Update WebUI screenshots for Encode/Decode pages

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

.github/workflows/release.yml

@@ -37,7 +37,8 @@ jobs:
   publish:
     needs: test  # Only run if tests pass
     runs-on: ubuntu-latest
-    
+    environment: pypi
+
     # Required for PyPI trusted publishing (recommended)
     permissions:
       id-token: write

.github/workflows/test.yml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       fail-fast: false  # Don't cancel other jobs if one fails
       matrix:
-        python-version: ["3.10", "3.11", "3.12"]
+        python-version: ["3.11", "3.12", "3.13"]
     
     steps:
       # 1. Get the code

.gitignore

@@ -97,3 +97,11 @@ rpi/*.tar.zst.zip
 rpi/*.img
 rpi/*.img.zst
 rpi/*.img.zst.zip
+
+# AUR build artifacts
+aur-upload/
+aur/.SRCINFO
+aur/*.pkg.tar.zst
+
+# Docker pre-built images and deps (release assets, too large for git)
+docker/*.tar.zst

CLI.md

@@ -164,7 +164,7 @@ stegasoo generate [OPTIONS]
 | `--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) |
+| `--rsa-bits` | | choice | 2048 | RSA key size (2048, 3072) |
 | `--words` | | 3-12 | 4 | Words in passphrase |
 | `--output` | `-o` | path | | Save RSA key to file |
 | `--password` | `-p` | string | | Password for RSA key file |
@@ -180,7 +180,7 @@ stegasoo generate
 stegasoo generate --words 6
 
 # Generate with RSA key
-stegasoo generate --rsa --rsa-bits 4096
+stegasoo generate --rsa --rsa-bits 3072
 
 # Save RSA key to encrypted file
 stegasoo generate --rsa -o mykey.pem -p "mysecretpassword"

INSTALL.md

@@ -20,22 +20,23 @@ Complete installation instructions for all platforms and deployment methods.
 
 ## Requirements
 
-### ⚠️ Python Version Requirements
+### Python Version Requirements
 
 | Python Version | Status | Notes |
 |----------------|--------|-------|
-| 3.10 | ✅ Supported | |
-| 3.11 | ✅ Supported | Recommended |
+| 3.10 | ❌ Not Supported | Dropped in v4.2.1 |
+| 3.11 | ✅ Supported | Minimum version |
 | 3.12 | ✅ Supported | Recommended |
-| 3.13 | ❌ **Not Supported** | jpegio C extension incompatible |
+| 3.13 | ✅ Supported | |
+| 3.14 | ✅ Supported | Tested on Arch |
 
-**Important:** Python 3.13 (released October 2024) is **not compatible** with jpegio due to C extension ABI changes. Use Python 3.12 or earlier.
+**Note:** v4.2.1 switched from `jpegio` to `jpeglib` for DCT steganography, enabling Python 3.11-3.14 support.
 
 ### Minimum Requirements
 
 | Requirement | Value |
 |-------------|-------|
-| Python | 3.10-3.12 |
+| Python | 3.11-3.14 |
 | RAM | 512 MB minimum (256MB for Argon2) |
 | Disk | ~100 MB |
 
@@ -423,16 +424,61 @@ pip install jpegio
 
 ### Windows
 
-1. Install Python 3.12 from [python.org](https://python.org) (NOT 3.13!)
-2. Install Visual Studio Build Tools
+Windows users have three options, listed from easiest to most complex:
+
+#### Option 1: Docker Desktop (Recommended)
+
+The easiest way to run Stegasoo on Windows. No Python installation needed.
+
+1. Install [Docker Desktop](https://www.docker.com/products/docker-desktop/)
+2. Enable WSL2 backend when prompted
+3. Clone and run:
+
+```powershell
+git clone https://github.com/adlee-was-taken/stegasoo.git
+cd stegasoo
+docker-compose -f docker/docker-compose.yml up -d web
+```
+
+Access at http://localhost:5000
+
+#### Option 2: WSL2 (Windows Subsystem for Linux)
+
+Run the Linux version natively on Windows.
+
+```powershell
+# Install WSL2 with Ubuntu
+wsl --install -d Ubuntu
+
+# Open Ubuntu terminal, then follow Linux instructions:
+sudo apt-get update
+sudo apt-get install -y python3.12 python3.12-venv libzbar0 libjpeg-dev
+git clone https://github.com/adlee-was-taken/stegasoo.git
+cd stegasoo
+python3.12 -m venv venv
+source venv/bin/activate
+pip install -e ".[all]"
+stegasoo --version
+```
+
+#### Option 3: Native Windows (Advanced)
+
+Native Windows installation requires Visual Studio Build Tools for compiling C extensions.
+
+1. Install Python 3.11 or 3.12 from [python.org](https://python.org)
+2. Install [Visual Studio Build Tools](https://visualstudio.microsoft.com/visual-cpp-build-tools/) with "Desktop development with C++"
 3. Install from pip:
 
 ```powershell
 python -m venv venv
 .\venv\Scripts\activate
-pip install stegasoo[all]
+pip install stegasoo[cli]  # CLI only (easiest)
+# or
+pip install stegasoo[all]  # Full install (may require additional setup)
 ```
 
