tag verified before decryption
+- [ ] No padding oracle vulnerabilities
+
+### 2.3 Channel Keys
+- [ ] Channel keys are 128-bit (32 hex chars)
+- [ ] Channel key derivation uses HKDF or similar
+- [ ] Channel isolation prevents cross-channel decryption
+- [ ] Fingerprint reveals no information about full key
+
+### 2.4 Random Number Generation
+- [ ] All random values use `secrets` module or OS CSPRNG
+- [ ] No use of `random` module for security-sensitive operations
+
+---
+
+## 3. Input Validation & Injection Prevention
+
+### 3.1 Web UI
+- [ ] All user input sanitized before rendering (XSS prevention)
+- [ ] Jinja2 auto-escaping enabled
+- [ ] No `| safe` filter on user-controlled content
+- [ ] Content-Security-Policy header configured
+- [ ] X-Content-Type-Options: nosniff
+
+### 3.2 File Uploads
+- [ ] File size limits enforced server-side
+- [ ] File type validation (magic bytes, not just extension)
+- [ ] Uploaded files not executed
+- [ ] Filenames sanitized (path traversal prevention)
+- [ ] Temporary files cleaned up after processing
+
+### 3.3 API Inputs
+- [ ] JSON schema validation on API endpoints
+- [ ] Integer overflow checks on size parameters
+- [ ] No SQL injection (parameterized queries only)
+- [ ] No command injection (no shell=True with user input)
+
+---
+
+## 4. Steganography-Specific Security
+
+### 4.1 Carrier Image Handling
+- [ ] Malformed images don't crash the server (PIL/jpegio hardening)
+- [ ] DCT mode subprocess isolation for crash protection
+- [ ] Memory limits on image processing
+- [ ] No arbitrary code execution from image metadata
+
+### 4.2 Payload Security
+- [ ] Payload size limits enforced
+- [ ] Encrypted payload indistinguishable from random noise
+- [ ] No metadata leakage in output images
+- [ ] Reference photo required (prevents dictionary attacks)
+
+### 4.3 Capacity Reporting
+- [ ] Capacity calculation doesn't leak information about encoding method
+- [ ] Failed decodes don't reveal why (wrong key vs no data vs corrupted)
+
+---
+
+## 5. Network & Transport Security
+
+### 5.1 HTTPS Configuration
+- [ ] TLS 1.2+ only (no SSLv3, TLS 1.0/1.1)
+- [ ] Strong cipher suites configured
+- [ ] Certificate generation uses 2048+ bit RSA or P-256 EC
+- [ ] Private key file permissions restricted (600)
+
+### 5.2 Headers
+- [ ] X-Frame-Options: DENY (clickjacking prevention)
+- [ ] X-Content-Type-Options: nosniff
+- [ ] Referrer-Policy: same-origin
+- [ ] Permissions-Policy configured
+
+### 5.3 CORS (if applicable)
+- [ ] CORS not enabled (or restricted to specific origins)
+- [ ] Credentials not allowed cross-origin
+
+---
+
+## 6. Error Handling & Logging
+
+### 6.1 Error Messages
+- [ ] Stack traces not exposed to users in production
+- [ ] Error messages don't reveal sensitive paths or config
+- [ ] Failed login doesn't reveal if username exists
+
+### 6.2 Logging
+- [ ] Passwords never logged
+- [ ] Channel keys never logged
+- [ ] Passphrases never logged
+- [ ] Log files have appropriate permissions
+- [ ] Sensitive operations logged for audit trail (optional)
+
+---
+
+## 7. Dependency Security
+
+### 7.1 Python Dependencies
+- [ ] All dependencies pinned to specific versions
+- [ ] No known vulnerabilities in dependencies (run `pip-audit` or `safety`)
+- [ ] Dependencies from trusted sources only (PyPI)
+
+### 7.2 Frontend Dependencies
+- [ ] All JS/CSS served locally (air-gap ready)
+- [ ] No CDN dependencies
+- [ ] Bootstrap and libraries are official releases
+- [ ] Subresource integrity considered for any external loads
+
+---
+
+## 8. Deployment Security
+
+### 8.1 File Permissions
+- [ ] Database file not world-readable (600 or 640)
+- [ ] SSL certificates/keys not world-readable
+- [ ] Config files with secrets protected
+- [ ] Instance directory not in web root
+
+### 8.2 Docker Deployment
+- [ ] Container runs as non-root user
+- [ ] No unnecessary capabilities
+- [ ] Resource limits configured
+- [ ] Health checks don't expose sensitive info
+
+### 8.3 Raspberry Pi Deployment
+- [ ] Default passwords changed
+- [ ] SSH key-only authentication (recommended)
+- [ ] Unnecessary services disabled
+- [ ] Firewall configured (UFW/iptables)
+
+---
+
+## 9. Air-Gap Specific Considerations
+
+### 9.1 Network Isolation
+- [ ] Document expected network topology
+- [ ] No phone-home or telemetry
+- [ ] No external API calls
+- [ ] Works fully offline after deployment
+
+### 9.2 Key Distribution
+- [ ] QR code export for channel keys (offline transfer)
+- [ ] Print sheet for physical key backup
+- [ ] No cloud sync or external key servers
+
+### 9.3 Updates
+- [ ] Document offline update procedure
+- [ ] Signed releases (future consideration)
+- [ ] Checksum verification for downloads
+
+---
+
+## 10. Penetration Testing Checklist
+
+### 10.1 Authentication Attacks
+- [ ] Brute force login (note: no rate limiting by design)
+- [ ] Session fixation
+- [ ] Session hijacking
+- [ ] Password reset flow abuse
+
+### 10.2 Injection Attacks
+- [ ] SQL injection on all inputs
+- [ ] XSS (stored, reflected, DOM-based)
+- [ ] Command injection
+- [ ] Path traversal
+- [ ] SSTI (Server-Side Template Injection)
+
+### 10.3 Business Logic
+- [ ] Access control bypass
+- [ ] IDOR (Insecure Direct Object Reference)
+- [ ] Race conditions
+- [ ] Integer overflow in capacity calculations
+
+### 10.4 Cryptographic Attacks
+- [ ] Known-plaintext attacks on stego output
+- [ ] Timing attacks on password verification
+- [ ] Padding oracle attacks
+- [ ] Key reuse vulnerabilities
+
+---
+
+## Tools for Automated Testing
+
+```bash
+# Dependency vulnerability scan
+pip-audit
+safety check
+
+# Static analysis
+bandit -r stegasoo/ frontends/
+
+# Web security scan (if exposed)
+nikto -h https://localhost:5000
+OWASP ZAP (manual)
+
+# SSL/TLS configuration
+testssl.sh https://localhost:5000
+
+# Python code quality
+ruff check .
+mypy stegasoo/
+```
+
+---
+
+## Audit Schedule
+
+| Phase | Focus Area | Priority |
+|-------|-----------|----------|
+| Pre-release | Crypto implementation, auth flow | Critical |
+| Post-release | Dependency scan, static analysis | High |
+| Quarterly | Full penetration test | Medium |
+| Ongoing | CVE monitoring for dependencies | High |
+
+---
+
+## Notes
+
+- This plan assumes **trusted users on a private network** as the primary deployment model
+- Internet-facing deployments should add rate limiting, fail2ban, and reverse proxy hardening
+- For high-security deployments, consider external security audit by professionals
+
+---
+
+*Last updated: 2026-01-07*

UNDER_THE_HOOD.md

@@ -0,0 +1,818 @@
+# Stegasoo Technical Deep Dive: Encoding & Decoding
+
+A detailed breakdown of how Stegasoo's LSB and DCT steganography modes work under the hood.
+
+**Version 4.1** - Updated for channel keys and deployment isolation
+
+---
+
+## Table of Contents
+
+1. [High-Level Overview](#high-level-overview)
+2. [The Encoding Pipeline](#the-encoding-pipeline)
+3. [The Decoding Pipeline](#the-decoding-pipeline)
+4. [LSB Mode Deep Dive](#lsb-mode-deep-dive)
+5. [DCT Mode Deep Dive](#dct-mode-deep-dive)
+6. [Comparison Table](#comparison-table)
+7. [Security Considerations](#security-considerations)
+
+---
+
+## High-Level Overview
+
+```
+┌─────────────────────────────────────────────────────────────────────────────┐
+│                           STEGASOO ARCHITECTURE (v4.1)                      │
+├─────────────────────────────────────────────────────────────────────────────┤
+│                                                                             │
+│   INPUTS                    PROCESSING                      OUTPUT          │
+│   ───────                   ──────────                      ──────          │
+│                                                                             │
+│   Reference Photo ─┐                                                        │
+│   Passphrase ──────┼──► Argon2id KDF ──► AES-256 Key                        │
+│   PIN/RSA Key ─────┤                           │                            │
+│   Channel Key ─────┘  (v4.1)                   ▼                            │
+│   Message/File ────────────────────────► AES-256-GCM ──► Ciphertext         │
+│                                          Encryption            │            │
+│                                                                ▼            │
+│   Carrier Image ───────────────────────────────────────► Embedding ─► Stego │
+│                                                          (LSB/DCT)    Image │
+│                                                                             │
+└─────────────────────────────────────────────────────────────────────────────┘
+```
+
+### v4.0 Changes
+
+| Change | v3.x | v4.0 |
+|--------|------|------|
+| Authentication | day_phrase + date | passphrase (no date) |
+| Default words | 3 | 4 |
+| Header size | 75 bytes | 65 bytes (no date field) |
+| Python support | 3.10+ | 3.10-3.12 only |
+
+### v4.1 Changes
+
+| Change | v4.0 | v4.1 |
+|--------|------|------|
+| Channel keys | None | 32-byte deployment isolation |
+| Key derivation | passphrase + ref + pin | passphrase + ref + pin + channel |
+| Web auth | Session-based | Session + admin/user roles |
+| Raspberry Pi | Manual setup | First-boot wizard with gum |
+| Docker | Basic | Production-ready compose |
+
+**Channel Keys** provide deployment isolation - messages encoded on one Stegasoo instance cannot be decoded by another instance with a different channel key, even with the same passphrase/PIN/reference photo.
+
+### Module Responsibilities
+
+| Module | File | Purpose |
+|--------|------|---------|
+| **Crypto** | `crypto.py` | Key derivation (Argon2id), AES-256-GCM encryption/decryption |
+| **Channel** | `channel.py` | Channel key management, deployment isolation (v4.1) |
+| **Steganography** | `steganography.py` | LSB pixel manipulation, capacity calculation |
+| **DCT Steganography** | `dct_steganography.py` | Frequency-domain embedding, jpegio integration |
+| **Compression** | `compression.py` | Optional LZ4 compression of payload |
+| **Validation** | `validation.py` | Input validation, size limits |
+| **Utils** | `utils.py` | Image hashing, format detection |
+
+---
+
+## The Encoding Pipeline
+
+### Step 1: Input Collection & Validation
+
+```python
+# validation.py
+def validate_encode_inputs(reference_photo, carrier, message, passphrase, pin, rsa_key):
+    # Check image dimensions (max 24 megapixels)
+    # Validate PIN format (6-9 digits)
+    # Validate passphrase (3-12 words from BIP-39)
+    # Check payload size vs carrier capacity
+    # Ensure reference != carrier (security)
+```
+
+### Step 2: Reference Photo Processing
+
+```python
+# utils.py
+def get_image_hash(image_bytes: bytes) -> bytes:
+    """
+    Generate deterministic hash from reference photo.
+    This is the 'something you have' factor.
+    """
+    # Resize to 256x256 (normalize different resolutions)
+    # Convert to grayscale (normalize color variations)
+    # Apply slight blur (reduce JPEG artifact sensitivity)
+    # SHA-256 hash of processed pixels
+    return hashlib.sha256(processed_pixels).digest()  # 32 bytes
+```
+
+**Why process the image?** Minor variations (JPEG recompression, slight crops) in the reference photo between sender and receiver would produce different hashes, breaking decryption. The preprocessing makes the hash more resilient.
+
+### Step 3: Key Derivation (Argon2id)
+
+```python
+# crypto.py
+def derive_key(reference_hash: bytes, passphrase: str, pin: str, 
+               rsa_signature: bytes = None) -> bytes:
+    """
+    Combine all authentication factors into one AES key.
+    v4.0: No date parameter - simplified authentication.
+    """
+    # Concatenate all factors
+    key_material = reference_hash + passphrase.encode() + pin.encode()
+    
+    if rsa_signature:
+        key_material += rsa_signature
+    
+    # Argon2id parameters (memory-hard to resist GPU attacks)
+    # - Memory: 256 MB
+    # - Iterations: 4
+    # - Parallelism: 4
+    # - Output: 32 bytes (256 bits)
+    
+    key = argon2.hash_password_raw(
+        password=key_material,
+        salt=random_salt,  # 16 bytes, stored with ciphertext
+        time_cost=4,
+        memory_cost=262144,  # 256 MB
+        parallelism=4,
+        hash_len=32,
+        type=argon2.Type.ID
+    )
+    return key  # 32-byte AES-256 key
+```
+
+**Why Argon2id?**
+- **Memory-hard**: Requires 256MB RAM per attempt, defeating GPU/ASIC attacks
+- **Time-hard**: ~2-3 seconds per derivation
+- **Side-channel resistant**: ID variant protects against timing attacks
+
+### Step 4: Payload Preparation
+
+```python
+# compression.py (optional)
+def prepare_payload(data: bytes, filename: str = None) -> bytes:
+    """
+    Prepare the payload with metadata header.
+    """
+    # Header format (variable length):
+    # [1 byte]  - Flags (compression, file mode, etc.)
+    # [4 bytes] - Original data length (big-endian)
+    # [2 bytes] - Filename length (if file mode)
+    # [N bytes] - Filename (if file mode)
+    # [N bytes] - Data (possibly compressed)
+    
+    header = struct.pack('>BI', flags, len(data))
+    
+    if filename:
+        header += struct.pack('>H', len(filename)) + filename.encode()
+    
+    # Optional LZ4 compression
+    if should_compress(data):
+        data = lz4.frame.compress(data)
+        flags |= FLAG_COMPRESSED
+    
+    return header + data
+```
+
+### Step 5: AES-256-GCM Encryption
+
+```python
+# crypto.py
+def encrypt(plaintext: bytes, key: bytes) -> bytes:
+    """
+    Encrypt payload with AES-256-GCM.
+    Returns: salt + nonce + ciphertext + tag
+    """
+    salt = os.urandom(16)       # Random salt for key derivation
+    nonce = os.urandom(12)      # Random nonce for GCM
+    
+    cipher = AES.new(key, AES.MODE_GCM, nonce=nonce)
+    ciphertext, tag = cipher.encrypt_and_digest(plaintext)
+    
+    # Final encrypted blob:
+    # [16 bytes] Salt
+    # [12 bytes] Nonce  
+    # [16 bytes] Auth Tag
+    # [N bytes]  Ciphertext
+    
+    return salt + nonce + tag + ciphertext
+```
+
+**Why GCM?**
+- **Authenticated encryption**: Detects tampering
+- **No padding oracle**: Stream cipher mode
+- **Built-in integrity**: 128-bit authentication tag
+
+### Step 6: Stego Header Construction
+
+```python
+# steganography.py / dct_steganography.py
+def build_stego_header(encrypted_data: bytes, mode: str) -> bytes:
+    """
+    Build the header that precedes embedded data.
+    v4.0: Simplified header (no date field)
+    """
+    # Header format:
+    # [4 bytes]  - Magic number: "STGO" (v4)
+    # [1 byte]   - Version (0x04)
+    # [1 byte]   - Mode (0x01=LSB, 0x02=DCT)
+    # [4 bytes]  - Payload length
+    # [N bytes]  - Encrypted payload
+    
+    if mode == 'lsb':
+        magic = b'STGO\x04\x01'  # v4, mode 1 (LSB)
+    else:
+        magic = b'STGO\x04\x02'  # v4, mode 2 (DCT)
+    
+    length = struct.pack('>I', len(encrypted_data))
+    
+    return magic + length + encrypted_data
+```
+
+### Step 7: Embedding (Mode-Specific)
+
+This is where LSB and DCT diverge. See detailed sections below.
+
+---
+
+## The Decoding Pipeline
+
+### Step 1: Mode Detection
+
+```python
+def detect_mode(stego_image: bytes) -> str:
+    """
+    Detect which embedding mode was used.
+    Checks format and magic bytes.
+    """
+    img = Image.open(io.BytesIO(stego_image))
+    
+    # JPEG images with JPGS magic = DCT mode with jpegio
+    if img.format == 'JPEG':
+        # Check for jpegio magic
+        return 'dct'
+    
+    # PNG/BMP: Read first few bytes from LSB
+    # Check for STGO or DCTS magic
+    magic = extract_header_lsb(stego_image, 6)
+    
+    if magic.startswith(b'STGO'):
+        mode_byte = magic[5]
+        return 'lsb' if mode_byte == 0x01 else 'dct'
+    elif magic.startswith(b'DCTS'):
+        return 'dct'
+    
+    return 'lsb'  # Default fallback
+```
+
+### Step 2: Key Re-derivation
+
+```python
+# Same process as encoding
+def derive_key_for_decode(reference_hash, passphrase, pin, rsa_signature=None):
+    # Must use SAME parameters as encoding
+    # No date parameter in v4.0
+    return derive_key(reference_hash, passphrase, pin, rsa_signature)
+```
+
+### Step 3: Data Extraction
+
+```python
+def extract_data(stego_image: bytes, mode: str) -> bytes:
+    """
+    Extract raw bytes from stego image.
+    Mode-specific extraction.
+    """
+    if mode == 'dct':
+        return extract_from_dct(stego_image, pixel_key)
+    else:
+        return extract_from_lsb(stego_image, pixel_key)
+```
+
+### Step 4: Decryption & Payload Recovery
+
+```python
+def decrypt_and_recover(encrypted_data: bytes, key: bytes) -> Union[str, bytes]:
+    """
+    Decrypt and extract original message/file.
+    """
+    # Parse header
+    salt = encrypted_data[:16]
+    nonce = encrypted_data[16:28]
+    tag = encrypted_data[28:44]
+    ciphertext = encrypted_data[44:]
+    
+    # Decrypt
+    cipher = AES.new(key, AES.MODE_GCM, nonce=nonce)
+    plaintext = cipher.decrypt_and_verify(ciphertext, tag)
+    
+    # Decompress if needed
+    if plaintext[0] & FLAG_COMPRESSED:
+        plaintext = lz4.frame.decompress(plaintext[5:])
+    
+    # Extract payload
+    return parse_payload(plaintext)
+```
+
+---
+
+## LSB Mode Deep Dive
+
+### How LSB Embedding Works
+
+LSB (Least Significant Bit) embedding modifies the lowest bit of each color channel in selected pixels.
+
+```
+Original Pixel (RGB):
+  R: 11010110  G: 01101001  B: 10110100
+              ↓         ↓         ↓
+              └─────────┴─────────┘
+                 3 bits available
+
+After embedding "101":
+  R: 1101011[1]  G: 0110100[0]  B: 1011010[1]
+              ↑         ↑         ↑
+           modified  modified  modified
+```
+
+### Pixel Selection Algorithm
+
+```python
+def select_pixels(carrier_shape, num_bits, seed: bytes) -> List[Tuple[int, int, int]]:
+    """
+    Generate pseudo-random pixel coordinates.
+    Distributes modifications across entire image.
+    """
+    height, width, channels = carrier_shape
+    total_positions = height * width * 3  # RGB channels
+    
+    # Use seed to generate reproducible random order
+    rng = np.random.RandomState(int.from_bytes(seed[:4], 'big'))
+    all_positions = np.arange(total_positions)
+    rng.shuffle(all_positions)
+    
+    # Convert flat indices to (y, x, channel)
+    selected = []
+    for idx in all_positions[:num_bits]:
+        y = idx // (width * 3)
+        x = (idx % (width * 3)) // 3
+        c = idx % 3
+        selected.append((y, x, c))
+    
+    return selected
+```
+
+### Embedding Process
+
+```python
+def embed_lsb(carrier: np.ndarray, data: bytes, seed: bytes) -> np.ndarray:
+    """
+    Embed data using LSB substitution.
+    """
+    bits = bytes_to_bits(data)
+    positions = select_pixels(carrier.shape, len(bits), seed)
+    
+    stego = carrier.copy()
+    for i, (y, x, c) in enumerate(positions):
+        # Clear LSB and set to our bit
+        stego[y, x, c] = (stego[y, x, c] & 0xFE) | bits[i]
+    
+    return stego
+```
+
+### Capacity Calculation
+
+```python
+def calculate_lsb_capacity(width: int, height: int) -> int:
+    """
+    Calculate maximum payload size for LSB mode.
+    """
+    total_bits = width * height * 3  # 3 bits per pixel (RGB)
+    header_bits = 10 * 8  # 10-byte stego header
+    available_bits = total_bits - header_bits
+    
+    return available_bits // 8  # Convert to bytes
+```
+
+**Example capacities:**
+- 1920×1080: ~770 KB
+- 4000×3000: ~4.5 MB
+- 800×600: ~180 KB
+
+---
+
+## DCT Mode Deep Dive
+
+### How DCT Embedding Works
+
+DCT (Discrete Cosine Transform) mode embeds data in the frequency-domain coefficients, making it resilient to JPEG compression.
+
+```
+Image Block (8×8 pixels)
+         ↓
+    DCT Transform
+         ↓
+DCT Coefficients (8×8)
+┌────────────────────┐
+│ DC  AC₁ AC₂ AC₃ ...│  ← Lower frequencies (top-left)
+│ AC₄ AC₅ AC₆ ...    │
+│ ...        ...     │  ← Mid frequencies (embed here)
+│ ...            ... │
+│           AC₆₃ ────│  ← Higher frequencies (bottom-right)
+└────────────────────┘
+         ↓
+   Modify select ACs
+         ↓
+    IDCT Transform
+         ↓
+Modified Image Block
+```
+
+### Coefficient Selection
+
+```python
+# dct_steganography.py
+EMBED_POSITIONS = [
+    (0, 1), (1, 0), (2, 0), (1, 1), (0, 2), (0, 3), (1, 2), (2, 1), (3, 0),
+    (4, 0), (3, 1), (2, 2), (1, 3), (0, 4), (0, 5), (1, 4), (2, 3), (3, 2),
+    (4, 1), (5, 0), (5, 1), (4, 2), (3, 3), (2, 4), (1, 5), (0, 6), (0, 7),
+    (1, 6), (2, 5), (3, 4), (4, 3), (5, 2), (6, 1), (7, 0),
+]
+
+# Use positions 4-20 (mid-frequency, good balance)
+DEFAULT_EMBED_POSITIONS = EMBED_POSITIONS[4:20]  # 16 positions per block
+```
+
+**Why mid-frequency?**
+- DC coefficient (0,0): Too visible, contains brightness
+- Low AC: Visible changes, but survives compression
+- Mid AC: Best balance of invisibility + resilience
+- High AC: Invisible but destroyed by compression
+
+### Block Processing
+
+```python
+def embed_in_block(block: np.ndarray, bits: List[int]) -> np.ndarray:
+    """
+    Embed bits in a single 8×8 block.
+    """
+    # Forward DCT
+    dct_block = dct_2d(block)
+    
+    # Embed using quantization
+    for i, pos in enumerate(DEFAULT_EMBED_POSITIONS):
+        if i >= len(bits):
+            break
+        
+        coef = dct_block[pos[0], pos[1]]
+        # Quantize and modify LSB
+        quantized = round(coef / QUANT_STEP)
+        if (quantized % 2) != bits[i]:
+            quantized += 1 if coef > 0 else -1
+        dct_block[pos[0], pos[1]] = quantized * QUANT_STEP
+    
+    # Inverse DCT
+    return idct_2d(dct_block)
+```
+
+### jpegio Integration (Native JPEG Output)
+
+```python
+def embed_jpegio(data: bytes, carrier_jpeg: bytes, seed: bytes) -> bytes:
+    """
+    Embed directly in JPEG DCT coefficients using jpegio.
+    Preserves JPEG structure perfectly.
+    
+    Note: Requires Python 3.12 or earlier (jpegio incompatible with 3.13)
+    """
+    import jpegio as jio
+    
+    # Normalize problematic JPEGs (quality=100 causes crashes)
+    carrier_jpeg = normalize_jpeg_for_jpegio(carrier_jpeg)
+    
+    # Read existing JPEG coefficients
+    jpeg = jio.read(temp_file_from_bytes(carrier_jpeg))
+    coef_array = jpeg.coef_arrays[0]  # Y channel
+    
+    # Find usable coefficients (magnitude >= 2, non-DC)
+    positions = get_usable_positions(coef_array)
+    order = generate_order(len(positions), seed)
+    
+    # Embed by modifying coefficient LSBs
+    bits = bytes_to_bits(data)
+    for i, pos_idx in enumerate(order[:len(bits)]):
+        row, col = positions[pos_idx]
+        coef = coef_array[row, col]
+        
+        if (coef & 1) != bits[i]:
+            # Flip LSB while preserving sign
+            if coef > 0:
+                coef_array[row, col] = coef - 1 if (coef & 1) else coef + 1
+            else:
+                coef_array[row, col] = coef + 1 if (coef & 1) else coef - 1
+    
+    # Write modified JPEG
+    jio.write(jpeg, output_path)
+    return read_bytes(output_path)
+```
+
+### JPEG Normalization (v4.0)
+
+```python
+def normalize_jpeg_for_jpegio(image_data: bytes) -> bytes:
+    """
+    Normalize problematic JPEGs before jpegio processing.
+    
+    JPEGs with quality=100 have quantization tables with all values=1,
+    which causes jpegio to crash. Re-save at quality 95.
+    """
+    img = Image.open(io.BytesIO(image_data))
+    
+    if img.format != 'JPEG':
+        return image_data
+    
+    # Check if any quantization table has all values <= 1
+    needs_normalization = False
+    if hasattr(img, 'quantization'):
+        for table in img.quantization.values():
+            if max(table) <= 1:
+                needs_normalization = True
+                break
+    
+    if not needs_normalization:
+        return image_data
+    
+    # Re-save at safe quality
+    buffer = io.BytesIO()
+    img.save(buffer, format='JPEG', quality=95, subsampling=0)
+    return buffer.getvalue()
+```
+
+### DCT Capacity Calculation
+
+```python
+def calculate_dct_capacity(width: int, height: int) -> int:
+    """
+    Calculate maximum payload for DCT mode.
+    """
+    blocks_x = width // 8
+    blocks_y = height // 8
+    total_blocks = blocks_x * blocks_y
+    
+    bits_per_block = len(DEFAULT_EMBED_POSITIONS)  # 16
+    total_bits = total_blocks * bits_per_block
+    
+    header_bits = 10 * 8  # Stego header
+    available_bits = total_bits - header_bits
+    
+    return available_bits // 8
+```
+
+**Example capacities:**
+- 1920×1080: ~64 KB
+- 4000×3000: ~375 KB
+- 800×600: ~14 KB
+
+### Why DCT Survives JPEG Compression
+
+```
+Original JPEG:    Stego JPEG:      Re-compressed:
+                                   
+DCT coefficients  Modified DCT     Coefficients 
+preserved in      coefficients     re-quantized
+file format       still valid      
+      │                 │                │
+      ▼                 ▼                ▼
+   [DCT] ──────►  [Modified] ──────►  [Still
+   [coefs]        [DCT coefs]         Modified!]
+                                   
+LSB changes survive because they're embedded in 
+the frequency domain, not spatial pixel values.
+```
+
+### DCT Advantages
+
+| Advantage | Description |
+|-----------|-------------|
+| **JPEG resilient** | Survives social media upload |
+| **Better steganalysis resistance** | Harder to detect statistically |
+| **Natural-looking output** | JPEG artifacts expected |
+
+### DCT Limitations
+
+| Limitation | Description |
+|------------|-------------|
+| **Lower capacity** | ~10% of LSB capacity |
+| **Slower processing** | DCT transforms are compute-intensive |
+| **Requires scipy/jpegio** | Additional dependencies |
+| **Quality-dependent** | Heavy recompression still degrades data |
+| **Python version** | jpegio requires Python 3.12 or earlier |
+
+---
+
+## Comparison Table
+
+| Aspect | LSB Mode | DCT Mode |
+|--------|----------|----------|
+| **Capacity (1080p)** | ~770 KB | ~50 KB |
+| **Output Format** | PNG only | PNG or JPEG |
+| **Survives JPEG** | ❌ No | ✅ Yes |
+| **Social Media** | ❌ Broken | ✅ Works |
+| **Processing Speed** | Fast (~0.5s) | Slower (~2s) |
+| **Dependencies** | Pillow, NumPy | + scipy, jpegio |
+| **Color Support** | Full color | Color or Grayscale |
+| **Detection Resistance** | Moderate | Better |
+| **Best For** | Email, cloud storage | Social media, messaging |
+| **Max Tested Image** | 14MB+ | 14MB+ |
+
+---
+
+## Security Considerations
+
+### What Makes Stegasoo Secure?
+
+```
+MULTI-FACTOR AUTHENTICATION (v4.0)
+──────────────────────────────────
+Factor 1: Reference Photo    ─┐
+  • 80-256 bits entropy       │
+  • "Something you have"      │
+                              ├──► Combined entropy: 133-400+ bits
+Factor 2: Passphrase          │    (Beyond brute force)
+  • 43-132 bits entropy       │
+  • "Something you know"      │
+  • 4 words default (v4.0)    │
+                              │
+Factor 3: PIN                 │
+  • 20-30 bits entropy        │
+  • "Something you know"      │
+                              │
+Factor 4: RSA Key (optional) ─┘
+  • 112-128 bits entropy
+  • "Something you have"
+
+MEMORY-HARD KDF (Argon2id)
+──────────────────────────
+• 256 MB RAM per attempt
+• ~3 seconds per attempt
+• Defeats GPU/ASIC attacks
+• 10 attempts = 30 seconds, not 0.00001 seconds
+
+AUTHENTICATED ENCRYPTION (AES-256-GCM)
+──────────────────────────────────────
+• 256-bit key (unbreakable)
+• Built-in integrity check
+• Detects tampering
+• No padding oracle attacks
+```
+
+### Attack Surface Analysis
+
+| Attack | LSB Protection | DCT Protection |
+|--------|----------------|----------------|
+| Visual inspection | ✅ Imperceptible | ✅ Imperceptible |
+| File size analysis | ⚠️ PNG larger | ✅ JPEG natural |
+| Histogram analysis | ⚠️ Slight anomalies | ✅ Normal JPEG |
+| Chi-square attack | ⚠️ Detectable at scale | ✅ Resistant |
+| RS steganalysis | ⚠️ Detectable | ✅ Resistant |
+| JPEG recompression | ❌ Destroyed | ✅ Survives |
+
+### Threat Model
+
+**Stegasoo protects against:**
+- ✅ Passive eavesdropping
+- ✅ Casual inspection of images
+- ✅ Basic forensic analysis
+- ✅ Brute force key guessing
+- ✅ JPEG recompression (DCT mode)
+
+**Stegasoo does NOT protect against:**
+- ⚠️ Targeted forensic analysis with original carrier
+- ⚠️ Nation-state level steganalysis
+- ⚠️ Rubber hose cryptanalysis (coercion)
+- ⚠️ Compromise of reference photo or credentials
+
+---
+
+## Data Flow Diagrams
+
+### Complete Encode Flow (v4.0)
+
+```
+┌──────────────────────────────────────────────────────────────────────────────┐
+│                              ENCODE FLOW (v4.0)                              │
+└──────────────────────────────────────────────────────────────────────────────┘
+
+User Inputs                    Processing                           Output
+───────────                    ──────────                           ──────
+
+Reference Photo ──────┐
+                      ├──► get_image_hash() ──► ref_hash (32 bytes)
+                      │         │
+Passphrase ───────────┤         ▼
+                      ├──► derive_key() ──────► aes_key (32 bytes)
+PIN ──────────────────┤    (Argon2id)               │
+                      │                             │
+RSA Key (optional) ───┘                             │
+                                                    ▼
+Message/File ──────────► prepare_payload() ──► encrypt() ──► ciphertext
+                         (compress, header)    (AES-GCM)         │
+                                                                 │
+                                                                 ▼
+                                                    build_stego_header()
+                                                    (magic + length)
+                                                                 │
+Carrier Image ─────────────────────────────────────────►  embed()
+                                                          │     │
+                                              ┌───────────┴─────┴────────────┐
+                                              │                              │
+                                           LSB Mode                       DCT Mode
+                                              │                              │
+                                              ▼                              ▼
+                                         embed_lsb()                    embed_in_dct()
+                                         (pixel LSBs)                 (DCT coefficients)
+                                              │                              │
+                                              ▼                              ▼
+                                          PNG Output                    PNG or JPEG
+                                              │                              │
+                                              └──────────┬───────────────────┘
+                                                         │
+                                                         ▼
+                                                   Stego Image
+                                                   (downloadable)
+```
+
+### Complete Decode Flow (v4.0)
+
+```
+┌──────────────────────────────────────────────────────────────────────────────┐
+│                              DECODE FLOW (v4.0)                               │
+└──────────────────────────────────────────────────────────────────────────────┘
+
+User Inputs                    Processing                           Output
+───────────                    ──────────                           ──────
+
+Reference Photo ──────┐
+                      ├──► get_image_hash() ──► ref_hash (32 bytes)
+                      │         │
+Passphrase ───────────┤         ▼
+                      ├──► derive_key() ──────► aes_key (32 bytes)
+PIN ──────────────────┤    (Argon2id)               │
+                      │    (MUST MATCH!)            │
+RSA Key (optional) ───┘                             │
+                                                    │
+                                                    ▼
+Stego Image ──────────► detect_mode() ──────► extract()
+                        (read magic)          │     │
+                              │     ┌─────────┴─────┴──────────┐
+                              │     │                          │
+                              │  LSB Mode                DCT Mode
+                              │     │                          │
+                              │     ▼                          ▼
+                              │  extract_lsb()          extract_from_dct()
+                              │     │                          │
+                              │     └────────┬─────────────────┘
+                              │              │
+                              │              ▼
+                              │     parse_stego_header()
+                              │     (magic, length)
+                              │              │
+                              │              ▼
+                              └────────► decrypt()
+                                         (AES-GCM)
+                                              │
+                                              ▼
+                                     decompress()
+                                     (if compressed)
+                                              │
+                                              ▼
+                                     extract_payload()
+                                     (handle file/text)
+                                              │
+                                              ▼
+                                     Original Message
+                                     or File
+```
+
+---
+
+## Summary
+
+**LSB Mode** is simpler, faster, and higher capacity - perfect for controlled channels where images won't be modified.
+
+**DCT Mode** is more complex but survives real-world image processing - essential for social media and messaging apps.
+
+Both modes share the same cryptographic foundation (Argon2id + AES-256-GCM) and multi-factor authentication, ensuring security regardless of embedding method.
+
+The choice comes down to your use case:
+- **Public platform?** → DCT (maximum compatibility)
+- **Private channel?** → LSB (maximum capacity)
+
+### v4.0 Simplifications
+
+- **No more date tracking** - encode/decode anytime without remembering dates
+- **Single passphrase** - no daily rotation to manage
+- **Default 4 words** - better security out of the box
+- **JPEG normalization** - handles quality=100 images automatically
+- **Large image support** - tested with 14MB+ images

WISHLIST-4.2.md

@@ -0,0 +1,42 @@
+# Stegasoo v4.2 Wishlist
+
+Blue sky ideas for future development. No timeline - just capturing thoughts.
+
+---
+
+## Performance
+
+### GPU-Accelerated DCT Encoding/Decoding
+- **Idea**: Leverage GPU for JPEG DCT coefficient manipulation
+- **Potential Approaches**:
+  - OpenCL/CUDA for parallel DCT operations
+  - Raspberry Pi VideoCore IV/VI GPU compute
+  - WebGPU for browser-based acceleration
+- **Challenges**:
+  - jpegio library is CPU-bound (C extension)
+  - Would need custom DCT implementation
+  - Memory transfer overhead may negate gains for small images
+- **Research**:
+  - libjpeg-turbo uses SIMD but not GPU
+  - nvJPEG (NVIDIA) does GPU-accelerated JPEG
+  - Could potentially use GPU for the embedding math, not JPEG decode
+
+---
+
+## Features
+
+(Add ideas here)
+
+---
+
+## Infrastructure
+
+(Add ideas here)
+
+---
+
+## Notes
+
+- This is a living document - add ideas anytime
+- Not all ideas will be implemented
+- Feasibility research needed before committing to roadmap

docker-compose.yml

@@ -1,62 +0,0 @@
-version: '3.8'
-
-services:
-  # ============================================================================
-  # Web UI (Flask)
-  # ============================================================================
-  web:
-    build:
-      context: .
-      target: web
-    container_name: stegasoo-web
-    ports:
-      - "5000:5000"
-    environment:
-      - FLASK_ENV=production
-    restart: unless-stopped
-    deploy:
-      resources:
-        limits:
-          memory: 512M  # Argon2 needs 256MB per operation
-        reservations:
-          memory: 256M
-
-  # ============================================================================
-  # REST API (FastAPI)
-  # ============================================================================
-  api:
-    build:
-      context: .
-      target: api
-    container_name: stegasoo-api
-    ports:
-      - "8000:8000"
-    restart: unless-stopped
-    deploy:
-      resources:
-        limits:
-          memory: 512M
-        reservations:
-          memory: 256M
-
-  # ============================================================================
-  # Nginx Reverse Proxy (optional, for production)
-  # ============================================================================
-  # nginx:
-  #   image: nginx:alpine
-  #   container_name: stegasoo-nginx
-  #   ports:
-  #     - "80:80"
-  #     - "443:443"
-  #   volumes:
-  #     - ./nginx.conf:/etc/nginx/nginx.conf:ro
-  #     - ./certs:/etc/nginx/certs:ro
-  #   depends_on:
-  #     - web
-  #     - api
-  #   restart: unless-stopped
-
-# ============================================================================
-# Development overrides
-# ============================================================================
-# Use: docker-compose -f docker-compose.yml -f docker-compose.dev.yml up

docker/Dockerfile

@@ -0,0 +1,152 @@
+# Stegasoo Docker Image
+# Uses pre-built base image for fast rebuilds
+#
+# First time setup:
+#   docker build -f Dockerfile.base -t stegasoo-base:latest .
+#
+# Then build normally (fast!):
+#   docker-compose build
+#
+# Or if you don't have the base image, this falls back to building deps
+# (slow, but works)
+
+# ============================================================================
+# ARG to switch between base image and full build
+# ============================================================================
+ARG USE_BASE_IMAGE=true
+
+# ============================================================================
+# Base stage - use pre-built image if available
+# ============================================================================
+FROM stegasoo-base:latest AS base-prebuilt
+
+FROM python:3.12-slim AS base-full
+
+ENV PYTHONDONTWRITEBYTECODE=1
+ENV PYTHONUNBUFFERED=1
+ENV PIP_ROOT_USER_ACTION=ignore
+
+# Install system dependencies
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    gcc \
+    g++ \
+    libc-dev \
+    libffi-dev \
+    libzbar0 \
+    libjpeg-dev \
+    zlib1g-dev \
+    curl \
+    openssl \
+    && rm -rf /var/lib/apt/lists/*
+
+# Install ALL dependencies (slow path)
+RUN pip install --no-cache-dir \
+    cython numpy scipy>=1.10.0 jpegio>=0.2.0 \
+    argon2-cffi>=23.0.0 pillow>=10.0.0 cryptography>=41.0.0 \
+    reedsolo>=1.7.0 \
+    flask>=3.0.0 gunicorn>=21.0.0 \
+    fastapi>=0.100.0 "uvicorn[standard]>=0.20.0" python-multipart>=0.0.6 \
+    qrcode>=7.3.0 pyzbar>=0.1.9 click>=8.0.0 lz4>=4.0.0
+
+# ============================================================================
+# Select which base to use (default: prebuilt)
+# ============================================================================
+FROM base-prebuilt AS base
+
+# ============================================================================
+# Production stage - Web UI
+# ============================================================================
+FROM base AS web
+
+WORKDIR /app
+
+# Install runtime dependencies (curl for healthcheck, openssl for cert generation)
+USER root
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    curl openssl \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy application files (this is all that rebuilds normally!)
+COPY src/ src/
+COPY data/ data/
+COPY frontends/web/ frontends/web/
+
+# Create upload directory and instance directories (for volumes)
+# temp_files is for multi-worker temp file sharing
+RUN mkdir -p /tmp/stego_uploads /app/frontends/web/instance /app/frontends/web/certs /app/frontends/web/temp_files
+
+# Copy and set up entrypoint (before switching to non-root user)
+COPY frontends/web/docker-entrypoint.sh /app/frontends/web/
+RUN chmod +x /app/frontends/web/docker-entrypoint.sh
+
+# Create non-root user
+RUN useradd -m -u 1000 stego && chown -R stego:stego /app /tmp/stego_uploads
+USER stego
+
+# Set Python path
+ENV PYTHONPATH=/app/src
+
+# Expose port
+EXPOSE 5000
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=10s --retries=3 \
+    CMD curl -fsk https://localhost:5000/ || curl -fs http://localhost:5000/ || exit 1
+
+# Run with entrypoint (handles HTTPS/HTTP mode)
+WORKDIR /app/frontends/web
+ENTRYPOINT ["/app/frontends/web/docker-entrypoint.sh"]
+
+# ============================================================================
+# API stage - REST API
+# ============================================================================
+FROM base AS api
+
+WORKDIR /app
+
+# Copy application files
+COPY src/ src/
+COPY data/ data/
+COPY frontends/api/ frontends/api/
+
+# Create non-root user
+RUN useradd -m -u 1000 stego && chown -R stego:stego /app
+USER stego
+
+# Set Python path
+ENV PYTHONPATH=/app/src
+
+# Expose port
+EXPOSE 8000
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+    CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8000/')" || exit 1
+
+# Run with uvicorn
+WORKDIR /app/frontends/api
+CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]
+
+# ============================================================================
+# CLI stage - Command line tool
+# ============================================================================
+FROM base AS cli
+
+WORKDIR /app
+
+# Copy application files
+COPY src/ src/
+COPY data/ data/
+COPY frontends/cli/ frontends/cli/
+
+# Create non-root user
+RUN useradd -m -u 1000 stego && chown -R stego:stego /app
+USER stego
+
+# Set Python path
+ENV PYTHONPATH=/app/src
+
+# Default to help
+WORKDIR /app/frontends/cli
+ENTRYPOINT ["python", "main.py"]
+CMD ["--help"]

docker/Dockerfile.base

@@ -0,0 +1,56 @@
+# Stegasoo Base Image
+# Contains all slow-to-compile dependencies (jpegio, scipy, argon2)
+# Build once: docker build -f Dockerfile.base -t stegasoo-base:latest .
+# Push to registry for team use: docker push yourregistry/stegasoo-base:latest
+
+FROM python:3.12-slim
+
+# Set environment variables
+ENV PYTHONDONTWRITEBYTECODE=1
+ENV PYTHONUNBUFFERED=1
+ENV PIP_ROOT_USER_ACTION=ignore
+
+# Install system dependencies
+# NOTE: g++ is required for jpegio C++ compilation
+# NOTE: libjpeg-dev is required for jpegio
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    gcc \
+    g++ \
+    libc-dev \
+    libffi-dev \
+    libzbar0 \
+    libjpeg-dev \
+    zlib1g-dev \
+    && rm -rf /var/lib/apt/lists/*
+
+# Install the slow-to-compile packages
+# These rarely change, so they get cached in this base image
+RUN pip install --no-cache-dir \
+    cython \
+    numpy \
+    scipy>=1.10.0 \
+    jpegio>=0.2.0 \
+    argon2-cffi>=23.0.0 \
+    pillow>=10.0.0 \
+    cryptography>=41.0.0 \
+    reedsolo>=1.7.0
+
+# Install web/api framework packages (also stable)
+RUN pip install --no-cache-dir \
+    flask>=3.0.0 \
+    gunicorn>=21.0.0 \
+    fastapi>=0.100.0 \
+    "uvicorn[standard]>=0.20.0" \
+    python-multipart>=0.0.6 \
+    qrcode>=7.3.0 \
+    pyzbar>=0.1.9 \
+    click>=8.0.0 \
+    lz4>=4.0.0
+
+# Verify key packages work
+RUN python -c "import jpegio; import scipy; import numpy; print('jpegio + scipy + numpy OK')"
+
+# Label for tracking
+LABEL org.opencontainers.image.title="Stegasoo Base"
+LABEL org.opencontainers.image.description="Pre-compiled dependencies for Stegasoo"
+LABEL org.opencontainers.image.version="4.0.0"

docker/docker-compose.yml

@@ -0,0 +1,64 @@
+# Shared environment variables
+x-common-env: &common-env
+  STEGASOO_CHANNEL_KEY: ${STEGASOO_CHANNEL_KEY:-}
+
+services:
+  # ============================================================================
+  # Web UI (Flask)
+  # ============================================================================
+  web:
+    build:
+      context: ..
+      dockerfile: docker/Dockerfile
+      target: web
+    container_name: stegasoo-web
+    ports:
+      - "5000:5000"
+    environment:
+      <<: *common-env
+      FLASK_ENV: production
+      # Authentication (v4.0.2)
+      STEGASOO_AUTH_ENABLED: ${STEGASOO_AUTH_ENABLED:-true}
+      # HTTPS enabled by default - generates self-signed cert if none provided
+      # To disable: STEGASOO_HTTPS_ENABLED=false docker-compose up
+      STEGASOO_HTTPS_ENABLED: ${STEGASOO_HTTPS_ENABLED:-true}
+      STEGASOO_HOSTNAME: ${STEGASOO_HOSTNAME:-localhost}
+    volumes:
+      # Persist auth database and SSL certs (v4.0.2)
+      - stegasoo-web-data:/app/frontends/web/instance
+      - stegasoo-web-certs:/app/frontends/web/certs
+    restart: unless-stopped
+    deploy:
+      resources:
+        limits:
+          memory: 2048M
+        reservations:
+          memory: 1024M
+
+  # ============================================================================
+  # REST API (FastAPI)
+  # ============================================================================
+  api:
+    build:
+      context: ..
+      dockerfile: docker/Dockerfile
+      target: api
+    container_name: stegasoo-api
+    ports:
+      - "8000:8000"
+    environment:
+      <<: *common-env
+    restart: unless-stopped
+    deploy:
+      resources:
+        limits:
+          memory: 2048M
+        reservations:
+          memory: 1024M
+
+# Named volumes for persistent data
+volumes:
+  stegasoo-web-data:
+    driver: local
+  stegasoo-web-certs:
+    driver: local

docs/DOCKER_QUICKSTART.md

@@ -0,0 +1,162 @@
+# Docker Quickstart
+
+Get Stegasoo running in Docker in under 5 minutes.
+
+## Build
+
+```bash
+# From project root:
+
+# Build web UI image
+sudo docker build -t stegasoo-web --target web -f docker/Dockerfile .
+
+# Or build all targets
+sudo docker build -t stegasoo-api --target api -f docker/Dockerfile .
+sudo docker build -t stegasoo-cli --target cli -f docker/Dockerfile .
+
+# Or use docker-compose
+sudo docker-compose -f docker/docker-compose.yml build
+```
+
+## Run (Basic)
+
+```bash
+# HTTP only, no auth
+sudo docker run -d \
+  -p 5000:5000 \
+  -e STEGASOO_AUTH_ENABLED=false \
+  --name stegasoo \
+  stegasoo-web
+```
+
+Visit http://localhost:5000
+
+## Run (Production)
+
+```bash
+# HTTPS + Auth + Channel Key
+sudo docker run -d \
+  -p 5000:5000 \
+  -e STEGASOO_AUTH_ENABLED=true \
+  -e STEGASOO_HTTPS_ENABLED=true \
+  -e STEGASOO_HOSTNAME=stegasoo.local \
+  -e STEGASOO_CHANNEL_KEY=ABCD-1234-EFGH-5678-IJKL-9012-MNOP-3456 \
+  -v stegasoo-data:/opt/stegasoo/frontends/web/instance \
+  -v stegasoo-certs:/opt/stegasoo/frontends/web/certs \
+  --name stegasoo \
+  stegasoo-web
+```
+
+Visit https://localhost:5000 (accept self-signed cert warning)
+
+## Environment Variables
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `STEGASOO_AUTH_ENABLED` | `true` | Require login |
+| `STEGASOO_HTTPS_ENABLED` | `false` | Enable HTTPS |
+| `STEGASOO_HOSTNAME` | `localhost` | Hostname for SSL cert |
+| `STEGASOO_CHANNEL_KEY` | *(none)* | Shared channel key (32 alphanumeric chars with dashes) |
+
+## Docker Compose
+
+Create `.env` file in project root:
+```bash
+STEGASOO_AUTH_ENABLED=true
+STEGASOO_HTTPS_ENABLED=true
+STEGASOO_HOSTNAME=stegasoo.local
+STEGASOO_CHANNEL_KEY=
+```
+
+Run:
+```bash
+sudo docker-compose -f docker/docker-compose.yml up -d web
+```
+
+## Custom SSL Certificates
+
+### Use Your Own Certs
+
+```bash
+# Stop container
+sudo docker stop stegasoo
+
+# Copy certs to volume
+sudo docker run --rm -v stegasoo-certs:/certs -v $(pwd):/src alpine \
+  sh -c "cp /src/your-cert.crt /certs/server.crt && cp /src/your-key.key /certs/server.key && chmod 600 /certs/server.key"
+
+# Start container
+sudo docker start stegasoo
+```
+
+### Use mkcert (Local Development)
+
+```bash
+# Install mkcert
+brew install mkcert  # macOS
+# or: sudo apt install mkcert  # Debian/Ubuntu
+
+# Create local CA and certs
+mkcert -install
+mkcert -cert-file server.crt -key-file server.key localhost 127.0.0.1 stegasoo.local
+
+# Copy to Docker volume (see above)
+```
+
+### Use Let's Encrypt (Public Server)
+
+```bash
+# Get cert
+sudo certbot certonly --standalone -d yourdomain.com
+
+# Copy to Docker volume
+sudo docker run --rm -v stegasoo-certs:/certs alpine \
+  sh -c "cp /etc/letsencrypt/live/yourdomain.com/fullchain.pem /certs/server.crt && \
+         cp /etc/letsencrypt/live/yourdomain.com/privkey.pem /certs/server.key && \
+         chmod 600 /certs/server.key"
+```
+
+## Volumes
+
+| Volume | Purpose |
+|--------|---------|
+| `stegasoo-data` | User database, settings |
+| `stegasoo-certs` | SSL certificates |
+
+## Smoke Test
+
+```bash
+# Check container logs
+sudo docker logs stegasoo
+
+# Test HTTP endpoint
+curl -k https://localhost:5000/health
+
+# Expected: {"status":"ok","version":"4.1.7",...}
+```
+
+## Troubleshooting
+
+**Container won't start:**
+```bash
+sudo docker logs stegasoo
+```
+
+**Out of memory:**
+```bash
+# Argon2 needs 256MB+ per operation
+sudo docker run --memory=768m ...
+```
+
+**Certificate errors:**
+```bash
+# Regenerate self-signed cert
+sudo docker exec stegasoo rm -rf /opt/stegasoo/frontends/web/certs/*
+sudo docker restart stegasoo
+```
+
+**Reset everything:**
+```bash
+sudo docker stop stegasoo && sudo docker rm stegasoo
+sudo docker volume rm stegasoo-data stegasoo-certs
+```