+**Note:** Native Windows installation may have issues with `jpegio` (DCT mode). Docker or WSL2 is recommended for full functionality.
+
 ### Raspberry Pi
 
 Stegasoo works on Raspberry Pi 4/5 (4GB+ RAM recommended for Web UI).

README.md

@@ -4,7 +4,7 @@ A secure steganography system for hiding encrypted messages in images using hybr
 
 [![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)
+![Python](https://img.shields.io/badge/Python-3.11--3.14-blue)
 [![License: MIT](https://img.shields.io/badge/License-MIT-green.svg)](LICENSE)
 ![Security](https://img.shields.io/badge/Security-AES--256--GCM-red)
 

RELEASE_NOTES.md

@@ -1,52 +1,131 @@
-## Stegasoo v4.1.7
+## Stegasoo v4.2.1
 
-### 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
+### API Security
 
-### 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
+**API Key Authentication**
+- All protected endpoints require `X-API-Key` header
+- Keys stored hashed (SHA-256) in `~/.stegasoo/api_keys.json`
+- Auth disabled when no keys configured (easy onboarding)
 
+**TLS Support**
+- Self-signed certificates auto-generated on first run
+- Certs valid for localhost, all local IPs, hostname.local
+- CLI: `stegasoo api tls generate` to pre-generate
+
+### CLI Improvements
+
+**New API Management Commands**
+```bash
+stegasoo api keys create NAME    # Create new key
+stegasoo api keys list           # List API keys
+stegasoo api tls generate        # Generate TLS cert
+stegasoo api serve               # Start server with TLS
+```
+
+**New Image Tools**
+```bash
+stegasoo tools compress IMG -q 75   # JPEG compression
+stegasoo tools rotate IMG -r 90     # Lossless rotation
+stegasoo tools convert IMG -f png   # Format conversion
+```
+
+### Bug Fixes
+
+- **DCT rotation**: Portrait photos no longer export rotated 90°
+- **jpegtran**: Removed `-trim` flag that destroyed DCT stego data
+- **CLI encode**: Now outputs JPEG when carrier is JPEG (was always PNG)
+- **Import paths**: Fixed for installed packages (AUR/pip)
+
+### Installation
+
+**AUR (Arch Linux)**
+```bash
+yay -S stegasoo-git       # Full (Web + API + CLI)
+yay -S stegasoo-cli-git   # CLI only
+```
+
+**Docker**
 ```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
-```
-
+**Raspberry Pi**
+Flash `stegasoo-rpi-4.2.1.img.zst.zip` to SD card.
 Default login: `admin` / `stegasoo`
 
-First boot runs the setup wizard for WiFi, HTTPS, and channel key configuration.
+### Requirements
 
-### 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
-```
+- Python 3.11 - 3.14 (dropped 3.10 support)
+
+### Release Assets
+
+| File | Description |
+|------|-------------|
+| `stegasoo-rpi-4.2.1.img.zst.zip` | Raspberry Pi SD card image |
+| `stegasoo-docker-base-4.2.1.tar.zst` | Docker base image |
+| Source code (zip/tar.gz) | Auto-generated |
+
+---
+
+## Stegasoo v4.2.0
+
+### Performance Optimizations
+
+Major performance improvements for Raspberry Pi and resource-constrained deployments.
+
+#### DCT Vectorization (~14x faster)
+- Batch DCT processing using `scipy.fft.dctn` with `axes=(1,2)`
+- Processes 500 blocks at once instead of one-by-one
+- Decode time reduced from ~2.6s to ~0.8s on 1MB images
+
+#### Memory Optimization (50% reduction)
+- Switched from `float64` to `float32` for all DCT operations
+- Peak RAM: 211 MB → 107 MB for encode, 104 MB → 52 MB for decode
+- Critical for Pi 3/4 avoiding swap thrashing
+
+#### Progress Callbacks for Decode
+- `progress_file` parameter added to `decode()` and extraction functions
+- UI can now show decode progress (phases: loading, extracting, decoding, complete)