docs/TEMPLATES.md

@@ -0,0 +1,361 @@
+# Stegasoo Web Templates Specification
+
+Quick reference for all Jinja2 templates in `frontends/web/templates/`.
+
+## Table of Contents
+
+- [Layout](#layout)
+- [Auth & Setup](#auth--setup)
+- [Core Features](#core-features)
+- [Tools & Account](#tools--account)
+- [Admin](#admin)
+
+---
+
+## Layout
+
+### `base.html`
+**Purpose:** Master layout template - all pages extend this.
+
+| Block | Description |
+|-------|-------------|
+| `{% block title %}` | Page title |
+| `{% block content %}` | Main page content |
+| `{% block scripts %}` | Page-specific JS |
+
+**Key Elements:**
+- `nav.navbar` - Bootstrap 5 navbar with logo, links, auth buttons
+- `div.toast-container` - Flash message toasts (10s auto-dismiss)
+- `main.container` - Content wrapper
+- `footer` - Copyright + version
+
+**Variables:** `is_authenticated`, `username`, `is_admin`
+
+---
+
+## Auth & Setup
+
+### `login.html`
+**Route:** `/login`
+
+**Form:** `POST /login`
+- `username` - text input
+- `password` - password input
+- "Forgot password?" link to `/recover`
+
+**JS:** `static/js/auth.js` - password toggle
+
+---
+
+### `setup.html`
+**Route:** `/setup` (first-run only)
+
+**Form:** `POST /setup`
+- `username` - admin username
+- `password` - password (min 8 chars)
+- `password_confirm` - confirmation
+
+**JS:** Password confirmation validation
+
+---
+
+### `setup_recovery.html`
+**Route:** `/setup/recovery`
+
+**Form:** `POST /setup/recovery`
+- `recovery_key` - hidden, pre-generated
+- `action` - "save" or "skip"
+- Checkbox confirmation required for save
+
+**Features:**
+- Recovery key display (readonly input)
+- Copy to clipboard button
+- QR code image (if available)
+- Download options: text file, QR image
+- Stego backup upload form
+
+---
+
+### `recover.html`
+**Route:** `/recover`
+
+**Form:** `POST /recover`
+- `recovery_key` - textarea for key input
+- `new_password` - new password
+- `new_password_confirm` - confirmation
+
+**Accordion:** "Extract from stego backup"
+- `POST /recover/stego` with `stego_image` + `reference_image`
+- Pre-fills recovery key on success
+
+---
+
+### `regenerate_recovery.html`
+**Route:** `/account/recovery/regenerate` (admin only)
+
+**Form:** `POST /account/recovery/regenerate`
+- `recovery_key` - hidden field
+- `action` - "save" or "cancel"
+- Confirmation checkbox
+
+**Features:**
+- New key display
+- QR code (obfuscated)
+- Download: text, QR, stego backup
+- Warning if replacing existing key
+
+---
+
+## Core Features
+
+### `index.html`
+**Route:** `/`
+
+**Structure:**
+- Hero section with tagline
+- 3 action cards: Encode, Decode, Generate
+- "How It Works" explainer section
+
+---
+
+### `generate.html`
+**Route:** `/generate`
+
+**Form:** `POST /generate`
+- `words` - passphrase word count (3-12)
+- `use_pin` - checkbox
+- `pin_length` - PIN digits (6-9)
+- `use_rsa` - checkbox
+- `rsa_bits` - key size (2048/3072/4096)
+
+**Output panels:**
+- Passphrase display
+- PIN display (if enabled)
+- RSA key + QR (if enabled)
+- Entropy calculator
+
+**JS:** `static/js/generate.js`
+
+---
+
+### `encode.html`
+**Route:** `/encode`
+
+**Form:** `POST /encode` (multipart)
+- `reference_photo` - file upload (drag-drop zone)
+- `carrier_image` - file upload (drag-drop zone)
+- `mode` - radio: DCT (default) / LSB
+- `dct_format` - PNG / JPEG
+- `dct_color` - Color / Grayscale
+- `payload_type` - radio: Text / File
+- `message` - textarea (if text)
+- `embed_file` - file input (if file)
+- `passphrase` - text input
+- `pin` - text input
+- `rsa_key` / `rsa_key_qr` - file inputs
+- `rsa_key_password` - password
+- `channel_key` - select (saved keys) or manual input
+
+**Panels:**
+- Reference preview with "Hash Acquired" status
+- Carrier preview with capacity info
+- Character counter for message
+
+**JS:** `static/js/encode.js`, `static/js/stegasoo.js`
+
+---
+
+### `encode_result.html`
+**Route:** `/encode/result/<file_id>`
+
+**Elements:**
+- Success message
+- Stego image preview
+- Download button
+- Share button (Web Share API)
+- Mode/capacity info
+- "Encode Another" link
+
+**Variables:** `file_id`, `filename`, `mode`, `capacity_used`
+
+---
+
+### `decode.html`
+**Route:** `/decode`
+
+**Form:** `POST /decode` (multipart)
+- `reference_photo` - file upload
+- `stego_image` - file upload
+- `passphrase` - text input
+- `pin` - text input
+- `rsa_key` / `rsa_key_qr` - file inputs
+- `rsa_key_password` - password
+- `channel_key` - select or manual
+
+**Output:**
+- Decoded message display
+- File download (if file payload)
+
+**JS:** `static/js/decode.js`, `static/js/stegasoo.js`
+
+---
+
+## Tools & Account
+
+### `tools.html`
+**Route:** `/tools`
+
+**Tabbed interface:**
+
+| Tab | Endpoint | Description |
+|-----|----------|-------------|
+| Capacity | `POST /api/tools/capacity` | Image capacity analysis |
+| Peek | `POST /api/tools/peek` | Check for Stegasoo header |
+| Strip | `POST /api/tools/strip` | Remove hidden data |
+| EXIF | `POST /api/tools/exif/*` | Metadata viewer/editor |
+
+**EXIF Editor features:**
+- Upload image → view all EXIF fields
+- Inline editing (click field to edit)
+- "Clear All" button
+- "Save" / "Download" buttons
+
+**JS:** `static/js/tools.js`
+
+---
+
+### `account.html`
+**Route:** `/account`
+
+**Sections:**
+
+1. **User Info** - Username, role badge, logout link
+
+2. **Recovery Key** (admin only)
+   - Status: Configured / Not Set
+   - Generate/Regenerate button
+   - Disable button
+
+3. **Password Change**
+   - `current_password`
+   - `new_password`
+   - `new_password_confirm`
+
+4. **Saved Channel Keys**
+   - List of saved keys with edit/delete
+   - "Add Key" form (name + key)
+   - Max 10 keys per user
+
+**Variables:** `username`, `is_admin`, `has_recovery`, `channel_keys`
+
+---
+
+### `about.html`
+**Route:** `/about`
+
+**Sections:**
+- Version info + feature badges
+- Security model explanation
+- Channel key QR (if configured)
+- Dependency status table
+- Credits + links
+
+**Variables:** `version`, `has_dct`, `has_qr_write`, `has_qr_read`, `channel_key`, `channel_qr`
+
+---
+
+## Admin
+
+### `admin/users.html`
+**Route:** `/admin/users`
+
+**Table columns:** Username | Role | Created | Actions
+
+**Actions per user:**
+- Reset Password button
+- Delete button (disabled for self)
+
+**Header:**
+- User count: "X of 16 users"
+- "Add User" button (modal trigger)
+
+**Modal:** Add User form
+- `username` input
+- `role` select (admin/user)
+- Auto-generated temp password display
+
+---
+
+### `admin/user_new.html`
+**Route:** `/admin/users/new`
+
+**Form:** `POST /admin/users/new`
+- `username` - text input
+- `role` - select (user/admin)
+
+Redirects to `user_created.html` on success.
+
+---
+
+### `admin/user_created.html`
+**Route:** `/admin/users/created`
+
+**Display:**
+- Success message
+- Username
+- Temporary password (copy button)
+- "User must change password on first login" notice
+- Back to users link
+
+---
+
+### `admin/password_reset.html`
+**Route:** `/admin/users/<id>/password-reset`
+
+**Display:**
+- Success message
+- New temporary password
+- Copy button
+- Back link
+
+---
+
+## Common Patterns
+
+### Drag-Drop Upload Zones
+```html
+<div class="upload-zone" id="referenceZone">
+    <input type="file" name="reference_photo" accept="image/*">
+    <div class="preview"></div>
+    <div class="status"></div>
+</div>
+```
+
+### Password Toggle
+```html
+<div class="input-group">
+    <input type="password" id="passwordInput">
+    <button onclick="togglePassword('passwordInput', this)">
+        <i class="bi bi-eye"></i>
+    </button>
+</div>
+```
+
+### Toast Flash Messages
+Rendered in `base.html`, auto-dismiss after 10 seconds:
+- `success` → green
+- `warning` → yellow
+- `error` → red
+
+---
+
+## External JS Files
+
+| File | Used By |
+|------|---------|
+| `static/js/stegasoo.js` | encode, decode, about |
+| `static/js/auth.js` | login, setup, recover, account |
+| `static/js/generate.js` | generate |
+| `static/js/encode.js` | encode |
+| `static/js/decode.js` | decode |
+| `static/js/tools.js` | tools |

docs/stegasoo.1

@@ -0,0 +1,340 @@
+.\" Stegasoo man page
+.\" Generate with: groff -man -Tascii stegasoo.1
+.TH STEGASOO 1 "January 2026" "Stegasoo 4.1.7" "User Commands"
+.SH NAME
+stegasoo \- steganography with hybrid authentication
+.SH SYNOPSIS
+.B stegasoo
+[\fB\-v\fR|\fB\-\-version\fR]
+[\fB\-\-json\fR]
+[\fB\-h\fR|\fB\-\-help\fR]
+.I command
+[\fIargs\fR]
+.SH DESCRIPTION
+.B stegasoo
+hides messages and files in images using PIN + passphrase security.
+It uses LSB (Least Significant Bit) steganography with optional DCT
+(Discrete Cosine Transform) encoding for JPEG resilience.
+.PP
+Messages are encrypted using a hybrid authentication scheme that combines
+a reference photo (shared secret), passphrase, and PIN code.
+.SH GLOBAL OPTIONS
+.TP
+.BR \-v ", " \-\-version
+Show version and exit.
+.TP
+.B \-\-json
+Output results as JSON (where supported).
+.TP
+.BR \-h ", " \-\-help
+Show help message and exit.
+.SH COMMANDS
+.SS encode
+Encode a message or file into an image.
+.PP
+.B stegasoo encode
+.I carrier
+.B \-r
+.I reference
+[\fB\-m\fR \fImessage\fR | \fB\-f\fR \fIfile\fR]
+[\fIoptions\fR]
+.TP
+.BR \-r ", " \-\-reference " " \fIPATH\fR
+Reference photo (shared secret). Required.
+.TP
+.BR \-m ", " \-\-message " " \fITEXT\fR
+Message to encode.
+.TP
+.BR \-f ", " \-\-file " " \fIPATH\fR
+File to embed instead of message.
+.TP
+.BR \-o ", " \-\-output " " \fIPATH\fR
+Output image path.
+.TP
+.B \-\-passphrase " " \fITEXT\fR
+Passphrase (recommend 4+ words). Prompts if not provided.
+.TP
+.B \-\-pin " " \fITEXT\fR
+PIN code. Prompts if not provided.
+.TP
+.B \-\-dry\-run
+Show capacity usage without encoding.
+.PP
+.B Examples:
+.nf
+    stegasoo encode photo.png -r ref.jpg -m "Secret" --passphrase --pin
+    stegasoo encode photo.png -r ref.jpg -f doc.pdf -o encoded.png
+.fi
+.SS decode
+Decode a message or file from an image.
+.PP
+.B stegasoo decode
+.I image
+.B \-r
+.I reference
+[\fIoptions\fR]
+.TP
+.BR \-r ", " \-\-reference " " \fIPATH\fR
+Reference photo (shared secret). Required.
+.TP
+.B \-\-passphrase " " \fITEXT\fR
+Passphrase. Prompts if not provided.
+.TP
+.B \-\-pin " " \fITEXT\fR
+PIN code. Prompts if not provided.
+.TP
+.BR \-o ", " \-\-output " " \fIPATH\fR
+Output path for file payloads.
+.PP
+.B Examples:
+.nf
+    stegasoo decode encoded.png -r ref.jpg --passphrase --pin
+    stegasoo decode encoded.png -r ref.jpg -o ./extracted/
+.fi
+.SS generate
+Generate random credentials (passphrase + PIN + optional channel key).
+.PP
+.B stegasoo generate
+[\fIoptions\fR]
+.TP
+.B \-\-words " " \fIINTEGER\fR
+Number of words in passphrase (default: 4).
+.TP
+.B \-\-pin\-length " " \fIINTEGER\fR
+PIN length (default: 6).
+.TP
+.B \-\-channel\-key
+Also generate a 256-bit channel key.
+.PP
+.B Examples:
+.nf
+    stegasoo generate
+    stegasoo generate --words 6 --pin-length 8
+    stegasoo generate --channel-key
+.fi
+.SS info
+Show version, features, and system information.
+.PP
+.B stegasoo info
+[\fB\-\-full\fR]
+.TP
+.B \-\-full
+Show full system information (CPU, temperature, disk on Pi).
+.SS batch
+Batch operations on multiple images.
+.PP
+.B stegasoo batch
+.I subcommand
+[\fIargs\fR]
+.TP
+.B batch encode
+Encode message into multiple images.
+.RS
+.PP
+.B stegasoo batch encode
+.I images...
+[\fB\-m\fR \fImessage\fR | \fB\-f\fR \fIfile\fR]
+[\fIoptions\fR]
+.PP
+Options: \fB\-m\fR, \fB\-f\fR, \fB\-o\fR/\fB\-\-output\-dir\fR, \fB\-\-suffix\fR, \fB\-\-passphrase\fR, \fB\-\-pin\fR,
+\fB\-r\fR/\fB\-\-recursive\fR, \fB\-j\fR/\fB\-\-jobs\fR, \fB\-v\fR/\fB\-\-verbose\fR.
+.RE
+.TP
+.B batch decode
+Decode messages from multiple images.
+.RS
+.PP
+.B stegasoo batch decode
+.I images...
+[\fIoptions\fR]
+.PP
+Options: \fB\-o\fR/\fB\-\-output\-dir\fR, \fB\-\-passphrase\fR, \fB\-\-pin\fR, \fB\-r\fR/\fB\-\-recursive\fR,
+\fB\-j\fR/\fB\-\-jobs\fR, \fB\-v\fR/\fB\-\-verbose\fR.
+.RE
+.TP
+.B batch check
+Check capacity of multiple images.
+.RS
+.PP
+.B stegasoo batch check
+.I images...
+[\fB\-r\fR/\fB\-\-recursive\fR]
+.RE
+.SS channel
+Manage channel keys for deployment isolation.
+.PP
+Channel keys bind encode/decode operations to a specific group or deployment.
+Messages encoded with one channel key can only be decoded by systems with
+the same channel key.
+.PP
+.B stegasoo channel
+.I subcommand
+[\fIargs\fR]
+.TP
+.B channel generate
+Generate a new random channel key.
+.RS
+.PP
+Options: \fB\-\-save\fR (project config), \fB\-\-save\-user\fR (user config).
+.RE
+.TP
+.B channel show
+Show the current channel key.
+.RS
+.PP
+Options: \fB\-\-key\fR \fITEXT\fR (show specific key instead).
+.RE
+.TP
+.B channel qr
+Display channel key as QR code.
+.RS
+.PP
+Options: \fB\-\-key\fR \fITEXT\fR, \fB\-\-format\fR [\fIascii\fR|\fIpng\fR], \fB\-o\fR/\fB\-\-output\fR \fIPATH\fR.
+.RE
+.TP
+.B channel status
+Show channel key status and configuration.
+.TP
+.B channel clear
+Remove channel key configuration.
+.RS
+.PP
+Options: \fB\-\-project\fR, \fB\-\-user\fR.
+.RE
+.SS admin
+Web UI administration commands.
+.PP
+.B stegasoo admin
+.I subcommand
+[\fIargs\fR]
+.TP
+.B admin generate\-key
+Generate a new recovery key (for reference only).
+.RS
+.PP
+Options: \fB\-\-qr\fR (show QR code in terminal).
+.RE
+.TP
+.B admin recover
+Reset admin password using recovery key.
+.RS
+.PP
+Options: \fB\-\-db\fR \fIPATH\fR (path to stegasoo.db), \fB\-\-password\fR \fITEXT\fR.
+.RE
+.SS tools
+Image security tools.
+.PP
+.B stegasoo tools
+.I subcommand
+[\fIargs\fR]
+.TP
+.B tools capacity
+Show steganography capacity for an image.
+.RS
+.PP
+.B stegasoo tools capacity
+.I image
+[\fB\-\-json\fR]
+.RE
+.TP
+.B tools exif
+View or edit EXIF metadata.
+.RS
+.PP
+.B stegasoo tools exif
+.I image
+[\fB\-\-clear\fR] [\fB\-\-set\fR \fIFIELD=VALUE\fR] [\fB\-o\fR \fIPATH\fR] [\fB\-\-json\fR]
+.RE
+.TP
+.B tools peek
+Check if image contains Stegasoo hidden data.
+.RS
+.PP
+.B stegasoo tools peek
+.I image
+[\fB\-\-json\fR]
+.RE
+.TP
+.B tools strip
+Strip EXIF/metadata from an image.
+.RS
+.PP
+.B stegasoo tools strip
+.I image
+[\fB\-o\fR \fIPATH\fR] [\fB\-\-format\fR [\fIpng\fR|\fIbmp\fR]]
+.RE
+.SH ENVIRONMENT
+.TP
+.B STEGASOO_CHANNEL_KEY
+Channel key for encode/decode operations. Overrides config file settings.
+.TP
+.B STEGASOO_HTTPS_ENABLED
+Enable HTTPS for web UI (Docker/service mode).
+.TP
+.B STEGASOO_HOSTNAME
+Hostname for SSL certificate generation.
+.SH FILES
+.TP
+.I ~/.stegasoo/channel.key
+User's channel key configuration (encrypted).
+.TP
+.I .stegasoo.toml
+Project-level configuration file.
+.TP
+.I frontends/web/instance/stegasoo.db
+Web UI SQLite database (accounts, settings).
+.SH EXAMPLES
+.SS Basic encode/decode workflow
+.nf
+# Generate credentials
+stegasoo generate
+
+# Encode a secret message
+stegasoo encode vacation.png -r selfie.jpg -m "Meet at noon"
+
+# Decode the message (on another system with same reference photo)
+stegasoo decode vacation_steg.png -r selfie.jpg
+.fi
+.SS Using channel keys for team isolation
+.nf
+# Generate and save a channel key
+stegasoo channel generate --save-user
+
+# Share the key with your team
+stegasoo channel qr -o team-key.png
+
+# Now all encode/decode operations use this channel
+stegasoo encode photo.png -r ref.jpg -m "Team secret"
+.fi
+.SS Batch processing
+.nf
+# Check capacity of all PNGs in a directory
+stegasoo batch check ./photos/*.png
+
+# Encode same message into multiple images
+stegasoo batch encode ./photos/ -r ref.jpg -m "Secret" -o ./encoded/
+.fi
+.SH SECURITY
+Stegasoo uses multiple layers of security:
+.IP \(bu 2
+Reference photo provides a visual shared secret
+.IP \(bu 2
+Passphrase (recommend 4+ words) for strong encryption
+.IP \(bu 2
+PIN code adds additional entropy
+.IP \(bu 2
+Channel keys isolate different deployments
+.IP \(bu 2
+AES-256 encryption for payload data
+.PP
+For maximum security, share the reference photo out-of-band (in person,
+secure messenger) and use a strong passphrase.
+.SH SEE ALSO
+.BR openssl (1),
+.BR qrencode (1)
+.SH BUGS
+Report bugs at: https://github.com/adlee-was-taken/stegasoo/issues
+.SH AUTHOR
+Written by the Stegasoo contributors.
+.SH COPYRIGHT
+Copyright \(co 2024-2026. MIT License.

examples/README.md

@@ -0,0 +1,48 @@
+# Stegasoo Examples
+
+This directory contains example scripts demonstrating how to use Stegasoo.
+
+## Prerequisites
+
+Install Stegasoo first:
+
+```bash
+pip install stegasoo
+# Or for development:
+pip install -e ".[all]"
+```
+
+## Examples
+
+### basic_usage.py
+
+Basic encode/decode workflow with a text message.
+
+```bash
+python basic_usage.py
+```
+
+### embed_file.py
+
+Embed and extract files (documents, images, etc.) inside carrier images.
+
+```bash
+python embed_file.py
+```
+
+### channel_keys.py
+
+Use channel keys to create private communication channels for groups.
+
+```bash
+python channel_keys.py
+```
+
+## Test Images
+
+You'll need to provide your own images:
+
+- `my_secret_photo.png` - Your reference photo (keep this secret!)
+- `carrier.png` - The image that will carry your hidden message
+
+For testing, you can use any PNG or BMP image. JPEG carriers are supported with DCT mode.

examples/basic_usage.py

@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+"""
+Basic Stegasoo Usage Example
+
+This example demonstrates how to encode and decode a secret message
+using the Stegasoo library.
+"""
+
+from pathlib import Path
+
+import stegasoo
+
+
+def main():
+    # Load your images
+    # The reference photo is your "key" - keep it secret!
+    reference_photo = Path("my_secret_photo.png").read_bytes()
+    carrier_image = Path("carrier.png").read_bytes()
+
+    # Your secret message
+    message = "This is my secret message!"
+
+    # Your credentials
+    passphrase = "correct horse battery staple"  # Use 4+ words
+    pin = "123456"  # 6-9 digits
+
+    # === ENCODE ===
+    print("Encoding message...")
+    result = stegasoo.encode(
+        message=message,
+        reference_photo=reference_photo,
+        carrier_image=carrier_image,
+        passphrase=passphrase,
+        pin=pin,
+    )
+
+    # Save the stego image
+    output_path = Path(f"secret_{result.suggested_filename}")
+    output_path.write_bytes(result.stego_image)
+    print(f"Saved to: {output_path}")
+    print(f"Capacity used: {result.capacity_used_percent:.1f}%")
+
+    # === DECODE ===
+    print("\nDecoding message...")
+    stego_image = output_path.read_bytes()
+
+    decoded = stegasoo.decode(
+        stego_image=stego_image,
+        reference_photo=reference_photo,
+        passphrase=passphrase,
+        pin=pin,
+    )
+
+    print(f"Decoded message: {decoded.message}")
+    print(f"Message type: {decoded.payload_type}")
+
+
+if __name__ == "__main__":
+    main()

examples/channel_keys.py

@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+"""
+Channel Keys Example
+
+Channel keys allow you to create private communication channels.
+Only people with the same channel key can decode messages.
+"""
+
+from pathlib import Path
+
+import stegasoo
+from stegasoo.channel import generate_channel_key, get_channel_fingerprint
+
+
+def main():
+    # Generate a channel key for your group
+    channel_key = generate_channel_key()
+    fingerprint = get_channel_fingerprint(channel_key)
+
+    print("=== Channel Key Generated ===")
+    print(f"Key: {channel_key}")
+    print(f"Fingerprint: {fingerprint}")
+    print("\nShare this key securely with your group members!")
+    print("-" * 40)
+
+    # Load images
+    reference_photo = Path("my_secret_photo.png").read_bytes()
+    carrier_image = Path("carrier.png").read_bytes()
+
+    # Encode with channel key
+    print("\nEncoding message with channel key...")
+    result = stegasoo.encode(
+        message="Secret group message!",
+        reference_photo=reference_photo,
+        carrier_image=carrier_image,
+        passphrase="correct horse battery staple",
+        pin="123456",
+        channel_key=channel_key,  # Add the channel key
+    )
+
+    stego_data = result.stego_image
+    print(f"Encoded successfully!")
+
+    # Decode with correct channel key
+    print("\nDecoding with correct channel key...")
+    decoded = stegasoo.decode(
+        stego_image=stego_data,
+        reference_photo=reference_photo,
+        passphrase="correct horse battery staple",
+        pin="123456",
+        channel_key=channel_key,  # Same channel key
+    )
+    print(f"Message: {decoded.message}")
+
+    # Try to decode with wrong channel key
+    print("\nTrying to decode with wrong channel key...")
+    wrong_key = generate_channel_key()
+    try:
+        stegasoo.decode(
+            stego_image=stego_data,
+            reference_photo=reference_photo,
+            passphrase="correct horse battery staple",
+            pin="123456",
+            channel_key=wrong_key,  # Different channel key
+        )
+        print("ERROR: Should have failed!")
+    except (stegasoo.DecryptionError, stegasoo.ExtractionError):
+        print("Correctly rejected - wrong channel key!")
+
+
+if __name__ == "__main__":
+    main()

examples/embed_file.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+"""
+File Embedding Example
+
+This example demonstrates how to embed a file (like a document or image)
+inside a carrier image using Stegasoo.
+"""
+
+from pathlib import Path
+
+import stegasoo
+from stegasoo.models import FilePayload
+
+
+def main():
+    # Load images
+    reference_photo = Path("my_secret_photo.png").read_bytes()
+    carrier_image = Path("carrier.png").read_bytes()
+
+    # Load the file to embed
+    secret_file = Path("secret_document.pdf")
+    file_data = secret_file.read_bytes()
+
+    # Create a FilePayload
+    payload = FilePayload(
+        filename=secret_file.name,
+        data=file_data,
+        mime_type="application/pdf",
+    )
+
+    # Credentials
+    passphrase = "correct horse battery staple"
+    pin = "123456"
+
+    # Check capacity first
+    capacity = stegasoo.calculate_capacity(carrier_image)
+    print(f"Carrier capacity: {capacity['capacity_bytes']:,} bytes")
+    print(f"File size: {len(file_data):,} bytes")
+
+    if len(file_data) > capacity["capacity_bytes"]:
+        print("Error: File too large for this carrier!")
+        return
+
+    # Encode the file
+    print("\nEmbedding file...")
+    result = stegasoo.encode(
+        file_payload=payload,
+        reference_photo=reference_photo,
+        carrier_image=carrier_image,
+        passphrase=passphrase,
+        pin=pin,
+    )
+
+    output_path = Path(f"contains_file_{result.suggested_filename}")
+    output_path.write_bytes(result.stego_image)
+    print(f"Saved to: {output_path}")
+
+    # Decode and extract the file
+    print("\nExtracting file...")
+    decoded = stegasoo.decode(
+        stego_image=output_path.read_bytes(),
+        reference_photo=reference_photo,
+        passphrase=passphrase,
+        pin=pin,
+    )
+
+    if decoded.payload_type == "file":
+        extracted_path = Path(f"extracted_{decoded.filename}")
+        extracted_path.write_bytes(decoded.file_data)
+        print(f"Extracted: {extracted_path}")
+        print(f"Original filename: {decoded.filename}")
+        print(f"MIME type: {decoded.mime_type}")
+    else:
+        print(f"Unexpected payload type: {decoded.payload_type}")
+
+
+if __name__ == "__main__":
+    main()

frontends/API.md

@@ -1,952 +0,0 @@
-# Stegasoo REST API Documentation
-
-Complete REST API reference for Stegasoo steganography operations.
-
-## Table of Contents
-
-- [Overview](#overview)
-- [Installation](#installation)
-- [Authentication](#authentication)
-- [Base URL](#base-url)
-- [Endpoints](#endpoints)
-  - [GET /](#get--status)
-  - [POST /generate](#post-generate)
-  - [POST /encode](#post-encode-json)
-  - [POST /encode/multipart](#post-encodemultipart)
-  - [POST /decode](#post-decode-json)
-  - [POST /decode/multipart](#post-decodemultipart)
-  - [POST /image/info](#post-imageinfo)
-- [Data Models](#data-models)
-- [Error Handling](#error-handling)
-- [Code Examples](#code-examples)
-- [Rate Limiting](#rate-limiting)
-- [Security Considerations](#security-considerations)
-
----
-
-## Overview
-
-The Stegasoo REST API provides programmatic access to all steganography operations:
-
-- **Generate** credentials (phrases, PINs, RSA keys)
-- **Encode** messages into images
-- **Decode** messages from images
-- **Analyze** image capacity
-
-The API supports both JSON (base64-encoded images) and multipart form data (direct file uploads).
-
----
-
-## Installation
-
-### From PyPI
-
-```bash
-pip install stegasoo[api]
-```
-
-### From Source
-
-```bash
-git clone https://github.com/example/stegasoo.git
-cd stegasoo
-pip install -e ".[api]"
-```
-
-### Running the Server
-
-**Development:**
-```bash
-cd frontends/api
-python main.py
-```
-
-**Production:**
-```bash
-cd frontends/api
-uvicorn main:app --host 0.0.0.0 --port 8000 --workers 4
-```
-
-**Docker:**
-```bash
-docker-compose up api
-```
-
----
-
-## Authentication
-
-The API currently operates without authentication. For production deployments, implement authentication at the reverse proxy level (nginx, Caddy) or add API key middleware.
-
----
-
-## Base URL
-
-| Environment | URL |
-|-------------|-----|
-| Local Development | `http://localhost:8000` |
-| Docker | `http://localhost:8000` |
-| Production | Configure as needed |
-
----
-
-## Endpoints
-
-### GET / (Status)
-
-Check API status and configuration.
-
-#### Request
-
-```http
-GET / HTTP/1.1
-Host: localhost:8000
-```
-
-#### Response
-
-```json
-{
-  "version": "2.0.1",
-  "has_argon2": true,
-  "day_names": ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]
-}
-```
-
-#### Response Fields
-
-| Field | Type | Description |
-|-------|------|-------------|
-| `version` | string | Stegasoo library version |
-| `has_argon2` | boolean | Whether Argon2id is available |
-| `day_names` | array | Day names for phrase mapping |
-
-#### cURL Example
-
-```bash
-curl http://localhost:8000/
-```
-
----
-
-### POST /generate
-
-Generate credentials for encoding/decoding.
-
-#### Request
-
-```http
-POST /generate HTTP/1.1
-Host: localhost:8000
-Content-Type: application/json
-
-```
-
-#### Request Body
-
-| Field | Type | Default | Description |
-|-------|------|---------|-------------|
-| `use_pin` | boolean | `true` | Generate a PIN |
-| `use_rsa` | boolean | `false` | Generate an RSA key |
-| `pin_length` | integer | `6` | PIN length (6-9) |
-| `rsa_bits` | integer | `2048` | RSA key size (2048, 3072, 4096) |
-| `words_per_phrase` | integer | `3` | Words per phrase (3-12) |
-
-#### Response
-
-```json
-{
-  "phrases": {
-    "Monday": "abandon ability able",
-    "Tuesday": "actor actress actual",
-    "Wednesday": "advice aerobic affair",
-    "Thursday": "afraid again age",
-    "Friday": "agree ahead aim",
-    "Saturday": "airport aisle alarm",
-    "Sunday": "album alcohol alert"
-  },
-  "pin": "847293",
-  "rsa_key_pem": null,
-  "entropy": {
-    "phrase": 33,
-    "pin": 19,
-    "rsa": 0,
-    "total": 52
-  }
-}
-```
-
-#### Response Fields
-
-| Field | Type | Description |
-|-------|------|-------------|
-| `phrases` | object | Day-to-phrase mapping |
-| `pin` | string\|null | Generated PIN (if requested) |
-| `rsa_key_pem` | string\|null | PEM-encoded RSA key (if requested) |
-| `entropy.phrase` | integer | Entropy from phrases (bits) |
-| `entropy.pin` | integer | Entropy from PIN (bits) |
-| `entropy.rsa` | integer | Entropy from RSA key (bits) |
-| `entropy.total` | integer | Combined entropy (bits) |
-
-#### cURL Examples
-
-**PIN only:**
-```bash
-curl -X POST http://localhost:8000/generate \
-  -H "Content-Type: application/json" \
-  -d '{"use_pin": true, "use_rsa": false}'
-```
-
-**RSA only:**
-```bash
-curl -X POST http://localhost:8000/generate \
-  -H "Content-Type: application/json" \
-  -d '{"use_pin": false, "use_rsa": true, "rsa_bits": 4096}'
-```
-
-**Both with custom settings:**
-```bash
-curl -X POST http://localhost:8000/generate \
-  -H "Content-Type: application/json" \
-  -d '{
-    "use_pin": true,
-    "use_rsa": true,
-    "pin_length": 9,
-    "rsa_bits": 4096,
-    "words_per_phrase": 6
-  }'
-```
-
----
-
-### POST /encode (JSON)
-
-Encode a message using base64-encoded images.
-
-#### Request
-
-```http
-POST /encode HTTP/1.1
-Host: localhost:8000
-Content-Type: application/json
-
-```
-
-#### Request Body
-
-| Field | Type | Required | Description |
-|-------|------|----------|-------------|
-| `message` | string | ✓ | Message to encode |
-| `reference_photo_base64` | string | ✓ | Base64-encoded reference photo |
-| `carrier_image_base64` | string | ✓ | Base64-encoded carrier image |
-| `day_phrase` | string | ✓ | Today's passphrase |
-| `pin` | string | * | Static PIN (6-9 digits) |
-| `rsa_key_base64` | string | * | Base64-encoded RSA key PEM |
-| `rsa_password` | string | | Password for RSA key |
-| `date_str` | string | | Date override (YYYY-MM-DD) |
-
-\* At least one of `pin` or `rsa_key_base64` required.
-
-#### Response
-
-```json
-{
-  "stego_image_base64": "iVBORw0KGgo...",
-  "filename": "a1b2c3d4_20251227.png",
-  "capacity_used_percent": 12.4,
-  "date_used": "2025-12-27",
-  "day_of_week": "Saturday"
-}
-```
-
-#### Response Fields
-
-| Field | Type | Description |
-|-------|------|-------------|
-| `stego_image_base64` | string | Base64-encoded stego PNG |
-| `filename` | string | Suggested filename |
-| `capacity_used_percent` | float | Percentage of capacity used |
-| `date_used` | string | Date embedded in image (YYYY-MM-DD) |
-| `day_of_week` | string | Day name for passphrase rotation |
-
-#### cURL Example
-
-```bash
-# Prepare base64-encoded images
-REF_B64=$(base64 -w0 reference.jpg)
-CARRIER_B64=$(base64 -w0 carrier.png)
-
-curl -X POST http://localhost:8000/encode \
-  -H "Content-Type: application/json" \
-  -d "{
-    \"message\": \"Secret message\",
-    \"reference_photo_base64\": \"$REF_B64\",
-    \"carrier_image_base64\": \"$CARRIER_B64\",
-    \"day_phrase\": \"apple forest thunder\",
-    \"pin\": \"123456\"
-  }" | jq -r '.stego_image_base64' | base64 -d > stego.png
-```
-
----
-
-### POST /encode/multipart
-
-Encode a message using direct file uploads. Returns the stego image directly.
-
-#### Request
-
-```http
-POST /encode/multipart HTTP/1.1
-Host: localhost:8000
-Content-Type: multipart/form-data; boundary=----FormBoundary
-
-------FormBoundary
-Content-Disposition: form-data; name="message"
-
-Secret message here
-------FormBoundary
-Content-Disposition: form-data; name="day_phrase"
-
-apple forest thunder
-------FormBoundary
-Content-Disposition: form-data; name="pin"
-
-123456
-------FormBoundary
-Content-Disposition: form-data; name="reference_photo"; filename="ref.jpg"
-Content-Type: image/jpeg
-
-<binary image data>
-------FormBoundary
-Content-Disposition: form-data; name="carrier"; filename="carrier.png"
-Content-Type: image/png
-
-<binary image data>
-------FormBoundary--
-```
-
-#### Form Fields
-
-| Field | Type | Required | Description |
-|-------|------|----------|-------------|
-| `message` | string | ✓ | Message to encode |
-| `reference_photo` | file | ✓ | Reference photo file |
-| `carrier` | file | ✓ | Carrier image file |
-| `day_phrase` | string | ✓ | Today's passphrase |
-| `pin` | string | * | Static PIN |
-| `rsa_key` | file | * | RSA key file (.pem) |
-| `rsa_password` | string | | Password for RSA key |
-| `date_str` | string | | Date override (YYYY-MM-DD) |
-
-\* At least one of `pin` or `rsa_key` required.
-
-#### Response
-
-Returns the PNG image directly with headers:
-- `Content-Type: image/png`
-- `Content-Disposition: attachment; filename=<generated_filename>.png`
-- `X-Stegasoo-Date: 2025-12-27` (date used for encoding)
-- `X-Stegasoo-Day: Saturday` (day of week for passphrase rotation)
-- `X-Stegasoo-Capacity-Percent: 12.4` (capacity used)
-
-#### cURL Examples
-
-**With PIN:**
-```bash
-curl -X POST http://localhost:8000/encode/multipart \
-  -F "message=Secret message" \
-  -F "day_phrase=apple forest thunder" \
-  -F "pin=123456" \
-  -F "reference_photo=@reference.jpg" \
-  -F "carrier=@carrier.png" \
-  --output stego.png
-```
-
-**With RSA key:**
-```bash
-curl -X POST http://localhost:8000/encode/multipart \
-  -F "message=Secret message" \
-  -F "day_phrase=apple forest thunder" \
-  -F "rsa_key=@mykey.pem" \
-  -F "rsa_password=keypassword" \
-  -F "reference_photo=@reference.jpg" \
-  -F "carrier=@carrier.png" \
-  --output stego.png
-```
-
-**With both PIN and RSA:**
-```bash
-curl -X POST http://localhost:8000/encode/multipart \
-  -F "message=Maximum security message" \
-  -F "day_phrase=apple forest thunder" \
-  -F "pin=123456" \
-  -F "rsa_key=@mykey.pem" \
-  -F "rsa_password=keypassword" \
-  -F "reference_photo=@reference.jpg" \
-  -F "carrier=@carrier.png" \
-  --output stego.png
-```
-
-**With custom date:**
-```bash
-curl -X POST http://localhost:8000/encode/multipart \
-  -F "message=Backdated message" \
-  -F "day_phrase=monday phrase here" \
-  -F "pin=123456" \
-  -F "date_str=2025-12-29" \
-  -F "reference_photo=@reference.jpg" \
-  -F "carrier=@carrier.png" \
-  --output stego.png
-```
-
----
-
-### POST /decode (JSON)
-
-Decode a message using base64-encoded images.
-
-#### Request
-
-```http
-POST /decode HTTP/1.1
-Host: localhost:8000
-Content-Type: application/json
-
-```
-
-#### Request Body
-
-| Field | Type | Required | Description |
-|-------|------|----------|-------------|
-| `stego_image_base64` | string | ✓ | Base64-encoded stego image |
-| `reference_photo_base64` | string | ✓ | Base64-encoded reference photo |
-| `day_phrase` | string | ✓ | Passphrase for encoding day |
-| `pin` | string | * | Static PIN |
-| `rsa_key_base64` | string | * | Base64-encoded RSA key |
-| `rsa_password` | string | | Password for RSA key |
-
-\* Must match the security factors used during encoding.
-
-#### Response
-
-```json
-{
-  "message": "Secret message here"
-}
-```
-
-#### cURL Example
-
-```bash
-# Prepare base64-encoded images
-STEGO_B64=$(base64 -w0 stego.png)
-REF_B64=$(base64 -w0 reference.jpg)
-
-curl -X POST http://localhost:8000/decode \
-  -H "Content-Type: application/json" \
-  -d "{
-    \"stego_image_base64\": \"$STEGO_B64\",
-    \"reference_photo_base64\": \"$REF_B64\",
-    \"day_phrase\": \"apple forest thunder\",
-    \"pin\": \"123456\"
-  }"
-```
-
----
-
-### POST /decode/multipart
-
-Decode a message using direct file uploads.
-
-#### Request
-
-```http
-POST /decode/multipart HTTP/1.1
-Host: localhost:8000
-Content-Type: multipart/form-data
-```
-
-#### Form Fields
-
-| Field | Type | Required | Description |
-|-------|------|----------|-------------|
-| `stego_image` | file | ✓ | Stego image file |
-| `reference_photo` | file | ✓ | Reference photo file |
-| `day_phrase` | string | ✓ | Passphrase for encoding day |
-| `pin` | string | * | Static PIN |
-| `rsa_key` | file | * | RSA key file |
-| `rsa_password` | string | | Password for RSA key |
-
-#### Response
-
-```json
-{
-  "message": "Secret message here"
-}
-```
-
-#### cURL Examples
-
-**With PIN:**
-```bash
-curl -X POST http://localhost:8000/decode/multipart \
-  -F "day_phrase=apple forest thunder" \
-  -F "pin=123456" \
-  -F "reference_photo=@reference.jpg" \
-  -F "stego_image=@stego.png"
-```
-
-**With RSA key:**
-```bash
-curl -X POST http://localhost:8000/decode/multipart \
-  -F "day_phrase=apple forest thunder" \
-  -F "rsa_key=@mykey.pem" \
-  -F "rsa_password=keypassword" \
-  -F "reference_photo=@reference.jpg" \
-  -F "stego_image=@stego.png"
-```
-
----
-
-### POST /image/info
-
-Get information about an image's capacity.
-
-#### Request
-
-```http
-POST /image/info HTTP/1.1
-Host: localhost:8000
-Content-Type: multipart/form-data
-```
-
-#### Form Fields
-
-| Field | Type | Required | Description |
-|-------|------|----------|-------------|
-| `image` | file | ✓ | Image file to analyze |
-
-#### Response
-
-```json
-{
-  "width": 1920,
-  "height": 1080,
-  "pixels": 2073600,
-  "capacity_bytes": 776970,
-  "capacity_kb": 758
-}
-```
-
-#### Response Fields
-
-| Field | Type | Description |
-|-------|------|-------------|
-| `width` | integer | Image width in pixels |
-| `height` | integer | Image height in pixels |
-| `pixels` | integer | Total pixel count |
-| `capacity_bytes` | integer | Maximum message capacity (bytes) |
-| `capacity_kb` | integer | Maximum message capacity (KB) |
-
-#### cURL Example
-
-```bash
-curl -X POST http://localhost:8000/image/info \
-  -F "image=@myimage.png"
-```
-
----
-
-## Data Models
-
-### GenerateRequest
-
-```json
-{
-  "use_pin": true,
-  "use_rsa": false,
-  "pin_length": 6,
-  "rsa_bits": 2048,
-  "words_per_phrase": 3
-}
-```
-
-### GenerateResponse
-
-```json
-{
-  "phrases": {"Monday": "...", "Tuesday": "...", ...},
-  "pin": "123456",
-  "rsa_key_pem": "-----BEGIN PRIVATE KEY-----...",
-  "entropy": {"phrase": 33, "pin": 19, "rsa": 0, "total": 52}
-}
-```
-
-### EncodeRequest
-
-```json
-{
-  "message": "string",
-  "reference_photo_base64": "string",
-  "carrier_image_base64": "string",
-  "day_phrase": "string",
-  "pin": "string",
-  "rsa_key_base64": "string",
-  "rsa_password": "string",
-  "date_str": "YYYY-MM-DD"
-}
-```
-
-### EncodeResponse
-
-```json
-{
-  "stego_image_base64": "string",
-  "filename": "string",
-  "capacity_used_percent": 12.4,
-  "date_used": "YYYY-MM-DD",
-  "day_of_week": "Saturday"
-}
-```
-
-### DecodeRequest
-
-```json
-{
-  "stego_image_base64": "string",
-  "reference_photo_base64": "string",
-  "day_phrase": "string",
-  "pin": "string",
-  "rsa_key_base64": "string",
-  "rsa_password": "string"
-}
-```
-
-### DecodeResponse
-
-```json
-{
-  "message": "string"
-}
-```
-
-### ImageInfoResponse
-
-```json
-{
-  "width": 1920,
-  "height": 1080,
-  "pixels": 2073600,
-  "capacity_bytes": 776970,
-  "capacity_kb": 758
-}
-```
-
-### ErrorResponse
-
-```json
-{
-  "error": "ErrorType",
-  "detail": "Error description"
-}
-```
-
----
-
-## Error Handling
-
-### HTTP Status Codes
-
-| Code | Meaning | Use Case |
-|------|---------|----------|
-| 200 | OK | Successful operation |
-| 400 | Bad Request | Invalid input, capacity error |
-| 401 | Unauthorized | Decryption failed (wrong credentials) |
-| 500 | Internal Error | Unexpected server error |
-
-### Error Response Format
-
-```json
-{
-  "detail": "Error message describing the problem"
-}
-```
-
-### Common Errors
-
-| Status | Error | Solution |
-|--------|-------|----------|
-| 400 | "Must enable at least one of use_pin or use_rsa" | Set `use_pin` or `use_rsa` to true |
-| 400 | "rsa_bits must be one of [2048, 3072, 4096]" | Use valid RSA key size |
-| 400 | "Carrier image too small" | Use larger carrier image |
-| 400 | "PIN must be 6-9 digits" | Fix PIN format |
-| 401 | "Decryption failed. Check credentials." | Verify phrase, PIN, ref photo |
-| 400 | "Message too long" | Reduce message size or use larger carrier |
-
----
-
-## Code Examples
-
-### Python with requests
-
-```python
-import base64
-import requests
-
-BASE_URL = "http://localhost:8000"
-
-# Generate credentials
-response = requests.post(f"{BASE_URL}/generate", json={
-    "use_pin": True,
-    "use_rsa": False,
-    "words_per_phrase": 3
-})
-creds = response.json()
-print(f"PIN: {creds['pin']}")
-print(f"Monday phrase: {creds['phrases']['Monday']}")
-
-# Encode using multipart
-with open("reference.jpg", "rb") as ref, open("carrier.png", "rb") as carrier:
-    response = requests.post(f"{BASE_URL}/encode/multipart", files={
-        "reference_photo": ref,
-        "carrier": carrier,
-    }, data={
-        "message": "Secret message",
-        "day_phrase": "apple forest thunder",
-        "pin": "123456"
-    })
-    
-    with open("stego.png", "wb") as f:
-        f.write(response.content)
-
-# Decode using multipart
-with open("reference.jpg", "rb") as ref, open("stego.png", "rb") as stego:
-    response = requests.post(f"{BASE_URL}/decode/multipart", files={
-        "reference_photo": ref,
-        "stego_image": stego,
-    }, data={
-        "day_phrase": "apple forest thunder",
-        "pin": "123456"
-    })
-    
-    print(f"Decoded: {response.json()['message']}")
-```
-
-### JavaScript/Node.js
-
-```javascript
-const FormData = require('form-data');
-const fs = require('fs');
-const axios = require('axios');
-
-const BASE_URL = 'http://localhost:8000';
-
-async function encode() {
-    const form = new FormData();
-    form.append('message', 'Secret message');
-    form.append('day_phrase', 'apple forest thunder');
-    form.append('pin', '123456');
-    form.append('reference_photo', fs.createReadStream('reference.jpg'));
-    form.append('carrier', fs.createReadStream('carrier.png'));
-
-    const response = await axios.post(`${BASE_URL}/encode/multipart`, form, {
-        headers: form.getHeaders(),
-        responseType: 'arraybuffer'
-    });
-
-    fs.writeFileSync('stego.png', response.data);
-    console.log('Encoded successfully');
-}
-
-async function decode() {
-    const form = new FormData();
-    form.append('day_phrase', 'apple forest thunder');
-    form.append('pin', '123456');
-    form.append('reference_photo', fs.createReadStream('reference.jpg'));
-    form.append('stego_image', fs.createReadStream('stego.png'));
-
-    const response = await axios.post(`${BASE_URL}/decode/multipart`, form, {
-        headers: form.getHeaders()
-    });
-
-    console.log('Decoded:', response.data.message);
-}
-
-encode().then(decode);
-```
-
-### Go
-
-```go
-package main
-
-import (
-    "bytes"
-    "encoding/json"
-    "fmt"
-    "io"
-    "mime/multipart"
-    "net/http"
-    "os"
-)
-
-func main() {
-    // Encode
-    body := &bytes.Buffer{}
-    writer := multipart.NewWriter(body)
-
-    writer.WriteField("message", "Secret message")
-    writer.WriteField("day_phrase", "apple forest thunder")
-    writer.WriteField("pin", "123456")
-
-    ref, _ := os.Open("reference.jpg")
-    refPart, _ := writer.CreateFormFile("reference_photo", "reference.jpg")
-    io.Copy(refPart, ref)
-    ref.Close()
-
-    carrier, _ := os.Open("carrier.png")
-    carrierPart, _ := writer.CreateFormFile("carrier", "carrier.png")
-    io.Copy(carrierPart, carrier)
-    carrier.Close()
-
-    writer.Close()
-
-    resp, _ := http.Post(
-        "http://localhost:8000/encode/multipart",
-        writer.FormDataContentType(),
-        body,
-    )
-
-    stego, _ := os.Create("stego.png")
-    io.Copy(stego, resp.Body)
-    stego.Close()
-    resp.Body.Close()
-
-    fmt.Println("Encoded successfully")
-}
-```
-
-### Shell Script (Bash)
-
-```bash
-#!/bin/bash
-
-BASE_URL="http://localhost:8000"
-REF_PHOTO="reference.jpg"
-CARRIER="carrier.png"
-PHRASE="apple forest thunder"
-PIN="123456"
-MESSAGE="Secret message"
-
-# Encode
-echo "Encoding..."
-curl -s -X POST "$BASE_URL/encode/multipart" \
-  -F "message=$MESSAGE" \
-  -F "day_phrase=$PHRASE" \
-  -F "pin=$PIN" \
-  -F "reference_photo=@$REF_PHOTO" \
-  -F "carrier=@$CARRIER" \
-  --output stego.png
-
-echo "Encoded to stego.png"
-
-# Decode
-echo "Decoding..."
-DECODED=$(curl -s -X POST "$BASE_URL/decode/multipart" \
-  -F "day_phrase=$PHRASE" \
-  -F "pin=$PIN" \
-  -F "reference_photo=@$REF_PHOTO" \
-  -F "stego_image=@stego.png" | jq -r '.message')
-
-echo "Decoded message: $DECODED"
-```
-
----
-
-## Rate Limiting
-
-The API does not implement rate limiting by default. For production:
-
-1. **Reverse Proxy**: Use nginx or Caddy rate limiting
-2. **Application Level**: Add FastAPI middleware
-
-Example nginx rate limiting:
-```nginx
-limit_req_zone $binary_remote_addr zone=stegasoo:10m rate=10r/s;
-
-location /api/ {
-    limit_req zone=stegasoo burst=20 nodelay;
-    proxy_pass http://localhost:8000/;
-}
-```
-
----
-
-## Security Considerations
-
-### In Transit
-
-- Use HTTPS in production
-- Configure TLS at reverse proxy level
-
-### Memory Usage
-
-- Argon2id requires 256MB RAM per operation
-- Concurrent requests can exhaust memory
-- Limit workers based on available RAM
-
-### Input Validation
-
-The API validates:
-- PIN format (6-9 digits, no leading zero)
-- Message size (max 50KB)
-- Image size (max 5MB file, ~4MP dimensions)
-- RSA key validity
-
-### Credential Handling
-
-- Credentials are never logged
-- No persistent storage of secrets
-- Memory cleared after operations
-
----
-
-## Interactive Documentation
-
-When the API is running, visit:
-
-- **Swagger UI**: http://localhost:8000/docs
-- **ReDoc**: http://localhost:8000/redoc
-
----
-
-## See Also
-
-- [CLI Documentation](CLI.md) - Command-line interface
-- [Web UI Documentation](WEB_UI.md) - Browser interface
-- [README](README.md) - Project overview
-- Image size (max 5MB file, ~4MP dimensions)
-- RSA key validity
-
-### Credential Handling
-
-- Credentials are never logged
-- No persistent storage of secrets
-- Memory cleared after operations
-
----
-
-## Interactive Documentation
-
-When the API is running, visit:
-
-- **Swagger UI**: http://localhost:8000/docs
-- **ReDoc**: http://localhost:8000/redoc
-
----
-
-## See Also
-
-- [CLI Documentation](CLI.md) - Command-line interface
-- [Web UI Documentation](WEB_UI.md) - Browser interface
-- [README](README.md) - Project overview