+- JSON format: `{"current": 80, "total": 100, "percent": 80.0, "phase": "decoding"}`
+
+#### Async API Endpoints
+- Encode/decode operations now run in thread pool via `asyncio.to_thread()`
+- API server can handle concurrent requests without blocking
+- Essential for multi-user Pi deployments
+
+### Compression
+
+#### Zstd Default Compression
+- `zstandard` is now a core dependency (always installed)
+- Better compression ratio than zlib for QR code RSA keys
+- New `STEGASOO-ZS:` prefix for zstd, backward compatible with `STEGASOO-Z:` (zlib)
+
+### QR Code Generation
+
+#### CLI Support
+- `stegasoo generate --rsa --qr key.png` - save RSA key as QR image (PNG/JPG)
+- `stegasoo generate --rsa --qr-ascii` - print ASCII QR to terminal
+
+#### API Support
+- `POST /generate-key-qr` - generate QR from RSA key
+- Supports `png`, `jpg`, and `ascii` output formats
+- Uses zstd compression by default
+
+### Other Changes
+
+- RSA key size capped at 3072 bits (4096 too large for QR codes)
+- File auto-expire increased to 10 minutes
+- Progress bar "candy cane" animation during Argon2 key derivation
+- Optional API service in Pi setup (with security warning)
+
+### Summary
+
+| Metric | v4.1.7 | v4.2.0 | Improvement |
+|--------|--------|--------|-------------|
+| Decode (1MB) | ~2.6s | ~0.8s | **70% faster** |
+| Peak RAM | 211 MB | 107 MB | **50% less** |
+| Concurrent API | No | Yes | check |
+| QR Compression | zlib | zstd | **~15% smaller** |
 
 ### Full Changelog
 See [CHANGELOG.md](CHANGELOG.md) for complete version history.

TODO-4.2.1.md

@@ -0,0 +1,54 @@
+# Stegasoo 4.2.1 Plan
+
+## Bugs
+- [x] Fix EXIF viewer panel not loading metadata in Web UI
+  - Redesigned with card-based grid layout and categories
+  - Compact styling for better space usage
+- [x] DCT mode: portrait photos export rotated 90° (EXIF orientation not handled)
+  - Added `_apply_exif_orientation()` to apply EXIF rotation before embedding
+- [x] DCT mode: add rotation fallback (try as-is, rotate 90°, retry on failure)
+  - Added rotation fallback in `extract_from_dct()` with quick header validation
+- [x] Rotate tool: use jpegtran for lossless JPEG rotation (preserves DCT stego!)
+  - Web UI rotate tool now uses jpegtran for JPEGs
+  - DCT decode rotation fallback now uses jpegtran for JPEGs
+  - Dynamic UI shows "DCT Safe" for JPEGs, warning for other formats
+
+## Tools Audit
+- [x] Web UI tools - full shakedown and fixes
+  - Compress, Rotate, Strip, EXIF viewer all working
+  - Rotate uses jpegtran for lossless JPEG rotation
+  - Compact UI styling
+- [x] CLI tools - full shakedown and fixes
+  - Fixed encode to output JPEG when carrier is JPEG (was always PNG)
+  - Fixed jpegtran -trim flag destroying DCT stego data
+  - Added compress, rotate, convert tools (matching Web UI)
+  - Rotate uses jpegtran for JPEGs, supports flip-only operations
+
+## AUR Packages
+- [x] `stegasoo-cli` - standalone CLI package (no web dependencies)
+  - Created aur-cli/PKGBUILD with [cli,dct,compression] extras only
+  - No flask/gunicorn/fastapi/uvicorn/pyzbar deps
+  - 68MB vs 79MB for full package
+- [x] `stegasoo-api` - REST API package
+  - Created aur-api/PKGBUILD with [api,cli,compression] extras
+  - Has fastapi/uvicorn, no flask/gunicorn
+  - 74MB package size
+  - Includes systemd service with TLS
+
+## API Auth Work
+- [x] API key authentication (simpler than OAuth2 for personal use)
+  - `frontends/api/auth.py` - key generation, hashing, validation
+  - Keys stored in `~/.stegasoo/api_keys.json` (hashed)
+  - `X-API-Key` header for authentication
+  - Auth disabled when no keys configured
+- [x] TLS with self-signed certificates
+  - Auto-generates certs on first run
+  - CLI: `stegasoo api tls generate`
+  - Certs stored in `~/.stegasoo/certs/`
+- [x] CLI commands for API management
+  - `stegasoo api keys list/create/delete`
+  - `stegasoo api tls generate/info`
+  - `stegasoo api serve` (starts with TLS by default)
+
+## API Documentation
+- [ ] Postman collection (with environment templates)

WEB_UI.md

@@ -411,7 +411,7 @@ Create a new set of credentials for steganography operations.
 | 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 |
+| RSA key size | 2048/3072 | 2048 | Key size in bits |
 
 #### Entropy Calculator
 

aur-api/.SRCINFO

@@ -0,0 +1,23 @@
+pkgbase = stegasoo-api-git
+	pkgdesc = Stegasoo REST API with TLS and API key authentication
+	pkgver = 4.2.1
+	pkgrel = 1
+	url = https://github.com/adlee-was-taken/stegasoo
+	install = stegasoo-api-git.install
+	arch = x86_64
+	license = MIT
+	makedepends = git
+	makedepends = python
+	makedepends = python-build
+	makedepends = python-hatchling
+	depends = python>=3.11
+	depends = zbar
+	optdepends = libjpeg-turbo: jpegtran for lossless JPEG rotation (DCT-safe)
+	provides = stegasoo-api
+	conflicts = stegasoo-api
+	conflicts = stegasoo
+	conflicts = stegasoo-git
+	source = stegasoo-api-git::git+https://github.com/adlee-was-taken/stegasoo.git#branch=main
+	sha256sums = SKIP
+
+pkgname = stegasoo-api-git

aur-api/PKGBUILD

@@ -0,0 +1,109 @@
+# Maintainer: Aaron D. Lee <your-email@example.com>
+pkgname=stegasoo-api-git
+pkgver=4.2.1
+pkgrel=1
+pkgdesc="Stegasoo REST API with TLS and API key authentication"
+arch=('x86_64')
+url="https://github.com/adlee-was-taken/stegasoo"
+license=('MIT')
+
+# Python 3.11-3.14 supported
+depends=(
+    'python>=3.11'
+    'zbar'  # QR code reading for RSA key extraction
+)
+makedepends=(
+    'git'
+    'python'
+    'python-build'
+    'python-hatchling'
+)
+optdepends=(
+    'libjpeg-turbo: jpegtran for lossless JPEG rotation (DCT-safe)'
+)
+provides=('stegasoo-api')
+conflicts=('stegasoo-api' 'stegasoo' 'stegasoo-git')
+install=stegasoo-api-git.install
+source=("${pkgname}::git+https://github.com/adlee-was-taken/stegasoo.git#branch=main")
+sha256sums=('SKIP')
+
+pkgver() {
+    cd "$pkgname"
+    git describe --long --tags 2>/dev/null | sed 's/^v//;s/\([^-]*-g\)/r\1/;s/-/./g' || \
+    printf "%s.r%s.g%s" "4.2.1" "$(git rev-list --count HEAD)" "$(git rev-parse --short HEAD)"
+}
+
+build() {
+    cd "$pkgname"
+    python -m build --wheel --no-isolation
+}
+
+package() {
+    cd "$pkgname"
+
+    # Detect Python version for site-packages path
+    local pyver=$(python -c 'import sys; print(f"{sys.version_info.major}.{sys.version_info.minor}")')
+
+    # Install to /opt/stegasoo-api with dedicated venv
+    install -dm755 "$pkgdir/opt/stegasoo-api"
+
+    # Create fresh venv in package
+    python -m venv "$pkgdir/opt/stegasoo-api/venv"
+
+    # Install the wheel with API + CLI + compression extras
+    local wheel=$(ls dist/*.whl | head -1)
+    "$pkgdir/opt/stegasoo-api/venv/bin/pip" install --no-cache-dir "${wheel}[api,cli,compression]"
+
+    # Install API frontend (not included in wheel by default)
+    local site_packages="$pkgdir/opt/stegasoo-api/venv/lib/python${pyver}/site-packages"
+    install -dm755 "$site_packages/frontends/api"
+    cp -r frontends/api/*.py "$site_packages/frontends/api/"
+    cp -r frontends/__init__.py "$site_packages/frontends/" 2>/dev/null || true
+
+    # Create temp directory for API
+    install -dm755 "$site_packages/frontends/api/temp_files"