frontends/CLI.md

@@ -1,634 +0,0 @@
-# Stegasoo CLI Documentation
-
-Complete command-line interface reference for Stegasoo steganography operations.
-
-## Table of Contents
-
-- [Installation](#installation)
-- [Quick Start](#quick-start)
-- [Commands](#commands)
-  - [generate](#generate-command)
-  - [encode](#encode-command)
-  - [decode](#decode-command)
-  - [info](#info-command)
-- [Security Factors](#security-factors)
-- [Workflow Examples](#workflow-examples)
-- [Piping & Scripting](#piping--scripting)
-- [Error Handling](#error-handling)
-- [Exit Codes](#exit-codes)
-
----
-
-## Installation
-
-### From PyPI
-
-```bash
-# CLI only
-pip install stegasoo[cli]
-
-# With all extras
-pip install stegasoo[all]
-```
-
-### From Source
-
-```bash
-git clone https://github.com/example/stegasoo.git
-cd stegasoo
-pip install -e ".[cli]"
-```
-
-### Verify Installation
-
-```bash
-stegasoo --version
-stegasoo --help
-```
-
----
-
-## Quick Start
-
-```bash
-# 1. Generate credentials (do this once, memorize results)
-stegasoo generate --pin --words 3
-
-# 2. Encode a message
-stegasoo encode \
-  --ref secret_photo.jpg \
-  --carrier meme.png \
-  --phrase "apple forest thunder" \
-  --pin 123456 \
-  --message "Meet at midnight"
-
-# 3. Decode a message
-stegasoo decode \
-  --ref secret_photo.jpg \
-  --stego stego_abc123_20251227.png \
-  --phrase "apple forest thunder" \
-  --pin 123456
-```
-
----
-
-## Commands
-
-### Generate Command
-
-Generate credentials for encoding/decoding operations. Creates daily passphrases and optionally a PIN and/or RSA key.
-
-#### Synopsis
-
-```bash
-stegasoo generate [OPTIONS]
-```
-
-#### Options
-
-| Option | Short | Type | Default | Description |
-|--------|-------|------|---------|-------------|
-| `--pin/--no-pin` | | flag | `--pin` | Generate a PIN |
-| `--rsa/--no-rsa` | | flag | `--no-rsa` | Generate an RSA key |
-| `--pin-length` | | 6-9 | 6 | PIN length in digits |
-| `--rsa-bits` | | choice | 2048 | RSA key size (2048, 3072, 4096) |
-| `--words` | | 3-12 | 3 | Words per daily phrase |
-| `--output` | `-o` | path | | Save RSA key to file |
-| `--password` | `-p` | string | | Password for RSA key file |
-| `--json` | | flag | | Output as JSON |
-
-#### Examples
-
-**Basic generation with PIN (default):**
-```bash
-stegasoo generate
-```
-
-Output:
-```
-════════════════════════════════════════════════════════════
-  STEGASOO CREDENTIALS
-════════════════════════════════════════════════════════════
-
-⚠️  MEMORIZE THESE AND CLOSE THIS WINDOW
-    Do not screenshot or save to file!
-
-─── STATIC PIN ───
-    847293
-
-─── DAILY PHRASES ───
-    Monday    │ abandon ability able
-    Tuesday   │ actor actress actual
-    Wednesday │ advice aerobic affair
-    Thursday  │ afraid again age
-    Friday    │ agree ahead aim
-    Saturday  │ airport aisle alarm
-    Sunday    │ album alcohol alert
-
-─── SECURITY ───
-    Phrase entropy:  33 bits
-    PIN entropy:     19 bits
-    Combined:        52 bits
-    + photo entropy: 80-256 bits
-```
-
-**Generate with RSA key:**
-```bash
-stegasoo generate --rsa --rsa-bits 4096
-```
-
-**Save RSA key to encrypted file:**
-```bash
-stegasoo generate --rsa -o mykey.pem -p "mysecretpassword"
-```
-
-**Maximum security (longer phrases + both factors):**
-```bash
-stegasoo generate --pin --rsa --words 6 --pin-length 9
-```
-
-**JSON output for scripting:**
-```bash
-stegasoo generate --json | jq '.phrases.Monday'
-```
-
-**RSA only (no PIN):**
-```bash
-stegasoo generate --no-pin --rsa -o key.pem -p "password123"
-```
-
----
-
-### Encode Command
-
-Encode a secret message into an image using steganography.
-
-#### Synopsis
-
-```bash
-stegasoo encode [OPTIONS]
-```
-
-#### Options
-
-| Option | Short | Type | Required | Description |
-|--------|-------|------|----------|-------------|
-| `--ref` | `-r` | path | ✓ | Reference photo (shared secret) |
-| `--carrier` | `-c` | path | ✓ | Carrier image to hide message in |
-| `--phrase` | `-p` | string | ✓ | Today's passphrase |
-| `--message` | `-m` | string | | Message to encode |
-| `--message-file` | `-f` | path | | Read message from file |
-| `--pin` | | string | * | Static PIN (6-9 digits) |
-| `--key` | `-k` | path | * | RSA key file |
-| `--key-password` | | string | | Password for RSA key |
-| `--output` | `-o` | path | | Output filename |
-| `--date` | | YYYY-MM-DD | | Date override |
-| `--quiet` | `-q` | flag | | Suppress output |
-
-\* At least one of `--pin` or `--key` is required.
-
-#### Message Input Methods
-
-1. **Command line argument:**
-   ```bash
-   stegasoo encode -r ref.jpg -c carrier.png -p "phrase" --pin 123456 -m "Secret message"
-   ```
-
-2. **From file:**
-   ```bash
-   stegasoo encode -r ref.jpg -c carrier.png -p "phrase" --pin 123456 -f message.txt
-   ```
-
-3. **From stdin (pipe):**
-   ```bash
-   echo "Secret message" | stegasoo encode -r ref.jpg -c carrier.png -p "phrase" --pin 123456
-   ```
-
-#### Examples
-
-**Basic encoding with PIN:**
-```bash
-stegasoo encode \
-  --ref photos/vacation.jpg \
-  --carrier memes/funny_cat.png \
-  --phrase "correct horse battery" \
-  --pin 847293 \
-  --message "The package arrives Tuesday"
-```
-
-Output:
-```
-✓ Encoded successfully!
-  Output: a1b2c3d4_20251227.png
-  Size: 245,832 bytes
-  Capacity used: 12.4%
-  Date: 2025-12-27
-```
-
-**With RSA key:**
-```bash
-stegasoo encode \
-  -r reference.jpg \
-  -c carrier.png \
-  -p "apple forest thunder" \
-  -k mykey.pem \
-  --key-password "secretpassword" \
-  -m "Encrypted with RSA"
-```
-
-**Both PIN and RSA (maximum security):**
-```bash
-stegasoo encode \
-  -r ref.jpg \
-  -c carrier.png \
-  -p "word1 word2 word3" \
-  --pin 123456 \
-  -k mykey.pem \
-  --key-password "pass" \
-  -m "Double-locked message"
-```
-
-**Custom output filename:**
-```bash
-stegasoo encode \
-  -r ref.jpg \
-  -c carrier.png \
-  -p "phrase words here" \
-  --pin 123456 \
-  -m "Message" \
-  -o holiday_photo.png
-```
-
-**Encoding with specific date (for testing):**
-```bash
-stegasoo encode \
-  -r ref.jpg \
-  -c carrier.png \
-  -p "monday phrase here" \
-  --pin 123456 \
-  -m "Message" \
-  --date 2025-12-29
-```
-
-**Long message from file:**
-```bash
-stegasoo encode \
-  -r ref.jpg \
-  -c large_image.png \
-  -p "phrase" \
-  --pin 123456 \
-  -f secret_document.txt \
-  -o output.png
-```
-
-**Quiet mode for scripting:**
-```bash
-stegasoo encode -r ref.jpg -c carrier.png -p "phrase" --pin 123456 -m "msg" -q -o out.png
-# No output, just creates the file
-```
-
----
-
-### Decode Command
-
-Decode a secret message from a stego image.
-
-#### Synopsis
-
-```bash
-stegasoo decode [OPTIONS]
-```
-
-#### Options
-
-| Option | Short | Type | Required | Description |
-|--------|-------|------|----------|-------------|
-| `--ref` | `-r` | path | ✓ | Reference photo (same as encoding) |
-| `--stego` | `-s` | path | ✓ | Stego image to decode |
-| `--phrase` | `-p` | string | ✓ | Passphrase for the encoding day |
-| `--pin` | | string | * | Static PIN |
-| `--key` | `-k` | path | * | RSA key file |
-| `--key-password` | | string | | Password for RSA key |
-| `--output` | `-o` | path | | Save message to file |
-| `--quiet` | `-q` | flag | | Output only the message |
-
-\* Must provide the same security factors used during encoding.
-
-#### Examples
-
-**Basic decoding with PIN:**
-```bash
-stegasoo decode \
-  --ref photos/vacation.jpg \
-  --stego received_image.png \
-  --phrase "correct horse battery" \
-  --pin 847293
-```
-
-Output:
-```
-✓ Decoded successfully!
-
-The package arrives Tuesday
-```
-
-**With RSA key:**
-```bash
-stegasoo decode \
-  -r reference.jpg \
-  -s stego_image.png \
-  -p "apple forest thunder" \
-  -k mykey.pem \
-  --key-password "secretpassword"
-```
-
-**Save decoded message to file:**
-```bash
-stegasoo decode \
-  -r ref.jpg \
-  -s stego.png \
-  -p "phrase" \
-  --pin 123456 \
-  -o decoded_message.txt
-```
-
-Output:
-```
-✓ Decoded successfully!
-  Saved to: decoded_message.txt
-```
-
-**Quiet mode (message only):**
-```bash
-stegasoo decode -r ref.jpg -s stego.png -p "phrase" --pin 123456 -q
-```
-
-Output:
-```
-The package arrives Tuesday
-```
-
-**Pipe to another command:**
-```bash
-stegasoo decode -r ref.jpg -s stego.png -p "phrase" --pin 123456 -q | gpg --decrypt
-```
-
----
-
-### Info Command
-
-Display information about an image's capacity and embedded date.
-
-#### Synopsis
-
-```bash
-stegasoo info IMAGE
-```
-
-#### Arguments
-
-| Argument | Type | Description |
-|----------|------|-------------|
-| `IMAGE` | path | Path to image file |
-
-#### Examples
-
-**Check carrier image capacity:**
-```bash
-stegasoo info vacation_photo.png
-```
-
-Output:
-```
-Image: vacation_photo.png
-  Dimensions:  1920 × 1080
-  Pixels:      2,073,600
-  Mode:        RGB
-  Format:      PNG
-  Capacity:    ~776,970 bytes (758 KB)
-```
-
-**Check stego image (shows encoding date):**
-```bash
-stegasoo info stego_a1b2c3d4_20251227.png
-```
-
-Output:
-```
-Image: stego_a1b2c3d4_20251227.png
-  Dimensions:  1920 × 1080
-  Pixels:      2,073,600
-  Mode:        RGB
-  Format:      PNG
-  Capacity:    ~776,970 bytes (758 KB)
-  Embed date:  2025-12-27 (Saturday)
-```
-
----
-
-## Security Factors
-
-Stegasoo uses multiple authentication factors:
-
-| Factor | Description | Entropy |
-|--------|-------------|---------|
-| Reference Photo | A photo both parties have | ~80-256 bits |
-| Day Phrase | Changes daily (e.g., 3 BIP-39 words) | ~33 bits (3 words) |
-| Static PIN | Same every day (6-9 digits) | ~20 bits (6 digits) |
-| RSA Key | Shared key file | ~128 bits effective |
-
-### Minimum Requirements
-
-- At least one of PIN or RSA key must be provided
-- Reference photo is always required
-- Day phrase is always required
-
-### Security Configurations
-
-| Configuration | Entropy (excl. photo) | Use Case |
-|--------------|----------------------|----------|
-| 3-word phrase + 6-digit PIN | ~53 bits | Casual use |
-| 6-word phrase + 9-digit PIN | ~96 bits | Standard security |
-| 3-word phrase + RSA 2048 | ~161 bits | File-based auth |
-| 6-word phrase + PIN + RSA | ~224 bits | Maximum security |
-
----
-
-## Workflow Examples
-
-### Daily Secure Communication
-
-**Setup (once):**
-```bash
-# Both parties generate same credentials
-stegasoo generate --pin --words 3
-
-# Or share RSA key securely
-stegasoo generate --rsa -o shared_key.pem -p "agreedpassword"
-# Securely transfer shared_key.pem to recipient
-```
-
-**Sender (daily):**
-```bash
-# Get today's phrase from your memorized list
-TODAY_PHRASE="monday phrase words"
-
-# Encode message
-stegasoo encode \
-  -r our_shared_photo.jpg \
-  -c random_meme.png \
-  -p "$TODAY_PHRASE" \
-  --pin 847293 \
-  -m "Meeting moved to 3pm"
-
-# Share output image via normal channels (email, chat, etc.)
-```
-
-**Recipient (daily):**
-```bash
-# Use the phrase for the day the message was SENT
-stegasoo decode \
-  -r our_shared_photo.jpg \
-  -s received_image.png \
-  -p "monday phrase words" \
-  --pin 847293
-```
-
-### Batch Processing
-
-**Encode multiple messages:**
-```bash
-#!/bin/bash
-PHRASE="apple forest thunder"
-PIN="123456"
-REF="reference.jpg"
-
-for file in messages/*.txt; do
-  name=$(basename "$file" .txt)
-  stegasoo encode \
-    -r "$REF" \
-    -c "carriers/${name}.png" \
-    -p "$PHRASE" \
-    --pin "$PIN" \
-    -f "$file" \
-    -o "output/${name}_stego.png" \
-    -q
-  echo "Encoded: $name"
-done
-```
-
-### Archive with Date Preservation
-
-```bash
-# Encode with specific date for archival
-stegasoo encode \
-  -r ref.jpg \
-  -c carrier.png \
-  -p "archive phrase words" \
-  --pin 123456 \
-  -m "Historical record" \
-  --date 2025-01-15 \
-  -o archive_2025-01-15.png
-```
-
----
-
-## Piping & Scripting
-
-### Stdin/Stdout Support
-
-**Encode from pipe:**
-```bash
-cat secret.txt | stegasoo encode -r ref.jpg -c carrier.png -p "phrase" --pin 123456 -o out.png
-```
-
-**Decode to pipe:**
-```bash
-stegasoo decode -r ref.jpg -s stego.png -p "phrase" --pin 123456 -q | less
-```
-
-**Chain with encryption:**
-```bash
-# Encode GPG-encrypted content
-gpg -e -r recipient@email.com secret.txt
-cat secret.txt.gpg | base64 | stegasoo encode -r ref.jpg -c carrier.png -p "phrase" --pin 123456
-
-# Decode and decrypt
-stegasoo decode -r ref.jpg -s stego.png -p "phrase" --pin 123456 -q | base64 -d | gpg -d
-```
-
-### JSON Output for Scripts
-
-```bash
-# Get credentials as JSON
-creds=$(stegasoo generate --json)
-
-# Extract specific fields
-pin=$(echo "$creds" | jq -r '.pin')
-monday=$(echo "$creds" | jq -r '.phrases.Monday')
-entropy=$(echo "$creds" | jq -r '.entropy.total')
-
-echo "PIN: $pin"
-echo "Monday phrase: $monday"
-echo "Total entropy: $entropy bits"
-```
-
-### Error Handling in Scripts
-
-```bash
-#!/bin/bash
-set -e
-
-if ! stegasoo decode -r ref.jpg -s stego.png -p "phrase" --pin 123456 -q 2>/dev/null; then
-  echo "Decryption failed - check credentials"
-  exit 1
-fi
-```
-
----
-
-## Error Handling
-
-### Common Errors
-
-| Error | Cause | Solution |
-|-------|-------|----------|
-| "Must provide --pin or --key" | No security factor given | Add `--pin` or `--key` option |
-| "PIN must be 6-9 digits" | Invalid PIN format | Use numeric PIN, 6-9 chars |
-| "PIN cannot start with zero" | Leading zero in PIN | Use PIN starting with 1-9 |
-| "Carrier image too small" | Message exceeds capacity | Use larger carrier image |
-| "Decryption failed" | Wrong credentials | Verify phrase, PIN, ref photo |
-| "RSA key is password-protected" | Missing key password | Add `--key-password` option |
-
-### Troubleshooting Decryption Failures
-
-1. **Check the encoding date:** The filename often contains the date (e.g., `_20251227`)
-2. **Use correct phrase:** The phrase must match the day the message was encoded, not today
-3. **Verify reference photo:** Must be the exact same file, not a resized copy
-4. **Check stego image:** Ensure it wasn't resized, recompressed, or converted
-
----
-
-## Exit Codes
-
-| Code | Meaning |
-|------|---------|
-| 0 | Success |
-| 1 | General error |
-| 2 | Invalid arguments/options |
-
----
-
-## Environment Variables
-
-| Variable | Description |
-|----------|-------------|
-| `PYTHONPATH` | Include `src/` for development |
-
----
-
-## See Also
-
-- [API Documentation](API.md) - REST API reference
-- [Web UI Documentation](WEB_UI.md) - Browser interface guide
-- [README](README.md) - Project overview and security model

frontends/WEB_UI.md

@@ -1,739 +0,0 @@
-# Stegasoo Web UI Documentation
-
-Complete guide for the Stegasoo web-based steganography interface.
-
-## Table of Contents
-
-- [Overview](#overview)
-- [Installation & Setup](#installation--setup)
-- [Pages & Features](#pages--features)
-  - [Home Page](#home-page)
-  - [Generate Credentials](#generate-credentials)
-  - [Encode Message](#encode-message)
-  - [Decode Message](#decode-message)
-  - [About Page](#about-page)
-- [User Interface Guide](#user-interface-guide)
-- [Workflow Examples](#workflow-examples)
-- [Security Features](#security-features)
-- [Configuration](#configuration)
-- [Troubleshooting](#troubleshooting)
-- [Mobile Support](#mobile-support)
-
----
-
-## Overview
-
-The Stegasoo Web UI provides a user-friendly browser-based interface for:
-
-- **Generating** secure credentials (phrases, PINs, RSA keys)
-- **Encoding** secret messages into images
-- **Decoding** hidden messages from images
-- **Learning** about the security model
-
-Built with Flask, Bootstrap 5, and a modern dark theme.
-
-### Features
-
-- ✅ Drag-and-drop file uploads
-- ✅ Image previews
-- ✅ Client-side date detection
-- ✅ Native sharing (Web Share API)
-- ✅ Responsive design (mobile-friendly)
-- ✅ Password-protected RSA key downloads
-- ✅ Real-time entropy calculations
-- ✅ Automatic file cleanup
-
----
-
-## Installation & Setup
-
-### From PyPI
-
-```bash
-pip install stegasoo[web]
-```
-
-### From Source
-
-```bash
-git clone https://github.com/example/stegasoo.git
-cd stegasoo
-pip install -e ".[web]"
-```
-
-### Running the Server
-
-**Development:**
-```bash
-cd frontends/web
-python app.py
-```
-Server starts at http://localhost:5000
-
-**Production with Gunicorn:**
-```bash
-cd frontends/web
-gunicorn --bind 0.0.0.0:5000 --workers 2 --threads 4 --timeout 60 app:app
-```
-
-**Docker:**
-```bash
-docker-compose up web
-```
-
-### First-Time Setup
-
-1. Navigate to http://localhost:5000
-2. Click "Generate" to create your credentials
-3. **Memorize** your phrases and PIN
-4. Share credentials securely with your communication partner
-
----
-
-## Pages & Features
-
-### Home Page
-
-**URL:** `/`
-
-The landing page introduces Stegasoo and provides quick access to all features.
-
-#### Main Actions
-
-| Card | Description | Link |
-|------|-------------|------|
-| **Encode Message** | Hide a secret in an image | `/encode` |
-| **Decode Message** | Extract a hidden message | `/decode` |
-| **Generate Keys** | Create new credentials | `/generate` |
-
-#### "How It Works" Section
-
-Explains the three key components:
-1. **Reference Photo** - Shared secret image
-2. **Day Phrase** - Changes daily
-3. **Static PIN** - Same every day
-
----
-
-### Generate Credentials
-
-**URL:** `/generate`
-
-Create a new set of credentials for steganography operations.
-
-#### Configuration Options
-
-| Option | Range | Default | Description |
-|--------|-------|---------|-------------|
-| Words per phrase | 3-12 | 3 | BIP-39 words per daily phrase |
-| Use PIN | on/off | on | Generate a numeric PIN |
-| PIN length | 6-9 | 6 | Digits in the PIN |
-| Use RSA Key | on/off | off | Generate an RSA key pair |
-| RSA key size | 2048/3072/4096 | 2048 | Key size in bits |
-
-#### Entropy Calculator
-
-The UI displays real-time entropy calculations:
-
-```
-Estimated entropy: ~53 bits
-[==========>                    ] Good for most use cases
-• Reference photo adds ~80-256 bits more
-```
-
-#### Generated Output
-
-After clicking "Generate Credentials":
-
-**Static PIN** (if enabled):
-```
-┌─────────────────────┐
-│      8 4 7 2 9 3    │
-└─────────────────────┘
-Use this 6-digit PIN every day
-```
-
-**Daily Phrases:**
-```
-Day         │ Phrase
-─────────────────────────────────────────
-Monday      │ abandon ability able
-Tuesday     │ actor actress actual
-Wednesday   │ advice aerobic affair
-Thursday    │ afraid again age
-Friday      │ agree ahead aim
-Saturday    │ airport aisle alarm
-Sunday      │ album alcohol alert
-```
-
-**RSA Key** (if enabled):
-- Copy to clipboard button
-- Download as password-protected .pem file
-
-**Security Summary:**
-```
-Phrase entropy: 33 bits/phrase
-PIN entropy:    19 bits/PIN
-RSA entropy:    128 bits/RSA
-─────────────────────────────
-Total:          180 bits
-+ reference photo (~80-256 bits) = 260+ bits combined
-```
-
-#### RSA Key Download
-
-1. Click "Download as .pem"
-2. Enter a password (minimum 8 characters)
-3. Click "Download Protected Key"
-4. Save the file securely
-5. Share with your communication partner through a secure channel
-
----
-
-### Encode Message
-
-**URL:** `/encode`
-
-Hide a secret message inside an image.
-
-#### Input Fields
-
-| Field | Type | Required | Description |
-|-------|------|----------|-------------|
-| Reference Photo | Image file | ✓ | Your shared secret photo |
-| Carrier Image | Image file | ✓ | Image to hide message in |
-| Secret Message | Text | ✓ | Message to hide (max 50KB) |
-| Day Phrase | Text | ✓ | Today's passphrase |
-| PIN | Number | * | Your static PIN |
-| RSA Key | .pem file | * | Your shared RSA key |
-| RSA Key Password | Password | | Password for encrypted key |
-
-\* At least one security factor (PIN or RSA Key) required.
-
-#### Drag-and-Drop Upload
-
-Both image upload zones support:
-- Click to browse
-- Drag and drop files
-- Instant image preview
-- File name display
-
-#### Character Counter
-
-```
-Message: [                                              ]
-         1,234 / 50,000 characters                  2%
-```
-
-Shows warning at 80% capacity.
-
-#### Day Detection
-
-The page automatically detects your local day of week and updates the label:
-```
-Saturday's Phrase: [                    ]
-```
-
-#### Encoding Process
-
-1. Fill in all required fields
-2. Click "Encode Message"
-3. Wait for processing (shows spinner)
-4. Redirected to result page
-
-#### Result Page
-
-**URL:** `/encode/result/<file_id>`
-
-After successful encoding:
-
-```
-┌────────────────────────────────────────┐
-│  ✓ Message Encoded Successfully!       │
-│                                        │
-│     📄 a1b2c3d4_20251227.png          │
-│     Your secret message is hidden      │
-│     in this image                      │
-│                                        │
-│     [    Download Image    ]           │
-│     [      Share Image     ]           │
-│                                        │
-│  ⚠️ File expires in 5 minutes.         │
-│     Download or share now.             │
-│                                        │
-│     [ Encode Another Message ]         │
-└────────────────────────────────────────┘
-```
-
-**Share Options:**
-
-1. **Native Share** (mobile/supported browsers):
-   - Uses Web Share API
-   - Opens system share sheet
-   - Can share directly to apps
-
-2. **Fallback Share** (desktop):
-   - Email link
-   - Telegram link
-   - WhatsApp link
-   - Copy link to clipboard
-
----
-
-### Decode Message
-
-**URL:** `/decode`
-
-Extract a hidden message from a stego image.
-
-#### Input Fields
-
-| Field | Type | Required | Description |
-|-------|------|----------|-------------|
-| Reference Photo | Image file | ✓ | Same photo used for encoding |
-| Stego Image | Image file | ✓ | Image containing hidden message |
-| Day Phrase | Text | ✓ | Phrase for the **encoding** day |
-| PIN | Number | * | Same PIN used for encoding |
-| RSA Key | .pem file | * | Same RSA key used for encoding |
-| RSA Key Password | Password | | Password for encrypted key |
-
-\* Must match security factors used during encoding.
-
-#### Date Detection from Filename
-
-When you upload a stego image with a date in the filename (e.g., `stego_20251227.png`), the UI:
-1. Extracts the date
-2. Determines the day of week
-3. Updates the phrase label: "Saturday's Phrase"
-
-This helps you use the correct daily phrase.
-
-#### Decoding Process
-
-1. Fill in all required fields
-2. Click "Decode Message"
-3. Wait for processing
-4. View decoded message on same page
-
-#### Successful Decode
-
-```
-┌────────────────────────────────────────┐
-│  ✓ Message Decrypted Successfully!     │
-│                                        │
-│  Decoded Message:                      │
-│  ┌──────────────────────────────────┐  │
-│  │ Meet at midnight. The package    │  │
-│  │ will be under the bridge.        │  │
-│  └──────────────────────────────────┘  │
-│                                        │
-│     [ Decode Another Message ]         │
-└────────────────────────────────────────┘
-```
-
-#### Troubleshooting Tips
-
-The page includes built-in troubleshooting guidance:
-
-- ✓ Use the **exact same reference photo** file
-- ✓ Use the phrase for the **encoding day**, not today
-- ✓ Provide the **same security factors** used during encoding
-- ✓ Ensure the stego image hasn't been **resized or recompressed**
-- ✓ If using RSA key, verify the **password is correct**
-
----
-
-### About Page
-
-**URL:** `/about`
-
-Learn about Stegasoo's security model and best practices.
-
-#### Sections
-
-**System Status:**
-- Argon2id availability (vs PBKDF2 fallback)
-- AES-256-GCM encryption status
-
-**Security Model Table:**
-
-| Component | Entropy | Purpose |
-|-----------|---------|---------|
-| Reference Photo | ~80-256 bits | Something you have |
-| 3-Word Phrase | ~33 bits | Something you know (daily) |
-| 6-Digit PIN | ~20 bits | Something you know (static) |
-| Date | N/A | Automatic key rotation |
-| **Combined** | **133+ bits** | **Beyond brute force** |
-
-**Attack Resistance:**
-
-What attackers can't do:
-- Brute force (2^133 combinations)
-- Use rainbow tables (random salt)
-- Detect hidden data (random pixels)
-- Use GPU farms (256MB RAM per attempt)
-
-Real threats:
-- Social engineering
-- Physical device access
-- Malware/keyloggers
-- Shoulder surfing
-
-**Best Practices:**
-
-Do:
-- Memorize phrases and PIN
-- Use reference photo both parties have
-- Use different carrier images each time
-- Share stego images through normal channels
-
-Don't:
-- Transmit the reference photo
-- Reuse carrier images
-- Store credentials digitally
-- Resize/recompress stego images
-
----
-
-## User Interface Guide
-
-### Navigation
-
-The navbar provides quick access to all pages:
-
-```
-[Logo] Stegasoo    Home | Encode | Decode | Generate | About
-```
-
-### Color Scheme
-
-| Element | Color | Purpose |
-|---------|-------|---------|
-| Background | Dark gradient | Reduce eye strain |
-| Cards | Semi-transparent | Visual hierarchy |
-| Headers | Purple gradient | Brand identity |
-| Success | Green | Positive actions |
-| Warning | Yellow | Caution messages |
-| Error | Red | Error states |
-
-### Form Validation
-
-- Real-time validation feedback
-- Clear error messages in alerts
-- Required field indicators
-- Input constraints (max length, format)
-
-### Loading States
-
-During long operations:
-- Button shows spinner
-- Button text changes (e.g., "Encoding...")
-- Button is disabled to prevent double-submit
-
-### Flash Messages
-
-```
-┌──────────────────────────────────────────────┐
-│ ✓ Credentials Generated!              [×]   │
-└──────────────────────────────────────────────┘
-```
-
-Types:
-- Success (green) - Operation completed
-- Error (red) - Operation failed
-- Warning (yellow) - Caution needed
-
----
-
-## Workflow Examples
-
-### First-Time Setup (Both Parties)
-
-**Party A:**
-1. Go to `/generate`
-2. Configure: PIN ✓, 3 words, 6 digits
-3. Click "Generate Credentials"
-4. **Write down** phrases and PIN on paper
-5. **Memorize** over the next few days
-6. Destroy the paper
-
-**Share with Party B (in person or secure channel):**
-- The 7 daily phrases
-- The PIN
-- The reference photo file (if not already shared)
-
-### Sending a Secret Message
-
-1. Go to `/encode`
-2. Upload your shared reference photo
-3. Upload any carrier image (meme, vacation photo, etc.)
-4. Type your secret message
-5. Enter today's phrase (check your memory!)
-6. Enter your PIN
-7. Click "Encode Message"
-8. Download or share the resulting image
-9. Send via any channel (email, social media, chat)
-
-### Receiving a Secret Message
-
-1. Receive the stego image through any channel
-2. Go to `/decode`
-3. Upload the same reference photo
-4. Upload the received stego image
-5. Note the date in the filename (e.g., `_20251227`)
-6. Enter the phrase for **that day** (not today!)
-7. Enter the PIN
-8. Click "Decode Message"
-9. Read the secret message
-
-### Changing Credentials
-
-To rotate to new credentials:
-1. Both parties generate new credentials together
-2. Agree on a cutover date
-3. Messages encoded before cutover use old credentials
-4. Messages encoded after cutover use new credentials
-
----
-
-## Security Features
-
-### Client-Side Security
-
-| Feature | Implementation |
-|---------|----------------|
-| Local date detection | JavaScript `Date()` object |
-| No credential storage | Nothing saved in browser |
-| Automatic cleanup | Files deleted after 5 minutes |
-| HTTPS support | Configure at server level |
-
-### Server-Side Security
-
-| Feature | Implementation |
-|---------|----------------|
-| Memory-hard KDF | Argon2id (256MB RAM) |
-| Authenticated encryption | AES-256-GCM |
-| Random salt | Per-message salt |
-| Temporary storage | In-memory, auto-expiring |
-| Input validation | All inputs validated |
-| File size limits | 5MB max upload |
-
-### File Security
-
-| Aspect | Protection |
-|--------|------------|
-| Upload location | `/tmp/stego_uploads` (Docker) |
-| Storage duration | 5 minutes maximum |
-| Access control | Random 16-byte file ID |
-| Cleanup | Automatic + manual |
-
----
-
-## Configuration
-
-### Environment Variables
-
-| Variable | Default | Description |
-|----------|---------|-------------|
-| `FLASK_ENV` | production | Flask environment |
-| `PYTHONPATH` | - | Include `src/` for development |
-
-### Application Limits
-
-| Limit | Value | Config Location |
-|-------|-------|-----------------|
-| Max file upload | 5 MB | `app.config['MAX_CONTENT_LENGTH']` |
-| File expiry | 5 minutes | `TEMP_FILE_EXPIRY` |
-| Max image pixels | 4 MP | `stegasoo.constants` |
-| Max message size | 50 KB | `stegasoo.constants` |
-| PIN length | 6-9 digits | `stegasoo.constants` |
-
-### Production Deployment
-
-**With Gunicorn:**
-```bash
-gunicorn \
-  --bind 0.0.0.0:5000 \
-  --workers 2 \
-  --threads 4 \
-  --timeout 60 \
-  app:app
-```
-
-**Worker Calculation:**
-- Each encode/decode uses ~256MB RAM (Argon2)
-- Formula: `workers = (available_RAM - 512MB) / 256MB`
-
-**With Nginx (reverse proxy):**
-```nginx
-server {
-    listen 80;
-    server_name stegasoo.example.com;
-
-    client_max_body_size 10M;
-
-    location / {
-        proxy_pass http://127.0.0.1:5000;
-        proxy_set_header Host $host;
-        proxy_set_header X-Real-IP $remote_addr;
-        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
-        proxy_read_timeout 120s;
-    }
-}
-```
-
-**With Docker Compose:**
-```yaml
-services:
-  web:
-    build:
-      context: .
-      target: web
-    ports:
-      - "5000:5000"
-    deploy:
-      resources:
-        limits:
-          memory: 512M
-        reservations:
-          memory: 256M
-```
-
----
-
-## Troubleshooting
-
-### Common Issues
-
-#### "Decryption failed"
-
-**Causes:**
-- Wrong day phrase
-- Wrong PIN
-- Different reference photo
-- Stego image was modified
-
-**Solutions:**
-1. Check the date in the stego filename
-2. Use the phrase for that specific day
-3. Verify you're using the original reference photo
-4. Ensure the stego image wasn't resized/recompressed
-
-#### "Carrier image too small"
-
-**Cause:** Message too large for carrier capacity
-
-**Solutions:**
-1. Use a larger carrier image (more pixels)
-2. Shorten the message
-3. Check capacity with `/info` command (CLI)
-
-#### "You must provide at least a PIN or RSA Key"
-
-**Cause:** No security factor selected
-
-**Solution:** Enter a PIN and/or upload an RSA key
-
-#### Upload fails silently
-
-**Causes:**
-- File too large (>5MB)
-- Invalid file type
-- Browser issue
-
-**Solutions:**
-1. Reduce file size
-2. Use PNG, JPG, or BMP formats
-3. Try a different browser
-
-#### RSA key password error
-
-**Causes:**
-- Wrong password
-- Unencrypted key with password provided
-- Corrupted key file
-
-**Solutions:**
-1. Verify the correct password
-2. If key is unencrypted, leave password blank
-3. Re-download or regenerate the key
-
-### Browser Compatibility
-
-| Browser | Status | Notes |
-|---------|--------|-------|
-| Chrome 80+ | ✓ Full | Web Share API supported |
-| Firefox 80+ | ✓ Full | Limited Web Share |
-| Safari 14+ | ✓ Full | Web Share on iOS |
-| Edge 80+ | ✓ Full | Web Share API supported |
-| IE 11 | ✗ None | Not supported |
-
-### Performance Issues
-
-**Slow encoding/decoding:**
-- Normal: Argon2 is intentionally slow (security feature)
-- Expected time: 2-5 seconds per operation
-
-**High memory usage:**
-- Normal: Argon2 requires 256MB RAM
-- Configure worker count based on available RAM
-
----
-
-## Mobile Support
-
-### Responsive Design
-
-The UI adapts to mobile screens:
-- Single-column layout on small screens
-- Touch-friendly buttons (48px minimum)
-- Readable text without zooming
-- Scrollable tables
-
-### Mobile-Specific Features
-
-**Native Sharing:**
-On supported mobile browsers, the "Share Image" button opens the native share sheet, allowing you to share directly to:
-- Messaging apps (iMessage, WhatsApp, Telegram)
-- Social media (Instagram, Twitter)
-- Email
-- Other installed apps
-
-**Camera Upload:**
-File input accepts camera capture:
-- Take a new photo as reference
-- Capture carrier image directly
-
-### PWA Support (Future)
-
-The web app can be added to home screen on mobile devices for quick access.
-
----
-
-## Keyboard Shortcuts
-
-| Shortcut | Action |
-|----------|--------|
-| `Tab` | Navigate between fields |
-| `Enter` | Submit form (when focused) |
-| `Esc` | Close modal/alert |
-
----
-
-## Accessibility
-
-| Feature | Implementation |
-|---------|----------------|
-| Screen readers | ARIA labels on interactive elements |
-| Keyboard navigation | Full tab support |
-| Color contrast | WCAG AA compliant |
-| Focus indicators | Visible focus rings |
-| Form labels | All inputs labeled |
-
----
-
-## See Also
-
-- [CLI Documentation](CLI.md) - Command-line interface
-- [API Documentation](API.md) - REST API reference
-- [README](README.md) - Project overview

frontends/web/.env.example

@@ -0,0 +1,16 @@
+# Stegasoo Web UI Configuration
+# Copy this file to .env and customize
+
+# Authentication (v4.0.2+)
+STEGASOO_AUTH_ENABLED=true
+STEGASOO_HTTPS_ENABLED=false
+STEGASOO_HOSTNAME=localhost
+STEGASOO_PORT=5000
+
+# Channel Key (format: XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX)
+# Generate with: stegasoo generate --channel-key
+# Leave empty for public mode
+STEGASOO_CHANNEL_KEY=
+
+# Flask settings
+FLASK_ENV=production

frontends/web/README_subprocess.md

@@ -0,0 +1,62 @@
+# Subprocess Isolation for Stegasoo WebUI
+
+This update runs encode/decode/compare operations in isolated subprocesses
+to prevent jpegio/scipy crashes from taking down the Flask server.
+
+## Files
+
+- **app.py** - Updated Flask app using subprocess isolation
+- **subprocess_stego.py** - Flask-side wrapper with clean API  
+- **stego_worker.py** - Subprocess script that does actual stegasoo operations
+
+## Setup
+
+1. Place all three files in your `webui/` directory (same level as templates/)
+
+2. Make sure stego_worker.py is executable (optional):
+   ```bash
+   chmod +x stego_worker.py
+   ```
+
+3. Run the Flask app:
+   ```bash
+   python app.py
+   ```
+
+## How It Works
+
+Instead of calling stegasoo functions directly in the Flask process:
+
+```python
+# OLD (crashes could kill Flask)
+result = encode(...)
+```
+
+We now run them in subprocesses:
+
+```python
+# NEW (crashes only kill the subprocess)
+result = subprocess_stego.encode(...)
+```
+
+If jpegio or scipy crashes due to memory corruption, only the subprocess
+dies. Flask logs the error and continues running. The next request spawns
+a fresh subprocess.
+
+## Configuration
+
+In `app.py`, you can adjust the timeout:
+
+```python
+subprocess_stego = SubprocessStego(timeout=180)  # 3 minutes
+```
+
+Larger images may need longer timeouts.
+
+## Troubleshooting
+
+If you see "Worker script not found" errors, make sure `stego_worker.py`
+is in the same directory as `app.py`.
+
+If subprocess operations fail, check the Flask logs for error details.
+The subprocess wrapper captures both stdout and stderr from the worker.

frontends/web/auth.py

@@ -0,0 +1,979 @@
+"""
+Stegasoo Authentication Module (v4.1.0)
+
+Multi-user authentication with role-based access control.
+- Admin user created at first-run setup
+- Admin can create up to 16 additional users
+- Uses Argon2id password hashing
+- Flask sessions for authentication state
+- SQLite3 for user storage
+"""
+
+import functools
+import secrets
+import sqlite3
+import string
+from dataclasses import dataclass
+from pathlib import Path
+
+from argon2 import PasswordHasher
+from argon2.exceptions import VerifyMismatchError
+from flask import current_app, flash, g, redirect, session, url_for
+
+# Argon2 password hasher (lighter than stegasoo's 256MB for faster login)
+ph = PasswordHasher(
+    time_cost=3,
+    memory_cost=65536,  # 64MB
+    parallelism=4,
+    hash_len=32,
+    salt_len=16,
+)
+
+# Constants
+MAX_USERS = 16  # Plus 1 admin = 17 total
+MAX_CHANNEL_KEYS = 10  # Per user
+ROLE_ADMIN = "admin"
+ROLE_USER = "user"
+
+
+@dataclass
+class User:
+    """User data class."""
+
+    id: int
+    username: str
+    role: str
+    created_at: str
+
+    @property
+    def is_admin(self) -> bool:
+        return self.role == ROLE_ADMIN
+
+
+def get_db_path() -> Path:
+    """Get database path in Flask instance folder."""
+    instance_path = Path(current_app.instance_path)
+    instance_path.mkdir(parents=True, exist_ok=True)
+    return instance_path / "stegasoo.db"
+
+
+def get_db() -> sqlite3.Connection:
+    """Get database connection, cached on Flask g object."""
+    if "db" not in g:
+        g.db = sqlite3.connect(get_db_path())
+        g.db.row_factory = sqlite3.Row
+    return g.db
+
+
+def close_db(e=None):
+    """Close database connection at end of request."""
+    db = g.pop("db", None)
+    if db is not None:
+        db.close()
+
+
+def init_db():
+    """Initialize database schema with migration support."""
+    db = get_db()
+
+    # Check if we need to migrate from old single-user schema
+    cursor = db.execute(
+        "SELECT name FROM sqlite_master WHERE type='table' AND name='admin_user'"
+    )
+    has_old_table = cursor.fetchone() is not None
+
+    cursor = db.execute(
+        "SELECT name FROM sqlite_master WHERE type='table' AND name='users'"
+    )
+    has_new_table = cursor.fetchone() is not None
+
+    if has_old_table and not has_new_table:
+        # Migrate from old schema
+        _migrate_from_single_user(db)
+    elif not has_new_table:
+        # Fresh install - create new schema
+        _create_schema(db)
+    else:
+        # Existing install - check for new tables (migrations)
+        _ensure_channel_keys_table(db)
+        _ensure_app_settings_table(db)
+
+
+def _create_schema(db: sqlite3.Connection):
+    """Create the multi-user schema."""
+    db.executescript("""
+        CREATE TABLE IF NOT EXISTS users (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            username TEXT NOT NULL UNIQUE,
+            password_hash TEXT NOT NULL,
+            role TEXT NOT NULL DEFAULT 'user',
+            created_at TEXT DEFAULT CURRENT_TIMESTAMP,
+            updated_at TEXT DEFAULT CURRENT_TIMESTAMP
+        );
+
+        CREATE INDEX IF NOT EXISTS idx_users_username ON users(username);
+        CREATE INDEX IF NOT EXISTS idx_users_role ON users(role);
+
+        CREATE TABLE IF NOT EXISTS user_channel_keys (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            user_id INTEGER NOT NULL,
+            name TEXT NOT NULL,
+            channel_key TEXT NOT NULL,
+            created_at TEXT DEFAULT CURRENT_TIMESTAMP,
+            last_used_at TEXT,
+            FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
+            UNIQUE(user_id, channel_key)
+        );
+
+        CREATE INDEX IF NOT EXISTS idx_channel_keys_user ON user_channel_keys(user_id);
+
+        -- App-level settings (v4.1.0)
+        -- Stores recovery key hash and other instance-wide settings
+        CREATE TABLE IF NOT EXISTS app_settings (
+            key TEXT PRIMARY KEY,
+            value TEXT NOT NULL,
+            created_at TEXT DEFAULT CURRENT_TIMESTAMP,
+            updated_at TEXT DEFAULT CURRENT_TIMESTAMP
+        );
+    """)
+    db.commit()
+
+
+def _migrate_from_single_user(db: sqlite3.Connection):
+    """Migrate from old single-user admin_user table to multi-user users table."""
+    # Create new table
+    _create_schema(db)
+
+    # Copy admin user from old table
+    old_user = db.execute(
+        "SELECT username, password_hash, created_at FROM admin_user WHERE id = 1"
+    ).fetchone()
+
+    if old_user:
+        db.execute(
+            """
+            INSERT INTO users (username, password_hash, role, created_at)
+            VALUES (?, ?, 'admin', ?)
+            """,
+            (old_user["username"], old_user["password_hash"], old_user["created_at"]),
+        )
+        db.commit()
+
+    # Drop old table
+    db.execute("DROP TABLE admin_user")
+    db.commit()
+
+
+def _ensure_channel_keys_table(db: sqlite3.Connection):
+    """Ensure user_channel_keys table exists (migration for existing installs)."""
+    cursor = db.execute(
+        "SELECT name FROM sqlite_master WHERE type='table' AND name='user_channel_keys'"
+    )
+    if cursor.fetchone() is None:
+        db.executescript("""
+            CREATE TABLE IF NOT EXISTS user_channel_keys (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                user_id INTEGER NOT NULL,
+                name TEXT NOT NULL,
+                channel_key TEXT NOT NULL,
+                created_at TEXT DEFAULT CURRENT_TIMESTAMP,
+                last_used_at TEXT,
+                FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
+                UNIQUE(user_id, channel_key)
+            );
+
+            CREATE INDEX IF NOT EXISTS idx_channel_keys_user ON user_channel_keys(user_id);
+        """)
+        db.commit()
+
+
+def _ensure_app_settings_table(db: sqlite3.Connection):
+    """Ensure app_settings table exists (v4.1.0 migration)."""
+    cursor = db.execute(
+        "SELECT name FROM sqlite_master WHERE type='table' AND name='app_settings'"
+    )
+    if cursor.fetchone() is None:
+        db.executescript("""
+            CREATE TABLE IF NOT EXISTS app_settings (
+                key TEXT PRIMARY KEY,
+                value TEXT NOT NULL,
+                created_at TEXT DEFAULT CURRENT_TIMESTAMP,
+                updated_at TEXT DEFAULT CURRENT_TIMESTAMP
+            );
+        """)
+        db.commit()
+
+
+# =============================================================================
+# App Settings (v4.1.0)
+# =============================================================================
+
+
+def get_app_setting(key: str) -> str | None:
+    """Get an app-level setting value."""
+    db = get_db()
+    row = db.execute(
+        "SELECT value FROM app_settings WHERE key = ?", (key,)
+    ).fetchone()
+    return row["value"] if row else None
+
+
+def set_app_setting(key: str, value: str) -> None:
+    """Set an app-level setting value."""
+    db = get_db()
+    db.execute(
+        """
+        INSERT INTO app_settings (key, value)
+        VALUES (?, ?)
+        ON CONFLICT(key) DO UPDATE SET value = ?, updated_at = CURRENT_TIMESTAMP
+        """,
+        (key, value, value),
+    )
+    db.commit()
+
+
+def delete_app_setting(key: str) -> bool:
+    """Delete an app-level setting. Returns True if deleted."""
+    db = get_db()
+    cursor = db.execute("DELETE FROM app_settings WHERE key = ?", (key,))
+    db.commit()
+    return cursor.rowcount > 0
+
+
+# =============================================================================
+# Recovery Key Management (v4.1.0)
+# =============================================================================
+
+
+# Setting key for recovery hash
+RECOVERY_KEY_SETTING = "recovery_key_hash"
+
+
+def has_recovery_key() -> bool:
+    """Check if a recovery key has been configured."""
+    return get_app_setting(RECOVERY_KEY_SETTING) is not None
+
+
+def get_recovery_key_hash() -> str | None:
+    """Get the stored recovery key hash."""
+    return get_app_setting(RECOVERY_KEY_SETTING)
+
+
+def set_recovery_key_hash(key_hash: str) -> None:
+    """Store a recovery key hash."""
+    set_app_setting(RECOVERY_KEY_SETTING, key_hash)
+
+
+def clear_recovery_key() -> bool:
+    """Remove the recovery key. Returns True if removed."""
+    return delete_app_setting(RECOVERY_KEY_SETTING)
+
+
+def verify_and_reset_admin_password(recovery_key: str, new_password: str) -> tuple[bool, str]:
+    """
+    Verify recovery key and reset the first admin's password.
+
+    Args:
+        recovery_key: User-provided recovery key
+        new_password: New password to set
+
+    Returns:
+        (success, message) tuple
+    """
+    from stegasoo.recovery import verify_recovery_key
+
+    stored_hash = get_recovery_key_hash()
+    if not stored_hash:
+        return False, "No recovery key configured for this instance"
+
+    if not verify_recovery_key(recovery_key, stored_hash):
+        return False, "Invalid recovery key"
+
+    # Find first admin user
+    db = get_db()
+    admin = db.execute(
+        "SELECT id, username FROM users WHERE role = 'admin' ORDER BY id LIMIT 1"
+    ).fetchone()
+
+    if not admin:
+        return False, "No admin user found"
+
+    # Reset password
+    new_hash = ph.hash(new_password)
+    db.execute(
+        "UPDATE users SET password_hash = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?",
+        (new_hash, admin["id"]),
+    )
+    db.commit()
+
+    # Invalidate all sessions for this user
+    invalidate_user_sessions(admin["id"])
+
+    return True, f"Password reset for '{admin['username']}'"
+
+
+# =============================================================================
+# User Queries
+# =============================================================================
+
+
+def any_users_exist() -> bool:
+    """Check if any users have been created (for first-run detection)."""
+    db = get_db()
+    result = db.execute("SELECT 1 FROM users LIMIT 1").fetchone()
+    return result is not None
+
+
+def user_exists() -> bool:
+    """Alias for any_users_exist() for backwards compatibility."""
+    return any_users_exist()
+
+
+def get_user_count() -> int:
+    """Get total number of users."""
+    db = get_db()
+    result = db.execute("SELECT COUNT(*) FROM users").fetchone()
+    return result[0] if result else 0
+
+
+def get_non_admin_count() -> int:
+    """Get number of non-admin users."""
+    db = get_db()
+    result = db.execute("SELECT COUNT(*) FROM users WHERE role != 'admin'").fetchone()
+    return result[0] if result else 0
+
+
+def can_create_user() -> bool:
+    """Check if we can create more users (within limit)."""
+    return get_non_admin_count() < MAX_USERS
+
+
+def get_user_by_id(user_id: int) -> User | None:
+    """Get user by ID."""
+    db = get_db()
+    row = db.execute(
+        "SELECT id, username, role, created_at FROM users WHERE id = ?", (user_id,)
+    ).fetchone()
+    if row:
+        return User(
+            id=row["id"],
+            username=row["username"],
+            role=row["role"],
+            created_at=row["created_at"],
+        )
+    return None
+
+
+def get_user_by_username(username: str) -> User | None:
+    """Get user by username."""
+    db = get_db()
+    row = db.execute(
+        "SELECT id, username, role, created_at FROM users WHERE username = ?",
+        (username,),
+    ).fetchone()
+    if row:
+        return User(
+            id=row["id"],
+            username=row["username"],
+            role=row["role"],
+            created_at=row["created_at"],
+        )
+    return None
+
+
+def get_all_users() -> list[User]:
+    """Get all users, admins first, then by creation date."""
+    db = get_db()
+    rows = db.execute(
+        """
+        SELECT id, username, role, created_at FROM users
+        ORDER BY role = 'admin' DESC, created_at ASC
+        """
+    ).fetchall()
+    return [
+        User(
+            id=row["id"],
+            username=row["username"],
+            role=row["role"],
+            created_at=row["created_at"],
+        )
+        for row in rows
+    ]
+
+
+def get_current_user() -> User | None:
+    """Get the currently logged-in user from session."""
+    user_id = session.get("user_id")
+    if user_id:
+        return get_user_by_id(user_id)
+    return None
+
+
+def get_username() -> str:
+    """Get current user's username (backwards compatibility)."""
+    user = get_current_user()
+    return user.username if user else "unknown"
+
+
+# =============================================================================
+# Authentication
+# =============================================================================
+
+
+def verify_user_password(username: str, password: str) -> User | None:
+    """
+    Verify password for a user.
+
+    Returns User if valid, None if invalid.
+    Also rehashes password if needed.
+    """
+    db = get_db()
+    row = db.execute(
+        "SELECT id, username, role, created_at, password_hash FROM users WHERE username = ?",
+        (username,),
+    ).fetchone()
+
+    if not row:
+        return None
+
+    try:
+        ph.verify(row["password_hash"], password)
+
+        # Rehash if parameters changed
+        if ph.check_needs_rehash(row["password_hash"]):
+            new_hash = ph.hash(password)
+            db.execute(
+                "UPDATE users SET password_hash = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?",
+                (new_hash, row["id"]),
+            )
+            db.commit()
+
+        return User(
+            id=row["id"],
+            username=row["username"],
+            role=row["role"],
+            created_at=row["created_at"],
+        )
+    except VerifyMismatchError:
+        return None
+
+
+def verify_password(password: str) -> bool:
+    """Verify password for current user (backwards compatibility)."""
+    user = get_current_user()
+    if not user:
+        return False
+    result = verify_user_password(user.username, password)
+    return result is not None
+
+
+def is_authenticated() -> bool:
+    """Check if current session is authenticated."""
+    return session.get("user_id") is not None
+
+
+def is_admin() -> bool:
+    """Check if current user is an admin."""
+    user = get_current_user()
+    return user.is_admin if user else False
+
+
+def login_user(user: User):
+    """Set up session for logged-in user."""
+    session["user_id"] = user.id
+    session["username"] = user.username
+    session["role"] = user.role
+    # Legacy compatibility
+    session["authenticated"] = True
+
+
+def logout_user():
+    """Clear session for logout."""
+    session.clear()
+
+
+# =============================================================================
+# User Management
+# =============================================================================
+
+
+def generate_temp_password(length: int = 8) -> str:
+    """Generate a random temporary password."""
+    alphabet = string.ascii_letters + string.digits
+    return "".join(secrets.choice(alphabet) for _ in range(length))
+
+
+def validate_username(username: str) -> tuple[bool, str]:
+    """
+    Validate username format.
+
+    Rules: 3-80 chars, alphanumeric + underscore/hyphen + @/. for email-style
+    """
+    if not username:
+        return False, "Username is required"
+
+    if len(username) < 3:
+        return False, "Username must be at least 3 characters"
+
+    if len(username) > 80:
+        return False, "Username must be at most 80 characters"
+
+    # Allow: alphanumeric, underscore, hyphen, @, . (for email-style)
+    allowed = set(string.ascii_letters + string.digits + "_-@.")
+    if not all(c in allowed for c in username):
+        return False, "Username can only contain letters, numbers, underscore, hyphen, @ and ."
+
+    # Must start with letter or number
+    if username[0] not in string.ascii_letters + string.digits:
+        return False, "Username must start with a letter or number"
+
+    return True, ""
+
+
+def validate_password(password: str) -> tuple[bool, str]:
+    """Validate password requirements."""
+    if not password:
+        return False, "Password is required"
+
+    if len(password) < 8:
+        return False, "Password must be at least 8 characters"
+
+    return True, ""
+
+
+def create_user(
+    username: str, password: str, role: str = ROLE_USER
+) -> tuple[bool, str, User | None]:
+    """
+    Create a new user.
+
+    Returns (success, message, user).
+    """
+    # Validate username
+    valid, msg = validate_username(username)
+    if not valid:
+        return False, msg, None
+
+    # Validate password
+    valid, msg = validate_password(password)
+    if not valid:
+        return False, msg, None
+
+    # Check if username already exists
+    if get_user_by_username(username):
+        return False, "Username already exists", None
+
+    # Check user limit (only for non-admin users)
+    if role != ROLE_ADMIN and not can_create_user():
+        return False, f"Maximum of {MAX_USERS} users reached", None
+
+    # Create user
+    password_hash = ph.hash(password)
+    db = get_db()
+
+    try:
+        cursor = db.execute(
+            """
+            INSERT INTO users (username, password_hash, role)
+            VALUES (?, ?, ?)
+            """,
+            (username, password_hash, role),
+        )
+        db.commit()
+
+        user = get_user_by_id(cursor.lastrowid)
+        return True, "User created successfully", user
+    except sqlite3.IntegrityError:
+        return False, "Username already exists", None
+
+
+def create_admin_user(username: str, password: str) -> tuple[bool, str]:
+    """Create the initial admin user (first-run setup)."""
+    if any_users_exist():
+        return False, "Admin user already exists"
+
+    success, msg, _ = create_user(username, password, ROLE_ADMIN)
+    return success, msg
+
+
+def change_password(
+    user_id: int, current_password: str, new_password: str
+) -> tuple[bool, str]:
+    """Change a user's password (requires current password)."""
+    user = get_user_by_id(user_id)
+    if not user:
+        return False, "User not found"
+
+    # Verify current password
+    if not verify_user_password(user.username, current_password):
+        return False, "Current password is incorrect"
+
+    # Validate new password
+    valid, msg = validate_password(new_password)
+    if not valid:
+        return False, msg
+
+    # Update password
+    new_hash = ph.hash(new_password)
+    db = get_db()
+    db.execute(
+        "UPDATE users SET password_hash = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?",
+        (new_hash, user_id),
+    )
+    db.commit()
+
+    return True, "Password changed successfully"
+
+
+def reset_user_password(user_id: int, new_password: str) -> tuple[bool, str]:
+    """Reset a user's password (admin function, no current password required)."""
+    user = get_user_by_id(user_id)
+    if not user:
+        return False, "User not found"
+
+    # Validate new password
+    valid, msg = validate_password(new_password)
+    if not valid:
+        return False, msg
+
+    # Update password
+    new_hash = ph.hash(new_password)
+    db = get_db()
+    db.execute(
+        "UPDATE users SET password_hash = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?",
+        (new_hash, user_id),
+    )
+    db.commit()
+
+    # Invalidate user's sessions
+    invalidate_user_sessions(user_id)
+
+    return True, "Password reset successfully"
+
+
+def delete_user(user_id: int, current_user_id: int) -> tuple[bool, str]:
+    """
+    Delete a user.
+
+    Cannot delete yourself or the last admin.
+    """
+    if user_id == current_user_id:
+        return False, "Cannot delete yourself"
+
+    user = get_user_by_id(user_id)
+    if not user:
+        return False, "User not found"
+
+    # Check if this is the last admin
+    if user.role == ROLE_ADMIN:
+        db = get_db()
+        admin_count = db.execute(
+            "SELECT COUNT(*) FROM users WHERE role = 'admin'"
+        ).fetchone()[0]
+        if admin_count <= 1:
+            return False, "Cannot delete the last admin"
+
+    # Invalidate user's sessions before deletion
+    invalidate_user_sessions(user_id)
+
+    # Delete user
+    db = get_db()
+    db.execute("DELETE FROM users WHERE id = ?", (user_id,))
+    db.commit()
+
+    return True, f"User '{user.username}' deleted"
+
+
+def invalidate_user_sessions(user_id: int):
+    """
+    Invalidate all sessions for a user.
+
+    This is called when a user is deleted or their password is reset.
+    Since we use server-side sessions, we increment a "session version"
+    that's checked on each request.
+    """
+    # For Flask's default session (client-side), we can't truly invalidate.
+    # But we can add a check - store a "valid_from" timestamp in the DB
+    # and compare against session creation time.
+    #
+    # For now, we'll use a simpler approach: store invalidated user IDs
+    # in app config (memory) which gets checked by login_required.
+    #
+    # This works for single-process deployments (like RPi).
+    # For multi-process, would need Redis or DB-backed sessions.
+
+    if "invalidated_users" not in current_app.config:
+        current_app.config["invalidated_users"] = set()
+
+    current_app.config["invalidated_users"].add(user_id)
+
+
+def is_session_valid() -> bool:
+    """Check if current session is still valid (user not deleted/invalidated)."""
+    user_id = session.get("user_id")
+    if not user_id:
+        return False
+
+    # Check if user was invalidated
+    invalidated = current_app.config.get("invalidated_users", set())
+    if user_id in invalidated:
+        return False
+
+    # Check if user still exists
+    if not get_user_by_id(user_id):
+        return False
+
+    return True
+
+
+# =============================================================================
+# Channel Keys
+# =============================================================================
+
+
+@dataclass
+class ChannelKey:
+    """Saved channel key data class."""
+
+    id: int
+    user_id: int
+    name: str
+    channel_key: str
+    created_at: str
+    last_used_at: str | None
+
+
+def get_user_channel_keys(user_id: int) -> list[ChannelKey]:
+    """Get all saved channel keys for a user, most recently used first."""
+    db = get_db()
+    rows = db.execute(
+        """
+        SELECT id, user_id, name, channel_key, created_at, last_used_at
+        FROM user_channel_keys
+        WHERE user_id = ?
+        ORDER BY last_used_at DESC NULLS LAST, created_at DESC
+        """,
+        (user_id,),
+    ).fetchall()
+    return [
+        ChannelKey(
+            id=row["id"],
+            user_id=row["user_id"],
+            name=row["name"],
+            channel_key=row["channel_key"],
+            created_at=row["created_at"],
+            last_used_at=row["last_used_at"],
+        )
+        for row in rows
+    ]
+
+
+def get_channel_key_by_id(key_id: int, user_id: int) -> ChannelKey | None:
+    """Get a specific channel key (ensures user owns it)."""
+    db = get_db()
+    row = db.execute(
+        """
+        SELECT id, user_id, name, channel_key, created_at, last_used_at
+        FROM user_channel_keys
+        WHERE id = ? AND user_id = ?
+        """,
+        (key_id, user_id),
+    ).fetchone()
+    if row:
+        return ChannelKey(
+            id=row["id"],
+            user_id=row["user_id"],
+            name=row["name"],
+            channel_key=row["channel_key"],
+            created_at=row["created_at"],
+            last_used_at=row["last_used_at"],
+        )
+    return None
+
+
+def get_channel_key_count(user_id: int) -> int:
+    """Get count of saved channel keys for a user."""
+    db = get_db()
+    result = db.execute(
+        "SELECT COUNT(*) FROM user_channel_keys WHERE user_id = ?", (user_id,)
+    ).fetchone()
+    return result[0] if result else 0
+
+
+def can_save_channel_key(user_id: int) -> bool:
+    """Check if user can save more channel keys (within limit)."""
+    return get_channel_key_count(user_id) < MAX_CHANNEL_KEYS
+
+
+def save_channel_key(
+    user_id: int, name: str, channel_key: str
+) -> tuple[bool, str, ChannelKey | None]:
+    """
+    Save a channel key for a user.
+
+    Returns (success, message, key).
+    """
+    # Validate name
+    name = name.strip()
+    if not name:
+        return False, "Key name is required", None
+    if len(name) > 50:
+        return False, "Key name must be at most 50 characters", None
+
+    # Validate channel key format (hex string)
+    channel_key = channel_key.strip().lower()
+    if not channel_key:
+        return False, "Channel key is required", None
+    if not all(c in "0123456789abcdef" for c in channel_key):
+        return False, "Invalid channel key format", None
+
+    # Check limit
+    if not can_save_channel_key(user_id):
+        return False, f"Maximum of {MAX_CHANNEL_KEYS} saved keys reached", None
+
+    db = get_db()
+    try:
+        cursor = db.execute(
+            """
+            INSERT INTO user_channel_keys (user_id, name, channel_key)
+            VALUES (?, ?, ?)
+            """,
+            (user_id, name, channel_key),
+        )
+        db.commit()
+
+        key = get_channel_key_by_id(cursor.lastrowid, user_id)
+        return True, "Channel key saved", key
+    except sqlite3.IntegrityError:
+        return False, "This channel key is already saved", None
+
+
+def update_channel_key_name(
+    key_id: int, user_id: int, new_name: str
+) -> tuple[bool, str]:
+    """Update the name of a saved channel key."""
+    new_name = new_name.strip()
+    if not new_name:
+        return False, "Key name is required"
+    if len(new_name) > 50:
+        return False, "Key name must be at most 50 characters"
+
+    key = get_channel_key_by_id(key_id, user_id)
+    if not key:
+        return False, "Channel key not found"
+
+    db = get_db()
+    db.execute(
+        "UPDATE user_channel_keys SET name = ? WHERE id = ? AND user_id = ?",
+        (new_name, key_id, user_id),
+    )
+    db.commit()
+    return True, "Key name updated"
+
+
+def update_channel_key_last_used(key_id: int, user_id: int):
+    """Update the last_used_at timestamp for a channel key."""
+    db = get_db()
+    db.execute(
+        """
+        UPDATE user_channel_keys
+        SET last_used_at = CURRENT_TIMESTAMP
+        WHERE id = ? AND user_id = ?
+        """,
+        (key_id, user_id),
+    )
+    db.commit()
+
+
+def delete_channel_key(key_id: int, user_id: int) -> tuple[bool, str]:
+    """Delete a saved channel key."""
+    key = get_channel_key_by_id(key_id, user_id)
+    if not key:
+        return False, "Channel key not found"
+
+    db = get_db()
+    db.execute(
+        "DELETE FROM user_channel_keys WHERE id = ? AND user_id = ?",
+        (key_id, user_id),
+    )
+    db.commit()
+    return True, f"Key '{key.name}' deleted"
+
+
+# =============================================================================
+# Decorators
+# =============================================================================
+
+
+def login_required(f):
+    """Decorator to require login for a route."""
+
+    @functools.wraps(f)
+    def decorated_function(*args, **kwargs):
+        # Check if auth is enabled
+        if not current_app.config.get("AUTH_ENABLED", True):
+            return f(*args, **kwargs)
+
+        # Check for first-run setup
+        if not any_users_exist():
+            return redirect(url_for("setup"))
+
+        # Check authentication
+        if not is_authenticated():
+            return redirect(url_for("login"))
+
+        # Check if session is still valid (user not deleted)
+        if not is_session_valid():
+            logout_user()
+            flash("Your session has expired. Please log in again.", "warning")
+            return redirect(url_for("login"))
+
+        return f(*args, **kwargs)
+
+    return decorated_function
+
+
+def admin_required(f):
+    """Decorator to require admin role for a route."""
+
+    @functools.wraps(f)
+    def decorated_function(*args, **kwargs):
+        # Check if auth is enabled
+        if not current_app.config.get("AUTH_ENABLED", True):
+            return f(*args, **kwargs)
+
+        # Check for first-run setup
+        if not any_users_exist():
+            return redirect(url_for("setup"))
+
+        # Check authentication
+        if not is_authenticated():
+            return redirect(url_for("login"))
+
+        # Check if session is still valid
+        if not is_session_valid():
+            logout_user()
+            flash("Your session has expired. Please log in again.", "warning")
+            return redirect(url_for("login"))
+
+        # Check admin role
+        if not is_admin():
+            flash("Admin access required", "error")
+            return redirect(url_for("index"))
+
+        return f(*args, **kwargs)
+
+    return decorated_function
+
+
+# =============================================================================
+# App Initialization
+# =============================================================================
+
+
+def init_app(app):
+    """Initialize auth module with Flask app."""
+    app.teardown_appcontext(close_db)
+
+    with app.app_context():
+        init_db()

frontends/web/dev_run.sh

@@ -0,0 +1,52 @@
+#!/bin/bash
+# Stegasoo Web Frontend - Development Runner
+# Press 'r' to restart, 'q' to quit (single keypress, no Enter needed)
+
+cd "$(dirname "$0")"
+
+PID=""
+
+cleanup() {
+    echo -e "\n\033[33mShutting down...\033[0m"
+    [[ -n "$PID" ]] && kill "$PID" 2>/dev/null
+    stty sane 2>/dev/null
+    exit 0
+}
+
+trap cleanup SIGINT SIGTERM EXIT
+
+start_server() {
+    clear
+    echo -e "\033[36m┌──────────────────────────────────────┐\033[0m"
+    echo -e "\033[36m│  Stegasoo Dev Server                 │\033[0m"
+    echo -e "\033[36m│  \033[0m[r] restart  [q] quit\033[36m              │\033[0m"
+    echo -e "\033[36m└──────────────────────────────────────┘\033[0m"
+
+    pkill -f "python app.py" 2>/dev/null
+    sleep 0.3
+
+    python app.py 2>&1 &
+    PID=$!
+    echo -e "\033[32m✓ Running on http://localhost:5000 (PID: $PID)\033[0m\n"
+}
+
+start_server
+
+# Single keypress mode
+stty -echo -icanon time 0 min 0
+
+while true; do
+    key=$(dd bs=1 count=1 2>/dev/null)
+    case "$key" in
+        r|R) start_server ;;
+        q|Q) cleanup ;;
+    esac
+
+    # Check if crashed
+    if [[ -n "$PID" ]] && ! kill -0 "$PID" 2>/dev/null; then
+        echo -e "\033[31m✗ Crashed! Press 'r' to restart\033[0m"
+        PID=""
+    fi
+
+    sleep 0.1
+done

frontends/web/docker-entrypoint.sh

@@ -0,0 +1,75 @@
+#!/bin/bash
+#
+# Docker entrypoint for Stegasoo Web UI
+# Handles SSL certificate generation and gunicorn startup
+#
+# Supports mkcert for browser-trusted certificates (no warning screen)
+#
+
+set -e
+
+CERT_DIR="/app/frontends/web/certs"
+CERT_FILE="$CERT_DIR/cert.pem"
+KEY_FILE="$CERT_DIR/key.pem"
+HOSTNAME="${STEGASOO_HOSTNAME:-localhost}"
+
+# Generate SSL certificates
+# Priority: 1) Existing certs, 2) mkcert (trusted), 3) openssl (self-signed)
+generate_certs() {
+    if [ -f "$CERT_FILE" ] && [ -f "$KEY_FILE" ]; then
+        echo "Using existing SSL certificates."
+        return
+    fi
+
+    mkdir -p "$CERT_DIR"
+
+    # Try mkcert first (creates browser-trusted certs)
+    if command -v mkcert &> /dev/null; then
+        echo "Generating trusted certificate with mkcert for $HOSTNAME..."
+        cd "$CERT_DIR"
+        mkcert -key-file key.pem -cert-file cert.pem "$HOSTNAME" localhost 127.0.0.1 ::1
+        echo "Trusted certificate generated."
+        echo ""
+        echo "  To trust on other devices, install the CA cert from:"
+        echo "  $(mkcert -CAROOT)/rootCA.pem"
+        echo ""
+        return
+    fi
+
+    # Fallback to self-signed (shows browser warning)
+    echo "Generating self-signed SSL certificate for $HOSTNAME..."
+    echo "(Install mkcert for browser-trusted certs without warnings)"
+
+    openssl req -x509 -newkey rsa:2048 \
+        -keyout "$KEY_FILE" \
+        -out "$CERT_FILE" \
+        -sha256 -days 365 -nodes \
+        -subj "/CN=$HOSTNAME" \
+        -addext "subjectAltName=DNS:$HOSTNAME,DNS:localhost,IP:127.0.0.1" \
+        2>/dev/null
+
+    echo "Self-signed certificate generated."
+}
+
+# Start gunicorn with appropriate settings
+if [ "${STEGASOO_HTTPS_ENABLED:-false}" = "true" ]; then
+    echo "HTTPS mode enabled"
+    generate_certs
+
+    exec gunicorn \
+        --bind 0.0.0.0:5000 \
+        --workers 2 \
+        --threads 4 \
+        --timeout 120 \
+        --certfile "$CERT_FILE" \
+        --keyfile "$KEY_FILE" \
+        app:app
+else
+    echo "HTTP mode (HTTPS disabled)"
+    exec gunicorn \
+        --bind 0.0.0.0:5000 \
+        --workers 2 \
+        --threads 4 \
+        --timeout 120 \
+        app:app
+fi

frontends/web/ssl_utils.py

@@ -0,0 +1,153 @@
+"""
+SSL Certificate Utilities
+
+Auto-generates self-signed certificates for HTTPS.
+Uses cryptography library (already a dependency).
+"""
+
+import datetime
+import ipaddress
+import socket
+from pathlib import Path
+
+from cryptography import x509
+from cryptography.hazmat.primitives import hashes, serialization
+from cryptography.hazmat.primitives.asymmetric import rsa
+from cryptography.x509.oid import NameOID
+
+
+def _get_local_ips() -> list[str]:
+    """Get local IP addresses for this machine."""
+    ips = []
+    try:
+        # Get hostname and resolve to IP
+        hostname = socket.gethostname()
+        for addr_info in socket.getaddrinfo(hostname, None, socket.AF_INET):
+            ip = addr_info[4][0]
+            if ip not in ips and not ip.startswith("127."):
+                ips.append(ip)
+    except Exception:
+        pass
+
+    # Also try connecting to external to get primary interface IP
+    try:
+        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        s.connect(("8.8.8.8", 80))
+        ip = s.getsockname()[0]
+        if ip not in ips:
+            ips.append(ip)
+        s.close()
+    except Exception:
+        pass
+
+    return ips
+
+
+def get_cert_paths(base_dir: Path) -> tuple[Path, Path]:
+    """Get paths for cert and key files."""
+    cert_dir = base_dir / "certs"
+    cert_dir.mkdir(parents=True, exist_ok=True)
+    return cert_dir / "server.crt", cert_dir / "server.key"
+
+
+def certs_exist(base_dir: Path) -> bool:
+    """Check if both cert files exist."""
+    cert_path, key_path = get_cert_paths(base_dir)
+    return cert_path.exists() and key_path.exists()
+
+
+def generate_self_signed_cert(
+    base_dir: Path,
+    hostname: str = "localhost",
+    days_valid: int = 365,
+) -> tuple[Path, Path]:
+    """
+    Generate self-signed SSL certificate.
+
+    Args:
+        base_dir: Base directory for certs folder
+        hostname: Server hostname for certificate
+        days_valid: Certificate validity in days
+
+    Returns:
+        Tuple of (cert_path, key_path)
+    """
+    cert_path, key_path = get_cert_paths(base_dir)
+
+    # Generate RSA key
+    key = rsa.generate_private_key(
+        public_exponent=65537,
+        key_size=2048,
+    )
+
+    # Create certificate
+    subject = issuer = x509.Name([
+        x509.NameAttribute(NameOID.ORGANIZATION_NAME, "Stegasoo"),
+        x509.NameAttribute(NameOID.COMMON_NAME, hostname),
+    ])
+
+    # Subject Alternative Names
+    san_list = [
+        x509.DNSName(hostname),
+        x509.DNSName("localhost"),
+        x509.IPAddress(ipaddress.IPv4Address("127.0.0.1")),
+    ]
+
+    # Add hostname.local for mDNS access
+    if not hostname.endswith(".local"):
+        san_list.append(x509.DNSName(f"{hostname}.local"))
+
+    # Add the hostname as IP if it looks like one
+    try:
+        san_list.append(x509.IPAddress(ipaddress.IPv4Address(hostname)))
+    except ipaddress.AddressValueError:
+        pass
+
+    # Add local network IPs
+    for local_ip in _get_local_ips():
+        try:
+            ip_addr = ipaddress.IPv4Address(local_ip)
+            if x509.IPAddress(ip_addr) not in san_list:
+                san_list.append(x509.IPAddress(ip_addr))
+        except (ipaddress.AddressValueError, ValueError):
+            pass
+
+    now = datetime.datetime.now(datetime.timezone.utc)
+    cert = (
+        x509.CertificateBuilder()
+        .subject_name(subject)
+        .issuer_name(issuer)
+        .public_key(key.public_key())
+        .serial_number(x509.random_serial_number())
+        .not_valid_before(now)
+        .not_valid_after(now + datetime.timedelta(days=days_valid))
+        .add_extension(
+            x509.SubjectAlternativeName(san_list),
+            critical=False,
+        )
+        .sign(key, hashes.SHA256())
+    )
+
+    # Write key file (chmod 600)
+    key_path.write_bytes(
+        key.private_bytes(
+            encoding=serialization.Encoding.PEM,
+            format=serialization.PrivateFormat.TraditionalOpenSSL,
+            encryption_algorithm=serialization.NoEncryption(),
+        )
+    )
+    key_path.chmod(0o600)
+
+    # Write cert file
+    cert_path.write_bytes(cert.public_bytes(serialization.Encoding.PEM))
+
+    return cert_path, key_path
+
+
+def ensure_certs(base_dir: Path, hostname: str = "localhost") -> tuple[Path, Path]:
+    """Ensure certificates exist, generating if needed."""
+    if certs_exist(base_dir):
+        return get_cert_paths(base_dir)
+
+    print(f"Generating self-signed SSL certificate for {hostname}...")
+    return generate_self_signed_cert(base_dir, hostname)

frontends/web/static/js/auth.js

@@ -0,0 +1,142 @@
+/**
+ * Stegasoo Authentication Pages JavaScript
+ * Handles login, setup, account, and admin user management pages
+ */
+
+const StegasooAuth = {
+
+    // ========================================================================
+    // PASSWORD VISIBILITY TOGGLE
+    // ========================================================================
+
+    /**
+     * Toggle password field visibility
+     * @param {string} inputId - ID of the password input
+     * @param {HTMLElement} btn - The toggle button element
+     */
+    togglePassword(inputId, btn) {
+        const input = document.getElementById(inputId);
+        const icon = btn.querySelector('i');
+        if (!input) return;
+
+        if (input.type === 'password') {
+            input.type = 'text';
+            icon?.classList.replace('bi-eye', 'bi-eye-slash');
+        } else {
+            input.type = 'password';
+            icon?.classList.replace('bi-eye-slash', 'bi-eye');
+        }
+    },
+
+    // ========================================================================
+    // PASSWORD CONFIRMATION VALIDATION
+    // ========================================================================
+
+    /**
+     * Initialize password confirmation validation on a form
+     * @param {string} formId - ID of the form
+     * @param {string} passwordId - ID of the password field
+     * @param {string} confirmId - ID of the confirmation field
+     */
+    initPasswordConfirmation(formId, passwordId, confirmId) {
+        const form = document.getElementById(formId);
+        if (!form) return;
+
+        form.addEventListener('submit', function(e) {
+            const password = document.getElementById(passwordId)?.value;
+            const confirm = document.getElementById(confirmId)?.value;
+
+            if (password !== confirm) {
+                e.preventDefault();
+                alert('Passwords do not match');
+            }
+        });
+    },
+
+    // ========================================================================
+    // COPY TO CLIPBOARD
+    // ========================================================================
+
+    /**
+     * Copy field value to clipboard with visual feedback
+     * @param {string} fieldId - ID of the input field to copy
+     */
+    copyField(fieldId) {
+        const field = document.getElementById(fieldId);
+        if (!field) return;
+
+        field.select();
+        navigator.clipboard.writeText(field.value).then(() => {
+            const btn = field.nextElementSibling;
+            if (!btn) return;
+
+            const originalHTML = btn.innerHTML;
+            btn.innerHTML = '<i class="bi bi-check"></i>';
+            setTimeout(() => btn.innerHTML = originalHTML, 1000);
+        });
+    },
+
+    // ========================================================================
+    // PASSWORD GENERATION
+    // ========================================================================
+
+    /**
+     * Generate a random password
+     * @param {number} length - Password length (default 8)
+     * @returns {string} Generated password
+     */
+    generatePassword(length = 8) {
+        const chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
+        let password = '';
+        for (let i = 0; i < length; i++) {
+            password += chars.charAt(Math.floor(Math.random() * chars.length));
+        }
+        return password;
+    },
+
+    /**
+     * Regenerate password and update input field
+     * @param {string} inputId - ID of the password input
+     * @param {number} length - Password length
+     */
+    regeneratePassword(inputId = 'passwordInput', length = 8) {
+        const input = document.getElementById(inputId);
+        if (input) {
+            input.value = this.generatePassword(length);
+        }
+    },
+
+    // ========================================================================
+    // DELETE CONFIRMATION
+    // ========================================================================
+
+    /**
+     * Confirm deletion with a prompt
+     * @param {string} itemName - Name of item being deleted
+     * @param {string} formId - ID of the form to submit if confirmed
+     * @returns {boolean} True if confirmed
+     */
+    confirmDelete(itemName, formId = null) {
+        const confirmed = confirm(`Are you sure you want to delete "${itemName}"? This cannot be undone.`);
+        if (confirmed && formId) {
+            const form = document.getElementById(formId);
+            form?.submit();
+        }
+        return confirmed;
+    }
+};
+
+// Make togglePassword available globally for onclick handlers
+function togglePassword(inputId, btn) {
+    StegasooAuth.togglePassword(inputId, btn);
+}
+
+// Make copyField available globally for onclick handlers
+function copyField(fieldId) {
+    StegasooAuth.copyField(fieldId);
+}
+
+// Make regeneratePassword available globally for onclick handlers
+function regeneratePassword() {
+    StegasooAuth.regeneratePassword();
+}

frontends/web/static/js/generate.js

@@ -0,0 +1,279 @@
+/**
+ * Stegasoo Generate Page JavaScript
+ * Handles credential generation form and display
+ */
+
+const StegasooGenerate = {
+
+    // ========================================================================
+    // FORM CONTROLS
+    // ========================================================================
+
+    /**
+     * Initialize the words range slider
+     */
+    initWordsSlider() {
+        const wordsRange = document.getElementById('wordsRange');
+        const wordsValue = document.getElementById('wordsValue');
+
+        wordsRange?.addEventListener('input', function() {
+            const bits = this.value * 11;
+            wordsValue.textContent = `${this.value} words (~${bits} bits)`;
+        });
+    },
+
+    /**
+     * Initialize PIN/RSA option toggles
+     */
+    initOptionToggles() {
+        const usePinCheck = document.getElementById('usePinCheck');
+        const useRsaCheck = document.getElementById('useRsaCheck');
+        const pinOptions = document.getElementById('pinOptions');
+        const rsaOptions = document.getElementById('rsaOptions');
+        const rsaQrWarning = document.getElementById('rsaQrWarning');
+        const rsaBitsSelect = document.getElementById('rsaBitsSelect');
+
+        usePinCheck?.addEventListener('change', function() {
+            pinOptions?.classList.toggle('d-none', !this.checked);
+        });
+
+        useRsaCheck?.addEventListener('change', function() {
+            rsaOptions?.classList.toggle('d-none', !this.checked);
+        });
+
+        // RSA key size QR warning (>3072 bits)
+        rsaBitsSelect?.addEventListener('change', function() {
+            rsaQrWarning?.classList.toggle('d-none', parseInt(this.value) <= 3072);
+        });
+    },
+
+    // ========================================================================
+    // CREDENTIAL VISIBILITY
+    // ========================================================================
+
+    pinHidden: false,
+    passphraseHidden: false,
+
+    /**
+     * Toggle PIN visibility
+     */
+    togglePinVisibility() {
+        const pinDigits = document.getElementById('pinDigits');
+        const icon = document.getElementById('pinToggleIcon');
+        const text = document.getElementById('pinToggleText');
+
+        this.pinHidden = !this.pinHidden;
+        pinDigits?.classList.toggle('blurred', this.pinHidden);
+
+        if (icon) icon.className = this.pinHidden ? 'bi bi-eye' : 'bi bi-eye-slash';
+        if (text) text.textContent = this.pinHidden ? 'Show' : 'Hide';
+    },
+
+    /**
+     * Toggle passphrase visibility
+     */
+    togglePassphraseVisibility() {
+        const display = document.getElementById('passphraseDisplay');
+        const icon = document.getElementById('passphraseToggleIcon');
+        const text = document.getElementById('passphraseToggleText');
+
+        this.passphraseHidden = !this.passphraseHidden;
+        display?.classList.toggle('blurred', this.passphraseHidden);
+
+        if (icon) icon.className = this.passphraseHidden ? 'bi bi-eye' : 'bi bi-eye-slash';
+        if (text) text.textContent = this.passphraseHidden ? 'Show' : 'Hide';
+    },
+
+    // ========================================================================
+    // MEMORY AID STORY GENERATION
+    // ========================================================================
+
+    currentStoryTemplate: 0,
+
+    /**
+     * Story templates organized by word count (3-12 words supported)
+     */
+    storyTemplates: {
+        3: [
+            w => `The ${w[0]} ${w[1]} ${w[2]}.`,
+            w => `${w[0]} loves ${w[1]} and ${w[2]}.`,
+            w => `A ${w[0]} found a ${w[1]} near the ${w[2]}.`,
+            w => `${w[0]}, ${w[1]}, ${w[2]} — never forget.`,
+            w => `The ${w[0]} hid the ${w[1]} under the ${w[2]}.`,
+        ],
+        4: [
+            w => `${w[0]} and ${w[1]} discovered a ${w[2]} made of ${w[3]}.`,
+            w => `The ${w[0]} ${w[1]} ate ${w[2]} for ${w[3]}.`,
+            w => `In the ${w[0]}, a ${w[1]} met a ${w[2]} carrying ${w[3]}.`,
+            w => `${w[0]} said "${w[1]}" while holding a ${w[2]} ${w[3]}.`,
+            w => `The secret: ${w[0]}, ${w[1]}, ${w[2]}, ${w[3]}.`,
+        ],
+        5: [
+            w => `${w[0]} traveled to ${w[1]} seeking the ${w[2]} of ${w[3]} and ${w[4]}.`,
+            w => `The ${w[0]} ${w[1]} lived in a ${w[2]} house with ${w[3]} ${w[4]}.`,
+            w => `"${w[0]}!" shouted ${w[1]} as the ${w[2]} ${w[3]} flew toward ${w[4]}.`,
+            w => `Captain ${w[0]} sailed the ${w[1]} ${w[2]} searching for ${w[3]} ${w[4]}.`,
+            w => `In ${w[0]} kingdom, ${w[1]} guards protected the ${w[2]} ${w[3]} ${w[4]}.`,
+        ],
+        6: [
+            w => `${w[0]} met ${w[1]} at the ${w[2]}. Together they found ${w[3]}, ${w[4]}, and ${w[5]}.`,
+            w => `The ${w[0]} ${w[1]} wore a ${w[2]} hat while eating ${w[3]} ${w[4]} ${w[5]}.`,
+            w => `Detective ${w[0]} found ${w[1]} ${w[2]} near the ${w[3]} ${w[4]} ${w[5]}.`,
+            w => `In the ${w[0]} ${w[1]}, a ${w[2]} ${w[3]} sang about ${w[4]} ${w[5]}.`,
+            w => `Chef ${w[0]} combined ${w[1]}, ${w[2]}, ${w[3]}, ${w[4]}, and ${w[5]}.`,
+        ],
+        7: [
+            w => `${w[0]} and ${w[1]} walked through the ${w[2]} ${w[3]} to find the ${w[4]} ${w[5]} ${w[6]}.`,
+            w => `The ${w[0]} professor studied ${w[1]} ${w[2]} while drinking ${w[3]} ${w[4]} with ${w[5]} ${w[6]}.`,
+            w => `"${w[0]} ${w[1]}!" yelled ${w[2]} as ${w[3]} ${w[4]} attacked the ${w[5]} ${w[6]}.`,
+            w => `In ${w[0]}, King ${w[1]} decreed that ${w[2]} ${w[3]} must honor ${w[4]} ${w[5]} ${w[6]}.`,
+        ],
+        8: [
+            w => `${w[0]} ${w[1]} and ${w[2]} ${w[3]} met at the ${w[4]} ${w[5]} to discuss ${w[6]} ${w[7]}.`,
+            w => `The ${w[0]} ${w[1]} ${w[2]} traveled from ${w[3]} to ${w[4]} carrying ${w[5]} ${w[6]} ${w[7]}.`,
+            w => `${w[0]} discovered that ${w[1]} ${w[2]} plus ${w[3]} ${w[4]} equals ${w[5]} ${w[6]} ${w[7]}.`,
+        ],
+        9: [
+            w => `${w[0]} ${w[1]} ${w[2]} watched as ${w[3]} ${w[4]} ${w[5]} danced with ${w[6]} ${w[7]} ${w[8]}.`,
+            w => `In the ${w[0]} ${w[1]} ${w[2]}, three friends — ${w[3]}, ${w[4]}, ${w[5]} — found ${w[6]} ${w[7]} ${w[8]}.`,
+            w => `The recipe: ${w[0]}, ${w[1]}, ${w[2]}, ${w[3]}, ${w[4]}, ${w[5]}, ${w[6]}, ${w[7]}, ${w[8]}.`,
+        ],
+        10: [
+            w => `${w[0]} ${w[1]} told ${w[2]} ${w[3]} about the ${w[4]} ${w[5]} ${w[6]} hidden in ${w[7]} ${w[8]} ${w[9]}.`,
+            w => `The ${w[0]} ${w[1]} ${w[2]} ${w[3]} ${w[4]} lived beside ${w[5]} ${w[6]} ${w[7]} ${w[8]} ${w[9]}.`,
+        ],
+        11: [
+            w => `${w[0]} ${w[1]} ${w[2]} and ${w[3]} ${w[4]} ${w[5]} discovered ${w[6]} ${w[7]} ${w[8]} ${w[9]} ${w[10]}.`,
+            w => `In ${w[0]} ${w[1]}, the ${w[2]} ${w[3]} ${w[4]} sang of ${w[5]} ${w[6]} ${w[7]} ${w[8]} ${w[9]} ${w[10]}.`,
+        ],
+        12: [
+            w => `${w[0]} ${w[1]} ${w[2]} met ${w[3]} ${w[4]} ${w[5]} at the ${w[6]} ${w[7]} ${w[8]} ${w[9]} ${w[10]} ${w[11]}.`,
+            w => `The twelve treasures: ${w[0]}, ${w[1]}, ${w[2]}, ${w[3]}, ${w[4]}, ${w[5]}, ${w[6]}, ${w[7]}, ${w[8]}, ${w[9]}, ${w[10]}, ${w[11]}.`,
+        ],
+    },
+
+    /**
+     * Wrap word in highlight span
+     */
+    hl(word) {
+        return `<span class="passphrase-word">${word}</span>`;
+    },
+
+    /**
+     * Generate a memory story for given words
+     * @param {string[]} words - Array of passphrase words
+     * @param {number|null} idx - Template index (null for current)
+     * @returns {string} HTML story
+     */
+    generateStory(words, idx = null) {
+        const count = words.length;
+        if (count === 0) return '';
+
+        // Clamp to supported range (3-12)
+        const templateKey = Math.max(3, Math.min(12, count));
+        const templates = this.storyTemplates[templateKey];
+
+        if (!templates || templates.length === 0) {
+            // Fallback: just list the words
+            return words.map(w => this.hl(w)).join(' &mdash; ');
+        }
+
+        const templateIdx = (idx ?? this.currentStoryTemplate) % templates.length;
+        // Apply highlighting to words
+        const highlighted = words.map(w => this.hl(w));
+        return templates[templateIdx](highlighted);
+    },
+
+    /**
+     * Toggle memory aid visibility
+     * @param {string[]} words - Passphrase words array
+     */
+    toggleMemoryAid(words) {
+        const container = document.getElementById('memoryAidContainer');
+        const icon = document.getElementById('memoryAidIcon');
+        const text = document.getElementById('memoryAidText');
+
+        const isHidden = container?.classList.contains('d-none');
+        container?.classList.toggle('d-none', !isHidden);
+
+        if (icon) icon.className = isHidden ? 'bi bi-lightbulb-fill' : 'bi bi-lightbulb';
+        if (text) text.textContent = isHidden ? 'Hide Aid' : 'Memory Aid';
+
+        if (isHidden) {
+            document.getElementById('memoryStory').innerHTML = this.generateStory(words);
+        }
+    },
+
+    /**
+     * Regenerate story with next template
+     * @param {string[]} words - Passphrase words array
+     */
+    regenerateStory(words) {
+        const count = words.length;
+        const templateKey = Math.max(3, Math.min(12, count));
+        const templates = this.storyTemplates[templateKey] || [];
+        this.currentStoryTemplate = (this.currentStoryTemplate + 1) % Math.max(1, templates.length);
+        document.getElementById('memoryStory').innerHTML = this.generateStory(words, this.currentStoryTemplate);
+    },
+
+    // ========================================================================
+    // QR CODE PRINTING
+    // ========================================================================
+
+    /**
+     * Print QR code in new window
+     */
+    printQrCode() {
+        const qrImg = document.getElementById('qrCodeImage');
+        if (!qrImg) return;
+
+        const printWindow = window.open('', '_blank');
+        printWindow.document.write(`<!DOCTYPE html>
+<html>
+<head>
+    <title>QR Code</title>
+    <style>
+        body { display: flex; flex-direction: column; align-items: center; justify-content: center; min-height: 100vh; margin: 0; }
+        img { max-width: 400px; }
+    </style>
+</head>
+<body>
+    <img src="${qrImg.src}" alt="QR Code">
+    <script>window.onload = function() { window.print(); }<\/script>
+</body>
+</html>`);
+        printWindow.document.close();
+    },
+
+    // ========================================================================
+    // INITIALIZATION
+    // ========================================================================
+
+    /**
+     * Initialize generate form page
+     */
+    initForm() {
+        this.initWordsSlider();
+        this.initOptionToggles();
+    }
+};
+
+// Global function wrappers for onclick handlers
+function togglePinVisibility() {
+    StegasooGenerate.togglePinVisibility();
+}
+
+function togglePassphraseVisibility() {
+    StegasooGenerate.togglePassphraseVisibility();
+}
+
+function printQrCode() {
+    StegasooGenerate.printQrCode();
+}
+
+// Auto-init form controls
+document.addEventListener('DOMContentLoaded', () => {
+    if (document.querySelector('[data-page="generate"]')) {
+        StegasooGenerate.initForm();
+    }
+});

frontends/web/stego_worker.py

@@ -0,0 +1,296 @@
+#!/usr/bin/env python3
+"""
+Stegasoo Subprocess Worker (v4.0.0)
+
+This script runs in a subprocess and handles encode/decode operations.
+If it crashes due to jpegio/scipy issues, the parent Flask process survives.
+
+CHANGES in v4.0.0:
+- Added channel_key support for encode/decode operations
+- New channel_status operation
+
+Communication is via JSON over stdin/stdout:
+- Input: JSON object with operation parameters
+- Output: JSON object with results or error
+
+Usage:
+    echo '{"operation": "encode", ...}' | python stego_worker.py
+"""
+
+import base64
+import json
+import sys
+import traceback
+from pathlib import Path
+
+# Ensure stegasoo is importable
+sys.path.insert(0, str(Path(__file__).parent.parent.parent / "src"))
+sys.path.insert(0, str(Path(__file__).parent))
+
+
+def _resolve_channel_key(channel_key_param):
+    """
+    Resolve channel_key parameter to value for stegasoo.
+
+    Args:
+        channel_key_param: 'auto', 'none', explicit key, or None
+
+    Returns:
+        None (auto), "" (public), or explicit key string
+    """
+    if channel_key_param is None or channel_key_param == "auto":
+        return None  # Auto mode - use server config
+    elif channel_key_param == "none":
+        return ""  # Public mode
+    else:
+        return channel_key_param  # Explicit key
+
+
+def _get_channel_info(resolved_key):
+    """
+    Get channel mode and fingerprint for response.
+
+    Returns:
+        (mode, fingerprint) tuple
+    """
+    from stegasoo import get_channel_status, has_channel_key
+
+    if resolved_key == "":
+        return "public", None
+
+    if resolved_key is not None:
+        # Explicit key
+        fingerprint = f"{resolved_key[:4]}-••••-••••-••••-••••-••••-••••-{resolved_key[-4:]}"
+        return "private", fingerprint
+
+    # Auto mode - check server config
+    if has_channel_key():
+        status = get_channel_status()
+        return "private", status.get("fingerprint")
+
+    return "public", None
+
+
+def encode_operation(params: dict) -> dict:
+    """Handle encode operation."""
+    from stegasoo import FilePayload, encode
+
+    # Decode base64 inputs
+    carrier_data = base64.b64decode(params["carrier_b64"])
+    reference_data = base64.b64decode(params["reference_b64"])
+
+    # Optional RSA key
+    rsa_key_data = None
+    if params.get("rsa_key_b64"):
+        rsa_key_data = base64.b64decode(params["rsa_key_b64"])
+
+    # Determine payload type
+    if params.get("file_b64"):
+        file_data = base64.b64decode(params["file_b64"])
+        payload = FilePayload(
+            data=file_data,
+            filename=params.get("file_name", "file"),
+            mime_type=params.get("file_mime", "application/octet-stream"),
+        )
+    else:
+        payload = params.get("message", "")
+
+    # Resolve channel key (v4.0.0)
+    resolved_channel_key = _resolve_channel_key(params.get("channel_key", "auto"))
+
+    # Call encode with correct parameter names
+    result = encode(
+        message=payload,
+        reference_photo=reference_data,
+        carrier_image=carrier_data,
+        passphrase=params.get("passphrase", ""),
+        pin=params.get("pin"),
+        rsa_key_data=rsa_key_data,
+        rsa_password=params.get("rsa_password"),
+        embed_mode=params.get("embed_mode", "lsb"),
+        dct_output_format=params.get("dct_output_format", "png"),
+        dct_color_mode=params.get("dct_color_mode", "color"),
+        channel_key=resolved_channel_key,  # v4.0.0
+        progress_file=params.get("progress_file"),  # v4.1.2
+    )
+
+    # Build stats dict if available
+    stats = None
+    if hasattr(result, "stats") and result.stats:
+        stats = {
+            "pixels_modified": getattr(result.stats, "pixels_modified", 0),
+            "capacity_used": getattr(result.stats, "capacity_used", 0),
+            "bytes_embedded": getattr(result.stats, "bytes_embedded", 0),
+        }
+
+    # Get channel info for response (v4.0.0)
+    channel_mode, channel_fingerprint = _get_channel_info(resolved_channel_key)
+
+    return {
+        "success": True,
+        "stego_b64": base64.b64encode(result.stego_image).decode("ascii"),
+        "filename": getattr(result, "filename", None),
+        "stats": stats,
+        "channel_mode": channel_mode,
+        "channel_fingerprint": channel_fingerprint,
+    }
+
+
+def _write_decode_progress(progress_file: str | None, percent: int, phase: str) -> None:
+    """Write decode progress to file."""
+    if not progress_file:
+        return
+    try:
+        import json
+        with open(progress_file, "w") as f:
+            json.dump({"percent": percent, "phase": phase}, f)
+    except Exception:
+        pass  # Best effort
+
+
+def decode_operation(params: dict) -> dict:
+    """Handle decode operation."""
+    from stegasoo import decode
+
+    progress_file = params.get("progress_file")
+
+    # Progress: starting
+    _write_decode_progress(progress_file, 5, "reading")
+
+    # Decode base64 inputs
+    stego_data = base64.b64decode(params["stego_b64"])
+    reference_data = base64.b64decode(params["reference_b64"])
+
+    _write_decode_progress(progress_file, 15, "reading")
+
+    # Optional RSA key
+    rsa_key_data = None
+    if params.get("rsa_key_b64"):
+        rsa_key_data = base64.b64decode(params["rsa_key_b64"])
+
+    # Resolve channel key (v4.0.0)
+    resolved_channel_key = _resolve_channel_key(params.get("channel_key", "auto"))
+
+    _write_decode_progress(progress_file, 25, "extracting")
+
+    # Call decode with correct parameter names
+    result = decode(
+        stego_image=stego_data,
+        reference_photo=reference_data,
+        passphrase=params.get("passphrase", ""),
+        pin=params.get("pin"),
+        rsa_key_data=rsa_key_data,
+        rsa_password=params.get("rsa_password"),
+        embed_mode=params.get("embed_mode", "auto"),
+        channel_key=resolved_channel_key,  # v4.0.0
+    )
+
+    _write_decode_progress(progress_file, 90, "finalizing")
+
+    if result.is_file:
+        return {
+            "success": True,
+            "is_file": True,
+            "file_b64": base64.b64encode(result.file_data).decode("ascii"),
+            "filename": result.filename,
+            "mime_type": result.mime_type,
+        }
+    else:
+        return {
+            "success": True,
+            "is_file": False,
+            "message": result.message,
+        }
+
+
+def compare_operation(params: dict) -> dict:
+    """Handle compare_modes operation."""
+    from stegasoo import compare_modes
+
+    carrier_data = base64.b64decode(params["carrier_b64"])
+    result = compare_modes(carrier_data)
+
+    return {
+        "success": True,
+        "comparison": result,
+    }
+
+
+def capacity_check_operation(params: dict) -> dict:
+    """Handle will_fit_by_mode operation."""
+    from stegasoo import will_fit_by_mode
+
+    carrier_data = base64.b64decode(params["carrier_b64"])
+
+    result = will_fit_by_mode(
+        payload=params["payload_size"],
+        carrier_image=carrier_data,
+        embed_mode=params.get("embed_mode", "lsb"),
+    )
+
+    return {
+        "success": True,
+        "result": result,
+    }
+
+
+def channel_status_operation(params: dict) -> dict:
+    """Handle channel status check (v4.0.0)."""
+    from stegasoo import get_channel_status
+
+    status = get_channel_status()
+    reveal = params.get("reveal", False)
+
+    return {
+        "success": True,
+        "status": {
+            "mode": status["mode"],
+            "configured": status["configured"],
+            "fingerprint": status.get("fingerprint"),
+            "source": status.get("source"),
+            "key": status.get("key") if reveal and status["configured"] else None,
+        },
+    }
+
+
+def main():
+    """Main entry point - read JSON from stdin, write JSON to stdout."""
+    try:
+        # Read all input
+        input_text = sys.stdin.read()
+
+        if not input_text.strip():
+            output = {"success": False, "error": "No input provided"}
+        else:
+            params = json.loads(input_text)
+            operation = params.get("operation")
+
+            if operation == "encode":
+                output = encode_operation(params)
+            elif operation == "decode":
+                output = decode_operation(params)
+            elif operation == "compare":
+                output = compare_operation(params)
+            elif operation == "capacity":
+                output = capacity_check_operation(params)
+            elif operation == "channel_status":
+                output = channel_status_operation(params)
+            else:
+                output = {"success": False, "error": f"Unknown operation: {operation}"}
+
+    except json.JSONDecodeError as e:
+        output = {"success": False, "error": f"Invalid JSON: {e}"}
+    except Exception as e:
+        output = {
+            "success": False,
+            "error": str(e),
+            "error_type": type(e).__name__,
+            "traceback": traceback.format_exc(),
+        }
+
+    # Write output as JSON
+    print(json.dumps(output), flush=True)
+
+
+if __name__ == "__main__":
+    main()