+
+    # Create config directories
+    install -dm755 "$pkgdir/opt/stegasoo-api/config"
+    install -dm700 "$pkgdir/opt/stegasoo-api/certs"
+
+    # Fix shebangs - replace build-time paths with installed paths
+    find "$pkgdir/opt/stegasoo-api/venv/bin" -type f -exec \
+        sed -i "s|$pkgdir/opt/stegasoo-api/venv|/opt/stegasoo-api/venv|g" {} \;
+
+    # Fix pyvenv.cfg
+    sed -i "s|$pkgdir||g" "$pkgdir/opt/stegasoo-api/venv/pyvenv.cfg"
+
+    # Create symlink to /usr/bin
+    install -dm755 "$pkgdir/usr/bin"
+    ln -s /opt/stegasoo-api/venv/bin/stegasoo "$pkgdir/usr/bin/stegasoo"
+
+    # Install license
+    install -Dm644 LICENSE "$pkgdir/usr/share/licenses/$pkgname/LICENSE"
+
+    # Install docs
+    install -Dm644 README.md "$pkgdir/usr/share/doc/$pkgname/README.md"
+
+    # Install systemd service
+    install -Dm644 /dev/stdin "$pkgdir/usr/lib/systemd/system/stegasoo-api.service" <<EOF
+[Unit]
+Description=Stegasoo REST API (HTTPS)
+After=network.target
+
+[Service]
+Type=simple
+User=stegasoo
+WorkingDirectory=/opt/stegasoo-api/venv/lib/python${pyver}/site-packages/frontends/api
+Environment="PATH=/opt/stegasoo-api/venv/bin"
+Environment="HOME=/opt/stegasoo-api"
+# TLS enabled by default - certs auto-generated on first run
+# Use: stegasoo api tls generate (to pre-generate certs)
+# Use: stegasoo api keys create <name> (to create API keys)
+ExecStart=/opt/stegasoo-api/venv/bin/stegasoo api serve --host 127.0.0.1 --port 8000
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target
+EOF
+}

aur-api/README.md

@@ -0,0 +1,102 @@
+# Stegasoo API AUR Package
+
+REST API server package for programmatic steganography operations. Includes HTTPS support and API key authentication.
+
+## Installation
+
+### From AUR (once published)
+```bash
+yay -S stegasoo-api-git
+# or
+paru -S stegasoo-api-git
+```
+
+### Manual build
+```bash
+git clone https://aur.archlinux.org/stegasoo-api-git.git
+cd stegasoo-api-git
+makepkg -si
+```
+
+## What Gets Installed
+
+- `/opt/stegasoo-api/venv/` - Self-contained Python venv with API dependencies
+- `/opt/stegasoo-api/config/` - API key storage
+- `/opt/stegasoo-api/certs/` - TLS certificates
+- `/usr/bin/stegasoo` - CLI executable
+- `/usr/lib/systemd/system/stegasoo-api.service` - Systemd service
+
+## Quick Start
+
+```bash
+# 1. Create an API key
+sudo -u stegasoo stegasoo api keys create mykey
+
+# 2. Start the service
+sudo systemctl enable --now stegasoo-api
+
+# 3. Test the API
+curl -k -H "X-API-Key: YOUR_KEY" https://localhost:8000/
+```
+
+## Service Details
+
+| Setting | Value |
+|---------|-------|
+| Port | 8000 |
+| Protocol | HTTPS (self-signed cert auto-generated) |
+| API Docs | https://localhost:8000/docs |
+| OpenAPI | https://localhost:8000/openapi.json |
+
+## API Key Management
+
+```bash
+# List all keys
+stegasoo api keys list
+
+# Create a new key
+sudo -u stegasoo stegasoo api keys create <name>
+
+# Revoke a key
+sudo -u stegasoo stegasoo api keys revoke <name>
+```
+
+## TLS Configuration
+
+```bash
+# View current certificate info
+stegasoo api tls info
+
+# Generate new self-signed certificate
+sudo -u stegasoo stegasoo api tls generate
+
+# Use custom certificates (edit service)
+sudo systemctl edit stegasoo-api
+# Add:
+# [Service]
+# ExecStart=
+# ExecStart=/opt/stegasoo-api/venv/bin/stegasoo api serve \
+#     --host 0.0.0.0 --port 8000 \
+#     --cert /path/to/cert.pem --key /path/to/key.pem
+```
+
+## Manual Run (without systemd)
+
+```bash
+# Development mode (auto-reload)
+/opt/stegasoo-api/venv/bin/stegasoo api serve --reload
+