frontends/web/subprocess_stego.py

@@ -0,0 +1,546 @@
+"""
+Subprocess Steganography Wrapper (v4.0.0)
+
+Runs stegasoo operations in isolated subprocesses to prevent crashes
+from taking down the Flask server.
+
+CHANGES in v4.0.0:
+- Added channel_key parameter to encode() and decode() methods
+- Channel keys enable deployment/group isolation
+
+Usage:
+    from subprocess_stego import SubprocessStego
+
+    stego = SubprocessStego()
+
+    # Encode with channel key
+    result = stego.encode(
+        carrier_data=carrier_bytes,
+        reference_data=ref_bytes,
+        message="secret message",
+        passphrase="my passphrase",
+        pin="123456",
+        embed_mode="dct",
+        channel_key="auto",  # or "none", or explicit key
+    )
+
+    if result.success:
+        stego_bytes = result.stego_data
+        extension = result.extension
+    else:
+        error_message = result.error
+
+    # Decode
+    result = stego.decode(
+        stego_data=stego_bytes,
+        reference_data=ref_bytes,
+        passphrase="my passphrase",
+        pin="123456",
+        channel_key="auto",
+    )
+
+    # Compare modes (capacity)
+    result = stego.compare_modes(carrier_bytes)
+"""
+
+import base64
+import json
+import subprocess
+import sys
+import tempfile
+import uuid
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any
+
+# Default timeout for operations (seconds)
+DEFAULT_TIMEOUT = 120
+
+# Path to worker script - adjust if needed
+WORKER_SCRIPT = Path(__file__).parent / "stego_worker.py"
+
+
+@dataclass
+class EncodeResult:
+    """Result from encode operation."""
+
+    success: bool
+    stego_data: bytes | None = None
+    filename: str | None = None
+    stats: dict[str, Any] | None = None
+    # Channel info (v4.0.0)
+    channel_mode: str | None = None
+    channel_fingerprint: str | None = None
+    error: str | None = None
+    error_type: str | None = None
+
+
+@dataclass
+class DecodeResult:
+    """Result from decode operation."""
+
+    success: bool
+    is_file: bool = False
+    message: str | None = None
+    file_data: bytes | None = None
+    filename: str | None = None
+    mime_type: str | None = None
+    error: str | None = None
+    error_type: str | None = None
+
+
+@dataclass
+class CompareResult:
+    """Result from compare_modes operation."""
+
+    success: bool
+    width: int = 0
+    height: int = 0
+    lsb: dict[str, Any] | None = None
+    dct: dict[str, Any] | None = None
+    error: str | None = None
+
+
+@dataclass
+class CapacityResult:
+    """Result from capacity check operation."""
+
+    success: bool
+    fits: bool = False
+    payload_size: int = 0
+    capacity: int = 0
+    usage_percent: float = 0.0
+    headroom: int = 0
+    mode: str = ""
+    error: str | None = None
+
+
+@dataclass
+class ChannelStatusResult:
+    """Result from channel status check (v4.0.0)."""
+
+    success: bool
+    mode: str = "public"
+    configured: bool = False
+    fingerprint: str | None = None
+    source: str | None = None
+    key: str | None = None
+    error: str | None = None
+
+
+class SubprocessStego:
+    """
+    Subprocess-isolated steganography operations.
+
+    All operations run in a separate Python process. If jpegio or scipy
+    crashes, only the subprocess dies - Flask keeps running.
+    """
+
+    def __init__(
+        self,
+        worker_path: Path | None = None,
+        python_executable: str | None = None,
+        timeout: int = DEFAULT_TIMEOUT,
+    ):
+        """
+        Initialize subprocess wrapper.
+
+        Args:
+            worker_path: Path to stego_worker.py (default: same directory)
+            python_executable: Python interpreter to use (default: same as current)
+            timeout: Default timeout in seconds
+        """
+        self.worker_path = worker_path or WORKER_SCRIPT
+        self.python = python_executable or sys.executable
+        self.timeout = timeout
+
+        if not self.worker_path.exists():
+            raise FileNotFoundError(f"Worker script not found: {self.worker_path}")
+
+    def _run_worker(self, params: dict[str, Any], timeout: int | None = None) -> dict[str, Any]:
+        """
+        Run the worker subprocess with given parameters.
+
+        Args:
+            params: Dictionary of parameters (will be JSON-encoded)
+            timeout: Operation timeout in seconds
+
+        Returns:
+            Dictionary with results from worker
+        """
+        timeout = timeout or self.timeout
+        input_json = json.dumps(params)
+
+        try:
+            result = subprocess.run(
+                [self.python, str(self.worker_path)],
+                input=input_json,
+                capture_output=True,
+                text=True,
+                timeout=timeout,
+                cwd=str(self.worker_path.parent),
+            )
+
+            if result.returncode != 0:
+                # Worker crashed
+                return {
+                    "success": False,
+                    "error": f"Worker crashed (exit code {result.returncode})",
+                    "stderr": result.stderr,
+                }
+
+            if not result.stdout.strip():
+                return {
+                    "success": False,
+                    "error": "Worker returned empty output",
+                    "stderr": result.stderr,
+                }
+
+            return json.loads(result.stdout)
+
+        except subprocess.TimeoutExpired:
+            return {
+                "success": False,
+                "error": f"Operation timed out after {timeout} seconds",
+                "error_type": "TimeoutError",
+            }
+        except json.JSONDecodeError as e:
+            return {
+                "success": False,
+                "error": f"Invalid JSON from worker: {e}",
+                "raw_output": result.stdout if "result" in dir() else None,
+            }
+        except Exception as e:
+            return {
+                "success": False,
+                "error": str(e),
+                "error_type": type(e).__name__,
+            }
+
+    def encode(
+        self,
+        carrier_data: bytes,
+        reference_data: bytes,
+        message: str | None = None,
+        file_data: bytes | None = None,
+        file_name: str | None = None,
+        file_mime: str | None = None,
+        passphrase: str = "",
+        pin: str | None = None,
+        rsa_key_data: bytes | None = None,
+        rsa_password: str | None = None,
+        embed_mode: str = "lsb",
+        dct_output_format: str = "png",
+        dct_color_mode: str = "color",
+        # Channel key (v4.0.0)
+        channel_key: str | None = "auto",
+        timeout: int | None = None,
+        # Progress file (v4.1.2)
+        progress_file: str | None = None,
+    ) -> EncodeResult:
+        """
+        Encode a message or file into an image.
+
+        Args:
+            carrier_data: Carrier image bytes
+            reference_data: Reference photo bytes
+            message: Text message to encode (if not file)
+            file_data: File bytes to encode (if not message)
+            file_name: Original filename (for file payload)
+            file_mime: MIME type (for file payload)
+            passphrase: Encryption passphrase
+            pin: Optional PIN
+            rsa_key_data: Optional RSA key PEM bytes
+            rsa_password: RSA key password if encrypted
+            embed_mode: 'lsb' or 'dct'
+            dct_output_format: 'png' or 'jpeg' (for DCT mode)
+            dct_color_mode: 'grayscale' or 'color' (for DCT mode)
+            channel_key: 'auto' (server config), 'none' (public), or explicit key (v4.0.0)
+            timeout: Operation timeout in seconds
+
+        Returns:
+            EncodeResult with stego_data and extension on success
+        """
+        params = {
+            "operation": "encode",
+            "carrier_b64": base64.b64encode(carrier_data).decode("ascii"),
+            "reference_b64": base64.b64encode(reference_data).decode("ascii"),
+            "message": message,
+            "passphrase": passphrase,
+            "pin": pin,
+            "embed_mode": embed_mode,
+            "dct_output_format": dct_output_format,
+            "dct_color_mode": dct_color_mode,
+            "channel_key": channel_key,  # v4.0.0
+            "progress_file": progress_file,  # v4.1.2
+        }
+
+        if file_data:
+            params["file_b64"] = base64.b64encode(file_data).decode("ascii")
+            params["file_name"] = file_name
+            params["file_mime"] = file_mime
+
+        if rsa_key_data:
+            params["rsa_key_b64"] = base64.b64encode(rsa_key_data).decode("ascii")
+            params["rsa_password"] = rsa_password
+
+        result = self._run_worker(params, timeout)
+
+        if result.get("success"):
+            return EncodeResult(
+                success=True,
+                stego_data=base64.b64decode(result["stego_b64"]),
+                filename=result.get("filename"),
+                stats=result.get("stats"),
+                channel_mode=result.get("channel_mode"),
+                channel_fingerprint=result.get("channel_fingerprint"),
+            )
+        else:
+            return EncodeResult(
+                success=False,
+                error=result.get("error", "Unknown error"),
+                error_type=result.get("error_type"),
+            )
+
+    def decode(
+        self,
+        stego_data: bytes,
+        reference_data: bytes,
+        passphrase: str = "",
+        pin: str | None = None,
+        rsa_key_data: bytes | None = None,
+        rsa_password: str | None = None,
+        embed_mode: str = "auto",
+        # Channel key (v4.0.0)
+        channel_key: str | None = "auto",
+        timeout: int | None = None,
+        # Progress tracking (v4.1.5)
+        progress_file: str | None = None,
+    ) -> DecodeResult:
+        """
+        Decode a message or file from a stego image.
+
+        Args:
+            stego_data: Stego image bytes
+            reference_data: Reference photo bytes
+            passphrase: Decryption passphrase
+            pin: Optional PIN
+            rsa_key_data: Optional RSA key PEM bytes
+            rsa_password: RSA key password if encrypted
+            embed_mode: 'auto', 'lsb', or 'dct'
+            channel_key: 'auto' (server config), 'none' (public), or explicit key (v4.0.0)
+            timeout: Operation timeout in seconds
+            progress_file: Path to write progress updates (v4.1.5)
+
+        Returns:
+            DecodeResult with message or file_data on success
+        """
+        params = {
+            "operation": "decode",
+            "stego_b64": base64.b64encode(stego_data).decode("ascii"),
+            "reference_b64": base64.b64encode(reference_data).decode("ascii"),
+            "passphrase": passphrase,
+            "pin": pin,
+            "embed_mode": embed_mode,
+            "channel_key": channel_key,  # v4.0.0
+            "progress_file": progress_file,  # v4.1.5
+        }
+
+        if rsa_key_data:
+            params["rsa_key_b64"] = base64.b64encode(rsa_key_data).decode("ascii")
+            params["rsa_password"] = rsa_password
+
+        result = self._run_worker(params, timeout)
+
+        if result.get("success"):
+            if result.get("is_file"):
+                return DecodeResult(
+                    success=True,
+                    is_file=True,
+                    file_data=base64.b64decode(result["file_b64"]),
+                    filename=result.get("filename"),
+                    mime_type=result.get("mime_type"),
+                )
+            else:
+                return DecodeResult(
+                    success=True,
+                    is_file=False,
+                    message=result.get("message"),
+                )
+        else:
+            return DecodeResult(
+                success=False,
+                error=result.get("error", "Unknown error"),
+                error_type=result.get("error_type"),
+            )
+
+    def compare_modes(
+        self,
+        carrier_data: bytes,
+        timeout: int | None = None,
+    ) -> CompareResult:
+        """
+        Compare LSB and DCT capacity for a carrier image.
+
+        Args:
+            carrier_data: Carrier image bytes
+            timeout: Operation timeout in seconds
+
+        Returns:
+            CompareResult with capacity information
+        """
+        params = {
+            "operation": "compare",
+            "carrier_b64": base64.b64encode(carrier_data).decode("ascii"),
+        }
+
+        result = self._run_worker(params, timeout)
+
+        if result.get("success"):
+            comparison = result.get("comparison", {})
+            return CompareResult(
+                success=True,
+                width=comparison.get("width", 0),
+                height=comparison.get("height", 0),
+                lsb=comparison.get("lsb"),
+                dct=comparison.get("dct"),
+            )
+        else:
+            return CompareResult(
+                success=False,
+                error=result.get("error", "Unknown error"),
+            )
+
+    def check_capacity(
+        self,
+        carrier_data: bytes,
+        payload_size: int,
+        embed_mode: str = "lsb",
+        timeout: int | None = None,
+    ) -> CapacityResult:
+        """
+        Check if a payload will fit in the carrier.
+
+        Args:
+            carrier_data: Carrier image bytes
+            payload_size: Size of payload in bytes
+            embed_mode: 'lsb' or 'dct'
+            timeout: Operation timeout in seconds
+
+        Returns:
+            CapacityResult with fit information
+        """
+        params = {
+            "operation": "capacity",
+            "carrier_b64": base64.b64encode(carrier_data).decode("ascii"),
+            "payload_size": payload_size,
+            "embed_mode": embed_mode,
+        }
+
+        result = self._run_worker(params, timeout)
+
+        if result.get("success"):
+            r = result.get("result", {})
+            return CapacityResult(
+                success=True,
+                fits=r.get("fits", False),
+                payload_size=r.get("payload_size", 0),
+                capacity=r.get("capacity", 0),
+                usage_percent=r.get("usage_percent", 0.0),
+                headroom=r.get("headroom", 0),
+                mode=r.get("mode", embed_mode),
+            )
+        else:
+            return CapacityResult(
+                success=False,
+                error=result.get("error", "Unknown error"),
+            )
+
+    def get_channel_status(
+        self,
+        reveal: bool = False,
+        timeout: int | None = None,
+    ) -> ChannelStatusResult:
+        """
+        Get current channel key status (v4.0.0).
+
+        Args:
+            reveal: Include full key in response
+            timeout: Operation timeout in seconds
+
+        Returns:
+            ChannelStatusResult with channel info
+        """
+        params = {
+            "operation": "channel_status",
+            "reveal": reveal,
+        }
+
+        result = self._run_worker(params, timeout)
+
+        if result.get("success"):
+            status = result.get("status", {})
+            return ChannelStatusResult(
+                success=True,
+                mode=status.get("mode", "public"),
+                configured=status.get("configured", False),
+                fingerprint=status.get("fingerprint"),
+                source=status.get("source"),
+                key=status.get("key") if reveal else None,
+            )
+        else:
+            return ChannelStatusResult(
+                success=False,
+                error=result.get("error", "Unknown error"),
+            )
+
+
+# Convenience function for quick usage
+_default_stego: SubprocessStego | None = None
+
+
+def get_subprocess_stego() -> SubprocessStego:
+    """Get or create default SubprocessStego instance."""
+    global _default_stego
+    if _default_stego is None:
+        _default_stego = SubprocessStego()
+    return _default_stego
+
+
+# =============================================================================
+# Progress File Utilities (v4.1.2)
+# =============================================================================
+
+
+def generate_job_id() -> str:
+    """Generate a unique job ID for tracking encode/decode operations."""
+    return str(uuid.uuid4())[:8]
+
+
+def get_progress_file_path(job_id: str) -> str:
+    """Get the progress file path for a job ID."""
+    return str(Path(tempfile.gettempdir()) / f"stegasoo_progress_{job_id}.json")
+
+
+def read_progress(job_id: str) -> dict | None:
+    """
+    Read progress from file for a job ID.
+
+    Returns:
+        Progress dict with current, total, percent, phase, or None if not found
+    """
+    progress_file = get_progress_file_path(job_id)
+    try:
+        with open(progress_file) as f:
+            return json.load(f)
+    except (FileNotFoundError, json.JSONDecodeError):
+        return None
+
+
+def cleanup_progress_file(job_id: str) -> None:
+    """Remove progress file for a completed job."""
+    progress_file = get_progress_file_path(job_id)
+    try:
+        Path(progress_file).unlink(missing_ok=True)
+    except Exception:
+        pass

frontends/web/temp_storage.py

@@ -0,0 +1,212 @@
+"""
+File-based Temporary Storage
+
+Stores temp files on disk instead of in-memory dict.
+This allows multiple Gunicorn workers to share temp files
+and survives service restarts within the expiry window.
+
+Files are stored in a temp directory with:
+- {file_id}.data - The actual file data
+- {file_id}.json - Metadata (filename, timestamp, mime_type, etc.)
+
+IMPORTANT: This module ONLY manages files in the temp_files/ directory.
+It does NOT touch instance/ (auth database) or any other directories.
+"""
+
+import json
+import time
+from pathlib import Path
+from threading import Lock
+
+# Default temp directory (can be overridden)
+DEFAULT_TEMP_DIR = Path(__file__).parent / "temp_files"
+
+# Lock for thread-safe operations
+_lock = Lock()
+
+# Module-level temp directory (set on init)
+_temp_dir: Path = DEFAULT_TEMP_DIR
+
+
+def init(temp_dir: Path | str | None = None):
+    """Initialize temp storage with optional custom directory."""
+    global _temp_dir
+    _temp_dir = Path(temp_dir) if temp_dir else DEFAULT_TEMP_DIR
+    _temp_dir.mkdir(parents=True, exist_ok=True)
+
+
+def _data_path(file_id: str) -> Path:
+    """Get path for file data."""
+    return _temp_dir / f"{file_id}.data"
+
+
+def _meta_path(file_id: str) -> Path:
+    """Get path for file metadata."""
+    return _temp_dir / f"{file_id}.json"
+
+
+def _thumb_path(thumb_id: str) -> Path:
+    """Get path for thumbnail data."""
+    return _temp_dir / f"{thumb_id}.thumb"
+
+
+def save_temp_file(file_id: str, data: bytes, metadata: dict) -> None:
+    """
+    Save a temp file with its metadata.
+
+    Args:
+        file_id: Unique identifier for the file
+        data: File contents as bytes
+        metadata: Dict with filename, mime_type, timestamp, etc.
+    """
+    init()  # Ensure directory exists
+
+    with _lock:
+        # Add timestamp if not present
+        if "timestamp" not in metadata:
+            metadata["timestamp"] = time.time()
+
+        # Write data file
+        _data_path(file_id).write_bytes(data)
+
+        # Write metadata
+        _meta_path(file_id).write_text(json.dumps(metadata))
+
+
+def get_temp_file(file_id: str) -> dict | None:
+    """
+    Get a temp file and its metadata.
+
+    Returns:
+        Dict with 'data' (bytes) and all metadata fields, or None if not found.
+    """
+    init()
+
+    data_file = _data_path(file_id)
+    meta_file = _meta_path(file_id)
+
+    if not data_file.exists() or not meta_file.exists():
+        return None
+
+    try:
+        data = data_file.read_bytes()
+        metadata = json.loads(meta_file.read_text())
+        return {"data": data, **metadata}
+    except (OSError, json.JSONDecodeError):
+        return None
+
+
+def has_temp_file(file_id: str) -> bool:
+    """Check if a temp file exists."""
+    init()
+    return _data_path(file_id).exists() and _meta_path(file_id).exists()
+
+
+def delete_temp_file(file_id: str) -> None:
+    """Delete a temp file and its metadata."""
+    init()
+
+    with _lock:
+        _data_path(file_id).unlink(missing_ok=True)
+        _meta_path(file_id).unlink(missing_ok=True)
+
+
+def save_thumbnail(thumb_id: str, data: bytes) -> None:
+    """Save a thumbnail."""
+    init()
+
+    with _lock:
+        _thumb_path(thumb_id).write_bytes(data)
+
+
+def get_thumbnail(thumb_id: str) -> bytes | None:
+    """Get thumbnail data."""
+    init()
+
+    thumb_file = _thumb_path(thumb_id)
+    if not thumb_file.exists():
+        return None
+
+    try:
+        return thumb_file.read_bytes()
+    except OSError:
+        return None
+
+
+def delete_thumbnail(thumb_id: str) -> None:
+    """Delete a thumbnail."""
+    init()
+
+    with _lock:
+        _thumb_path(thumb_id).unlink(missing_ok=True)
+
+
+def cleanup_expired(max_age_seconds: float) -> int:
+    """
+    Delete expired temp files.
+
+    Args:
+        max_age_seconds: Maximum age in seconds before expiry
+
+    Returns:
+        Number of files deleted
+    """
+    init()
+
+    now = time.time()
+    deleted = 0
+
+    with _lock:
+        # Find all metadata files
+        for meta_file in _temp_dir.glob("*.json"):
+            try:
+                metadata = json.loads(meta_file.read_text())
+                timestamp = metadata.get("timestamp", 0)
+
+                if now - timestamp > max_age_seconds:
+                    file_id = meta_file.stem
+                    _data_path(file_id).unlink(missing_ok=True)
+                    meta_file.unlink(missing_ok=True)
+                    # Also delete thumbnail if exists
+                    _thumb_path(f"{file_id}_thumb").unlink(missing_ok=True)
+                    deleted += 1
+            except (OSError, json.JSONDecodeError):
+                # Remove corrupted files
+                meta_file.unlink(missing_ok=True)
+                deleted += 1
+
+    return deleted
+
+
+def cleanup_all() -> int:
+    """
+    Delete all temp files. Call on service start/stop.
+
+    Returns:
+        Number of files deleted
+    """
+    init()
+
+    deleted = 0
+
+    with _lock:
+        for f in _temp_dir.iterdir():
+            if f.is_file():
+                f.unlink(missing_ok=True)
+                deleted += 1
+
+    return deleted
+
+
+def get_stats() -> dict:
+    """Get temp storage statistics."""
+    init()
+
+    files = list(_temp_dir.glob("*.data"))
+    total_size = sum(f.stat().st_size for f in files if f.exists())
+
+    return {
+        "file_count": len(files),
+        "total_size_bytes": total_size,
+        "temp_dir": str(_temp_dir),
+    }

frontends/web/templates/about.html

@@ -11,29 +11,32 @@
             </div>
             <div class="card-body">
                 <p class="lead">
-                    Stegasoo is a secure steganography tool that hides encrypted messages and files 
-                    inside ordinary images using multi-factor authentication.
+                    Stegasoo hides encrypted messages and files inside images using multi-factor authentication.
                 </p>
                 
-                <h6 class="text-primary mt-4 mb-3"><i class="bi bi-stars me-2"></i>Key Features</h6>
+                <h6 class="text-primary mt-4 mb-3">Features</h6>
                 <div class="row">
                     <div class="col-md-6">
                         <ul class="list-unstyled">
                             <li class="mb-2">
                                 <i class="bi bi-check-circle text-success me-2"></i>
-                                <strong>Text &amp; File Embedding</strong> — Hide messages or any file type (PDF, ZIP, documents)
+                                <strong>Text &amp; File Embedding</strong>
+                                <br><small class="text-muted">Any file type: PDF, ZIP, documents</small>
                             </li>
                             <li class="mb-2">
                                 <i class="bi bi-check-circle text-success me-2"></i>
-                                <strong>Multi-Factor Security</strong> — Combines photo + phrase + PIN/RSA key
+                                <strong>Multi-Factor Security</strong>
+                                <br><small class="text-muted">Photo + passphrase + PIN/RSA key</small>
                             </li>
                             <li class="mb-2">
                                 <i class="bi bi-check-circle text-success me-2"></i>
-                                <strong>AES-256-GCM Encryption</strong> — Military-grade authenticated encryption
+                                <strong>AES-256-GCM Encryption</strong>
+                                <br><small class="text-muted">Authenticated encryption with integrity check</small>
                             </li>
                             <li class="mb-2">
                                 <i class="bi bi-check-circle text-success me-2"></i>
-                                <strong>Daily Rotating Phrases</strong> — Different passphrase each day of the week
+                                <strong>DCT &amp; LSB Modes</strong>
+                                <br><small class="text-muted">JPEG resilience (DCT) or high capacity (LSB)</small>
                             </li>
                         </ul>
                     </div>
@@ -41,19 +44,29 @@
                         <ul class="list-unstyled">
                             <li class="mb-2">
                                 <i class="bi bi-check-circle text-success me-2"></i>
-                                <strong>Random Pixel Embedding</strong> — Defeats statistical steganalysis
+                                <strong>Random Pixel Embedding</strong>
+                                <br><small class="text-muted">Defeats statistical analysis</small>
                             </li>
                             <li class="mb-2">
                                 <i class="bi bi-check-circle text-success me-2"></i>
-                                <strong>Format Preservation</strong> — Maintains PNG/BMP lossless formats
+                                <strong>Large Image Support</strong>
+                                <br><small class="text-muted">Up to {{ max_payload_kb }} KB, tested with 14MB+ images</small>
                             </li>
                             <li class="mb-2">
                                 <i class="bi bi-check-circle text-success me-2"></i>
-                                <strong>Large Capacity</strong> — Up to {{ max_payload_kb }} KB payload, 16MP images
+                                <strong>Zero Server Storage</strong>
+                                <br><small class="text-muted">Nothing saved, files auto-expire</small>
                             </li>
                             <li class="mb-2">
                                 <i class="bi bi-check-circle text-success me-2"></i>
-                                <strong>Zero Server Storage</strong> — Nothing saved, files auto-expire
+                                <strong>QR Code Keys</strong>
+                                <br><small class="text-muted">Import/export RSA keys via QR</small>
+                            </li>
+                            <li class="mb-2">
+                                <i class="bi bi-check-circle text-success me-2"></i>
+                                <strong>Channel Keys</strong>
+                                <span class="badge bg-info ms-1">v4.1</span>
+                                <br><small class="text-muted">Group/deployment isolation</small>
                             </li>
                         </ul>
                     </div>
@@ -61,113 +74,327 @@
             </div>
         </div>
         
+        <!-- Embedding Modes -->
+        <div class="card mb-4">
+            <div class="card-header">
+                <h5 class="mb-0"><i class="bi bi-cpu me-2"></i>Embedding Modes</h5>
+            </div>
+            <div class="card-body">
+                <p>Two modes optimized for different use cases.</p>
+                
+                <div class="row mt-4">
+                    <!-- DCT Mode -->
+                    <div class="col-md-6 mb-4">
+                        <div class="card bg-dark h-100">
+                            <div class="card-header">
+                                <i class="bi bi-soundwave text-warning me-2"></i>
+                                <strong>DCT Mode</strong>
+                                <span class="badge bg-success ms-2">Default</span>
+                            </div>
+                            <div class="card-body">
+                                <p class="small">
+                                    <strong>DCT (Discrete Cosine Transform)</strong> embeds data in frequency coefficients. Survives JPEG recompression.
+                                </p>
+                                <ul class="small mb-0">
+                                    <li><strong>Capacity:</strong> ~75 KB/MP</li>
+                                    <li><strong>Output:</strong> JPEG or PNG</li>
+                                    <li><strong>Color:</strong> Color or grayscale</li>
+                                    <li><strong>Speed:</strong> ~2s</li>
+                                    <li><strong>Error Correction:</strong> Reed-Solomon</li>
+                                </ul>
+                                <hr>
+                                <div class="small">
+                                    <i class="bi bi-check-circle text-success me-1"></i> Instagram, Facebook<br>
+                                    <i class="bi bi-check-circle text-success me-1"></i> WhatsApp, Signal, Telegram<br>
+                                    <i class="bi bi-check-circle text-success me-1"></i> Twitter/X<br>
+                                    <i class="bi bi-check-circle text-success me-1"></i> Any recompressing platform
+                                </div>
+                            </div>
+                        </div>
+                    </div>
+                    
+                    <!-- LSB Mode -->
+                    <div class="col-md-6 mb-4">
+                        <div class="card bg-dark h-100">
+                            <div class="card-header">
+                                <i class="bi bi-grid-3x3-gap text-primary me-2"></i>
+                                <strong>LSB Mode</strong>
+                            </div>
+                            <div class="card-body">
+                                <p class="small">
+                                    <strong>LSB (Least Significant Bit)</strong> embeds data in the lowest bit of each color channel. Imperceptible to the eye.
+                                </p>
+                                <ul class="small mb-0">
+                                    <li><strong>Capacity:</strong> ~375 KB/MP</li>
+                                    <li><strong>Output:</strong> PNG (lossless)</li>
+                                    <li><strong>Color:</strong> Full color</li>
+                                    <li><strong>Speed:</strong> ~0.5s</li>
+                                </ul>
+                                <hr>
+                                <div class="small">
+                                    <i class="bi bi-check-circle text-success me-1"></i> Email attachments<br>
+                                    <i class="bi bi-check-circle text-success me-1"></i> Cloud storage<br>
+                                    <i class="bi bi-check-circle text-success me-1"></i> Direct file transfer<br>
+                                    <i class="bi bi-x-circle text-danger me-1"></i> Social media
+                                </div>
+                            </div>
+                        </div>
+                    </div>
+                </div>
+                
+                <!-- Mode Comparison Table -->
+                <h6 class="mt-3"><i class="bi bi-table me-2"></i>Comparison</h6>
+                <div class="table-responsive">
+                    <table class="table table-dark table-sm small">
+                        <thead>
+                            <tr>
+                                <th>Aspect</th>
+                                <th>DCT Mode <span class="badge bg-success ms-1">Default</span></th>
+                                <th>LSB Mode</th>
+                            </tr>
+                        </thead>
+                        <tbody>
+                            <tr>
+                                <td>Capacity (1080p)</td>
+                                <td class="text-warning">~50 KB</td>
+                                <td class="text-success">~770 KB</td>
+                            </tr>
+                            <tr>
+                                <td>Survives JPEG</td>
+                                <td class="text-success">✅ Yes</td>
+                                <td class="text-danger">❌ No</td>
+                            </tr>
+                            <tr>
+                                <td>Social Media</td>
+                                <td class="text-success">✅ Works</td>
+                                <td class="text-danger">❌ Broken</td>
+                            </tr>
+                            <tr>
+                                <td>Detection Resistance</td>
+                                <td>Better</td>
+                                <td>Moderate</td>
+                            </tr>
+                        </tbody>
+                    </table>
+                </div>
+                
+                <div class="alert alert-info small mt-3 mb-0">
+                    <i class="bi bi-lightbulb me-2"></i>
+                    <strong>Auto-Detection:</strong> Mode is detected automatically when decoding.
+                </div>
+            </div>
+        </div>
+        
         <div class="card mb-4">
             <div class="card-header">
                 <h5 class="mb-0"><i class="bi bi-shield-lock me-2"></i>How Security Works</h5>
             </div>
             <div class="card-body">
-                <p>Stegasoo uses <strong>hybrid multi-factor authentication</strong> to derive encryption keys:</p>
+                <p>Multi-factor authentication derives encryption keys:</p>
                 
                 <div class="row text-center my-4">
-                    <div class="col-md-3 mb-3">
-                        <div class="p-3 bg-dark rounded">
+                    <div class="col-6 col-lg-3 mb-3">
+                        <div class="p-3 bg-dark rounded h-100 d-flex flex-column align-items-center">
                             <i class="bi bi-image text-info fs-2 d-block mb-2"></i>
                             <strong>Reference Photo</strong>
                             <div class="small text-muted mt-1">Something you have</div>
-                            <div class="small text-success">~80-256 bits</div>
+                            <div class="small text-success mt-auto pt-2">~80-256 bits</div>
                         </div>
                     </div>
-                    <div class="col-md-3 mb-3">
-                        <div class="p-3 bg-dark rounded">
+                    <div class="col-6 col-lg-3 mb-3">
+                        <div class="p-3 bg-dark rounded h-100 d-flex flex-column align-items-center">
                             <i class="bi bi-chat-quote text-warning fs-2 d-block mb-2"></i>
-                            <strong>Daily Phrase</strong>
-                            <div class="small text-muted mt-1">Something you know (rotates)</div>
-                            <div class="small text-success">~33 bits (3 words)</div>
+                            <strong>Passphrase</strong>
+                            <div class="small text-muted mt-1">Something you know</div>
+                            <div class="small text-success mt-auto pt-2">~44 bits (4 words)</div>
                         </div>
                     </div>
-                    <div class="col-md-3 mb-3">
-                        <div class="p-3 bg-dark rounded">
+                    <div class="col-6 col-lg-3 mb-3">
+                        <div class="p-3 bg-dark rounded h-100 d-flex flex-column align-items-center">
                             <i class="bi bi-123 text-danger fs-2 d-block mb-2"></i>
                             <strong>Static PIN</strong>
-                            <div class="small text-muted mt-1">Something you know (fixed)</div>
-                            <div class="small text-success">~20 bits (6 digits)</div>
+                            <div class="small text-muted mt-1">Something you know</div>
+                            <div class="small text-success mt-auto pt-2">~20 bits (6 digits)</div>
                         </div>
                     </div>
-                    <div class="col-md-3 mb-3">
-                        <div class="p-3 bg-dark rounded">
+                    <div class="col-6 col-lg-3 mb-3">
+                        <div class="p-3 bg-dark rounded h-100 d-flex flex-column align-items-center">
                             <i class="bi bi-key text-primary fs-2 d-block mb-2"></i>
                             <strong>RSA Key</strong>
-                            <div class="small text-muted mt-1">Something you have (optional)</div>
-                            <div class="small text-success">~128 bits (2048-bit)</div>
+                            <div class="small text-muted mt-1">Optional</div>
+                            <div class="small text-success mt-auto pt-2">~128 bits</div>
                         </div>
                     </div>
                 </div>
                 
                 <div class="alert alert-secondary">
                     <i class="bi bi-calculator me-2"></i>
-                    <strong>Combined entropy:</strong> 130-400+ bits depending on configuration.
-                    For reference, 128 bits is considered computationally infeasible to brute force.
+                    <strong>Combined entropy:</strong> 144-424+ bits. 128 bits is infeasible to brute force.
                 </div>
                 
                 <h6 class="mt-4">Key Derivation</h6>
                 <p>
                     {% if has_argon2 %}
-                    <span class="badge bg-success me-1"><i class="bi bi-check"></i> Argon2id Available</span>
-                    Using <strong>Argon2id</strong> with 256MB memory cost — the winner of the Password Hashing Competition 
-                    and current best practice for key derivation.
+                    <span class="badge bg-success me-1"><i class="bi bi-check"></i> Argon2id</span>
+                    256MB memory cost. Memory-hard KDF defeats GPU/ASIC attacks.
                     {% else %}
                     <span class="badge bg-warning text-dark me-1"><i class="bi bi-exclamation-triangle"></i> Argon2 Not Available</span>
-                    Falling back to <strong>PBKDF2-SHA512</strong> with 600,000 iterations.
+                    Using PBKDF2-SHA512 with 600k iterations.
                     Install <code>argon2-cffi</code> for stronger security.
                     {% endif %}
                 </p>
-                
-                <h6 class="mt-4">Steganography Technique</h6>
-                <p>
-                    Uses <strong>LSB (Least Significant Bit)</strong> embedding with pseudo-random pixel selection.
-                    The pixel locations are determined by a key derived from your credentials, making the 
-                    hidden data's location unpredictable without the correct inputs.
-                </p>
             </div>
         </div>
         
-        <div class="card mb-4">
+        <!-- Channel Keys (v4.0.0) -->
+        <div class="card mb-4" id="channel-keys">
             <div class="card-header">
-                <h5 class="mb-0"><i class="bi bi-file-earmark-binary me-2"></i>File Embedding</h5>
+                <h5 class="mb-0">
+                    <i class="bi bi-broadcast me-2"></i>Channel Keys
+                    <span class="badge bg-info ms-2">v4.1</span>
+                </h5>
             </div>
             <div class="card-body">
                 <p>
-                    <span class="badge bg-info me-1">New in v2.1</span>
-                    Stegasoo now supports embedding <strong>any file type</strong>, not just text messages.
+                    Channel keys provide <strong>deployment/group isolation</strong>. Messages encoded with one channel key 
+                    cannot be decoded with a different key, even if all other credentials match.
                 </p>
                 
-                <div class="row">
-                    <div class="col-md-6">
-                        <h6><i class="bi bi-check2-square text-success me-2"></i>Supported</h6>
-                        <ul class="small">
-                            <li>PDF documents</li>
-                            <li>ZIP/RAR archives</li>
-                            <li>Office documents (DOCX, XLSX, PPTX)</li>
-                            <li>Source code files</li>
-                            <li>Any binary file up to {{ max_payload_kb }} KB</li>
-                        </ul>
+                <div class="row mt-4">
+                    <!-- Auto Mode -->
+                    <div class="col-md-4 mb-3">
+                        <div class="card bg-dark h-100">
+                            <div class="card-header text-center">
+                                <i class="bi bi-gear-fill text-success fs-2 d-block mb-2"></i>
+                                <strong>Auto</strong>
+                            </div>
+                            <div class="card-body">
+                                <p class="small mb-2">Uses server-configured key if available, otherwise public mode.</p>
+                                <ul class="small mb-0">
+                                    <li>Server admin configures the shared key</li>
+                                    <li>All users share the same channel</li>
+                                </ul>
+                            </div>
+                        </div>
                     </div>
-                    <div class="col-md-6">
-                        <h6><i class="bi bi-info-circle text-info me-2"></i>How It Works</h6>
-                        <ul class="small">
-                            <li>Original filename is preserved</li>
-                            <li>MIME type is stored for proper handling</li>
-                            <li>File is encrypted identically to text</li>
-                            <li>Decoding auto-detects text vs. file</li>
-                        </ul>
+                    
+                    <!-- Public Mode -->
+                    <div class="col-md-4 mb-3">
+                        <div class="card bg-dark h-100">
+                            <div class="card-header text-center">
+                                <i class="bi bi-globe text-info fs-2 d-block mb-2"></i>
+                                <strong>Public</strong>
+                            </div>
+                            <div class="card-body">
+                                <p class="small mb-2">No channel key. Compatible with other public installations.</p>
+                                <ul class="small mb-0">
+                                    <li>Default if no server key configured</li>
+                                    <li>Anyone can decode (with credentials)</li>
+                                    <li>Interoperable between deployments</li>
+                                </ul>
+                            </div>
+                        </div>
+                    </div>
+                    
+                    <!-- Custom Mode -->
+                    <div class="col-md-4 mb-3">
+                        <div class="card bg-dark h-100">
+                            <div class="card-header text-center">
+                                <i class="bi bi-key-fill text-warning fs-2 d-block mb-2"></i>
+                                <strong>Custom</strong>
+                            </div>
+                            <div class="card-body">
+                                <p class="small mb-2">Your own group key. Share with recipients.</p>
+                                <ul class="small mb-0">
+                                    <li>Format: <code>XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX</code></li>
+                                    <li>32 chars (128 bits entropy)</li>
+                                    <li>Private group communication</li>
+                                </ul>
+                            </div>
+                        </div>
                     </div>
                 </div>
                 
-                <div class="alert alert-info small mt-3">
-                    <i class="bi bi-lightbulb me-2"></i>
-                    <strong>Tip:</strong> For larger files, compress them first (ZIP) to maximize capacity.
-                    A 16MP carrier image can hold approximately 6MB of raw data, but we limit payloads 
-                    to {{ max_payload_kb }} KB for reasonable processing times.
+                {% if channel_configured %}
+                <div class="alert alert-success mt-3 mb-0">
+                    <i class="bi bi-shield-lock me-2"></i>
+                    <strong>This server has a channel key configured:</strong>
+                    <code class="ms-2">{{ channel_fingerprint }}</code>
+                </div>
+                {% else %}
+                <div class="alert alert-info mt-3 mb-0">
+                    <i class="bi bi-info-circle me-2"></i>
+                    This server is running in <strong>public mode</strong>.
+                    Set <code>STEGASOO_CHANNEL_KEY</code> to enable server-wide channel isolation.
+                </div>
+                {% endif %}
+            </div>
+        </div>
+        
+        <!-- Version History -->
+        <div class="card mb-4">
+            <div class="card-header">
+                <h5 class="mb-0"><i class="bi bi-clock-history me-2"></i>Version History</h5>
+            </div>
+            <div class="card-body">
+                <!-- Current Version - Prominent -->
+                <div class="alert alert-success mb-4">
+                    <div class="d-flex align-items-center">
+                        <span class="badge bg-success fs-6 me-3">v4.1.2</span>
+                        <div>
+                            <strong>Progress bars</strong> for encode operations,
+                            <strong>mobile-responsive polish</strong>,
+                            DCT decode bug fix, release validation script
+                        </div>
+                    </div>
+                </div>
+
+                <!-- Previous Versions - Accordion -->
+                <div class="accordion" id="versionAccordion">
+                    <div class="accordion-item bg-dark">
+                        <h2 class="accordion-header">
+                            <button class="accordion-button collapsed bg-dark text-light py-2" type="button"
+                                    data-bs-toggle="collapse" data-bs-target="#olderVersions">
+                                <i class="bi bi-archive me-2"></i>Previous Versions
+                            </button>
+                        </h2>
+                        <div id="olderVersions" class="accordion-collapse collapse" data-bs-parent="#versionAccordion">
+                            <div class="accordion-body p-0">
+                                <table class="table table-dark table-sm small mb-0">
+                                    <tbody>
+                                        <tr>
+                                            <td width="80"><strong>4.1.1</strong></td>
+                                            <td>DCT RS format stability, Docker cleanup, first-boot wizard</td>
+                                        </tr>
+                                        <tr>
+                                            <td><strong>4.1.0</strong></td>
+                                            <td>Reed-Solomon error correction for DCT, majority voting headers</td>
+                                        </tr>
+                                        <tr>
+                                            <td><strong>4.0.0</strong></td>
+                                            <td>Channel keys, DCT default, subprocess isolation</td>
+                                        </tr>
+                                        <tr>
+                                            <td>3.2.0</td>
+                                            <td>Single passphrase, more default words</td>
+                                        </tr>
+                                        <tr>
+                                            <td>3.0.0</td>
+                                            <td>DCT mode, JPEG output, color preservation</td>
+                                        </tr>
+                                        <tr>
+                                            <td>2.x</td>
+                                            <td>Web UI, REST API, RSA keys, QR codes, file embedding</td>
+                                        </tr>
+                                        <tr>
+                                            <td>1.0.0</td>
+                                            <td>Initial release, CLI only, LSB mode</td>
+                                        </tr>
+                                    </tbody>
+                                </table>
+                            </div>
+                        </div>
+                    </div>
                 </div>
             </div>
         </div>
@@ -188,11 +415,11 @@
                         <div id="setup" class="accordion-collapse collapse show" data-bs-parent="#usageAccordion">
                             <div class="accordion-body">
                                 <ol>
-                                    <li>Both parties agree on a <strong>reference photo</strong> (shared secretly, never transmitted)</li>
-                                    <li>Go to <a href="/generate">Generate</a> and create credentials</li>
-                                    <li><strong>Memorize</strong> the 7 daily phrases and PIN</li>
-                                    <li>If using RSA, download and securely store the key file</li>
-                                    <li>Share credentials with your contact through a secure channel</li>
+                                    <li>Agree on a <strong>reference photo</strong> (never transmitted)</li>
+                                    <li>Go to <a href="/generate">Generate</a> to create credentials</li>
+                                    <li>Memorize passphrase and PIN</li>
+                                    <li>If using RSA, store the key file securely</li>
+                                    <li>Share credentials via secure channel</li>
                                 </ol>
                             </div>
                         </div>
@@ -202,20 +429,23 @@
                         <h2 class="accordion-header">
                             <button class="accordion-button collapsed bg-dark text-light" type="button" 
                                     data-bs-toggle="collapse" data-bs-target="#encoding">
-                                <i class="bi bi-2-circle me-2"></i>Encoding a Message or File
+                                <i class="bi bi-2-circle me-2"></i>Encoding
                             </button>
                         </h2>
                         <div id="encoding" class="accordion-collapse collapse" data-bs-parent="#usageAccordion">
                             <div class="accordion-body">
                                 <ol>
                                     <li>Go to <a href="/encode">Encode</a></li>
-                                    <li>Upload your <strong>reference photo</strong></li>
-                                    <li>Upload a <strong>carrier image</strong> (the image to hide data in)</li>
-                                    <li>Choose <strong>Text</strong> or <strong>File</strong> mode</li>
-                                    <li>Enter your message or select a file to embed</li>
-                                    <li>Enter <strong>today's phrase</strong> and your PIN/key</li>
-                                    <li>Download the resulting stego image</li>
-                                    <li>Send the stego image through any channel (email, social media, etc.)</li>
+                                    <li>Upload <strong>reference photo</strong> and <strong>carrier image</strong></li>
+                                    <li>Choose mode:
+                                        <ul>
+                                            <li><strong>DCT</strong> (default): social media</li>
+                                            <li><strong>LSB</strong>: email, cloud, direct transfer</li>
+                                        </ul>
+                                    </li>
+                                    <li>Enter message or select file</li>
+                                    <li>Enter passphrase and PIN/key</li>
+                                    <li>Download stego image</li>
                                 </ol>
                             </div>
                         </div>
@@ -225,23 +455,21 @@
                         <h2 class="accordion-header">
                             <button class="accordion-button collapsed bg-dark text-light" type="button" 
                                     data-bs-toggle="collapse" data-bs-target="#decoding">
-                                <i class="bi bi-3-circle me-2"></i>Decoding a Message or File
+                                <i class="bi bi-3-circle me-2"></i>Decoding
                             </button>
                         </h2>
                         <div id="decoding" class="accordion-collapse collapse" data-bs-parent="#usageAccordion">
                             <div class="accordion-body">
                                 <ol>
                                     <li>Go to <a href="/decode">Decode</a></li>
-                                    <li>Upload your <strong>reference photo</strong> (same one used for encoding)</li>
-                                    <li>Upload the <strong>stego image</strong> you received</li>
-                                    <li>Enter the phrase for <strong>the day it was encoded</strong> (check the filename for date)</li>
-                                    <li>Enter your PIN and/or RSA key</li>
-                                    <li>View the decoded message or download the extracted file</li>
+                                    <li>Upload <strong>reference photo</strong></li>
+                                    <li>Upload <strong>stego image</strong></li>
+                                    <li>Enter passphrase and PIN/key</li>
+                                    <li>View message or download file</li>
                                 </ol>
-                                <div class="alert alert-warning small mt-3 mb-0">
-                                    <i class="bi bi-exclamation-triangle me-2"></i>
-                                    The stego image filename contains the encoding date (e.g., <code>abc123_20251228.png</code>).
-                                    Use this to determine which day's phrase to use!
+                                <div class="alert alert-info small mt-3 mb-0">
+                                    <i class="bi bi-magic me-2"></i>
+                                    Mode is auto-detected.
                                 </div>
                             </div>
                         </div>
@@ -252,100 +480,117 @@
         
         <div class="card mb-4">
             <div class="card-header">
-                <h5 class="mb-0"><i class="bi bi-speedometer2 me-2"></i>Limits &amp; Specifications</h5>
+                <h5 class="mb-0"><i class="bi bi-speedometer2 me-2"></i>Limits &amp; Specs</h5>
             </div>
             <div class="card-body">
-                <table class="table table-dark table-striped">
-                    <tbody>
-                        <tr>
-                            <td><i class="bi bi-file-text me-2"></i>Max text message</td>
-                            <td><strong>250,000 characters</strong> (~250 KB)</td>
-                        </tr>
-                        <tr>
-                            <td><i class="bi bi-file-earmark me-2"></i>Max file payload</td>
-                            <td><strong>{{ max_payload_kb }} KB</strong></td>
-                        </tr>
-                        <tr>
-                            <td><i class="bi bi-image me-2"></i>Max carrier image</td>
-                            <td><strong>16 megapixels</strong> (~4000×4000)</td>
-                        </tr>
-                        <tr>
-                            <td><i class="bi bi-upload me-2"></i>Max upload size</td>
-                            <td><strong>10 MB</strong></td>
-                        </tr>
-                        <tr>
-                            <td><i class="bi bi-clock me-2"></i>Temp file expiry</td>
-                            <td><strong>5 minutes</strong></td>
-                        </tr>
-                        <tr>
-                            <td><i class="bi bi-key me-2"></i>PIN length</td>
-                            <td><strong>6-9 digits</strong></td>
-                        </tr>
-                        <tr>
-                            <td><i class="bi bi-shield me-2"></i>RSA key sizes</td>
-                            <td><strong>2048, 3072, 4096 bits</strong></td>
-                        </tr>
-                        <tr>
-                            <td><i class="bi bi-chat-quote me-2"></i>Phrase length</td>
-                            <td><strong>3-12 words</strong> (BIP-39 wordlist)</td>
-                        </tr>
-                    </tbody>
-                </table>
+                <!-- Key Specs - Always Visible -->
+                <div class="row text-center mb-4">
+                    <div class="col-6 col-md-4 col-lg-2 mb-3">
+                        <div class="p-3 bg-dark rounded h-100">
+                            <i class="bi bi-file-earmark text-primary fs-3 d-block mb-2"></i>
+                            <div class="small text-muted">Max Payload</div>
+                            <strong>{{ max_payload_kb }} KB</strong>
+                        </div>
+                    </div>
+                    <div class="col-6 col-md-4 col-lg-2 mb-3">
+                        <div class="p-3 bg-dark rounded h-100">
+                            <i class="bi bi-image text-info fs-3 d-block mb-2"></i>
+                            <div class="small text-muted">Max Carrier</div>
+                            <strong>24 MP</strong>
+                        </div>
+                    </div>
+                    <div class="col-6 col-md-4 col-lg-2 mb-3">
+                        <div class="p-3 bg-dark rounded h-100">
+                            <i class="bi bi-soundwave text-warning fs-3 d-block mb-2"></i>
+                            <div class="small text-muted">DCT Capacity</div>
+                            <strong>~75 KB/MP</strong>
+                        </div>
+                    </div>
+                    <div class="col-6 col-md-4 col-lg-2 mb-3">
+                        <div class="p-3 bg-dark rounded h-100">
+                            <i class="bi bi-grid-3x3 text-success fs-3 d-block mb-2"></i>
+                            <div class="small text-muted">LSB Capacity</div>
+                            <strong>~375 KB/MP</strong>
+                        </div>
+                    </div>
+                    <div class="col-6 col-md-4 col-lg-2 mb-3">
+                        <div class="p-3 bg-dark rounded h-100">
+                            <i class="bi bi-shield-check text-danger fs-3 d-block mb-2"></i>
+                            <div class="small text-muted">Encryption</div>
+                            <strong>AES-256</strong>
+                        </div>
+                    </div>
+                    <div class="col-6 col-md-4 col-lg-2 mb-3">
+                        <div class="p-3 bg-dark rounded h-100">
+                            <i class="bi bi-bandaid text-info fs-3 d-block mb-2"></i>
+                            <div class="small text-muted">DCT ECC</div>
+                            <strong>RS Code</strong>
+                        </div>
+                    </div>
+                </div>
+
+                <!-- Error Correction Detail -->
+                <div class="alert alert-info small mb-4">
+                    <i class="bi bi-info-circle me-2"></i>
+                    <strong>Reed-Solomon Error Correction:</strong> DCT mode corrects up to 16 byte errors per 223-byte chunk.
+                    Handles problematic carrier images with uniform areas that cause unstable DCT coefficients.
+                </div>
+
+                <!-- More Specs - Accordion -->
+                <div class="accordion" id="specsAccordion">
+                    <div class="accordion-item bg-dark">
+                        <h2 class="accordion-header">
+                            <button class="accordion-button collapsed bg-dark text-light py-2" type="button"
+                                    data-bs-toggle="collapse" data-bs-target="#moreSpecs">
+                                <i class="bi bi-list-ul me-2"></i>More Specifications
+                            </button>
+                        </h2>
+                        <div id="moreSpecs" class="accordion-collapse collapse" data-bs-parent="#specsAccordion">
+                            <div class="accordion-body p-0">
+                                <table class="table table-dark table-striped small mb-0">
+                                    <tbody>
+                                        <tr>
+                                            <td><i class="bi bi-file-text me-2"></i>Max text</td>
+                                            <td><strong>2M characters</strong></td>
+                                        </tr>
+                                        <tr>
+                                            <td><i class="bi bi-upload me-2"></i>Max upload</td>
+                                            <td><strong>30 MB</strong></td>
+                                        </tr>
+                                        <tr>
+                                            <td><i class="bi bi-clock me-2"></i>File expiry</td>
+                                            <td><strong>5 min</strong></td>
+                                        </tr>
+                                        <tr>
+                                            <td><i class="bi bi-key me-2"></i>PIN</td>
+                                            <td><strong>6-9 digits</strong></td>
+                                        </tr>
+                                        <tr>
+                                            <td><i class="bi bi-shield me-2"></i>RSA keys</td>
+                                            <td><strong>2048, 3072, 4096 bit</strong></td>
+                                        </tr>
+                                        <tr>
+                                            <td><i class="bi bi-chat-quote me-2"></i>Passphrase</td>
+                                            <td><strong>3-12 words</strong> (BIP-39)</td>
+                                        </tr>
+                                        <tr>
+                                            <td><i class="bi bi-code me-2"></i>Python Version</td>
+                                            <td><strong>3.10-3.12</strong></td>
+                                        </tr>
+                                        <tr>
+                                            <td><i class="bi bi-box me-2"></i>Built with</td>
+                                            <td>Flask, Pillow, NumPy, SciPy, jpegio, reedsolo, cryptography, argon2-cffi</td>
+                                        </tr>
+                                    </tbody>
+                                </table>
+                            </div>
+                        </div>
+                    </div>
+                </div>
             </div>
         </div>
         
-        <div class="card">
-            <div class="card-header">
-                <h5 class="mb-0"><i class="bi bi-terminal me-2"></i>CLI &amp; API</h5>
-            </div>
-            <div class="card-body">
-                <p>Stegasoo is also available as a command-line tool and REST API:</p>
-                
-                <h6 class="mt-3">Command Line</h6>
-                <pre class="bg-dark p-3 rounded"><code># Generate credentials
-stegasoo generate --pin --rsa
-
-# Encode a text message
-stegasoo encode -r photo.jpg -c meme.png -p "apple forest thunder" --pin 123456 -m "secret"
-
-# Encode a file
-stegasoo encode -r photo.jpg -c meme.png -p "apple forest thunder" --pin 123456 -e document.pdf
-
-# Decode (auto-detects text vs file)
-stegasoo decode -r photo.jpg -s stego.png -p "apple forest thunder" --pin 123456</code></pre>
-                
-                <h6 class="mt-4">REST API</h6>
-                <pre class="bg-dark p-3 rounded"><code># Encode with multipart upload
-curl -X POST http://localhost:8000/encode/multipart \
-  -F "reference_photo=@photo.jpg" \
-  -F "carrier=@meme.png" \
-  -F "message=secret" \
-  -F "day_phrase=apple forest thunder" \
-  -F "pin=123456" \
-  --output stego.png
-
-# Encode a file
-curl -X POST http://localhost:8000/encode/multipart \
-  -F "reference_photo=@photo.jpg" \
-  -F "carrier=@meme.png" \
-  -F "payload_file=@document.pdf" \
-  -F "day_phrase=apple forest thunder" \
-  -F "pin=123456" \
-  --output stego.png</code></pre>
-                
-                <p class="small text-muted mt-3 mb-0">
-                    API documentation available at <code>/docs</code> (Swagger) or <code>/redoc</code> when running the API server.
-                </p>
-            </div>
-        </div>
-        
-        <div class="text-center mt-4 text-muted small">
-            <p>
-                Stegasoo v2.1.0 &bull; 
-                <i class="bi bi-github me-1"></i>Open Source &bull;
-                Built with Python, Flask, and cryptography
-            </p>
-        </div>
     </div>
 </div>
 {% endblock %}
+

frontends/web/templates/account.html

@@ -0,0 +1,440 @@
+{% extends "base.html" %}
+
+{% block title %}Account - Stegasoo{% endblock %}
+
+{% block content %}
+<div class="row justify-content-center">
+    <div class="col-md-6 col-lg-5">
+        <div class="card">
+            <div class="card-header">
+                <h5 class="mb-0"><i class="bi bi-person-gear me-2"></i>Account Settings</h5>
+            </div>
+            <div class="card-body">
+                <p class="text-muted mb-4">
+                    Logged in as <strong>{{ username }}</strong>
+                    {% if is_admin %}
+                    <span class="badge bg-warning text-dark ms-2">
+                        <i class="bi bi-shield-check me-1"></i>Admin
+                    </span>
+                    {% endif %}
+                </p>
+
+                {% if is_admin %}
+                <div class="mb-4">
+                    <a href="{{ url_for('admin_users') }}" class="btn btn-outline-primary w-100">
+                        <i class="bi bi-people me-2"></i>Manage Users
+                    </a>
+                </div>
+
+                <!-- Recovery Key Management (Admin only) -->
+                <div class="card bg-dark mb-4">
+                    <div class="card-body py-3">
+                        <div class="d-flex justify-content-between align-items-center">
+                            <div>
+                                <i class="bi bi-shield-lock me-2"></i>
+                                <strong>Recovery Key</strong>
+                                {% if has_recovery %}
+                                <span class="badge bg-success ms-2">Configured</span>
+                                {% else %}
+                                <span class="badge bg-secondary ms-2">Not Set</span>
+                                {% endif %}
+                            </div>
+                            <div class="btn-group btn-group-sm">
+                                <a href="{{ url_for('regenerate_recovery') }}" class="btn btn-outline-warning"
+                                   onclick="return confirm('Generate a new recovery key? This will invalidate any existing key.')">
+                                    <i class="bi bi-arrow-repeat me-1"></i>
+                                    {{ 'Regenerate' if has_recovery else 'Generate' }}
+                                </a>
+                                {% if has_recovery %}
+                                <form method="POST" action="{{ url_for('disable_recovery') }}" style="display:inline;">
+                                    <button type="submit" class="btn btn-outline-danger"
+                                            onclick="return confirm('Disable recovery? If you forget your password, you will NOT be able to recover your account.')">
+                                        <i class="bi bi-x-lg"></i>
+                                    </button>
+                                </form>
+                                {% endif %}
+                            </div>
+                        </div>
+                        <small class="text-muted d-block mt-2">
+                            {% if has_recovery %}
+                            Allows password reset if you're locked out.
+                            {% else %}
+                            No recovery option - most secure, but no password reset possible.
+                            {% endif %}
+                        </small>
+                    </div>
+                </div>
+                {% endif %}
+
+                <h6 class="text-muted mb-3">Change Password</h6>
+
+                <form method="POST" action="{{ url_for('account') }}" id="accountForm">
+                    <div class="mb-3">
+                        <label class="form-label">
+                            <i class="bi bi-key me-1"></i> Current Password
+                        </label>
+                        <div class="input-group">
+                            <input type="password" name="current_password" class="form-control"
+                                   id="currentPasswordInput" required>
+                            <button class="btn btn-outline-secondary" type="button"
+                                    onclick="togglePassword('currentPasswordInput', this)">
+                                <i class="bi bi-eye"></i>
+                            </button>
+                        </div>
+                    </div>
+
+                    <div class="mb-3">
+                        <label class="form-label">
+                            <i class="bi bi-key-fill me-1"></i> New Password
+                        </label>
+                        <div class="input-group">
+                            <input type="password" name="new_password" class="form-control"
+                                   id="newPasswordInput" required minlength="8">
+                            <button class="btn btn-outline-secondary" type="button"
+                                    onclick="togglePassword('newPasswordInput', this)">
+                                <i class="bi bi-eye"></i>
+                            </button>
+                        </div>
+                        <div class="form-text">Minimum 8 characters</div>
+                    </div>
+
+                    <div class="mb-4">
+                        <label class="form-label">
+                            <i class="bi bi-key-fill me-1"></i> Confirm New Password
+                        </label>
+                        <div class="input-group">
+                            <input type="password" name="new_password_confirm" class="form-control"
+                                   id="newPasswordConfirmInput" required minlength="8">
+                            <button class="btn btn-outline-secondary" type="button"
+                                    onclick="togglePassword('newPasswordConfirmInput', this)">
+                                <i class="bi bi-eye"></i>
+                            </button>
+                        </div>
+                    </div>
+
+                    <button type="submit" class="btn btn-primary w-100">
+                        <i class="bi bi-check-lg me-2"></i>Update Password
+                    </button>
+                </form>
+
+            </div>
+        </div>
+
+        <!-- Saved Channel Keys Section -->
+        <div class="card mt-4">
+            <div class="card-header d-flex justify-content-between align-items-center">
+                <h5 class="mb-0"><i class="bi bi-key-fill me-2"></i>Saved Channel Keys</h5>
+                <span class="badge bg-secondary">{{ channel_keys|length }} / {{ max_channel_keys }}</span>
+            </div>
+            <div class="card-body">
+                {% if channel_keys %}
+                <div class="list-group list-group-flush mb-3">
+                    {% for key in channel_keys %}
+                    <div class="list-group-item d-flex justify-content-between align-items-center px-0">
+                        <div>
+                            <strong>{{ key.name }}</strong>
+                            <br>
+                            <code class="small text-muted">{{ key.channel_key[:4] }}...{{ key.channel_key[-4:] }}</code>
+                            {% if key.last_used_at %}
+                            <span class="text-muted small ms-2">Last used: {{ key.last_used_at[:10] }}</span>
+                            {% endif %}
+                        </div>
+                        <div class="btn-group btn-group-sm">
+                            {% if is_admin %}
+                            <button type="button" class="btn btn-outline-info"
+                                    onclick="showKeyQr('{{ key.channel_key }}', '{{ key.name }}')"
+                                    title="Show QR Code">
+                                <i class="bi bi-qr-code"></i>
+                            </button>
+                            {% endif %}
+                            <button type="button" class="btn btn-outline-secondary"
+                                    onclick="renameKey({{ key.id }}, '{{ key.name }}')"
+                                    title="Rename">
+                                <i class="bi bi-pencil"></i>
+                            </button>
+                            <form method="POST" action="{{ url_for('account_delete_key', key_id=key.id) }}"
+                                  style="display:inline;"
+                                  onsubmit="return confirm('Delete key &quot;{{ key.name }}&quot;?')">
+                                <button type="submit" class="btn btn-outline-danger" title="Delete">
+                                    <i class="bi bi-trash"></i>
+                                </button>
+                            </form>
+                        </div>
+                    </div>
+                    {% endfor %}
+                </div>
+                {% else %}
+                <p class="text-muted mb-3">No saved channel keys. Save keys for quick access on encode/decode pages.</p>
+                {% endif %}
+
+                {% if can_save_key %}
+                <hr>
+                <h6 class="text-muted mb-3">Add New Key</h6>
+                <form method="POST" action="{{ url_for('account_save_key') }}">
+                    <div class="row g-2 mb-2">
+                        <div class="col-5">
+                            <input type="text" name="key_name" class="form-control form-control-sm"
+                                   placeholder="Key name" required maxlength="50">
+                        </div>
+                        <div class="col-7">
+                            <div class="input-group input-group-sm">
+                                <input type="text" name="channel_key" id="channelKeyInput"
+                                       class="form-control font-monospace"
+                                       placeholder="XXXX-XXXX-..." required
+                                       pattern="[A-Za-z0-9]{4}(-[A-Za-z0-9]{4}){7}">
+                                <button type="button" class="btn btn-outline-secondary" id="scanChannelKeyBtn"
+                                        title="Scan QR code with camera">
+                                    <i class="bi bi-camera"></i>
+                                </button>
+                            </div>
+                        </div>
+                    </div>
+                    <button type="submit" class="btn btn-sm btn-outline-primary">
+                        <i class="bi bi-plus-lg me-1"></i>Save Key
+                    </button>
+                </form>
+                {% else %}
+                <div class="alert alert-info mb-0 small">
+                    <i class="bi bi-info-circle me-1"></i>
+                    Maximum of {{ max_channel_keys }} keys reached. Delete a key to add more.
+                </div>
+                {% endif %}
+            </div>
+        </div>
+
+        <!-- Logout -->
+        <div class="mt-4">
+            <a href="{{ url_for('logout') }}" class="btn btn-outline-danger w-100">
+                <i class="bi bi-box-arrow-left me-2"></i>Logout
+            </a>
+        </div>
+    </div>
+</div>
+
+<!-- Rename Modal -->
+<div class="modal fade" id="renameModal" tabindex="-1">
+    <div class="modal-dialog modal-sm">
+        <div class="modal-content">
+            <form method="POST" id="renameForm">
+                <div class="modal-header">
+                    <h6 class="modal-title">Rename Key</h6>
+                    <button type="button" class="btn-close" data-bs-dismiss="modal"></button>
+                </div>
+                <div class="modal-body">
+                    <input type="text" name="new_name" class="form-control" id="renameInput"
+                           required maxlength="50">
+                </div>
+                <div class="modal-footer">
+                    <button type="button" class="btn btn-sm btn-secondary" data-bs-dismiss="modal">Cancel</button>
+                    <button type="submit" class="btn btn-sm btn-primary">Rename</button>
+                </div>
+            </form>
+        </div>
+    </div>
+</div>
+
+{% if is_admin %}
+<!-- QR Code Modal (Admin only) -->
+<div class="modal fade" id="qrModal" tabindex="-1">
+    <div class="modal-dialog modal-sm">
+        <div class="modal-content">
+            <div class="modal-header">
+                <h6 class="modal-title"><i class="bi bi-qr-code me-2"></i><span id="qrKeyName">Channel Key</span></h6>
+                <button type="button" class="btn-close" data-bs-dismiss="modal"></button>
+            </div>
+            <div class="modal-body text-center">
+                <canvas id="qrCanvas" class="bg-white p-2 rounded"></canvas>
+                <div class="mt-2">
+                    <code class="small" id="qrKeyDisplay"></code>
+                </div>
+            </div>
+            <div class="modal-footer justify-content-center">
+                <button type="button" class="btn btn-sm btn-outline-secondary" id="qrDownload">
+                    <i class="bi bi-download me-1"></i>Download
+                </button>
+                <button type="button" class="btn btn-sm btn-outline-secondary" id="qrPrint">
+                    <i class="bi bi-printer me-1"></i>Print Sheet
+                </button>
+            </div>
+        </div>
+    </div>
+</div>
+{% endif %}
+{% endblock %}
+
+{% block scripts %}
+<script src="{{ url_for('static', filename='js/auth.js') }}"></script>
+<script src="{{ url_for('static', filename='js/stegasoo.js') }}"></script>
+{% if is_admin %}
+<script src="{{ url_for('static', filename='js/qrcode.min.js') }}"></script>
+{% endif %}
+<script>
+StegasooAuth.initPasswordConfirmation('accountForm', 'newPasswordInput', 'newPasswordConfirmInput');
+
+// Webcam QR scanning for channel key input (v4.1.5)
+document.getElementById('scanChannelKeyBtn')?.addEventListener('click', function() {
+    Stegasoo.showQrScanner((text) => {
+        const input = document.getElementById('channelKeyInput');
+        if (input) {
+            // Clean and format the key
+            const clean = text.replace(/[^A-Za-z0-9]/g, '').toUpperCase();
+            if (clean.length === 32) {
+                input.value = clean.match(/.{4}/g).join('-');
+            } else {
+                input.value = text.toUpperCase();
+            }
+        }
+    }, 'Scan Channel Key');
+});
+
+// Format channel key input as user types
+document.getElementById('channelKeyInput')?.addEventListener('input', function() {
+    Stegasoo.formatChannelKeyInput(this);
+});
+
+function renameKey(keyId, currentName) {
+    document.getElementById('renameInput').value = currentName;
+    document.getElementById('renameForm').action = '/account/keys/' + keyId + '/rename';
+    new bootstrap.Modal(document.getElementById('renameModal')).show();
+}
+
+{% if is_admin %}
+function showKeyQr(channelKey, keyName) {
+    // Format key with dashes if not already
+    const clean = channelKey.replace(/-/g, '').toUpperCase();
+    const formatted = clean.match(/.{4}/g)?.join('-') || clean;
+
+    // Update modal content
+    document.getElementById('qrKeyName').textContent = keyName;
+    document.getElementById('qrKeyDisplay').textContent = formatted;
+
+    // Generate QR code using QRious
+    const canvas = document.getElementById('qrCanvas');
+    if (typeof QRious !== 'undefined' && canvas) {
+        try {
+            new QRious({
+                element: canvas,
+                value: formatted,
+                size: 200,
+                level: 'M'
+            });
+            new bootstrap.Modal(document.getElementById('qrModal')).show();
+        } catch (error) {
+            console.error('QR generation error:', error);
+        }
+    }
+}
+
+// Download QR as PNG
+document.getElementById('qrDownload')?.addEventListener('click', function() {
+    const canvas = document.getElementById('qrCanvas');
+    const keyName = document.getElementById('qrKeyName').textContent;
+    if (canvas) {
+        const link = document.createElement('a');
+        link.download = 'stegasoo-channel-key-' + keyName.toLowerCase().replace(/\s+/g, '-') + '.png';
+        link.href = canvas.toDataURL('image/png');
+        link.click();
+    }
+});
+
+// Print tiled QR sheet (US Letter)
+document.getElementById('qrPrint')?.addEventListener('click', function() {
+    const canvas = document.getElementById('qrCanvas');
+    const keyText = document.getElementById('qrKeyDisplay').textContent;
+    const keyName = document.getElementById('qrKeyName').textContent;
+    if (canvas && keyText) {
+        printQrSheet(canvas, keyText, keyName);
+    }
+});
+
+// Print QR codes tiled on US Letter paper (8.5" x 11")
+function printQrSheet(canvas, keyText, title) {
+    const qrDataUrl = canvas.toDataURL('image/png');
+    const printWindow = window.open('', '_blank');
+    if (!printWindow) {
+        alert('Please allow popups to print');
+        return;
+    }
+
+    // US Letter: 8.5" x 11" - create 4x5 grid of QR codes
+    const cols = 4;
+    const rows = 5;
+
+    // Split key into two lines (4 groups each)
+    const keyParts = keyText.split('-');
+    const keyLine1 = keyParts.slice(0, 4).join('-');
+    const keyLine2 = keyParts.slice(4).join('-');
+
+    let qrGrid = '';
+    for (let i = 0; i < rows * cols; i++) {
+        qrGrid += `
+            <div class="qr-tile">
+                <div class="key-text">${keyLine1}</div>
+                <img src="${qrDataUrl}" alt="QR">
+                <div class="key-text">${keyLine2}</div>
+            </div>
+        `;
+    }
+
+    printWindow.document.write(`
+        <!DOCTYPE html>
+        <html>
+        <head>
+            <title></title>
+            <style>
+                @page {
+                    size: letter;
+                    margin: 0.2in;
+                    margin-top: 0.1in;
+                    margin-bottom: 0.1in;
+                }
+                @media print {
+                    @page { margin: 0.15in; }
+                    html, body { margin: 0; padding: 0; }
+                }
+                * { margin: 0; padding: 0; box-sizing: border-box; }
+                body {
+                    font-family: 'Courier New', monospace;
+                    background: white;
+                }
+                .grid {
+                    display: grid;
+                    grid-template-columns: repeat(${cols}, 1fr);
+                    gap: 0;
+                    margin-top: 0.09in;
+                }
+                .qr-tile {
+                    border: 1px dashed #ccc;
+                    padding: 0.04in;
+                    text-align: center;
+                    page-break-inside: avoid;
+                }
+                .qr-tile img {
+                    width: 1.6in;
+                    height: 1.6in;
+                }
+                .key-text {
+                    font-size: 10pt;
+                    font-weight: bold;
+                    color: #333;
+                    line-height: 1.2;
+                }
+                .footer {
+                    display: none;
+                }
+            </style>
+        </head>
+        <body>
+            <div class="grid">${qrGrid}</div>
+            <div class="footer">Cut along dashed lines</div>
+            <script>
+                window.onload = function() { window.print(); };
+            <\/script>
+        </body>
+        </html>
+    `);
+    printWindow.document.close();
+}
+{% endif %}
+</script>
+{% endblock %}

frontends/web/templates/admin/password_reset.html

@@ -0,0 +1,50 @@
+{% extends "base.html" %}
+
+{% block title %}Password Reset - Stegasoo{% endblock %}
+
+{% block content %}
+<div class="row justify-content-center">
+    <div class="col-md-6 col-lg-5">
+        <div class="card border-warning">
+            <div class="card-header bg-warning text-dark">
+                <i class="bi bi-key fs-4 me-2"></i>
+                <span class="fs-5">Password Reset</span>
+            </div>
+            <div class="card-body">
+                <div class="alert alert-warning">
+                    <i class="bi bi-exclamation-triangle me-2"></i>
+                    <strong>Important:</strong> This password will only be shown once.
+                    Make sure to share it with <strong>{{ username }}</strong> securely.
+                </div>
+
+                <p class="text-muted">
+                    The user's sessions have been invalidated. They will need to log in
+                    again with the new password.
+                </p>
+
+                <div class="mb-4">
+                    <label class="form-label text-muted small">New Password for {{ username }}</label>
+                    <div class="input-group">
+                        <input type="text" class="form-control form-control-lg font-monospace"
+                               value="{{ password }}" readonly id="passwordField">
+                        <button class="btn btn-outline-secondary" type="button"
+                                onclick="copyField('passwordField')" title="Copy password">
+                            <i class="bi bi-clipboard"></i>
+                        </button>
+                    </div>
+                </div>
+
+                <div class="d-grid">
+                    <a href="{{ url_for('admin_users') }}" class="btn btn-primary">
+                        <i class="bi bi-arrow-left me-2"></i>Back to Users
+                    </a>
+                </div>
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script src="{{ url_for('static', filename='js/auth.js') }}"></script>
+{% endblock %}

frontends/web/templates/admin/settings.html

@@ -0,0 +1,506 @@
+{% extends "base.html" %}
+
+{% block title %}System Settings - Stegasoo{% endblock %}
+
+{% block content %}
+<div class="row justify-content-center">
+    <div class="col-lg-10">
+        <!-- Channel Key Configuration -->
+        <div class="card mb-4">
+            <div class="card-header">
+                <h5 class="mb-0"><i class="bi bi-broadcast me-2"></i>Channel Key Configuration</h5>
+            </div>
+            <div class="card-body">
+                {% if channel_configured %}
+                <div class="alert alert-success mb-4">
+                    <i class="bi bi-shield-lock me-2"></i>
+                    <strong>Server channel key active:</strong>
+                    <code class="ms-2">{{ channel_fingerprint }}</code>
+                    <span class="text-muted ms-2">({{ channel_source }})</span>
+                </div>
+                {% else %}
+                <div class="alert alert-info mb-4">
+                    <i class="bi bi-info-circle me-2"></i>
+                    Server running in <strong>public mode</strong>.
+                    Set <code>STEGASOO_CHANNEL_KEY</code> environment variable to enable server-wide channel isolation.
+                </div>
+                {% endif %}
+
+                <!-- QR Code Generator -->
+                <div class="card bg-dark border-secondary">
+                    <div class="card-header">
+                        <i class="bi bi-qr-code me-2"></i>Share Channel Key via QR
+                    </div>
+                    <div class="card-body">
+                        <p class="small text-muted mb-3">Generate a QR code to share a channel key with others.</p>
+
+                        <!-- Locked state - requires password -->
+                        <div id="channelKeyLocked">
+                            <div class="row g-2 align-items-end">
+                                <div class="col-md-8">
+                                    <label class="form-label small">Channel Key</label>
+                                    <div class="input-group">
+                                        <input type="password" class="form-control font-monospace"
+                                               value="********************************" disabled>
+                                        <span class="input-group-text"><i class="bi bi-lock"></i></span>
+                                    </div>
+                                </div>
+                                <div class="col-md-4">
+                                    <button class="btn btn-warning w-100" type="button" id="channelKeyUnlock">
+                                        <i class="bi bi-unlock me-1"></i>Unlock
+                                    </button>
+                                </div>
+                            </div>
+                            <small class="text-muted mt-2 d-block">
+                                <i class="bi bi-shield-lock me-1"></i>Re-enter your password to view or export the channel key.
+                            </small>
+                        </div>
+
+                        <!-- Unlocked state - shows key and QR options -->
+                        <div id="channelKeyUnlocked" style="display: none;">
+                            <div class="row g-2 align-items-end">
+                                <div class="col-md-8">
+                                    <label class="form-label small">Channel Key</label>
+                                    <div class="input-group">
+                                        <input type="text" class="form-control font-monospace" id="channelKeyQrInput"
+                                               placeholder="Enter or generate a key">
+                                        <button class="btn btn-outline-secondary" type="button" id="channelKeyQrGenerate"
+                                                title="Generate random key">
+                                            <i class="bi bi-shuffle"></i>
+                                        </button>
+                                    </div>
+                                </div>
+                                <div class="col-md-4">
+                                    <button class="btn btn-primary w-100" type="button" id="channelKeyQrShow">
+                                        <i class="bi bi-qr-code me-1"></i>Show QR
+                                    </button>
+                                </div>
+                            </div>
+                            <small class="text-success mt-2 d-block">
+                                <i class="bi bi-unlock me-1"></i>Unlocked for this session.
+                            </small>
+                        </div>
+                    </div>
+                </div>
+            </div>
+        </div>
+
+        <!-- Server Configuration -->
+        <div class="card mb-4">
+            <div class="card-header">
+                <h5 class="mb-0"><i class="bi bi-gear me-2"></i>Server Configuration</h5>
+            </div>
+            <div class="card-body">
+                <div class="row">
+                    <div class="col-md-6">
+                        <table class="table table-dark table-sm">
+                            <tbody>
+                                <tr>
+                                    <td><i class="bi bi-hdd-network me-2"></i>Hostname</td>
+                                    <td><code>{{ hostname }}</code></td>
+                                </tr>
+                                <tr>
+                                    <td><i class="bi bi-ethernet me-2"></i>Port</td>
+                                    <td><code>{{ port }}</code></td>
+                                </tr>
+                                <tr>
+                                    <td><i class="bi bi-shield-lock me-2"></i>HTTPS</td>
+                                    <td>
+                                        {% if https_enabled %}
+                                        <span class="badge bg-success"><i class="bi bi-lock me-1"></i>Enabled</span>
+                                        {% else %}
+                                        <span class="badge bg-warning text-dark"><i class="bi bi-unlock me-1"></i>Disabled</span>
+                                        {% endif %}
+                                    </td>
+                                </tr>
+                                <tr>
+                                    <td><i class="bi bi-person-lock me-2"></i>Authentication</td>
+                                    <td>
+                                        {% if auth_enabled %}
+                                        <span class="badge bg-success"><i class="bi bi-check me-1"></i>Enabled</span>
+                                        {% else %}
+                                        <span class="badge bg-danger"><i class="bi bi-x me-1"></i>Disabled</span>
+                                        {% endif %}
+                                    </td>
+                                </tr>
+                            </tbody>
+                        </table>
+                    </div>
+                    <div class="col-md-6">
+                        <table class="table table-dark table-sm">
+                            <tbody>
+                                <tr>
+                                    <td><i class="bi bi-file-earmark me-2"></i>Max Payload</td>
+                                    <td><code>{{ max_payload_kb }} KB</code></td>
+                                </tr>
+                                <tr>
+                                    <td><i class="bi bi-upload me-2"></i>Max Upload</td>
+                                    <td><code>{{ max_upload_mb }} MB</code></td>
+                                </tr>
+                                <tr>
+                                    <td><i class="bi bi-soundwave me-2"></i>DCT Mode</td>
+                                    <td>
+                                        {% if dct_available %}
+                                        <span class="badge bg-success"><i class="bi bi-check me-1"></i>Available</span>
+                                        {% else %}
+                                        <span class="badge bg-secondary">Not Available</span>
+                                        {% endif %}
+                                    </td>
+                                </tr>
+                                <tr>
+                                    <td><i class="bi bi-qr-code me-2"></i>QR Support</td>
+                                    <td>
+                                        {% if qr_available %}
+                                        <span class="badge bg-success"><i class="bi bi-check me-1"></i>Available</span>
+                                        {% else %}
+                                        <span class="badge bg-secondary">Not Available</span>
+                                        {% endif %}
+                                    </td>
+                                </tr>
+                            </tbody>
+                        </table>
+                    </div>
+                </div>
+
+                <div class="alert alert-secondary small mt-3 mb-0">
+                    <i class="bi bi-info-circle me-2"></i>
+                    To change server settings, edit environment variables or config file and restart the service.
+                    <br>See <code>STEGASOO_HTTPS_ENABLED</code>, <code>STEGASOO_PORT</code>, <code>STEGASOO_CHANNEL_KEY</code>
+                </div>
+            </div>
+        </div>
+
+        <!-- Environment Info -->
+        <div class="card mb-4">
+            <div class="card-header">
+                <h5 class="mb-0"><i class="bi bi-info-circle me-2"></i>Environment</h5>
+            </div>
+            <div class="card-body">
+                <div class="row text-center">
+                    <div class="col-6 col-md-3 mb-3">
+                        <div class="p-3 bg-dark rounded h-100">
+                            <i class="bi bi-box text-primary fs-3 d-block mb-2"></i>
+                            <div class="small text-muted">Version</div>
+                            <strong>{{ version }}</strong>
+                        </div>
+                    </div>
+                    <div class="col-6 col-md-3 mb-3">
+                        <div class="p-3 bg-dark rounded h-100">
+                            <i class="bi bi-terminal text-info fs-3 d-block mb-2"></i>
+                            <div class="small text-muted">Python</div>
+                            <strong>{{ python_version }}</strong>
+                        </div>
+                    </div>
+                    <div class="col-6 col-md-3 mb-3">
+                        <div class="p-3 bg-dark rounded h-100">
+                            <i class="bi bi-cpu text-warning fs-3 d-block mb-2"></i>
+                            <div class="small text-muted">Platform</div>
+                            <strong>{{ platform }}</strong>
+                        </div>
+                    </div>
+                    <div class="col-6 col-md-3 mb-3">
+                        <div class="p-3 bg-dark rounded h-100">
+                            <i class="bi bi-shield-check text-success fs-3 d-block mb-2"></i>
+                            <div class="small text-muted">KDF</div>
+                            <strong>{{ kdf_type }}</strong>
+                        </div>
+                    </div>
+                </div>
+            </div>
+        </div>
+    </div>
+</div>
+
+<!-- Password Verification Modal -->
+<div class="modal fade" id="passwordModal" tabindex="-1">
+    <div class="modal-dialog modal-sm modal-dialog-centered">
+        <div class="modal-content">
+            <div class="modal-header">
+                <h6 class="modal-title"><i class="bi bi-shield-lock me-2"></i>Verify Password</h6>
+                <button type="button" class="btn-close" data-bs-dismiss="modal"></button>
+            </div>
+            <div class="modal-body">
+                <p class="small text-muted mb-3">Re-enter your password to access sensitive data.</p>
+                <div class="mb-3">
+                    <label class="form-label small">Password</label>
+                    <input type="password" class="form-control" id="verifyPassword" autocomplete="current-password">
+                    <div class="invalid-feedback" id="passwordError">Incorrect password</div>
+                </div>
+            </div>
+            <div class="modal-footer">
+                <button type="button" class="btn btn-secondary btn-sm" data-bs-dismiss="modal">Cancel</button>
+                <button type="button" class="btn btn-warning btn-sm" id="verifyPasswordBtn">
+                    <i class="bi bi-unlock me-1"></i>Unlock
+                </button>
+            </div>
+        </div>
+    </div>
+</div>
+
+<!-- QR Code Modal -->
+<div class="modal fade" id="channelKeyQrModal" tabindex="-1">
+    <div class="modal-dialog modal-sm modal-dialog-centered">
+        <div class="modal-content">
+            <div class="modal-header">
+                <h6 class="modal-title"><i class="bi bi-qr-code me-2"></i>Channel Key</h6>
+                <button type="button" class="btn-close" data-bs-dismiss="modal"></button>
+            </div>
+            <div class="modal-body text-center">
+                <canvas id="channelKeyQrCanvas" class="bg-white p-2 rounded"></canvas>
+                <div class="mt-2">
+                    <code class="small" id="channelKeyQrDisplay"></code>
+                </div>
+            </div>
+            <div class="modal-footer justify-content-center">
+                <button type="button" class="btn btn-sm btn-outline-secondary" id="channelKeyQrDownload">
+                    <i class="bi bi-download me-1"></i>Download
+                </button>
+                <button type="button" class="btn btn-sm btn-outline-secondary" id="channelKeyQrPrint">
+                    <i class="bi bi-printer me-1"></i>Print Sheet
+                </button>
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script src="{{ url_for('static', filename='js/qrcode.min.js') }}"></script>
+<script src="{{ url_for('static', filename='js/stegasoo.js') }}"></script>
+<script>
+document.addEventListener('DOMContentLoaded', function() {
+    const input = document.getElementById('channelKeyQrInput');
+    const generateBtn = document.getElementById('channelKeyQrGenerate');
+    const showBtn = document.getElementById('channelKeyQrShow');
+    const canvas = document.getElementById('channelKeyQrCanvas');
+    const displayEl = document.getElementById('channelKeyQrDisplay');
+    const downloadBtn = document.getElementById('channelKeyQrDownload');
+    const modalEl = document.getElementById('channelKeyQrModal');
+    const modal = modalEl ? new bootstrap.Modal(modalEl) : null;
+
+    // Password verification elements
+    const lockedDiv = document.getElementById('channelKeyLocked');
+    const unlockedDiv = document.getElementById('channelKeyUnlocked');
+    const unlockBtn = document.getElementById('channelKeyUnlock');
+    const passwordModalEl = document.getElementById('passwordModal');
+    const passwordModal = passwordModalEl ? new bootstrap.Modal(passwordModalEl) : null;
+    const verifyPasswordInput = document.getElementById('verifyPassword');
+    const verifyPasswordBtn = document.getElementById('verifyPasswordBtn');
+    const passwordError = document.getElementById('passwordError');
+
+    // Unlock button shows password modal
+    unlockBtn?.addEventListener('click', function() {
+        verifyPasswordInput.value = '';
+        verifyPasswordInput.classList.remove('is-invalid');
+        passwordModal?.show();
+        setTimeout(() => verifyPasswordInput.focus(), 300);
+    });
+
+    // Handle Enter key in password field
+    verifyPasswordInput?.addEventListener('keypress', function(e) {
+        if (e.key === 'Enter') {
+            e.preventDefault();
+            verifyPasswordBtn?.click();
+        }
+    });
+
+    // Verify password and unlock
+    verifyPasswordBtn?.addEventListener('click', async function() {
+        const password = verifyPasswordInput.value;
+        if (!password) {
+            verifyPasswordInput.classList.add('is-invalid');
+            return;
+        }
+
+        verifyPasswordBtn.disabled = true;
+        verifyPasswordBtn.innerHTML = '<span class="spinner-border spinner-border-sm me-1"></span>Verifying...';
+
+        try {
+            const response = await fetch('/admin/settings/unlock', {
+                method: 'POST',
+                headers: {
+                    'Content-Type': 'application/json',
+                    'X-Requested-With': 'XMLHttpRequest'
+                },
+                body: JSON.stringify({ password })
+            });
+
+            const data = await response.json();
+
+            if (data.success) {
+                // Unlock successful
+                passwordModal?.hide();
+                lockedDiv.style.display = 'none';
+                unlockedDiv.style.display = 'block';
+                if (data.channel_key && input) {
+                    input.value = data.channel_key;
+                }
+            } else {
+                // Password incorrect
+                verifyPasswordInput.classList.add('is-invalid');
+                passwordError.textContent = data.error || 'Incorrect password';
+            }
+        } catch (error) {
+            verifyPasswordInput.classList.add('is-invalid');
+            passwordError.textContent = 'Verification failed';
+        } finally {
+            verifyPasswordBtn.disabled = false;
+            verifyPasswordBtn.innerHTML = '<i class="bi bi-unlock me-1"></i>Unlock';
+        }
+    });
+
+    // Generate random key
+    generateBtn?.addEventListener('click', function() {
+        if (!input) return;
+        if (typeof Stegasoo !== 'undefined' && Stegasoo.generateChannelKey) {
+            input.value = Stegasoo.generateChannelKey();
+        } else {
+            const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
+            let key = '';
+            for (let i = 0; i < 8; i++) {
+                if (i > 0) key += '-';
+                for (let j = 0; j < 4; j++) {
+                    key += chars.charAt(Math.floor(Math.random() * chars.length));
+                }
+            }
+            input.value = key;
+        }
+    });
+
+    // Show QR code in modal
+    showBtn?.addEventListener('click', function() {
+        const key = input?.value?.trim().replace(/-/g, '');
+        if (!key || key.length !== 32) {
+            alert('Please enter a valid 32-character channel key');
+            return;
+        }
+
+        const formatted = key.match(/.{4}/g)?.join('-') || key;
+
+        if (typeof QRious === 'undefined') {
+            alert('QR Code library failed to load.');
+            return;
+        }
+
+        try {
+            new QRious({
+                element: canvas,
+                value: formatted,
+                size: 200,
+                level: 'M'
+            });
+            if (displayEl) displayEl.textContent = formatted;
+            modal?.show();
+        } catch (error) {
+            alert('Failed to generate QR code: ' + error.message);
+        }
+    });
+
+    // Download QR as PNG
+    downloadBtn?.addEventListener('click', function() {
+        if (canvas) {
+            const link = document.createElement('a');
+            link.download = 'stegasoo-channel-key.png';
+            link.href = canvas.toDataURL('image/png');
+            link.click();
+        }
+    });
+
+    // Print tiled QR sheet (US Letter)
+    document.getElementById('channelKeyQrPrint')?.addEventListener('click', function() {
+        if (canvas && displayEl) {
+            printQrSheet(canvas, displayEl.textContent, 'Channel Key');
+        }
+    });
+});
+
+// Print QR codes tiled on US Letter paper (8.5" x 11")
+function printQrSheet(canvas, keyText, title) {
+    const qrDataUrl = canvas.toDataURL('image/png');
+    const printWindow = window.open('', '_blank');
+    if (!printWindow) {
+        alert('Please allow popups to print');
+        return;
+    }
+
+    // US Letter: 8.5" x 11" - create 4x5 grid of QR codes
+    const cols = 4;
+    const rows = 5;
+
+    // Split key into two lines (4 groups each)
+    const keyParts = keyText.split('-');
+    const keyLine1 = keyParts.slice(0, 4).join('-');
+    const keyLine2 = keyParts.slice(4).join('-');
+
+    let qrGrid = '';
+    for (let i = 0; i < rows * cols; i++) {
+        qrGrid += `
+            <div class="qr-tile">
+                <div class="key-text">${keyLine1}</div>
+                <img src="${qrDataUrl}" alt="QR">
+                <div class="key-text">${keyLine2}</div>
+            </div>
+        `;
+    }
+
+    printWindow.document.write(`
+        <!DOCTYPE html>
+        <html>
+        <head>
+            <title></title>
+            <style>
+                @page {
+                    size: letter;
+                    margin: 0.2in;
+                    margin-top: 0.1in;
+                    margin-bottom: 0.1in;
+                }
+                @media print {
+                    @page { margin: 0.15in; }
+                    html, body { margin: 0; padding: 0; }
+                }
+                * { margin: 0; padding: 0; box-sizing: border-box; }
+                body {
+                    font-family: 'Courier New', monospace;
+                    background: white;
+                }
+                .grid {
+                    display: grid;
+                    grid-template-columns: repeat(${cols}, 1fr);
+                    gap: 0;
+                    margin-top: 0.09in;
+                }
+                .qr-tile {
+                    border: 1px dashed #ccc;
+                    padding: 0.04in;
+                    text-align: center;
+                    page-break-inside: avoid;
+                }
+                .qr-tile img {
+                    width: 1.6in;
+                    height: 1.6in;
+                }
+                .key-text {
+                    font-size: 10pt;
+                    font-weight: bold;
+                    color: #333;
+                    line-height: 1.2;
+                }
+                .footer {
+                    display: none;
+                }
+            </style>
+        </head>
+        <body>
+            <div class="grid">${qrGrid}</div>
+            <div class="footer">Cut along dashed lines</div>
+            <script>
+                window.onload = function() { window.print(); };
+            <\/script>
+        </body>
+        </html>
+    `);
+    printWindow.document.close();
+}
+</script>
+{% endblock %}

frontends/web/templates/admin/user_created.html

@@ -0,0 +1,60 @@
+{% extends "base.html" %}
+
+{% block title %}User Created - Stegasoo{% endblock %}
+
+{% block content %}
+<div class="row justify-content-center">
+    <div class="col-md-6 col-lg-5">
+        <div class="card border-success">
+            <div class="card-header bg-success text-white">
+                <i class="bi bi-check-circle fs-4 me-2"></i>
+                <span class="fs-5">User Created Successfully</span>
+            </div>
+            <div class="card-body">
+                <div class="alert alert-warning">
+                    <i class="bi bi-exclamation-triangle me-2"></i>
+                    <strong>Important:</strong> This password will only be shown once.
+                    Make sure to share it with the user securely.
+                </div>
+
+                <div class="mb-3">
+                    <label class="form-label text-muted small">Username</label>
+                    <div class="input-group">
+                        <input type="text" class="form-control form-control-lg font-monospace"
+                               value="{{ username }}" readonly id="usernameField">
+                        <button class="btn btn-outline-secondary" type="button"
+                                onclick="copyField('usernameField')" title="Copy username">
+                            <i class="bi bi-clipboard"></i>
+                        </button>
+                    </div>
+                </div>
+
+                <div class="mb-4">
+                    <label class="form-label text-muted small">Password</label>
+                    <div class="input-group">
+                        <input type="text" class="form-control form-control-lg font-monospace"
+                               value="{{ password }}" readonly id="passwordField">
+                        <button class="btn btn-outline-secondary" type="button"
+                                onclick="copyField('passwordField')" title="Copy password">
+                            <i class="bi bi-clipboard"></i>
+                        </button>
+                    </div>
+                </div>
+
+                <div class="d-grid gap-2">
+                    <a href="{{ url_for('admin_user_new') }}" class="btn btn-primary">
+                        <i class="bi bi-person-plus me-2"></i>Add Another User
+                    </a>
+                    <a href="{{ url_for('admin_users') }}" class="btn btn-outline-secondary">
+                        <i class="bi bi-arrow-left me-2"></i>Back to Users
+                    </a>
+                </div>
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script src="{{ url_for('static', filename='js/auth.js') }}"></script>
+{% endblock %}

frontends/web/templates/admin/user_new.html

@@ -0,0 +1,166 @@
+{% extends "base.html" %}
+
+{% block title %}Add User - Stegasoo{% endblock %}
+
+{% block content %}
+<div class="row justify-content-center">
+    <div class="col-md-6 col-lg-5">
+        <div class="card">
+            <div class="card-header">
+                <i class="bi bi-person-plus fs-4 me-2"></i>
+                <span class="fs-5">Add New User</span>
+            </div>
+            <div class="card-body">
+                <form id="createUserForm">
+                    <div class="mb-3">
+                        <label class="form-label">
+                            <i class="bi bi-person me-1"></i> Username
+                        </label>
+                        <input type="text" name="username" id="usernameInput" class="form-control"
+                               placeholder="e.g., john_doe or john@example.com"
+                               pattern="[a-zA-Z0-9][a-zA-Z0-9_\-@.]{2,79}"
+                               title="3-80 characters, letters/numbers/underscore/hyphen/@/."
+                               required autofocus>
+                        <div class="form-text">
+                            Letters, numbers, underscore, hyphen, @ and . allowed.
+                        </div>
+                    </div>
+
+                    <div class="mb-4">
+                        <label class="form-label">
+                            <i class="bi bi-key me-1"></i> Password
+                        </label>
+                        <div class="input-group">
+                            <input type="text" name="password" id="passwordInput"
+                                   class="form-control" value="{{ temp_password }}"
+                                   minlength="8" required>
+                            <button class="btn btn-outline-secondary" type="button"
+                                    onclick="regeneratePassword()" title="Generate new password">
+                                <i class="bi bi-arrow-repeat"></i>
+                            </button>
+                        </div>
+                        <div class="form-text">
+                            Auto-generated password. You can edit or regenerate it.
+                        </div>
+                    </div>
+
+                    <div id="errorAlert" class="alert alert-danger d-none"></div>
+
+                    <div class="d-flex gap-2">
+                        <button type="submit" class="btn btn-primary flex-grow-1" id="createBtn">
+                            <i class="bi bi-person-check me-2"></i>Create User
+                        </button>
+                        <a href="{{ url_for('admin_users') }}" class="btn btn-outline-secondary">
+                            Cancel
+                        </a>
+                    </div>
+                </form>
+            </div>
+        </div>
+    </div>
+</div>
+
+<!-- Success Modal -->
+<div class="modal fade" id="successModal" tabindex="-1" data-bs-backdrop="static">
+    <div class="modal-dialog modal-dialog-centered">
+        <div class="modal-content border-success">
+            <div class="modal-header bg-success text-white">
+                <h5 class="modal-title">
+                    <i class="bi bi-check-circle me-2"></i>User Created
+                </h5>
+            </div>
+            <div class="modal-body">
+                <div class="alert alert-warning mb-3 py-2">
+                    <i class="bi bi-exclamation-triangle me-1"></i>
+                    Password shown once. Copy it now.
+                </div>
+
+                <div class="row mb-3">
+                    <div class="col-6">
+                        <label class="form-label text-muted small mb-1">Username</label>
+                        <div class="input-group">
+                            <input type="text" class="form-control font-monospace"
+                                   id="createdUsername" readonly>
+                            <button class="btn btn-outline-secondary" type="button"
+                                    onclick="copyField('createdUsername')" title="Copy">
+                                <i class="bi bi-clipboard"></i>
+                            </button>
+                        </div>
+                    </div>
+                    <div class="col-6">
+                        <label class="form-label text-muted small mb-1">Password</label>
+                        <div class="input-group">
+                            <input type="text" class="form-control font-monospace"
+                                   id="createdPassword" readonly>
+                            <button class="btn btn-outline-secondary" type="button"
+                                    onclick="copyField('createdPassword')" title="Copy">
+                                <i class="bi bi-clipboard"></i>
+                            </button>
+                        </div>
+                    </div>
+                </div>
+
+                <div class="d-flex justify-content-end gap-2">
+                    <button type="button" class="btn btn-primary" onclick="addAnother()">
+                        <i class="bi bi-person-plus me-1"></i>Add Another
+                    </button>
+                    <a href="{{ url_for('admin_users') }}" class="btn btn-outline-secondary">
+                        Done
+                    </a>
+                </div>
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script src="{{ url_for('static', filename='js/auth.js') }}"></script>
+<script>
+const form = document.getElementById('createUserForm');
+const errorAlert = document.getElementById('errorAlert');
+const createBtn = document.getElementById('createBtn');
+const successModal = new bootstrap.Modal(document.getElementById('successModal'));
+
+form.addEventListener('submit', async function(e) {
+    e.preventDefault();
+    errorAlert.classList.add('d-none');
+    createBtn.disabled = true;
+    createBtn.innerHTML = '<span class="spinner-border spinner-border-sm me-2"></span>Creating...';
+
+    const formData = new FormData(form);
+
+    try {
+        const response = await fetch('{{ url_for("admin_user_new") }}', {
+            method: 'POST',
+            body: formData,
+            headers: { 'X-Requested-With': 'XMLHttpRequest' }
+        });
+
+        const data = await response.json();
+
+        if (data.success) {
+            document.getElementById('createdUsername').value = data.username;
+            document.getElementById('createdPassword').value = data.password;
+            successModal.show();
+        } else {
+            errorAlert.textContent = data.error;
+            errorAlert.classList.remove('d-none');
+        }
+    } catch (err) {
+        errorAlert.textContent = 'An error occurred. Please try again.';
+        errorAlert.classList.remove('d-none');
+    }
+
+    createBtn.disabled = false;
+    createBtn.innerHTML = '<i class="bi bi-person-check me-2"></i>Create User';
+});
+
+function addAnother() {
+    successModal.hide();
+    document.getElementById('usernameInput').value = '';
+    regeneratePassword();
+    document.getElementById('usernameInput').focus();
+}
+</script>
+{% endblock %}

frontends/web/templates/admin/users.html

@@ -0,0 +1,95 @@
+{% extends "base.html" %}
+
+{% block title %}Manage Users - Stegasoo{% endblock %}
+
+{% block content %}
+<div class="row justify-content-center">
+    <div class="col-md-10 col-lg-8">
+        <div class="card">
+            <div class="card-header d-flex justify-content-between align-items-center">
+                <div>
+                    <i class="bi bi-people fs-4 me-2"></i>
+                    <span class="fs-5">User Management</span>
+                </div>
+                <div class="text-muted small">
+                    {{ user_count }} / {{ max_users }} users
+                </div>
+            </div>
+            <div class="card-body">
+                {% if can_create %}
+                <div class="mb-4">
+                    <a href="{{ url_for('admin_user_new') }}" class="btn btn-primary">
+                        <i class="bi bi-person-plus me-2"></i>Add User
+                    </a>
+                </div>
+                {% else %}
+                <div class="alert alert-warning mb-4">
+                    <i class="bi bi-exclamation-triangle me-2"></i>
+                    Maximum of {{ max_users }} users reached.
+                </div>
+                {% endif %}
+
+                <div class="table-responsive">
+                    <table class="table table-hover mb-0">
+                        <thead>
+                            <tr>
+                                <th>Username</th>
+                                <th>Role</th>
+                                <th>Created</th>
+                                <th class="text-end">Actions</th>
+                            </tr>
+                        </thead>
+                        <tbody>
+                            {% for user in users %}
+                            <tr>
+                                <td>
+                                    <i class="bi bi-person me-2"></i>
+                                    {{ user.username }}
+                                    {% if user.id == current_user.id %}
+                                    <span class="badge bg-info ms-2">You</span>
+                                    {% endif %}
+                                </td>
+                                <td>
+                                    {% if user.is_admin %}
+                                    <span class="badge bg-warning text-dark">
+                                        <i class="bi bi-shield-check me-1"></i>Admin
+                                    </span>
+                                    {% else %}
+                                    <span class="badge bg-secondary">User</span>
+                                    {% endif %}
+                                </td>
+                                <td class="text-muted small">
+                                    {{ user.created_at[:10] if user.created_at else 'Unknown' }}
+                                </td>
+                                <td class="text-end">
+                                    {% if user.id != current_user.id %}
+                                    <form method="POST" action="{{ url_for('admin_user_reset_password', user_id=user.id) }}"
+                                          class="d-inline" onsubmit="return confirm('Reset password for {{ user.username }}?')">
+                                        <button type="submit" class="btn btn-sm btn-outline-warning" title="Reset Password">
+                                            <i class="bi bi-key"></i>
+                                        </button>
+                                    </form>
+                                    <form method="POST" action="{{ url_for('admin_user_delete', user_id=user.id) }}"
+                                          class="d-inline" onsubmit="return confirm('Delete user {{ user.username }}? This cannot be undone.')">
+                                        <button type="submit" class="btn btn-sm btn-outline-danger" title="Delete User">
+                                            <i class="bi bi-trash"></i>
+                                        </button>
+                                    </form>
+                                    {% else %}
+                                    <span class="text-muted small">-</span>
+                                    {% endif %}
+                                </td>
+                            </tr>
+                            {% endfor %}
+                        </tbody>
+                    </table>
+                </div>
+            </div>
+            <div class="card-footer text-muted small">
+                <i class="bi bi-info-circle me-1"></i>
+                Admins can add up to {{ max_users }} regular users.
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}

frontends/web/templates/base.html

@@ -5,56 +5,91 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>{% block title %}Stegasoo{% endblock %}</title>
     <link rel="icon" type="image/svg+xml" href="{{ url_for('static', filename='favicon.svg') }}">
-    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/css/bootstrap.min.css" rel="stylesheet">
-    <link href="https://cdn.jsdelivr.net/npm/bootstrap-icons@1.11.1/font/bootstrap-icons.css" rel="stylesheet">
+    <link href="{{ url_for('static', filename='vendor/css/bootstrap.min.css') }}" rel="stylesheet">
+    <link href="{{ url_for('static', filename='vendor/css/bootstrap-icons.min.css') }}" rel="stylesheet">
     <link href="{{ url_for('static', filename='style.css') }}" rel="stylesheet">
 </head>
 <body>
     <nav class="navbar navbar-expand-lg navbar-dark">
-        <div class="container">
-            <a class="navbar-brand d-flex align-items-center" href="/">
-                <img src="{{ url_for('static', filename='logo.svg') }}" alt="Stegasoo" height="36" class="me-2">
-                <span class="fw-bold">Stegasoo</span>
+        <div class="container-fluid">
+            <a class="navbar-brand" href="/" style="padding-left: 6px; margin-right: 8px;">
+                <img src="{{ url_for('static', filename='logo.svg') }}" alt="Stegasoo" height="28">
             </a>
+            {% if channel_configured %}
+            <span class="badge bg-success bg-opacity-25 small" style="padding-left: 0.35rem;" title="Private Channel: {{ channel_fingerprint }}">
+                <i class="bi bi-shield-lock me-2" style="color: #6ee7b7;"></i><code style="font-size: 0.7rem; font-weight: 300; color: #c9a860;">{{ channel_fingerprint[:4] }}-••••-{{ channel_fingerprint[-4:] }}</code>
+            </span>
+            {% else %}
+            <span class="badge bg-secondary bg-opacity-25 small text-muted" style="padding-left: 0.35rem;" title="Public Channel: No shared channel key configured. Messages use only passphrase and PIN for encryption.">
+                <i class="bi bi-globe me-1"></i>Public Channel
+            </span>
+            {% endif %}
             <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNav">
                 <span class="navbar-toggler-icon"></span>
             </button>
             <div class="collapse navbar-collapse" id="navbarNav">
-                <ul class="navbar-nav ms-auto">
+                <ul class="navbar-nav ms-auto nav-icons">
                     <li class="nav-item">
-                        <a class="nav-link" href="/"><i class="bi bi-house me-1"></i> Home</a>
+                        <a class="nav-link nav-expand" href="/"><i class="bi bi-house"></i><span>Home</span></a>
+                    </li>
+                    {% if not auth_enabled or is_authenticated %}
+                    <li class="nav-item">
+                        <a class="nav-link nav-expand" href="/encode"><i class="bi bi-lock"></i><span>Encode</span></a>
                     </li>
                     <li class="nav-item">
-                        <a class="nav-link" href="/encode"><i class="bi bi-lock me-1"></i> Encode</a>
+                        <a class="nav-link nav-expand" href="/decode"><i class="bi bi-unlock"></i><span>Decode</span></a>
                     </li>
                     <li class="nav-item">
-                        <a class="nav-link" href="/decode"><i class="bi bi-unlock me-1"></i> Decode</a>
+                        <a class="nav-link nav-expand" href="/generate"><i class="bi bi-key"></i><span>Generate</span></a>
                     </li>
-
+                    {% endif %}
                     <li class="nav-item">
-                        <a class="nav-link" href="/generate"><i class="bi bi-key me-1"></i> Generate</a>
-                    </li>
-
-                    <li class="nav-item">
-                        <a class="nav-link" href="/about"><i class="bi bi-info-circle me-1"></i> About</a>
+                        <a class="nav-link nav-expand" href="/tools"><i class="bi bi-tools"></i><span>Tools</span></a>
                     </li>
+                    {% if auth_enabled %}
+                        {% if is_authenticated %}
+                        <li class="nav-item dropdown">
+                            <a class="nav-link dropdown-toggle" href="#" role="button" data-bs-toggle="dropdown">
+                                <i class="bi bi-person-circle me-1"></i> {{ username }}
+                            </a>
+                            <ul class="dropdown-menu dropdown-menu-end dropdown-menu-dark">
+                                <li><a class="dropdown-item" href="/account"><i class="bi bi-gear me-2"></i>Account</a></li>
+                                {% if is_admin %}
+                                <li><a class="dropdown-item" href="/admin/users"><i class="bi bi-people me-2"></i>Users</a></li>
+                                <li><a class="dropdown-item" href="/admin/settings"><i class="bi bi-sliders me-2"></i>System Settings</a></li>
+                                {% endif %}
+                                <li><hr class="dropdown-divider"></li>
+                                <li><a class="dropdown-item" href="/logout"><i class="bi bi-box-arrow-left me-2"></i>Logout</a></li>
+                            </ul>
+                        </li>
+                        {% else %}
+                        <li class="nav-item">
+                            <a class="nav-link" href="/login"><i class="bi bi-box-arrow-in-right me-1"></i> Login</a>
+                        </li>
+                        {% endif %}
+                    {% endif %}
                 </ul>
             </div>
         </div>
     </nav>
 
     <main class="container py-5">
-        {% with messages = get_flashed_messages(with_categories=true) %}
-            {% if messages %}
+        <!-- Toast notifications container -->
+        <div class="toast-container position-fixed end-0 p-3" style="z-index: 1100; top: 70px;">
+            {% with messages = get_flashed_messages(with_categories=true) %}
                 {% for category, message in messages %}
-                    <div class="alert alert-{{ 'danger' if category == 'error' else 'success' }} alert-dismissible fade show" role="alert">
-                        <i class="bi bi-{{ 'exclamation-triangle' if category == 'error' else 'check-circle' }} me-2"></i>
-                        {{ message }}
-                        <button type="button" class="btn-close" data-bs-dismiss="alert"></button>
+                    <div class="toast show align-items-center text-bg-{{ 'danger' if category == 'error' else ('warning' if category == 'warning' else 'success') }} border-0 fade" role="alert" data-bs-autohide="true" data-bs-delay="10000">
+                        <div class="d-flex">
+                            <div class="toast-body">
+                                <i class="bi bi-{{ 'exclamation-triangle' if category == 'error' else ('exclamation-circle' if category == 'warning' else 'check-circle') }} me-2"></i>
+                                {{ message }}
+                            </div>
+                            <button type="button" class="btn-close btn-close-white me-2 m-auto" data-bs-dismiss="toast"></button>
+                        </div>
                     </div>
                 {% endfor %}
-            {% endif %}
-        {% endwith %}
+            {% endwith %}
+        </div>
 
         {% block content %}{% endblock %}
     </main>
@@ -63,12 +98,20 @@
         <div class="container text-center text-muted">
             <small>
                 <img src="{{ url_for('static', filename='favicon.svg') }}" alt="" height="16" class="me-1" style="vertical-align: text-bottom;">
-                Stegasoo v2.1.0 — Hybrid Photo + Day-Phrase + PIN Steganography
+                Stegasoo v{{ version }} — Steganography with Reference Photo + Passphrase + PIN/Key
+                <span class="mx-2">|</span>
+                <a href="/about" class="text-muted text-decoration-none"><i class="bi bi-info-circle me-1"></i>About</a>
             </small>
         </div>
     </footer>
 
-    <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/js/bootstrap.bundle.min.js"></script>
+    <script src="{{ url_for('static', filename='vendor/js/bootstrap.bundle.min.js') }}"></script>
+    <!-- QR Code scanning library (local) -->
+    <script src="{{ url_for('static', filename='vendor/js/html5-qrcode.min.js') }}"></script>
+    <script>
+    // Initialize toasts (auto-hide after delay)
+    document.querySelectorAll('.toast').forEach(el => new bootstrap.Toast(el));
+    </script>
     {% block scripts %}{% endblock %}
 </body>
 </html>

frontends/web/templates/decode.html

@@ -3,28 +3,137 @@
 {% block title %}Decode Message - Stegasoo{% endblock %}
 
 {% block content %}
+<style>
+/* Accordion styling */
+.step-accordion .accordion-button {
+    background: rgba(35, 45, 55, 0.8);
+    color: #fff;
+    padding: 0.75rem 1rem;
+    border-left: 3px solid rgba(255, 230, 153, 0.3);
+    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
+    transition: all 0.3s ease;
+}
+.step-accordion .accordion-button:hover {
+    background: rgba(45, 55, 65, 0.9);
+    border-left-color: rgba(255, 230, 153, 0.5);
+}
+.step-accordion .accordion-button:not(.collapsed) {
+    background: linear-gradient(90deg, rgba(255, 230, 153, 0.12) 0%, rgba(40, 50, 60, 0.85) 40%, rgba(40, 50, 60, 0.85) 100%);
+    color: #fff;
+    box-shadow: inset 0 1px 0 rgba(255, 230, 153, 0.1);
+    border-left: 3px solid #ffe699;
+}
+.step-accordion .accordion-button::after {
+    filter: invert(1) sepia(1) saturate(2) hue-rotate(5deg) brightness(1.2);
+}
+.step-accordion .accordion-body {
+    background: rgba(30, 40, 50, 0.4);
+    padding: 1rem;
+}
+.step-accordion .accordion-item {
+    border-color: rgba(255,255,255,0.1);
+    background: transparent;
+}
+.step-accordion .accordion-item:first-child .accordion-button {
+    border-radius: 0;
+}
+.step-accordion .accordion-item:last-child .accordion-button.collapsed {
+    border-radius: 0;
+}
+.step-summary {
+    font-size: 0.8rem;
+    color: rgba(255,255,255,0.5);
+    margin-left: auto;
+    padding-right: 1rem;
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    max-width: 50%;
+}
+.step-summary.has-content {
+    color: rgba(99, 179, 237, 0.8);
+}
+.step-title {
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+}
+.step-number {
+    background: rgba(246, 173, 85, 0.2);
+    color: #f6ad55;
+    width: 1.5rem;
+    height: 1.5rem;
+    border-radius: 50%;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    font-size: 0.75rem;
+    font-weight: bold;
+    border: 1px solid rgba(246, 173, 85, 0.3);
+}
+.step-number.complete {
+    background: rgba(72, 187, 120, 0.2);
+    color: #48bb78;
+    border-color: rgba(72, 187, 120, 0.3);
+}
+
+/* Glowing passphrase input */
+.passphrase-input {
+    background: rgba(30, 40, 50, 0.8) !important;
+    border: 2px solid rgba(99, 179, 237, 0.3) !important;
+    color: #63b3ed !important;
+    font-family: 'Courier New', monospace;
+    font-size: 1.1rem;
+    letter-spacing: 0.5px;
+    padding: 12px 16px;
+    transition: border-color 0.3s ease, box-shadow 0.3s ease;
+}
+.passphrase-input:focus {
+    border-color: rgba(99, 179, 237, 0.8) !important;
+    box-shadow: 0 0 20px rgba(99, 179, 237, 0.4) !important;
+}
+.passphrase-input::placeholder {
+    color: rgba(99, 179, 237, 0.4);
+}
+
+/* PIN input */
+.pin-input-container .form-control {
+    background: rgba(30, 40, 50, 0.8) !important;
+    border: 2px solid rgba(246, 173, 85, 0.3) !important;
+    color: #f6ad55 !important;
+    font-family: 'Courier New', monospace;
+    font-size: 1.2rem;
+    letter-spacing: 3px;
+    text-align: center;
+}
+.pin-input-container .form-control:focus {
+    border-color: rgba(246, 173, 85, 0.8) !important;
+    box-shadow: 0 0 20px rgba(246, 173, 85, 0.4) !important;
+}
+
+/* QR Crop Animation - uses .qr-scan-container from style.css */
+</style>
+
 <div class="row justify-content-center">
     <div class="col-lg-8">
         <div class="card">
             <div class="card-header">
                 <h5 class="mb-0"><i class="bi bi-unlock-fill me-2"></i>Decode Secret Message or File</h5>
             </div>
-            <div class="card-body">
+            <div class="card-body {% if not decoded_message and not decoded_file %}p-0{% endif %}">
                 {% if decoded_message %}
                 <!-- Text Message Result -->
                 <div class="alert alert-success">
                     <h6><i class="bi bi-check-circle me-2"></i>Message Decrypted Successfully!</h6>
                 </div>
 
-                <label class="form-label text-muted">Decoded Message:</label>
-                <div class="position-relative">
-                  <div class="alert-message p-3 rounded bg-dark border border-secondary" id="decodedContent" style="white-space: pre-wrap;">{{ decoded_message }}</div>
-                  <button class="btn btn-sm btn-outline-light position-absolute top-0 end-0 m-2" onclick="navigator.clipboard.writeText(document.getElementById('decodedContent').innerText).then(() => this.innerHTML = '<i class=\'bi bi-check\'></i>').catch(() => alert('Failed to copy'))">
-                    <i class="bi bi-clipboard"></i> Copy
-                  </button>
-                </div>
+                <label class="form-label text-muted">Decoded Message: <small class="text-secondary">(click to copy)</small></label>
+                <div class="alert-message p-3 rounded bg-dark border border-secondary mb-3" id="decodedContent" style="white-space: pre-wrap; cursor: pointer; transition: border-color 0.2s;"
+                     onclick="navigator.clipboard.writeText(this.innerText).then(() => { this.style.borderColor = '#198754'; this.dataset.origText = this.innerHTML; this.innerHTML = '<i class=\'bi bi-check-circle text-success\'></i> Copied to clipboard!'; setTimeout(() => { this.innerHTML = this.dataset.origText; this.style.borderColor = ''; }, 1500); }).catch(() => alert('Failed to copy'))"
+                     onmouseover="this.style.borderColor = '#6c757d'"
+                     onmouseout="this.style.borderColor = ''">{{ decoded_message }}</div>
 
-                <a href="/decode" class="btn btn-outline-light w-100 mt-3">
+                <a href="/decode" class="btn btn-outline-light w-100">
                     <i class="bi bi-arrow-repeat me-2"></i>Decode Another
                 </a>
 
@@ -59,152 +168,245 @@
                 {% else %}
                 <!-- Decode Form -->
                 <form method="POST" enctype="multipart/form-data" id="decodeForm">
-                    <div class="row">
-                        <div class="col-md-6 mb-3">
-                            <label class="form-label">
-                                <i class="bi bi-image me-1"></i> Reference Photo
-                            </label>
-                            <div class="drop-zone">
-                                <input type="file" name="reference_photo" accept="image/*" required>
-                                <div class="drop-zone-label">
-                                    <i class="bi bi-cloud-arrow-up fs-3 d-block mb-2 text-muted"></i>
-                                    <span class="text-muted">Drop image or click to browse</span>
-                                </div>
-                                <img class="drop-zone-preview d-none">
-                            </div>
-                            <div class="form-text">
-                                The same reference photo used for encoding
-                            </div>
-                        </div>
 
-                        <div class="col-md-6 mb-3">
-                            <label class="form-label">
-                                <i class="bi bi-file-earmark-image me-1"></i> Stego Image
-                            </label>
-                            <div class="drop-zone" id="stegoDropZone">
-                                <input type="file" name="stego_image" accept="image/*" required>
-                                <div class="drop-zone-label">
-                                    <i class="bi bi-cloud-arrow-up fs-3 d-block mb-2 text-muted"></i>
-                                    <span class="text-muted">Drop image or click to browse</span>
-                                </div>
-                                <img class="drop-zone-preview d-none">
-                            </div>
-                            <div class="form-text">
-                                The image containing the hidden message/file
-                            </div>
-                        </div>
-                    </div>
+                    <div class="accordion step-accordion" id="decodeAccordion">
 
-                    <div class="mb-3">
-                        <label class="form-label" id="dayPhraseLabel">
-                            <i class="bi bi-chat-quote me-1"></i> Day Phrase
-                        </label>
-                        <input type="text" name="day_phrase" class="form-control" 
-                               placeholder="e.g., correct horse battery" required>
-                        <div class="form-text">
-                            The phrase for the day the message was encoded
-                        </div>
-                    </div>
-                    
-                    <hr class="my-4">
-                    
-                    <h6 class="text-muted mb-3">
-                        SECURITY FACTORS 
-                        <span class="text-warning small">(provide same factors used during encoding)</span>
-                    </h6>
-                    
-                    <div class="row">
-                        <div class="col-md-6 mb-3">
-
-                            <label class="form-label"><i class="bi bi-123 me-1"></i> PIN</label>
-                            <div class="input-group">
-                                <input type="password" name="pin" class="form-control" id="pinInput" placeholder="6-9 digits" maxlength="9">
-                                <button class="btn btn-outline-secondary" type="button" id="togglePin">
-                                    <i class="bi bi-eye"></i>
+                        <!-- ================================================================
+                             STEP 1: IMAGES & MODE
+                             ================================================================ -->
+                        <div class="accordion-item">
+                            <h2 class="accordion-header">
+                                <button class="accordion-button" type="button" data-bs-toggle="collapse" data-bs-target="#stepImages">
+                                    <span class="step-title">
+                                        <span class="step-number" id="stepImagesNumber">1</span>
+                                        <i class="bi bi-images me-1"></i> Images & Mode
+                                    </span>
+                                    <span class="step-summary" id="stepImagesSummary">Select reference & stego</span>
                                 </button>
-                            </div>
-                            <div class="form-text">
-                                If PIN was used during encoding
-                            </div>
+                            </h2>
+                            <div id="stepImages" class="accordion-collapse collapse show" data-bs-parent="#decodeAccordion">
+                                <div class="accordion-body">
 
-                        </div>
+                                    <div class="row">
+                                        <div class="col-md-6 mb-3">
+                                            <label class="form-label">
+                                                <i class="bi bi-image me-1"></i> Reference Photo
+                                            </label>
+                                            <div class="drop-zone scan-container" id="refDropZone">
+                                                <input type="file" name="reference_photo" accept="image/*" required id="refPhotoInput">
+                                                <div class="drop-zone-label">
+                                                    <i class="bi bi-cloud-arrow-up fs-3 d-block mb-2 text-muted"></i>
+                                                    <span class="text-muted">Drop image or click</span>
+                                                </div>
+                                                <img class="drop-zone-preview d-none" id="refPreview">
+                                                <div class="scan-overlay"><div class="scan-grid"></div><div class="scan-line"></div></div>
+                                                <div class="scan-corners">
+                                                    <div class="scan-corner tl"></div><div class="scan-corner tr"></div>
+                                                    <div class="scan-corner bl"></div><div class="scan-corner br"></div>
+                                                </div>
+                                                <div class="scan-data-panel">
+                                                    <div class="scan-data-filename"><i class="bi bi-check-circle-fill"></i><span id="refFileName">image.jpg</span></div>
+                                                    <div class="scan-data-row"><span class="scan-status-badge">Hash Acquired</span><span class="scan-data-value" id="refFileSize">--</span></div>
+                                                </div>
+                                            </div>
+                                            <div class="form-text">Same reference photo used for encoding</div>
+                                        </div>
+
+                                        <div class="col-md-6 mb-3">
+                                            <label class="form-label">
+                                                <i class="bi bi-file-earmark-image me-1"></i> Stego Image
+                                            </label>
+                                            <div class="drop-zone pixel-container" id="stegoDropZone">
+                                                <input type="file" name="stego_image" accept="image/*" required id="stegoInput">
+                                                <div class="drop-zone-label">
+                                                    <i class="bi bi-cloud-arrow-up fs-3 d-block mb-2 text-muted"></i>
+                                                    <span class="text-muted">Drop image or click</span>
+                                                </div>
+                                                <img class="drop-zone-preview d-none" id="stegoPreview">
+                                                <div class="pixel-blocks"></div>
+                                                <div class="pixel-scan-line"></div>
+                                                <div class="pixel-corners">
+                                                    <div class="pixel-corner tl"></div><div class="pixel-corner tr"></div>
+                                                    <div class="pixel-corner bl"></div><div class="pixel-corner br"></div>
+                                                </div>
+                                                <div class="pixel-data-panel">
+                                                    <div class="pixel-data-filename"><i class="bi bi-check-circle-fill"></i><span id="stegoFileName">image.png</span></div>
+                                                    <div class="pixel-data-row"><span class="pixel-status-badge">Stego Loaded</span><span class="pixel-data-value" id="stegoFileSize">--</span></div>
+                                                    <div class="pixel-dimensions" id="stegoDims">-- x -- px</div>
+                                                </div>
+                                            </div>
+                                            <div class="form-text">Image containing the hidden message</div>
+                                        </div>
+                                    </div>
+
+                                    <!-- Extraction Mode -->
+                                    <div class="d-flex gap-2 align-items-center flex-wrap mb-2">
+                                        <div class="btn-group" role="group">
+                                            <input type="radio" class="btn-check" name="embed_mode" id="modeAuto" value="auto" checked>
+                                            <label class="btn btn-outline-secondary text-nowrap" for="modeAuto"><i class="bi bi-magic me-1"></i>Auto</label>
+                                            <input type="radio" class="btn-check" name="embed_mode" id="modeLsb" value="lsb">
+                                            <label class="btn btn-outline-secondary text-nowrap" for="modeLsb"><i class="bi bi-grid-3x3-gap me-1"></i>LSB</label>
+                                            <input type="radio" class="btn-check" name="embed_mode" id="modeDct" value="dct" {% if not has_dct %}disabled{% endif %}>
+                                            <label class="btn btn-outline-secondary text-nowrap" for="modeDct" id="dctModeLabel"><i class="bi bi-soundwave me-1"></i>DCT</label>
+                                        </div>
+                                    </div>
+                                    <div class="form-text" id="modeHint">
+                                        <i class="bi bi-lightning me-1"></i>Tries LSB first, then DCT
+                                    </div>
 
-                        <div class="col-md-6 mb-3">
-                            <label class="form-label">
-                                <i class="bi bi-file-earmark-lock me-1"></i> RSA Key
-                            </label>
-                            <ul class="nav nav-tabs nav-tabs-sm mb-2" role="tablist">
-                                <li class="nav-item" role="presentation">
-                                    <button class="nav-link active py-1 px-2 small" data-bs-toggle="tab" data-bs-target="#rsaFileTabDec" type="button">
-                                        <i class="bi bi-file-earmark me-1"></i>.pem File
-                                    </button>
-                                </li>
-                                <li class="nav-item" role="presentation">
-                                    <button class="nav-link py-1 px-2 small" data-bs-toggle="tab" data-bs-target="#rsaQrTabDec" type="button">
-                                        <i class="bi bi-qr-code me-1"></i>QR Code
-                                    </button>
-                                </li>
-                            </ul>
-                            <div class="tab-content">
-                                <div class="tab-pane fade show active" id="rsaFileTabDec" role="tabpanel">
-                                    <input type="file" name="rsa_key" class="form-control form-control-sm" id="rsaKeyInput" accept=".pem,.key,application/x-pem-file">
-                                </div>
-                                <div class="tab-pane fade" id="rsaQrTabDec" role="tabpanel">
-                                  <input type="file" name="rsa_key_qr" class="form-control form-control-sm" id="rsaKeyQrInput" accept="image/*">
-                                    <div class="form-text small">PNG, JPG, or other image of QR code</div>
                                 </div>
                             </div>
-                            <div class="form-text">
-                                If RSA key was used during encoding (file or QR image)
+                        </div>
+
+                        <!-- ================================================================
+                             STEP 2: SECURITY
+                             ================================================================ -->
+                        <div class="accordion-item">
+                            <h2 class="accordion-header">
+                                <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#stepSecurity">
+                                    <span class="step-title">
+                                        <span class="step-number" id="stepSecurityNumber">2</span>
+                                        <i class="bi bi-shield-lock me-1"></i> Security
+                                    </span>
+                                    <span class="step-summary" id="stepSecuritySummary">Passphrase & keys</span>
+                                </button>
+                            </h2>
+                            <div id="stepSecurity" class="accordion-collapse collapse" data-bs-parent="#decodeAccordion">
+                                <div class="accordion-body">
+
+                                    <!-- Passphrase -->
+                                    <div class="mb-3">
+                                        <label class="form-label"><i class="bi bi-chat-quote me-1"></i> Passphrase</label>
+                                        <input type="text" name="passphrase" class="form-control passphrase-input"
+                                               placeholder="e.g., apple forest thunder mountain" required id="passphraseInput">
+                                        <div class="form-text">The passphrase used during encoding</div>
+                                    </div>
+
+                                    <hr class="my-3 opacity-25">
+                                    <div class="small text-muted mb-2">Provide same factors used during encoding</div>
+
+                                    <div class="row">
+                                        <!-- PIN -->
+                                        <div class="col-md-6 mb-2">
+                                            <div class="security-box h-100">
+                                                <label class="form-label"><i class="bi bi-123 me-1"></i> PIN</label>
+                                                <div class="input-group pin-input-container">
+                                                    <input type="password" name="pin" class="form-control" id="pinInput" placeholder="••••••" maxlength="9">
+                                                    <button class="btn btn-outline-secondary" type="button" data-toggle-password="pinInput">
+                                                        <i class="bi bi-eye"></i>
+                                                    </button>
+                                                </div>
+                                                </div>
+                                        </div>
+
+                                        <!-- Channel -->
+                                        <div class="col-md-6 mb-2">
+                                            <div class="security-box h-100">
+                                                <label class="form-label"><i class="bi bi-broadcast me-1"></i> Channel</label>
+                                                <select class="form-select form-select-sm" name="channel_key" id="channelSelectDec">
+                                                    <option value="auto" selected>Auto{% if channel_configured %} (Server){% endif %}</option>
+                                                    <option value="none">Public</option>
+                                                    {% if saved_channel_keys %}
+                                                    <optgroup label="Saved Keys">
+                                                        {% for key in saved_channel_keys %}
+                                                        <option value="{{ key.channel_key }}">{{ key.name }}</option>
+                                                        {% endfor %}
+                                                    </optgroup>
+                                                    {% endif %}
+                                                    <option value="custom">Custom...</option>
+                                                </select>
+                                            </div>
+                                        </div>
+                                    </div>
+
+                                    <!-- Custom Channel Key -->
+                                    <div class="mb-3 d-none" id="channelCustomInputDec">
+                                        <div class="security-box">
+                                            <label class="form-label"><i class="bi bi-key me-1"></i> Custom Channel Key</label>
+                                            <div class="input-group">
+                                                <input type="text" name="channel_key_custom" class="form-control form-control-sm font-monospace"
+                                                       placeholder="XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX" id="channelKeyInputDec">
+                                                <button class="btn btn-outline-secondary btn-sm" type="button" id="channelKeyScanDec" title="Scan QR"><i class="bi bi-camera"></i></button>
+                                            </div>
+                                        </div>
+                                    </div>
+
+                                    <!-- RSA Key -->
+                                    <div class="mb-3">
+                                        <div class="security-box">
+                                            <label class="form-label"><i class="bi bi-file-earmark-lock me-1"></i> RSA Key <span class="text-muted">(if used)</span></label>
+                                            <div class="btn-group w-100 mb-2" role="group">
+                                                <input type="radio" class="btn-check" name="rsa_input_method" id="rsaMethodFile" value="file" checked>
+                                                <label class="btn btn-outline-secondary btn-sm" for="rsaMethodFile"><i class="bi bi-file-earmark me-1"></i>.pem</label>
+                                                <input type="radio" class="btn-check" name="rsa_input_method" id="rsaMethodQr" value="qr">
+                                                <label class="btn btn-outline-secondary btn-sm" for="rsaMethodQr"><i class="bi bi-qr-code me-1"></i>QR</label>
+                                            </div>
+                                            <div id="rsaFileSection">
+                                                <input type="file" name="rsa_key" class="form-control form-control-sm" accept=".pem">
+                                            </div>
+                                            <div id="rsaQrSection" class="d-none d-flex flex-column">
+                                                <input type="hidden" name="rsa_key_pem" id="rsaKeyPem">
+                                                <div class="drop-zone p-2 w-100" id="qrDropZone">
+                                                    <input type="file" name="rsa_key_qr" accept="image/*" id="rsaQrInput">
+                                                    <div class="drop-zone-label text-center">
+                                                        <i class="bi bi-qr-code-scan fs-5 d-block text-muted mb-1"></i>
+                                                        <span class="text-muted small">Drop QR image</span>
+                                                    </div>
+                                                    <div class="qr-scan-container d-none" id="qrCropContainer">
+                                                        <img class="qr-original" id="qrOriginal" alt="Original">
+                                                        <img class="qr-cropped" id="qrCropped" alt="Cropped">
+                                                    </div>
+                                                </div>
+                                                <button type="button" class="btn btn-outline-secondary btn-sm w-100 mt-2" id="rsaQrWebcam">
+                                                    <i class="bi bi-camera me-1"></i>Scan with Camera
+                                                </button>
+                                            </div>
+                                            <div class="input-group input-group-sm mt-2">
+                                                <input type="password" name="rsa_password" class="form-control" id="rsaPasswordInput" placeholder="Key password (if encrypted)">
+                                                <button class="btn btn-outline-secondary" type="button" data-toggle-password="rsaPasswordInput"><i class="bi bi-eye"></i></button>
+                                            </div>
+                                        </div>
+                                    </div>
+
+                                </div>
                             </div>
                         </div>
+
                     </div>
 
-                    <!-- RSA Key Password (shown when key selected) -->
-                    <div class="mb-3 d-none" id="rsaPasswordGroup">
-                        <label class="form-label">
-                            <i class="bi bi-key me-1"></i> RSA Key Password
-                        </label>
-                        <input type="password" name="rsa_password" class="form-control"
-                               placeholder="Password for the .pem file (if encrypted)">
-                        <div class="form-text">
-                            Leave blank if your key file is not password-protected
-                        </div>
+                    <!-- Submit Button -->
+                    <div class="p-3">
+                        <button type="submit" class="btn btn-primary btn-lg w-100" id="decodeBtn">
+                            <i class="bi bi-unlock me-2"></i>Decode
+                        </button>
                     </div>
 
-                    <button type="submit" class="btn btn-primary btn-lg w-100" id="decodeBtn">
-                        <i class="bi bi-unlock me-2"></i>Decode
-                    </button>
                 </form>
-                
                 {% endif %}
             </div>
         </div>
 
         {% if not decoded_message and not decoded_file %}
+        <!-- Troubleshooting Card -->
         <div class="card mt-4">
             <div class="card-body">
                 <h6 class="text-muted mb-3"><i class="bi bi-question-circle me-2"></i>Troubleshooting</h6>
                 <ul class="list-unstyled text-muted small mb-0">
                     <li class="mb-2">
-                        <i class="bi bi-dot"></i>
-                        Make sure you're using the <strong>exact same reference photo</strong> file
+                        <i class="bi bi-check-circle-fill text-success me-1"></i>
+                        Use the <strong>exact same reference photo</strong> (byte-for-byte identical)
                     </li>
                     <li class="mb-2">
-                        <i class="bi bi-dot"></i>
-                        Use the phrase for the <strong>day the message was encoded</strong>, not today
+                        <i class="bi bi-check-circle-fill text-success me-1"></i>
+                        Enter the <strong>exact passphrase</strong> used during encoding
                     </li>
                     <li class="mb-2">
-                        <i class="bi bi-dot"></i>
-                        Provide the <strong>same security factors</strong> (PIN and/or RSA key) used during encoding
-                    </li>
-                    <li class="mb-2">
-                        <i class="bi bi-dot"></i>
+                        <i class="bi bi-exclamation-triangle-fill text-warning me-1"></i>
                         Ensure the stego image hasn't been <strong>resized or recompressed</strong>
                     </li>
                     <li class="mb-0">
-                        <i class="bi bi-dot"></i>
-                        If using an RSA key, make sure the <strong>password is correct</strong>
+                        <i class="bi bi-info-circle-fill text-info me-1"></i>
+                        If auto-detection fails, try specifying <strong>LSB or DCT mode</strong>
                     </li>
                 </ul>
             </div>
@@ -215,158 +417,108 @@
 {% endblock %}
 
 {% block scripts %}
+<script src="{{ url_for('static', filename='js/stegasoo.js') }}"></script>
 <script>
-// Form submit loading state
-document.getElementById('decodeForm')?.addEventListener('submit', function() {
-    const btn = document.getElementById('decodeBtn');
-    btn.innerHTML = '<span class="spinner-border spinner-border-sm me-2"></span>Decoding...';
-    btn.disabled = true;
+// ============================================================================
+// MODE HINT - Dynamic text based on selected extraction mode
+// ============================================================================
+const modeHints = {
+    auto: { icon: 'lightning', text: 'Tries LSB first, then DCT' },
+    lsb: { icon: 'hdd', text: 'For email and direct transfers' },
+    dct: { icon: 'phone', text: 'For social media images' }
+};
+
+document.querySelectorAll('input[name="embed_mode"]').forEach(radio => {
+    radio.addEventListener('change', function() {
+        const hint = document.getElementById('modeHint');
+        const data = modeHints[this.value];
+        if (hint && data) {
+            hint.innerHTML = `<i class="bi bi-${data.icon} me-1"></i>${data.text}`;
+        }
+    });
 });
 
-// Show RSA password field when key is selected (only for .pem files, not QR)
-const rsaKeyInput = document.getElementById('rsaKeyInput');
-const rsaKeyQrInput = document.getElementById('rsaKeyQrInput');
-const rsaPasswordGroup = document.getElementById('rsaPasswordGroup');
+// ============================================================================
+// ACCORDION SUMMARY UPDATES
+// ============================================================================
 
-if (rsaKeyInput) {
-    rsaKeyInput.addEventListener('change', function() {
-        // Show password field only for .pem files
-        rsaPasswordGroup.classList.toggle('d-none', !this.files.length);
-        // Clear QR input if file is selected
-        if (rsaKeyQrInput && this.files.length) {
-            rsaKeyQrInput.value = '';
-        }
-    });
-}
+function updateImagesSummary() {
+    const ref = document.getElementById('refPhotoInput')?.files[0];
+    const stego = document.getElementById('stegoInput')?.files[0];
+    const mode = document.querySelector('input[name="embed_mode"]:checked')?.value?.toUpperCase() || 'AUTO';
+    const summary = document.getElementById('stepImagesSummary');
+    const stepNum = document.getElementById('stepImagesNumber');
 
-if (rsaKeyQrInput) {
-    rsaKeyQrInput.addEventListener('change', function() {
-        // Hide password field for QR codes (they're unencrypted)
-        rsaPasswordGroup.classList.add('d-none');
-        // Clear file input if QR is selected
-        if (rsaKeyInput && this.files.length) {
-            rsaKeyInput.value = '';
-        }
-    });
-}
-
-// Day names for date detection
-const dayNames = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'];
-
-// Detect day from filename
-function detectDayFromFilename(filename) {
-    const dateMatch = filename.match(/_(\d{4})[-]?(\d{2})[-]?(\d{2})/);
-    
-    if (dateMatch) {
-        const [, year, month, day] = dateMatch;
-        const date = new Date(year, month - 1, day);
-        return dayNames[date.getDay()];
-    }
-    return null;
-}
-
-// Update day phrase label
-function updateDayLabel(dayName) {
-    const label = document.getElementById('dayPhraseLabel');
-    if (label && dayName) {
-        label.innerHTML = `<i class="bi bi-chat-quote me-1"></i> ${dayName}'s Phrase`;
-    }
-}
-
-// PIN Toggle
-document.getElementById('togglePin')?.addEventListener('click', function() {
-    const input = document.getElementById('pinInput');
-    const icon = this.querySelector('i');
-    if (input.type === 'password') {
-        input.type = 'text';
-        icon.classList.replace('bi-eye', 'bi-eye-slash');
+    if (ref && stego) {
+        const refName = ref.name.length > 12 ? ref.name.slice(0, 10) + '..' : ref.name;
+        const stegoName = stego.name.length > 12 ? stego.name.slice(0, 10) + '..' : stego.name;
+        summary.textContent = `${refName} + ${stegoName}, ${mode}`;
+        summary.classList.add('has-content');
+        stepNum.classList.add('complete');
+        stepNum.innerHTML = '<i class="bi bi-check"></i>';
+    } else if (ref || stego) {
+        summary.textContent = ref ? ref.name.slice(0, 15) : stego.name.slice(0, 15);
+        summary.classList.remove('has-content');
+        stepNum.classList.remove('complete');
+        stepNum.textContent = '1';
     } else {
-        input.type = 'password';
-        icon.classList.replace('bi-eye-slash', 'bi-eye');
+        summary.textContent = 'Select reference & stego';
+        summary.classList.remove('has-content');
+        stepNum.classList.remove('complete');
+        stepNum.textContent = '1';
     }
-});
+}
 
-// Paste from Clipboard
-document.addEventListener('paste', function(e) {
-    if (!document.getElementById('decodeForm')) return;
+function updateSecuritySummary() {
+    const passphrase = document.getElementById('passphraseInput')?.value || '';
+    const pin = document.getElementById('pinInput')?.value || '';
+    const rsaFile = document.querySelector('input[name="rsa_key"]')?.files[0];
+    const rsaPem = document.getElementById('rsaKeyPem')?.value || '';
+    const summary = document.getElementById('stepSecuritySummary');
+    const stepNum = document.getElementById('stepSecurityNumber');
 
-    const items = e.clipboardData.items;
-    for (let i = 0; i < items.length; i++) {
-        if (items[i].type.indexOf("image") !== -1) {
-            const blob = items[i].getAsFile();
+    const parts = [];
+    if (passphrase.trim()) parts.push('passphrase');
+    if (pin) parts.push('PIN');
+    if (rsaFile || rsaPem) parts.push('RSA');
 
-            const stegoInput = document.querySelector('input[name="stego_image"]');
-            const refInput = document.querySelector('input[name="reference_photo"]');
-            
-            const targetInput = (!stegoInput.files.length) ? stegoInput : refInput;
-            
-            const container = new DataTransfer();
-            container.items.add(blob);
-            targetInput.files = container.files;
-            
-            targetInput.dispatchEvent(new Event('change'));
-            break;
+    if (parts.length > 0) {
+        summary.textContent = parts.join(' + ');
+        summary.classList.add('has-content');
+        if (passphrase.trim()) {
+            stepNum.classList.add('complete');
+            stepNum.innerHTML = '<i class="bi bi-check"></i>';
         }
+    } else {
+        summary.textContent = 'Passphrase & keys';
+        summary.classList.remove('has-content');
+        stepNum.classList.remove('complete');
+        stepNum.textContent = '2';
     }
-});
+}
 
-// Drag & drop with preview
-document.querySelectorAll('.drop-zone').forEach(zone => {
-    const input = zone.querySelector('input[type="file"]');
-    const label = zone.querySelector('.drop-zone-label');
-    const preview = zone.querySelector('.drop-zone-preview');
-    const isStegoZone = zone.id === 'stegoDropZone';
+// Attach listeners
+document.getElementById('refPhotoInput')?.addEventListener('change', updateImagesSummary);
+document.getElementById('stegoInput')?.addEventListener('change', updateImagesSummary);
+document.querySelectorAll('input[name="embed_mode"]').forEach(r => r.addEventListener('change', updateImagesSummary));
 
-    ['dragenter', 'dragover'].forEach(evt => {
-        zone.addEventListener(evt, e => {
-            e.preventDefault();
-            zone.classList.add('drag-over');
-        });
-    });
+document.getElementById('passphraseInput')?.addEventListener('input', updateSecuritySummary);
+document.getElementById('pinInput')?.addEventListener('input', updateSecuritySummary);
+document.querySelector('input[name="rsa_key"]')?.addEventListener('change', updateSecuritySummary);
 
-    ['dragleave', 'drop'].forEach(evt => {
-        zone.addEventListener(evt, e => {
-            e.preventDefault();
-            zone.classList.remove('drag-over');
-        });
-    });
+// ============================================================================
+// MODE SWITCHING
+// ============================================================================
 
-    zone.addEventListener('drop', e => {
-        if (e.dataTransfer.files.length) {
-            input.files = e.dataTransfer.files;
-            const file = e.dataTransfer.files[0];
-            showPreview(file);
+// Apply disabled styling to DCT if not available
+if (document.getElementById('modeDct')?.disabled) {
+    document.getElementById('dctModeLabel')?.classList.add('disabled', 'text-muted');
+}
 
-            if (isStegoZone) {
-                const dayName = detectDayFromFilename(file.name);
-                updateDayLabel(dayName);
-            }
-        }
-    });
+// ============================================================================
+// LOADING STATE
+// ============================================================================
 
-    input.addEventListener('change', function() {
-        if (this.files && this.files[0]) {
-            const file = this.files[0];
-            showPreview(file);
-            
-            if (isStegoZone) {
-                const dayName = detectDayFromFilename(file.name);
-                updateDayLabel(dayName);
-            }
-        }
-    });
-    
-    function showPreview(file) {
-        if (!file.type.startsWith('image/')) return;
-        
-        const reader = new FileReader();
-        reader.onload = e => {
-            preview.src = e.target.result;
-            preview.classList.remove('d-none');
-            label.innerHTML = '<i class="bi bi-check-circle text-success me-1"></i>' + file.name;
-        };
-        reader.readAsDataURL(file);
-    }
-});
+Stegasoo.initFormLoading('decodeForm', 'decodeBtn', 'Decoding...');
 </script>
 {% endblock %}

frontends/web/templates/encode_result.html

@@ -7,7 +7,9 @@
     <div class="col-lg-6">
         <div class="card">
             <div class="card-header bg-success text-white">
-                <h5 class="mb-0"><i class="bi bi-check-circle me-2"></i>Encoding Successful!</h5>
+                <h5 class="mb-0">
+                    <i class="bi bi-check-circle me-2"></i>Encoding Successful!
+                </h5>
             </div>
             <div class="card-body text-center">
                 <div class="my-4">
@@ -34,6 +36,81 @@
                     <code class="fs-5">{{ filename }}</code>
                 </div>
                 
+                <!-- Mode and format badges -->
+                <div class="mb-4">
+                    {% if embed_mode == 'dct' %}
+                        <span class="badge bg-info fs-6">
+                            <i class="bi bi-soundwave me-1"></i>DCT Mode
+                        </span>
+                        
+                        <!-- Color mode badge (v3.0.1) -->
+                        {% if color_mode == 'color' %}
+                        <span class="badge bg-success fs-6 ms-1">
+                            <i class="bi bi-palette-fill me-1"></i>Color
+                        </span>
+                        {% else %}
+                        <span class="badge bg-secondary fs-6 ms-1">
+                            <i class="bi bi-circle-half me-1"></i>Grayscale
+                        </span>
+                        {% endif %}
+                        
+                        <!-- Output format badge -->
+                        {% if output_format == 'jpeg' %}
+                        <span class="badge bg-warning text-dark fs-6 ms-1">
+                            <i class="bi bi-file-earmark-richtext me-1"></i>JPEG
+                        </span>
+                        <div class="small text-muted mt-2">
+                            {% if color_mode == 'color' %}
+                            Color JPEG, frequency domain embedding (Q=95)
+                            {% else %}
+                            Grayscale JPEG, frequency domain embedding (Q=95)
+                            {% endif %}
+                        </div>
+                        {% else %}
+                        <span class="badge bg-primary fs-6 ms-1">
+                            <i class="bi bi-file-earmark-image me-1"></i>PNG
+                        </span>
+                        <div class="small text-muted mt-2">
+                            {% if color_mode == 'color' %}
+                            Color PNG, frequency domain embedding (lossless)
+                            {% else %}
+                            Grayscale PNG, frequency domain embedding (lossless)
+                            {% endif %}
+                        </div>
+                        {% endif %}
+                        
+                    {% else %}
+                        <span class="badge bg-primary fs-6">
+                            <i class="bi bi-grid-3x3-gap me-1"></i>LSB Mode
+                        </span>
+                        <span class="badge bg-success fs-6 ms-1">
+                            <i class="bi bi-palette-fill me-1"></i>Full Color
+                        </span>
+                        <span class="badge bg-primary fs-6 ms-1">
+                            <i class="bi bi-file-earmark-image me-1"></i>PNG
+                        </span>
+                        <div class="small text-muted mt-2">Full color PNG, spatial LSB embedding</div>
+                    {% endif %}
+                    
+                    <!-- Channel info (v4.0.0) -->
+                    <div class="mt-3">
+                        {% if channel_mode == 'private' %}
+                        <span class="badge bg-warning text-dark fs-6">
+                            <i class="bi bi-shield-lock me-1"></i>Private Channel
+                        </span>
+                        {% if channel_fingerprint %}
+                        <div class="small text-muted mt-1">
+                            <code>{{ channel_fingerprint }}</code>
+                        </div>
+                        {% endif %}
+                        {% else %}
+                        <span class="badge bg-info fs-6">
+                            <i class="bi bi-globe me-1"></i>Public Channel
+                        </span>
+                        {% endif %}
+                    </div>
+                </div>
+                
                 <div class="d-grid gap-2">
                     <a href="{{ url_for('encode_download', file_id=file_id) }}" 
                        class="btn btn-primary btn-lg" id="downloadBtn">
@@ -53,7 +130,20 @@
                     <ul class="mb-0 mt-2">
                         <li>This file expires in <strong>5 minutes</strong></li>
                         <li>Do <strong>not</strong> resize or recompress the image</li>
+                        {% if embed_mode == 'dct' and output_format == 'jpeg' %}
+                        <li>JPEG format is lossy - avoid re-saving or editing</li>
+                        {% else %}
                         <li>PNG format preserves your hidden data</li>
+                        {% endif %}
+                        {% if embed_mode == 'dct' %}
+                        <li>Recipient needs <strong>DCT mode</strong> or <strong>Auto</strong> detection to decode</li>
+                        {% if color_mode == 'color' %}
+                        <li>Color preserved - extraction works on both color and grayscale</li>
+                        {% endif %}
+                        {% endif %}
+                        {% if channel_mode == 'private' %}
+                        <li><i class="bi bi-shield-lock text-warning me-1"></i>Recipient needs the <strong>same channel key</strong> to decode</li>
+                        {% endif %}
                     </ul>
                 </div>
                 
@@ -72,13 +162,14 @@
 const shareBtn = document.getElementById('shareBtn');
 const fileUrl = "{{ url_for('encode_file_route', file_id=file_id, _external=True) }}";
 const fileName = "{{ filename }}";
+const mimeType = "{{ 'image/jpeg' if embed_mode == 'dct' and output_format == 'jpeg' else 'image/png' }}";
 
 if (navigator.share && navigator.canShare) {
     // Check if we can share files
     fetch(fileUrl)
         .then(response => response.blob())
         .then(blob => {
-            const file = new File([blob], fileName, { type: 'image/png' });
+            const file = new File([blob], fileName, { type: mimeType });
             if (navigator.canShare({ files: [file] })) {
                 shareBtn.style.display = 'block';
                 shareBtn.addEventListener('click', async () => {

frontends/web/templates/generate.html

@@ -3,7 +3,7 @@
 {% block title %}Generate Credentials - Stegasoo{% endblock %}
 
 {% block content %}
-<div class="row justify-content-center">
+<div class="row justify-content-center" data-page="generate">
     <div class="col-lg-8">
         <div class="card">
             <div class="card-header">
@@ -14,14 +14,18 @@
                 <!-- Generation Form -->
                 <form method="POST">
                     <div class="mb-4">
-                        <label class="form-label">Words per Phrase</label>
-                        <input type="range" class="form-range" name="words_per_phrase" 
-                               min="3" max="12" value="3" id="wordsRange">
+                        <label class="form-label">Words per Passphrase</label>
+                        <input type="range" class="form-range" name="words_per_passphrase" 
+                               min="{{ min_passphrase_words }}" max="12" value="{{ default_passphrase_words }}" id="wordsRange">
                         <div class="d-flex justify-content-between small text-muted">
-                            <span>3 (33 bits)</span>
-                            <span id="wordsValue" class="text-primary fw-bold">3 words (~33 bits)</span>
+                            <span>{{ min_passphrase_words }} (~33 bits)</span>
+                            <span id="wordsValue" class="text-primary fw-bold">{{ default_passphrase_words }} words (~44 bits)</span>
                             <span>12 (132 bits)</span>
                         </div>
+                        <div class="form-text">
+                            <i class="bi bi-shield-check me-1"></i>
+                            Recommended: <strong>{{ recommended_passphrase_words }}+ words</strong> for good security
+                        </div>
                     </div>
                     
                     <hr>
@@ -58,20 +62,60 @@
                             </div>
                             <div class="mt-2 d-none" id="rsaOptions">
                                 <label class="form-label small">Key Size</label>
-                                <select name="rsa_bits" class="form-select form-select-sm">
+                                <select name="rsa_bits" class="form-select form-select-sm" id="rsaBitsSelect">
                                     <option value="2048" selected>2048 bits (~128 bits entropy)</option>
                                     <option value="3072">3072 bits (~128 bits entropy)</option>
                                     <option value="4096">4096 bits (~128 bits entropy)</option>
                                 </select>
+                                <div class="form-text text-warning d-none" id="rsaQrWarning">
+                                    <i class="bi bi-exclamation-triangle me-1"></i>QR code unavailable for keys &gt;3072 bits
+                                </div>
                             </div>
                         </div>
                     </div>
                     
-                    <button type="submit" class="btn btn-primary btn-lg w-100 mt-3">
+                    <button type="submit" class="btn btn-primary btn-lg w-100 mt-4">
                         <i class="bi bi-shuffle me-2"></i>Generate Credentials
                     </button>
                 </form>
 
+                <!-- Channel Key Accordion (Advanced) -->
+                <div class="accordion mt-4" id="advancedAccordion">
+                    <div class="accordion-item bg-dark">
+                        <h2 class="accordion-header">
+                            <button class="accordion-button collapsed bg-dark text-light" type="button"
+                                    data-bs-toggle="collapse" data-bs-target="#channelKeyCollapse">
+                                <i class="bi bi-broadcast me-2"></i>Channel Key
+                                <span class="badge bg-info ms-2">Advanced</span>
+                            </button>
+                        </h2>
+                        <div id="channelKeyCollapse" class="accordion-collapse collapse" data-bs-parent="#advancedAccordion">
+                            <div class="accordion-body">
+                                <p class="text-muted small mb-3">
+                                    Channel keys create private encoding channels. Only users with the same key can decode each other's images.
+                                    <a href="{{ url_for('about') }}#channel-keys" class="text-info">Learn more</a>
+                                </p>
+
+                                <div class="input-group">
+                                    <span class="input-group-text"><i class="bi bi-key"></i></span>
+                                    <input type="text" class="form-control font-monospace" id="channelKeyGenerated"
+                                           placeholder="Click Generate to create a key" readonly>
+                                    <button class="btn btn-outline-primary" type="button" id="generateChannelKeyBtn" title="Generate Channel Key">
+                                        <i class="bi bi-shuffle"></i>
+                                    </button>
+                                    <button class="btn btn-outline-secondary" type="button" id="copyChannelKeyBtn" disabled title="Copy to clipboard">
+                                        <i class="bi bi-clipboard"></i>
+                                    </button>
+                                </div>
+                                <div class="form-text mt-2">
+                                    <i class="bi bi-info-circle me-1"></i>
+                                    After generating, configure this key in your server's environment or use <strong>Custom</strong> channel mode when encoding/decoding.
+                                </div>
+                            </div>
+                        </div>
+                    </div>
+                </div>
+                
                 {% else %}
                 <!-- Generated Credentials Display -->
                 <div class="alert alert-warning">
@@ -106,25 +150,57 @@
                 {% endif %}
                 
                 <div class="mb-4">
-                    <h6 class="text-muted"><i class="bi bi-chat-quote me-2"></i>DAILY PHRASES</h6>
-                    <div class="table-responsive">
-                        <table class="table table-dark table-striped mb-0">
-                            <tbody>
-                                {% for day in days %}
-                                <tr>
-                                    <td class="text-muted" style="width: 100px;">{{ day }}</td>
-                                    <td>
-                                        <span class="font-monospace phrase-display" id="phrase{{ loop.index }}">{{ phrases[day] }}</span>
-                                    </td>
-                                </tr>
-                                {% endfor %}
-                            </tbody>
-                        </table>
+                    <h6 class="text-muted">
+                        <i class="bi bi-chat-quote me-2"></i>PASSPHRASE
+                    </h6>
+                    
+                    <div class="passphrase-container">
+                        <div class="passphrase-display" id="passphraseDisplay">
+                            <code class="passphrase-text">{{ passphrase }}</code>
+                        </div>
+                        
+                        <div class="passphrase-buttons mt-3">
+                            <button type="button" class="btn btn-sm btn-outline-secondary me-2" onclick="togglePassphraseVisibility()">
+                                <i class="bi bi-eye-slash" id="passphraseToggleIcon"></i>
+                                <span id="passphraseToggleText">Hide</span>
+                            </button>
+                            <button type="button" class="btn btn-sm btn-outline-secondary me-2" onclick="copyPassphrase()">
+                                <i class="bi bi-clipboard" id="passphraseCopyIcon"></i>
+                                <span id="passphraseCopyText">Copy</span>
+                            </button>
+                            <button type="button" class="btn btn-sm btn-outline-primary" onclick="toggleMemoryAid()">
+                                <i class="bi bi-lightbulb" id="memoryAidIcon"></i>
+                                <span id="memoryAidText">Memory Aid</span>
+                            </button>
+                        </div>
                     </div>
-                    <div class="text-end mt-2">
-                        <button class="btn btn-sm btn-outline-secondary" onclick="toggleAllPhrases()">
-                            <i class="bi bi-eye-slash me-1"></i>Toggle Visibility
-                        </button>
+                    
+                    <!-- Memory Aid Story -->
+                    <div class="memory-aid-container mt-3 d-none" id="memoryAidContainer">
+                        <div class="card bg-dark border-primary">
+                            <div class="card-header bg-primary text-white">
+                                <i class="bi bi-book me-2"></i>Memory Story
+                            </div>
+                            <div class="card-body">
+                                <p class="memory-story mb-3" id="memoryStory">
+                                    <!-- Story will be generated by JavaScript -->
+                                </p>
+                                <div class="form-text">
+                                    <i class="bi bi-info-circle me-1"></i>
+                                    This story is generated from your passphrase to help you remember it.
+                                    The words appear in order within the narrative.
+                                </div>
+                                <button type="button" class="btn btn-sm btn-outline-light mt-2" onclick="regenerateStory()">
+                                    <i class="bi bi-arrow-repeat me-1"></i>Generate Different Story
+                                </button>
+                            </div>
+                        </div>
+                    </div>
+                    
+                    <div class="alert alert-info mt-3 mb-0">
+                        <small class="text-muted">
+                            ({{ words_per_passphrase }} words = ~{{ passphrase_entropy }} bits entropy)
+                        </small>
                     </div>
                 </div>
                 
@@ -229,8 +305,9 @@
                     <div class="row text-center">
                         <div class="col">
                             <div class="p-2 bg-dark rounded">
-                                <div class="small text-muted">Phrase</div>
-                                <div class="fs-5 text-info">{{ phrase_entropy }} bits</div>
+                                <div class="small text-muted">Passphrase</div>
+                                <div class="fs-5 text-info">{{ passphrase_entropy }} bits</div>
+                                <div class="small text-muted">{{ words_per_passphrase }} words</div>
                             </div>
                         </div>
                         {% if pin_entropy %}
@@ -279,7 +356,7 @@
                 <h6 class="text-muted mb-3"><i class="bi bi-info-circle me-2"></i>About Credentials</h6>
                 <ul class="small text-muted mb-0">
                     <li class="mb-2">
-                        <strong>Daily phrases</strong> rotate each day of the week for forward secrecy
+                        <strong>Passphrase</strong> is a single phrase you use each time
                     </li>
                     <li class="mb-2">
                         <strong>PIN</strong> is static and adds another factor both parties must know
@@ -343,147 +420,124 @@
     min-width: 80px;
 }
 
+/* Passphrase Container */
+.passphrase-container {
+    background: linear-gradient(145deg, #1e1e2e 0%, #2d2d44 100%);
+    border: 1px solid #0dcaf0;
+    border-radius: 16px;
+    padding: 1.5rem 2rem;
+    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3), 0 0 40px rgba(13, 202, 240, 0.1);
+}
+
+.passphrase-display {
+    background: rgba(0, 0, 0, 0.4);
+    border: 1px solid rgba(13, 202, 240, 0.3);
+    border-radius: 12px;
+    padding: 1.5rem;
+    text-align: center;
+    transition: filter 0.3s ease;
+}
+
+.passphrase-display.blurred {
+    filter: blur(8px);
+    user-select: none;
+}
+
+.passphrase-text {
+    font-family: 'Consolas', 'Monaco', monospace;
+    font-size: 1.5rem;
+    font-weight: bold;
+    color: #0dcaf0;
+    text-shadow: 0 0 10px rgba(13, 202, 240, 0.5);
+    word-wrap: break-word;
+    display: block;
+    line-height: 1.6;
+}
+
+.passphrase-buttons {
+    display: flex;
+    justify-content: center;
+    flex-wrap: wrap;
+    gap: 0.5rem;
+}
+
+.passphrase-buttons .btn {
+    min-width: 100px;
+}
+
+/* Memory Aid */
+.memory-story {
+    font-size: 1.1rem;
+    line-height: 1.8;
+    color: #e9ecef;
+}
+
+.memory-story .passphrase-word {
+    font-weight: bold;
+    color: #0dcaf0;
+    text-decoration: underline;
+    text-decoration-style: wavy;
+    text-decoration-color: rgba(13, 202, 240, 0.5);
+}
+
 /* Responsive */
 @media (max-width: 576px) {
-    .pin-container {
-        padding: 1rem 1.25rem;
+    .pin-container, .passphrase-container {
+        padding: 1rem 0.75rem;
     }
 
     .pin-digit-box {
-        width: 2.25rem;
-        height: 2.75rem;
-        font-size: 1.25rem;
+        width: 1.9rem;
+        height: 2.4rem;
+        font-size: 1.15rem;
     }
 
     .pin-digits-row {
-        gap: 0.35rem;
+        gap: 0.25rem;
+    }
+    
+    .passphrase-text {
+        font-size: 1.2rem;
+    }
+    
+    .memory-story {
+        font-size: 1rem;
     }
 }
 </style>
 {% endblock %}
 
 {% block scripts %}
+<script src="{{ url_for('static', filename='js/stegasoo.js') }}"></script>
+<script src="{{ url_for('static', filename='js/generate.js') }}"></script>
+{% if generated %}
 <script>
-// Words range slider
-const wordsRange = document.getElementById('wordsRange');
-const wordsValue = document.getElementById('wordsValue');
+// Page-specific data from Jinja
+const passphraseWords = '{{ passphrase|default("", true) }}'.split(' ').filter(w => w.length > 0);
 
-if (wordsRange) {
-    wordsRange.addEventListener('input', function() {
-        const bits = this.value * 11;
-        wordsValue.textContent = `${this.value} words (~${bits} bits)`;
-    });
-}
-
-// Toggle PIN/RSA options
-const usePinCheck = document.getElementById('usePinCheck');
-const useRsaCheck = document.getElementById('useRsaCheck');
-const pinOptions = document.getElementById('pinOptions');
-const rsaOptions = document.getElementById('rsaOptions');
-
-if (usePinCheck) {
-    usePinCheck.addEventListener('change', function() {
-        pinOptions.classList.toggle('d-none', !this.checked);
-    });
-}
-
-if (useRsaCheck) {
-    useRsaCheck.addEventListener('change', function() {
-        rsaOptions.classList.toggle('d-none', !this.checked);
-    });
-}
-
-// PIN visibility toggle
-let pinHidden = false;
-function togglePinVisibility() {
-    const pinDigits = document.getElementById('pinDigits');
-    const icon = document.getElementById('pinToggleIcon');
-    const text = document.getElementById('pinToggleText');
-    
-    pinHidden = !pinHidden;
-    
-    if (pinHidden) {
-        pinDigits.classList.add('blurred');
-        icon.className = 'bi bi-eye';
-        text.textContent = 'Show';
-    } else {
-        pinDigits.classList.remove('blurred');
-        icon.className = 'bi bi-eye-slash';
-        text.textContent = 'Hide';
-    }
-}
-
-// Copy PIN
 function copyPin() {
-    const pin = '{{ pin|default("", true) }}';
-    const icon = document.getElementById('pinCopyIcon');
-    const text = document.getElementById('pinCopyText');
-    
-    navigator.clipboard.writeText(pin).then(() => {
-        icon.className = 'bi bi-check';
-        text.textContent = 'Copied!';
-        setTimeout(() => {
-            icon.className = 'bi bi-clipboard';
-            text.textContent = 'Copy';
-        }, 2000);
-    });
+    Stegasoo.copyToClipboard(
+        '{{ pin|default("", true) }}',
+        document.getElementById('pinCopyIcon'),
+        document.getElementById('pinCopyText')
+    );
 }
 
-// Toggle all phrases visibility
-let phrasesHidden = false;
-function toggleAllPhrases() {
-    phrasesHidden = !phrasesHidden;
-    document.querySelectorAll('.phrase-display').forEach(el => {
-        el.style.filter = phrasesHidden ? 'blur(8px)' : 'none';
-    });
+function copyPassphrase() {
+    Stegasoo.copyToClipboard(
+        '{{ passphrase|default("", true) }}',
+        document.getElementById('passphraseCopyIcon'),
+        document.getElementById('passphraseCopyText')
+    );
 }
 
-// Print QR code
-function printQrCode() {
-    const qrImg = document.getElementById('qrCodeImage');
-    if (!qrImg) return;
+function toggleMemoryAid() {
+    StegasooGenerate.toggleMemoryAid(passphraseWords);
+}
 
-    const printWindow = window.open('', '_blank');
-    printWindow.document.write(`
-        <!DOCTYPE html>
-        <html>
-        <head>
-            <title>Stegasoo RSA Key QR Code</title>
-            <style>
-                body { 
-                    display: flex; 
-                    flex-direction: column;
-                    align-items: center; 
-                    justify-content: center; 
-                    min-height: 100vh;
-                    margin: 0;
-                    font-family: sans-serif;
-                }
-                img { max-width: 400px; }
-                .warning {
-                    margin-top: 20px;
-                    padding: 10px;
-                    border: 2px solid #ff9800;
-                    background: #fff3e0;
-                    max-width: 400px;
-                    text-align: center;
-                    font-size: 12px;
-                }
-            </style>
-        </head>
-        <body>
-            <h2>Stegasoo RSA Private Key</h2>
-            <img src="${qrImg.src}" alt="RSA Key QR Code">
-            <div class="warning">
-                <strong>⚠️ SECURITY WARNING</strong><br>
-                This QR code contains your unencrypted RSA private key.<br>
-                Store securely and destroy after use.
-            </div>
-            <script>window.onload = function() { window.print(); }<\/script>
-        </body>
-        </html>
-    `);
-    printWindow.document.close();
+function regenerateStory() {
+    StegasooGenerate.regenerateStory(passphraseWords);
 }
 </script>
+{% endif %}
 {% endblock %}

frontends/web/templates/index.html

@@ -3,106 +3,64 @@
 {% block title %}Stegasoo - Secure Steganography{% endblock %}
 
 {% block content %}
-<div class="text-center mb-5">
-    <img src="{{ url_for('static', filename='logo.svg') }}" alt="Stegasoo" height="120" class="mb-3">
-    <h1 class="display-4 fw-bold">Stegasoo</h1>
-    <p class="lead text-muted">Create hidden encrypted messages in images and photos using advanced steganography.</p>
-</div>
+<style>
+.home-icon {
+    display: inline-flex;
+    flex-direction: column;
+    align-items: center;
+    padding: 1rem 1.5rem;
+    text-decoration: none;
+    transition: all 0.15s ease;
+}
+.home-icon i {
+    font-size: 2.5rem;
+    color: #fff;
+    margin-bottom: 0.5rem;
+    filter: drop-shadow(0 3px 2px rgba(0, 0, 0, 0.9));
+    transition: all 0.15s ease;
+}
+.home-icon span {
+    font-size: 0.7rem;
+    font-weight: 500;
+    text-transform: uppercase;
+    letter-spacing: 1px;
+    color: rgba(255, 255, 255, 0.5);
+    opacity: 0;
+    transform: translateY(-8px);
+    transition: all 0.15s ease;
+}
+.home-icon:hover i {
+    color: #e5d058;
+    transform: translateY(-3px);
+    filter: drop-shadow(0 5px 4px rgba(0, 0, 0, 0.8));
+}
+.home-icon:hover span {
+    opacity: 1;
+    transform: translateY(0);
+    color: #e5d058;
+}
+</style>
 
-<div class="row g-4 mb-5">
-    <!-- Encode Card -->
-    <div class="col-md-4">
-        <a href="/encode" class="text-decoration-none card-link">
-            <div class="card h-100 feature-card">
-                <div class="card-header text-center py-3">
-                    <i class="bi bi-lock-fill fs-1 embossed-icon"></i>
-                </div>
-                <div class="card-body text-center">
-                    <h5 class="card-title">Encode Message</h5>
-                    <p class="card-text text-muted">
-                        Hide your secret message inside an innocent-looking image using your daily phrase + PIN.
-                    </p>
-                </div>
-            </div>
-        </a>
-    </div>
+<div class="d-flex flex-column align-items-center justify-content-center" style="min-height: 70vh;">
 
-    <!-- Decode Card -->
-    <div class="col-md-4">
-        <a href="/decode" class="text-decoration-none card-link">
-            <div class="card h-100 feature-card">
-                <div class="card-header text-center py-3">
-                    <i class="bi bi-unlock-fill fs-1 embossed-icon"></i>
-                </div>
-                <div class="card-body text-center">
-                    <h5 class="card-title">Decode Message</h5>
-                    <p class="card-text text-muted">
-                        Extract and decrypt hidden messages from Stegasoo-encoded images using your credentials.
-                    </p>
-                </div>
-            </div>
-        </a>
-    </div>
- 
-    <!-- Generate Card -->
-    <div class="col-md-4">
-        <a href="/generate" class="text-decoration-none card-link">
-            <div class="card h-100 feature-card">
-                <div class="card-header text-center py-3">
-                    <i class="bi bi-key-fill fs-1 embossed-icon"></i>
-                </div>
-                <div class="card-body text-center">
-                    <h5 class="card-title">Generate Keys</h5>
-                    <p class="card-text text-muted">
-                        Create your weekly phrase card and PIN. Memorize 21 words + 6 digits for maximum security.
-                    </p>
-                </div>
-            </div>
-        </a>
-    </div>
-</div>
-
-<div class="card">
-    <div class="card-header">
-        <h5 class="mb-0"><i class="bi bi-diagram-3 me-2"></i>How It Works</h5>
-    </div>
-    <div class="card-body">
-        <div class="row">
-            <div class="col-md-6">
-                <h6 class="text-primary"><i class="bi bi-1-circle me-2"></i>Key Components</h6>
-                <ul class="list-unstyled">
-                    <li class="mb-2">
-                        <i class="bi bi-image text-info me-2"></i>
-                        <strong>Reference Photo</strong> — Any photo you and recipient both have
-                    </li>
-                    <li class="mb-2">
-                        <i class="bi bi-chat-quote text-info me-2"></i>
-                        <strong>Day Phrase</strong> — 3 words, different each day of the week
-                    </li>
-                    <li class="mb-2">
-                        <i class="bi bi-123 text-info me-2"></i>
-                        <strong>Static PIN</strong> — 6 digits, same every day
-                    </li>
-                </ul>
-            </div>
-            <div class="col-md-6">
-                <h6 class="text-primary"><i class="bi bi-2-circle me-2"></i>Security Features</h6>
-                <ul class="list-unstyled">
-                    <li class="mb-2">
-                        <i class="bi bi-shield-check text-success me-2"></i>
-                        Argon2id memory-hard key derivation (256MB)
-                    </li>
-                    <li class="mb-2">
-                        <i class="bi bi-shuffle text-success me-2"></i>
-                        Pseudo-random pixel selection (defeats steganalysis)
-                    </li>
-                    <li class="mb-2">
-                        <i class="bi bi-lock text-success me-2"></i>
-                        AES-256-GCM authenticated encryption
-                    </li>
-                </ul>
-            </div>
+    <!-- Hero -->
+    <div class="d-flex align-items-center mb-4" style="gap: 8px;">
+        <div class="position-relative">
+            <img src="{{ url_for('static', filename='logo.svg') }}" alt="Stegasoo" height="80">
+            <span class="badge bg-success position-absolute" style="bottom: 1px; left: -6px; font-size: 0.6rem;">v4.1</span>
+        </div>
+        <div>
+            <h1 class="display-5 fw-bold title-gold mb-0">Stegasoo</h1>
+            <p class="text-muted mb-0 small" style="margin-top: 3px; padding-left: 3px; font-size: 0.85rem; text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);">Hide encrypted data in plain sight.</p>
         </div>
     </div>
+
+    <!-- Action Icons -->
+    <div class="d-flex gap-4">
+        <a href="/encode" class="home-icon"><i class="bi bi-lock-fill"></i><span>Encode</span></a>
+        <a href="/decode" class="home-icon"><i class="bi bi-unlock-fill"></i><span>Decode</span></a>
+        <a href="/generate" class="home-icon"><i class="bi bi-key-fill"></i><span>Generate</span></a>
+    </div>
+
 </div>
 {% endblock %}

frontends/web/templates/login.html

@@ -0,0 +1,55 @@
+{% extends "base.html" %}
+
+{% block title %}Login - Stegasoo{% endblock %}
+
+{% block content %}
+<div class="row justify-content-center">
+    <div class="col-md-5 col-lg-4">
+        <div class="card">
+            <div class="card-header text-center">
+                <i class="bi bi-shield-lock fs-1 d-block mb-2"></i>
+                <h5 class="mb-0">Login</h5>
+            </div>
+            <div class="card-body">
+                <form method="POST" action="{{ url_for('login') }}">
+                    <div class="mb-3">
+                        <label class="form-label">
+                            <i class="bi bi-person me-1"></i> Username
+                        </label>
+                        <input type="text" name="username" class="form-control"
+                               placeholder="Enter your username" required autofocus>
+                    </div>
+
+                    <div class="mb-4">
+                        <label class="form-label">
+                            <i class="bi bi-key me-1"></i> Password
+                        </label>
+                        <div class="input-group">
+                            <input type="password" name="password" class="form-control"
+                                   id="passwordInput" required>
+                            <button class="btn btn-outline-secondary" type="button"
+                                    onclick="togglePassword('passwordInput', this)">
+                                <i class="bi bi-eye"></i>
+                            </button>
+                        </div>
+                    </div>
+
+                    <button type="submit" class="btn btn-primary w-100">
+                        <i class="bi bi-box-arrow-in-right me-2"></i>Login
+                    </button>
+                </form>
+
+                <div class="text-center mt-3">
+                    <a href="{{ url_for('recover') }}" class="text-muted small">
+                        <i class="bi bi-key me-1"></i> Forgot password?
+                    </a>
+                </div>
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script src="{{ url_for('static', filename='js/auth.js') }}"></script>
+{% endblock %}

frontends/web/templates/recover.html

@@ -0,0 +1,129 @@
+{% extends "base.html" %}
+
+{% block title %}Password Recovery - Stegasoo{% endblock %}
+
+{% block content %}
+<div class="row justify-content-center">
+    <div class="col-md-6 col-lg-5">
+        <div class="card">
+            <div class="card-header text-center">
+                <i class="bi bi-shield-lock fs-1 d-block mb-2"></i>
+                <h5 class="mb-0">Password Recovery</h5>
+            </div>
+            <div class="card-body">
+                <p class="text-muted text-center mb-4">
+                    Enter your recovery key to reset your admin password.
+                </p>
+
+                <!-- Extract from Stego Backup -->
+                <div class="accordion mb-3" id="stegoAccordion">
+                    <div class="accordion-item">
+                        <h2 class="accordion-header">
+                            <button class="accordion-button collapsed py-2" type="button"
+                                    data-bs-toggle="collapse" data-bs-target="#stegoExtract">
+                                <i class="bi bi-incognito me-2"></i>
+                                <small>Extract from stego backup</small>
+                            </button>
+                        </h2>
+                        <div id="stegoExtract" class="accordion-collapse collapse"
+                             data-bs-parent="#stegoAccordion">
+                            <div class="accordion-body py-2">
+                                <form method="POST" action="{{ url_for('recover_from_stego') }}"
+                                      enctype="multipart/form-data">
+                                    <div class="mb-2">
+                                        <label class="form-label small mb-1">Stego Image</label>
+                                        <input type="file" name="stego_image"
+                                               class="form-control form-control-sm"
+                                               accept="image/*" required>
+                                    </div>
+                                    <div class="mb-2">
+                                        <label class="form-label small mb-1">Original Reference</label>
+                                        <input type="file" name="reference_image"
+                                               class="form-control form-control-sm"
+                                               accept="image/*" required>
+                                    </div>
+                                    <button type="submit" class="btn btn-sm btn-outline-primary w-100">
+                                        <i class="bi bi-unlock me-1"></i> Extract Key
+                                    </button>
+                                </form>
+                            </div>
+                        </div>
+                    </div>
+                </div>
+
+                <form method="POST" action="{{ url_for('recover') }}" id="recoverForm">
+                    <!-- Recovery Key Input -->
+                    <div class="mb-3">
+                        <label class="form-label">
+                            <i class="bi bi-key-fill me-1"></i> Recovery Key
+                        </label>
+                        <textarea name="recovery_key" class="form-control font-monospace"
+                                  rows="2" required
+                                  placeholder="XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX"
+                                  style="font-size: 0.9em;">{{ prefilled_key or '' }}</textarea>
+                        <div class="form-text">
+                            Paste your full recovery key (with or without dashes)
+                        </div>
+                    </div>
+
+                    <hr>
+
+                    <!-- New Password -->
+                    <div class="mb-3">
+                        <label class="form-label">
+                            <i class="bi bi-lock me-1"></i> New Password
+                        </label>
+                        <div class="input-group">
+                            <input type="password" name="new_password" class="form-control"
+                                   id="passwordInput" required minlength="8">
+                            <button class="btn btn-outline-secondary" type="button"
+                                    onclick="togglePassword('passwordInput', this)">
+                                <i class="bi bi-eye"></i>
+                            </button>
+                        </div>
+                        <div class="form-text">Minimum 8 characters</div>
+                    </div>
+
+                    <!-- Confirm Password -->
+                    <div class="mb-4">
+                        <label class="form-label">
+                            <i class="bi bi-lock-fill me-1"></i> Confirm Password
+                        </label>
+                        <div class="input-group">
+                            <input type="password" name="new_password_confirm" class="form-control"
+                                   id="passwordConfirmInput" required minlength="8">
+                            <button class="btn btn-outline-secondary" type="button"
+                                    onclick="togglePassword('passwordConfirmInput', this)">
+                                <i class="bi bi-eye"></i>
+                            </button>
+                        </div>
+                    </div>
+
+                    <button type="submit" class="btn btn-primary w-100">
+                        <i class="bi bi-check-lg me-2"></i>Reset Password
+                    </button>
+                </form>
+
+                <div class="text-center mt-3">
+                    <a href="{{ url_for('login') }}" class="text-muted small">
+                        <i class="bi bi-arrow-left me-1"></i> Back to Login
+                    </a>
+                </div>
+            </div>
+        </div>
+
+        <div class="alert alert-warning mt-4 small">
+            <i class="bi bi-exclamation-triangle me-2"></i>
+            <strong>Note:</strong> This will reset the admin password. If you don't have a valid recovery key,
+            you'll need to delete the database and reconfigure Stegasoo.
+        </div>
+    </div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script src="{{ url_for('static', filename='js/auth.js') }}"></script>
+<script>
+StegasooAuth.initPasswordConfirmation('recoverForm', 'passwordInput', 'passwordConfirmInput');
+</script>
+{% endblock %}

frontends/web/templates/regenerate_recovery.html

@@ -0,0 +1,183 @@
+{% extends "base.html" %}
+
+{% block title %}Regenerate Recovery Key - Stegasoo{% endblock %}
+
+{% block content %}
+<div class="row justify-content-center">
+    <div class="col-md-8 col-lg-6">
+        <div class="card">
+            <div class="card-header text-center">
+                <i class="bi bi-arrow-repeat fs-1 d-block mb-2"></i>
+                <h5 class="mb-0">{{ 'Regenerate' if has_existing else 'Generate' }} Recovery Key</h5>
+            </div>
+            <div class="card-body">
+                {% if has_existing %}
+                <!-- Warning for existing key -->
+                <div class="alert alert-warning">
+                    <i class="bi bi-exclamation-triangle me-2"></i>
+                    <strong>Warning:</strong> Your existing recovery key will be invalidated.
+                    Make sure to save this new key before continuing.
+                </div>
+                {% else %}
+                <!-- Info for first-time setup -->
+                <div class="alert alert-info">
+                    <i class="bi bi-info-circle me-2"></i>
+                    <strong>What is a recovery key?</strong><br>
+                    If you forget your admin password, this key is the ONLY way to reset it.
+                </div>
+                {% endif %}
+
+                <!-- Recovery Key Display -->
+                <div class="mb-4">
+                    <label class="form-label">
+                        <i class="bi bi-key-fill me-1"></i> Your New Recovery Key
+                    </label>
+                    <div class="input-group">
+                        <input type="text" class="form-control font-monospace text-center"
+                               id="recoveryKey" value="{{ recovery_key }}" readonly
+                               style="font-size: 1.1em; letter-spacing: 0.5px;">
+                        <button class="btn btn-outline-secondary" type="button"
+                                onclick="copyToClipboard()" title="Copy to clipboard">
+                            <i class="bi bi-clipboard" id="copyIcon"></i>
+                        </button>
+                    </div>
+                </div>
+
+                <!-- QR Code (if available) -->
+                {% if qr_base64 %}
+                <div class="mb-4 text-center">
+                    <label class="form-label d-block">
+                        <i class="bi bi-qr-code me-1"></i> QR Code
+                    </label>
+                    <img src="data:image/png;base64,{{ qr_base64 }}"
+                         alt="Recovery Key QR Code" class="img-fluid border rounded"
+                         style="max-width: 200px;" id="qrImage">
+                </div>
+                {% endif %}
+
+                <!-- Download Options -->
+                <div class="mb-4">
+                    <label class="form-label">
+                        <i class="bi bi-download me-1"></i> Download Options
+                    </label>
+                    <div class="d-flex gap-2 flex-wrap">
+                        <button class="btn btn-outline-primary btn-sm" onclick="downloadTextFile()">
+                            <i class="bi bi-file-text me-1"></i> Text File
+                        </button>
+                        {% if qr_base64 %}
+                        <button class="btn btn-outline-primary btn-sm" onclick="downloadQRImage()">
+                            <i class="bi bi-image me-1"></i> QR Image
+                        </button>
+                        {% endif %}
+                    </div>
+                </div>
+
+                <!-- Stego Backup Option -->
+                <div class="mb-4">
+                    <label class="form-label">
+                        <i class="bi bi-incognito me-1"></i> Hide in Image
+                    </label>
+                    <form method="POST" action="{{ url_for('create_stego_backup') }}"
+                          enctype="multipart/form-data" class="d-flex gap-2 align-items-end">
+                        <input type="hidden" name="recovery_key" value="{{ recovery_key }}">
+                        <div class="flex-grow-1">
+                            <input type="file" name="carrier_image" class="form-control form-control-sm"
+                                   accept="image/jpeg,image/png" required>
+                            <div class="form-text">JPG/PNG, 50KB-2MB</div>
+                        </div>
+                        <button type="submit" class="btn btn-outline-secondary btn-sm">
+                            <i class="bi bi-download me-1"></i> Stego
+                        </button>
+                    </form>
+                </div>
+
+                <hr>
+
+                <!-- Confirmation Form -->
+                <form method="POST" id="recoveryForm">
+                    <input type="hidden" name="recovery_key" value="{{ recovery_key }}">
+
+                    <!-- Confirm checkbox -->
+                    <div class="form-check mb-3">
+                        <input class="form-check-input" type="checkbox" id="confirmSaved"
+                               onchange="updateButtons()">
+                        <label class="form-check-label" for="confirmSaved">
+                            I have saved my recovery key in a secure location
+                        </label>
+                    </div>
+
+                    <div class="d-flex gap-2 justify-content-between">
+                        <!-- Cancel button -->
+                        <button type="submit" name="action" value="cancel"
+                                class="btn btn-outline-secondary">
+                            <i class="bi bi-x-lg me-1"></i> Cancel
+                        </button>
+
+                        <!-- Save button -->
+                        <button type="submit" name="action" value="save"
+                                class="btn btn-primary" id="saveBtn" disabled>
+                            <i class="bi bi-check-lg me-1"></i> Save New Key
+                        </button>
+                    </div>
+                </form>
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script>
+// Copy recovery key to clipboard
+function copyToClipboard() {
+    const keyInput = document.getElementById('recoveryKey');
+    navigator.clipboard.writeText(keyInput.value).then(() => {
+        const icon = document.getElementById('copyIcon');
+        icon.className = 'bi bi-clipboard-check';
+        setTimeout(() => { icon.className = 'bi bi-clipboard'; }, 2000);
+    });
+}
+
+// Download as text file
+function downloadTextFile() {
+    const key = document.getElementById('recoveryKey').value;
+    const content = `Stegasoo Recovery Key
+=====================
+
+${key}
+
+IMPORTANT:
+- Keep this file in a secure location
+- Anyone with this key can reset admin passwords
+- Do not store with your password
+
+Generated: ${new Date().toISOString()}
+`;
+    const blob = new Blob([content], { type: 'text/plain' });
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement('a');
+    a.href = url;
+    a.download = 'stegasoo-recovery-key.txt';
+    a.click();
+    URL.revokeObjectURL(url);
+}
+
+// Download QR as image
+function downloadQRImage() {
+    const img = document.getElementById('qrImage');
+    if (!img) return;
+
+    const a = document.createElement('a');
+    a.href = img.src;
+    a.download = 'stegasoo-recovery-qr.png';
+    a.click();
+}
+
+// Enable save button when checkbox is checked
+function updateButtons() {
+    const checkbox = document.getElementById('confirmSaved');
+    const saveBtn = document.getElementById('saveBtn');
+    saveBtn.disabled = !checkbox.checked;
+}
+</script>
+{% endblock %}

frontends/web/templates/setup.html

@@ -0,0 +1,76 @@
+{% extends "base.html" %}
+
+{% block title %}Setup - Stegasoo{% endblock %}
+
+{% block content %}
+<div class="row justify-content-center">
+    <div class="col-md-6 col-lg-5">
+        <div class="card">
+            <div class="card-header text-center">
+                <i class="bi bi-gear-fill fs-1 d-block mb-2"></i>
+                <h5 class="mb-0">Initial Setup</h5>
+            </div>
+            <div class="card-body">
+                <p class="text-muted text-center mb-4">
+                    Welcome to Stegasoo! Create your admin account to get started.
+                </p>
+
+                <form method="POST" action="{{ url_for('setup') }}" id="setupForm">
+                    <div class="mb-3">
+                        <label class="form-label">
+                            <i class="bi bi-person me-1"></i> Username
+                        </label>
+                        <input type="text" name="username" class="form-control"
+                               value="admin" required minlength="3">
+                    </div>
+
+                    <div class="mb-3">
+                        <label class="form-label">
+                            <i class="bi bi-key me-1"></i> Password
+                        </label>
+                        <div class="input-group">
+                            <input type="password" name="password" class="form-control"
+                                   id="passwordInput" required minlength="8">
+                            <button class="btn btn-outline-secondary" type="button"
+                                    onclick="togglePassword('passwordInput', this)">
+                                <i class="bi bi-eye"></i>
+                            </button>
+                        </div>
+                        <div class="form-text">Minimum 8 characters</div>
+                    </div>
+
+                    <div class="mb-4">
+                        <label class="form-label">
+                            <i class="bi bi-key-fill me-1"></i> Confirm Password
+                        </label>
+                        <div class="input-group">
+                            <input type="password" name="password_confirm" class="form-control"
+                                   id="passwordConfirmInput" required minlength="8">
+                            <button class="btn btn-outline-secondary" type="button"
+                                    onclick="togglePassword('passwordConfirmInput', this)">
+                                <i class="bi bi-eye"></i>
+                            </button>
+                        </div>
+                    </div>
+
+                    <button type="submit" class="btn btn-primary w-100">
+                        <i class="bi bi-check-lg me-2"></i>Create Admin Account
+                    </button>
+                </form>
+            </div>
+        </div>
+
+        <div class="alert alert-info mt-4 small">
+            <i class="bi bi-info-circle me-2"></i>
+            This is a single-user setup. The admin account has full access to all features.
+        </div>
+    </div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script src="{{ url_for('static', filename='js/auth.js') }}"></script>
+<script>
+StegasooAuth.initPasswordConfirmation('setupForm', 'passwordInput', 'passwordConfirmInput');
+</script>
+{% endblock %}

frontends/web/templates/setup_recovery.html

@@ -0,0 +1,176 @@
+{% extends "base.html" %}
+
+{% block title %}Recovery Key Setup - Stegasoo{% endblock %}
+
+{% block content %}
+<div class="row justify-content-center">
+    <div class="col-md-8 col-lg-6">
+        <div class="card">
+            <div class="card-header text-center">
+                <i class="bi bi-shield-lock fs-1 d-block mb-2"></i>
+                <h5 class="mb-0">Recovery Key Setup</h5>
+                <small class="text-muted">Step 2 of 2</small>
+            </div>
+            <div class="card-body">
+                <!-- Explanation -->
+                <div class="alert alert-info">
+                    <i class="bi bi-info-circle me-2"></i>
+                    <strong>What is a recovery key?</strong><br>
+                    If you forget your admin password, this key is the ONLY way to reset it.
+                    Save it somewhere safe - it will not be shown again.
+                </div>
+
+                <!-- Recovery Key Display -->
+                <div class="mb-4">
+                    <label class="form-label">
+                        <i class="bi bi-key-fill me-1"></i> Your Recovery Key
+                    </label>
+                    <div class="input-group">
+                        <input type="text" class="form-control font-monospace text-center"
+                               id="recoveryKey" value="{{ recovery_key }}" readonly
+                               style="font-size: 1.1em; letter-spacing: 0.5px;">
+                        <button class="btn btn-outline-secondary" type="button"
+                                onclick="copyToClipboard()" title="Copy to clipboard">
+                            <i class="bi bi-clipboard" id="copyIcon"></i>
+                        </button>
+                    </div>
+                </div>
+
+                <!-- QR Code (if available) -->
+                {% if qr_base64 %}
+                <div class="mb-4 text-center">
+                    <label class="form-label d-block">
+                        <i class="bi bi-qr-code me-1"></i> QR Code
+                    </label>
+                    <img src="data:image/png;base64,{{ qr_base64 }}"
+                         alt="Recovery Key QR Code" class="img-fluid border rounded"
+                         style="max-width: 200px;" id="qrImage">
+                    <div class="mt-2">
+                        <small class="text-muted">Scan with your phone's camera app</small>
+                    </div>
+                </div>
+                {% endif %}
+
+                <!-- Download Options -->
+                <div class="mb-4">
+                    <label class="form-label">
+                        <i class="bi bi-download me-1"></i> Download Options
+                    </label>
+                    <div class="d-flex gap-2 flex-wrap">
+                        <button class="btn btn-outline-primary btn-sm" onclick="downloadTextFile()">
+                            <i class="bi bi-file-text me-1"></i> Text File
+                        </button>
+                        {% if qr_base64 %}
+                        <button class="btn btn-outline-primary btn-sm" onclick="downloadQRImage()">
+                            <i class="bi bi-image me-1"></i> QR Image
+                        </button>
+                        {% endif %}
+                    </div>
+                </div>
+
+                <hr>
+
+                <!-- Confirmation Form -->
+                <form method="POST" id="recoveryForm">
+                    <input type="hidden" name="recovery_key" value="{{ recovery_key }}">
+
+                    <!-- Confirm checkbox -->
+                    <div class="form-check mb-3">
+                        <input class="form-check-input" type="checkbox" id="confirmSaved"
+                               onchange="updateButtons()">
+                        <label class="form-check-label" for="confirmSaved">
+                            I have saved my recovery key in a secure location
+                        </label>
+                    </div>
+
+                    <div class="d-flex gap-2 justify-content-between">
+                        <!-- Skip button (no recovery) -->
+                        <button type="submit" name="action" value="skip"
+                                class="btn btn-outline-secondary"
+                                onclick="return confirm('Are you sure? Without a recovery key, there is NO way to reset your password if you forget it.')">
+                            <i class="bi bi-skip-forward me-1"></i> Skip (No Recovery)
+                        </button>
+
+                        <!-- Save button (with key) -->
+                        <button type="submit" name="action" value="save"
+                                class="btn btn-primary" id="saveBtn" disabled>
+                            <i class="bi bi-check-lg me-1"></i> Continue
+                        </button>
+                    </div>
+                </form>
+            </div>
+        </div>
+
+        <!-- Security Notes -->
+        <div class="card mt-3">
+            <div class="card-header">
+                <i class="bi bi-shield-check me-2"></i>Security Notes
+            </div>
+            <div class="card-body small">
+                <ul class="mb-0">
+                    <li>The recovery key is <strong>not stored</strong> - only a hash is saved</li>
+                    <li>Keep it separate from your password (different location)</li>
+                    <li>Anyone with this key can reset admin passwords</li>
+                    <li>If you lose it and forget your password, you must recreate the database</li>
+                </ul>
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script>
+// Copy recovery key to clipboard
+function copyToClipboard() {
+    const keyInput = document.getElementById('recoveryKey');
+    navigator.clipboard.writeText(keyInput.value).then(() => {
+        const icon = document.getElementById('copyIcon');
+        icon.className = 'bi bi-clipboard-check';
+        setTimeout(() => { icon.className = 'bi bi-clipboard'; }, 2000);
+    });
+}
+
+// Download as text file
+function downloadTextFile() {
+    const key = document.getElementById('recoveryKey').value;
+    const content = `Stegasoo Recovery Key
+=====================
+
+${key}
+
+IMPORTANT:
+- Keep this file in a secure location
+- Anyone with this key can reset admin passwords
+- Do not store with your password
+
+Generated: ${new Date().toISOString()}
+`;
+    const blob = new Blob([content], { type: 'text/plain' });
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement('a');
+    a.href = url;
+    a.download = 'stegasoo-recovery-key.txt';
+    a.click();
+    URL.revokeObjectURL(url);
+}
+
+// Download QR as image
+function downloadQRImage() {
+    const img = document.getElementById('qrImage');
+    if (!img) return;
+
+    const a = document.createElement('a');
+    a.href = img.src;
+    a.download = 'stegasoo-recovery-qr.png';
+    a.click();
+}
+
+// Enable save button when checkbox is checked
+function updateButtons() {
+    const checkbox = document.getElementById('confirmSaved');
+    const saveBtn = document.getElementById('saveBtn');
+    saveBtn.disabled = !checkbox.checked;
+}
+</script>
+{% endblock %}

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "stegasoo"
-version = "2.0.1"
+version = "4.1.5"
 description = "Secure steganography with hybrid photo + passphrase + PIN authentication"
 readme = "README.md"
 license = "MIT"
@@ -43,24 +43,48 @@ dependencies = [
 ]
 
 [project.optional-dependencies]
+# DCT steganography support (v3.0+)
+dct = [
+    "numpy>=2.0.0",
+    "scipy>=1.10.0",
+    "jpegio>=0.2.0",
+    "reedsolo>=1.7.0",
+]
 cli = [
     "click>=8.0.0",
-    "qrcode>=7.30"
+    "qrcode>=7.30",
+    "piexif>=1.1.0",
+    "rich>=13.0.0",
+]
+compression = [
+    "lz4>=4.0.0",
 ]
 web = [
     "flask>=3.0.0",
     "gunicorn>=21.0.0",
     "qrcode>=7.3.0",
-    "pyzbar",
+    "pyzbar>=0.1.9",
+    "piexif>=1.1.0",
+    # Include DCT support for web UI
+    "numpy>=2.0.0",
+    "scipy>=1.10.0",
+    "jpegio>=0.2.0",
+    "reedsolo>=1.7.0",
 ]
 api = [
     "fastapi>=0.100.0",
     "uvicorn[standard]>=0.20.0",
     "python-multipart>=0.0.6",
     "qrcode>=7.30",
+    "pyzbar>=0.1.9",
+    # Include DCT support for API
+    "numpy>=2.0.0",
+    "scipy>=1.10.0",
+    "jpegio>=0.2.0",
+    "reedsolo>=1.7.0",
 ]
 all = [
-    "stegasoo[cli,web,api]",
+    "stegasoo[cli,web,api,dct,compression]",
 ]
 dev = [
     "stegasoo[all]",
@@ -99,9 +123,18 @@ target-version = ["py310", "py311", "py312"]
 
 [tool.ruff]
 line-length = 100
+exclude = ["frontends/web/test_routes.py"]  # Debug snippet, not a real module
+
+[tool.ruff.lint]
 select = ["E", "F", "I", "N", "W", "UP"]
 ignore = ["E501"]
 
+[tool.ruff.lint.per-file-ignores]
+# YCbCr colorspace variables (R, G, B, Y, Cb, Cr) are standard names
+"src/stegasoo/dct_steganography.py" = ["N803", "N806"]
+# Package __init__.py has imports after try/except and aliases - intentional structure
+"src/stegasoo/__init__.py" = ["E402"]
+
 [tool.mypy]
 python_version = "3.10"
 warn_return_any = true

requirements.txt

@@ -27,6 +27,11 @@ click>=8.1.0
 pytest>=7.4.0
 pytest-cov>=4.1.0
 
+
+scipy>=1.16.3
+jpegio>=0.2.8
+numpy>=2.4.0
+
 # Optional: Better performance for Pillow
 # pillow-simd>=9.0.0  # Uncomment if available for your platform
 

rpi/BUILD_IMAGE.md

@@ -0,0 +1,186 @@
+# Stegasoo Pi Image Build Workflow
+
+> **Note:** This guide is for developers building custom Pi images.
+> **End users:** Just download the pre-built `.img.zst` from [Releases](https://github.com/adlee-was-taken/stegasoo/releases), flash it, and boot. No build process needed.
+
+Quick reference for building a distributable SD card image.
+
+## Step 1: Flash Fresh Raspbian
+
+Use rpi-imager with these settings:
+- **OS**: Raspberry Pi OS Lite (64-bit)
+- **Hostname**: `stegasoo`
+- **Enable SSH**: Yes (password auth)
+- **Username**: `admin`
+- **Password**: `stegasoo`
+- **WiFi**: Configure for your network (sanitize script removes it later)
+
+## Step 2: Boot & SSH In
+
+```bash
+# Wait for Pi to boot (~60 seconds), then:
+ssh admin@stegasoo.local
+# or use IP from router DHCP list
+```
+
+## Step 3: Pre-Setup
+
+```bash
+# Take ownership of /opt (for pyenv, jpegio builds)
+sudo chown admin:admin /opt
+
+# Install git and zstd (not included in Lite image)
+sudo apt-get update && sudo apt-get install -y git zstd jq
+```
+
+## Step 4: Clone Repo
+
+```bash
+cd /opt
+git clone -b 4.1 https://github.com/adlee-was-taken/stegasoo.git stegasoo
+```
+
+## Step 5: Copy Pre-built Tarball (from host)
+
+> **Dev-only asset:** This tarball is for building Pi images, not for end users.
+> It's available on [Releases](https://github.com/adlee-was-taken/stegasoo/releases) for image builders.
+
+```bash
+# On your host machine:
+scp rpi/stegasoo-rpi-runtime-env-arm64.tar.zst admin@stegasoo.local:/opt/stegasoo/rpi/
+```
+
+This tarball contains:
+- pyenv with Python 3.12 (pre-compiled for ARM64)
+- venv with all dependencies (jpegio, scipy, etc.)
+
+Install time: **~2 minutes** (vs 20+ min from source)
+
+## Step 6: Run Setup
+
+```bash
+cd /opt/stegasoo
+./rpi/setup.sh  # Detects local tarball, skips download
+```
+
+### From-Source Build (optional)
+
+To build without the pre-built tarball:
+```bash
+./rpi/setup.sh --no-prebuilt  # Takes 15-20 minutes
+```
+
+## Step 7: Test It Works
+
+```bash
+sudo systemctl start stegasoo
+curl -k https://localhost:5000
+# Should return HTML
+```
+
+## Step 8: Sanitize for Distribution
+
+```bash
+# Full sanitize (for final image - removes WiFi, shuts down)
+sudo /opt/stegasoo/rpi/sanitize-for-image.sh
+
+# Or soft reset (for testing - keeps WiFi, reboots)
+sudo /opt/stegasoo/rpi/sanitize-for-image.sh --soft
+```
+
+This removes:
+- WiFi credentials (unless `--soft`)
+- SSH host keys (regenerate on boot)
+- SSH authorized keys
+- Bash history
+- Stegasoo auth database
+- Logs and temp files
+
+The script validates all cleanup steps before finishing.
+
+## Step 9: Pull the Image
+
+Remove SD card, insert into your Linux machine:
+
+```bash
+# Find the SD card device (CAREFUL!)
+lsblk
+
+# Pull image (auto-resizes to 16GB, compresses with zstd)
+sudo ./rpi/pull-image.sh /dev/sdX stegasoo-rpi-4.1.5.img.zst
+```
+
+The script automatically resizes rootfs to 16GB (for smaller download), preserves auto-expand, and compresses.
+
+## Step 10: Distribute
+
+Upload `.img.zst` to GitHub Releases.
+
+Users can flash with:
+```bash
+# Option 1: rpi-imager CLI (supports .zst.zip directly)
+sudo rpi-imager --cli --disable-verify stegasoo-rpi-*.img.zst.zip /dev/sdX
+
+# Option 2: flash-image.sh (auto-detects SD card, shows progress)
+sudo ./rpi/flash-image.sh stegasoo-rpi-*.img.zst.zip
+
+# Option 3: Manual dd
+zstdcat stegasoo-rpi-*.img.zst | sudo dd of=/dev/sdX bs=4M status=progress
+```
+
+---
+
+## Creating the Pre-built Tarball
+
+After a successful from-source build, create the pre-built tarball for future installs:
+
+```bash
+# On the Pi after successful setup:
+cd ~
+
+# Strip caches and tests from venv (295MB → 208MB)
+find /opt/stegasoo/venv/ -type d -name '__pycache__' -exec rm -rf {} + 2>/dev/null
+find /opt/stegasoo/venv/ -type d -name 'tests' -exec rm -rf {} + 2>/dev/null
+find /opt/stegasoo/venv/ -type d -name 'test' -exec rm -rf {} + 2>/dev/null
+
+# Create venv tarball
+cd /opt/stegasoo
+tar -cf - venv/ | zstd -19 -T0 > ~/stegasoo-venv.tar.zst
+
+# Create combined tarball (pyenv + venv pointer)
+cd ~
+tar -cf - .pyenv stegasoo-venv.tar.zst | zstd -19 -T0 > /tmp/stegasoo-rpi-runtime-env-arm64.tar.zst
+
+# Check size (should be ~50-60MB)
+ls -lh /tmp/stegasoo-rpi-runtime-env-arm64.tar.zst
+```
+
+Pull to host and upload to GitHub releases:
+```bash
+# On host:
+scp admin@stegasoo.local:/tmp/stegasoo-rpi-runtime-env-arm64.tar.zst ./
+# Upload to GitHub releases as stegasoo-rpi-runtime-env-arm64.tar.zst
+```
+
+---
+
+## Quick Command Summary
+
+```bash
+# On Pi (after SSH):
+sudo chown admin:admin /opt
+sudo apt-get update && sudo apt-get install -y git zstd jq
+cd /opt && git clone -b 4.1 https://github.com/adlee-was-taken/stegasoo.git stegasoo
+
+# On host (copy tarball):
+scp rpi/stegasoo-rpi-runtime-env-arm64.tar.zst admin@stegasoo.local:/opt/stegasoo/rpi/
+
+# On Pi (run setup):
+cd /opt/stegasoo && ./rpi/setup.sh
+sudo systemctl start stegasoo
+curl -k https://localhost:5000
+sudo /opt/stegasoo/rpi/sanitize-for-image.sh
+
+# On host (pull image - auto-resizes to 16GB):
+sudo ./rpi/pull-image.sh /dev/sdX stegasoo-rpi-4.1.5.img.zst
+```

rpi/README.md

@@ -0,0 +1,225 @@
+# Stegasoo Raspberry Pi
+
+Scripts and resources for deploying Stegasoo on Raspberry Pi.
+
+## Quick Install
+
+On a fresh Raspberry Pi OS Lite (64-bit) installation:
+
+```bash
+# Pre-setup (git not included in Lite image)
+sudo chown $USER:$USER /opt
+sudo apt-get update && sudo apt-get install -y git
+
+# Clone and run setup
+cd /opt
+git clone -b 4.1 https://github.com/adlee-was-taken/stegasoo.git stegasoo
+cd stegasoo
+./rpi/setup.sh
+```
+
+## What the Setup Script Does
+
+1. **Installs system dependencies** - build tools, libraries
+2. **Installs Python 3.12** - via pyenv (Pi OS ships with 3.13 which is incompatible)
+3. **Builds jpegio for ARM** - patches x86-specific flags
+4. **Installs Stegasoo** - with web UI and all dependencies
+5. **Creates systemd service** - auto-starts on boot
+6. **Enables the service** - ready to start
+
+## Requirements
+
+- Raspberry Pi 4 or 5
+- Raspberry Pi OS Lite (64-bit) - Bookworm or later
+- 4GB+ RAM recommended (2GB minimum)
+- 16GB+ SD card (pre-built images are 16GB)
+- Internet connection
+
+### Performance
+
+On a Pi 4 at 2GHz with USB 3.0 NVMe, expect ~60 seconds to encode/decode a 10MB JPEG with full encryption (passphrase + PIN + reference photo).
+
+## Pre-built Image Defaults
+
+If using a pre-built image from GitHub Releases:
+
+- **Default login**: `admin` / `stegasoo`
+- **Hostname**: `stegasoo.local`
+- **First boot**: A setup wizard runs on first SSH login
+
+> **Security note**: Change the default password after setup with `passwd`
+
+## Updating an Existing Installation
+
+To update to the latest version:
+
+```bash
+cd /opt/stegasoo
+git pull origin main
+sudo systemctl restart stegasoo
+```
+
+That's it - the editable install means Python uses the source directly.
+
+**If dependencies changed** (check release notes), also run:
+```bash
+source venv/bin/activate
+pip install -e ".[web]"
+sudo systemctl restart stegasoo
+```
+
+## After Installation
+
+### Start the Service
+
+```bash
+sudo systemctl start stegasoo
+```
+
+### Check Status
+
+```bash
+sudo systemctl status stegasoo
+```
+
+### View Logs
+
+```bash
+journalctl -u stegasoo -f
+```
+
+### Access Web UI
+
+Open in browser: `http://<pi-ip>:5000`
+
+On first access, you'll create an admin account.
+
+## Configuration
+
+Edit the systemd service to change settings:
+
+```bash
+sudo systemctl edit stegasoo
+```
+
+Add overrides:
+
+```ini
+[Service]
+Environment="STEGASOO_AUTH_ENABLED=true"
+Environment="STEGASOO_HTTPS_ENABLED=true"
+Environment="STEGASOO_HOSTNAME=stegasoo.local"
+```
+
+Then reload:
+
+```bash
+sudo systemctl daemon-reload
+sudo systemctl restart stegasoo
+```
+
+## Uninstall
+
+```bash
+sudo systemctl stop stegasoo
+sudo systemctl disable stegasoo
+sudo rm /etc/systemd/system/stegasoo.service
+rm -rf /opt/stegasoo
+```
+
+## Pre-built Images
+
+Check [GitHub Releases](https://github.com/adlee-was-taken/stegasoo/releases) for pre-built SD card images.
+
+---
+
+## Building Your Own Image
+
+To create a distributable SD card image:
+
+### 1. Flash Fresh Raspberry Pi OS
+
+Use rpi-imager to flash Raspberry Pi OS (64-bit) to an SD card.
+
+In advanced settings, set:
+- Hostname: `stegasoo`
+- Enable SSH (password auth for initial setup)
+- Username/password (temporary, will work for any user)
+- Skip WiFi for distributable image
+
+### 2. Boot and Run Setup
+
+```bash
+# SSH into the Pi
+ssh admin@stegasoo.local
+
+# Pre-setup
+sudo chown admin:admin /opt
+sudo apt-get update && sudo apt-get install -y git
+
+# Clone and run setup
+cd /opt
+git clone -b 4.1 https://github.com/adlee-was-taken/stegasoo.git stegasoo
+cd stegasoo
+./rpi/setup.sh
+```
+
+### 3. Test It Works
+
+```bash
+sudo systemctl start stegasoo
+curl -k https://localhost:5000  # Should return HTML
+```
+
+### 4. Sanitize for Distribution
+
+```bash
+# Full sanitize (removes WiFi, shuts down for imaging)
+sudo /opt/stegasoo/rpi/sanitize-for-image.sh
+
+# Or soft reset (keeps WiFi for testing, reboots)
+sudo /opt/stegasoo/rpi/sanitize-for-image.sh --soft
+```
+
+This removes:
+- WiFi credentials (unless `--soft`)
+- SSH host keys (regenerate on boot)
+- SSH authorized keys
+- Bash history
+- Stegasoo auth database (users create their own admin)
+- Logs and temp files
+
+The script validates cleanup and reports any issues.
+
+### 5. Create the Image
+
+After Pi shuts down, remove SD card and on another Linux machine:
+
+```bash
+# Find SD card device (BE CAREFUL - wrong device = data loss!)
+lsblk
+
+# Pull image (auto-resizes to 16GB, compresses with zstd)
+sudo ./rpi/pull-image.sh /dev/sdX stegasoo-rpi-4.1.5.img.zst
+```
+
+The `pull-image.sh` script automatically:
+- Resizes rootfs to exactly 16GB (for smaller download)
+- Preserves auto-expand (image fills SD card on first boot)
+- Compresses with zstd for fast decompression
+
+### 6. Distribute
+
+Upload the `.img.zst` file to GitHub Releases.
+
+Users flash with:
+```bash
+# Option 1: rpi-imager CLI (supports .zst.zip directly)
+sudo rpi-imager --cli --disable-verify stegasoo-rpi-*.img.zst.zip /dev/sdX
+
+# Option 2: flash-image.sh (auto-detects SD card, shows progress)
+sudo ./rpi/flash-image.sh stegasoo-rpi-*.img.zst.zip
+
+# Option 3: Manual dd
+zstdcat stegasoo-rpi-*.img.zst | sudo dd of=/dev/sdX bs=4M status=progress
+```