+# Production mode
+/opt/stegasoo-api/venv/bin/stegasoo api serve --host 0.0.0.0 --port 8000
+```
+
+## For Web UI
+
+Install the full package instead:
+```bash
+yay -S stegasoo-git
+```
+
+## Maintainer
+
+Aaron D. Lee

aur-api/stegasoo-api-git.install

@@ -0,0 +1,63 @@
+post_install() {
+    # Create stegasoo system user if it doesn't exist
+    if ! getent passwd stegasoo >/dev/null; then
+        useradd -r -s /usr/bin/nologin -d /opt/stegasoo-api stegasoo
+        echo "Created system user 'stegasoo'"
+    fi
+
+    # Set ownership of directories
+    chown -R stegasoo:stegasoo /opt/stegasoo-api/config 2>/dev/null || true
+    chown -R stegasoo:stegasoo /opt/stegasoo-api/certs 2>/dev/null || true
+
+    echo ""
+    echo "==============================================="
+    echo "  Stegasoo API installed successfully!"
+    echo "==============================================="
+    echo ""
+    echo "-----------------------------------------------"
+    echo "  Quick Start"
+    echo "-----------------------------------------------"
+    echo "  1. Create an API key:"
+    echo "     sudo -u stegasoo stegasoo api keys create mykey"
+    echo ""
+    echo "  2. Start the API server:"
+    echo "     sudo systemctl start stegasoo-api"
+    echo "     sudo systemctl enable stegasoo-api  # auto-start"
+    echo ""
+    echo "  3. Access the API:"
+    echo "     curl -k -H 'X-API-Key: YOUR_KEY' https://localhost:8000/"
+    echo ""
+    echo "-----------------------------------------------"
+    echo "  Service Details"
+    echo "-----------------------------------------------"
+    echo "  Port: 8000 (HTTPS by default)"
+    echo "  Docs: https://localhost:8000/docs"
+    echo "  Status: sudo systemctl status stegasoo-api"
+    echo ""
+    echo "-----------------------------------------------"
+    echo "  Management Commands"
+    echo "-----------------------------------------------"
+    echo "  stegasoo api keys list       # List API keys"
+    echo "  stegasoo api keys create X   # Create new key"
+    echo "  stegasoo api tls generate    # Generate TLS certs"
+    echo "  stegasoo api tls info        # Show certificate info"
+    echo "  stegasoo api serve --help    # Server options"
+    echo ""
+    echo "==============================================="
+    echo ""
+}
+
+post_upgrade() {
+    post_install
+}
+
+pre_remove() {
+    # Stop service if running
+    systemctl stop stegasoo-api 2>/dev/null || true
+}
+
+post_remove() {
+    echo "Stegasoo API removed."
+    echo "User 'stegasoo' and config in /opt/stegasoo-api were not removed."
+    echo "To remove: userdel stegasoo && rm -rf /opt/stegasoo-api"
+}

aur-api/test-build.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+# Test build the AUR API package locally
+
+set -e
+
+cd "$(dirname "$0")"
+
+echo "=== Cleaning previous builds ==="
+rm -rf stegasoo-api-git pkg src *.pkg.tar.zst *.whl 2>/dev/null || true
+
+echo "=== Generating .SRCINFO ==="
+makepkg --printsrcinfo > .SRCINFO
+
+echo "=== Building package ==="
+makepkg -sf
+
+echo "=== Package built ==="
+ls -la *.pkg.tar.zst
+
+echo ""
+echo "To install: sudo pacman -U stegasoo-api-git-*.pkg.tar.zst"
+echo "To test:    makepkg -si"

aur-cli/.SRCINFO

@@ -0,0 +1,22 @@
+pkgbase = stegasoo-cli-git
+	pkgdesc = Secure steganography CLI with hybrid photo + passphrase + PIN authentication
+	pkgver = 4.2.1
+	pkgrel = 1
+	url = https://github.com/adlee-was-taken/stegasoo
+	install = stegasoo-cli-git.install
+	arch = x86_64
+	license = MIT
+	makedepends = git
+	makedepends = python
+	makedepends = python-build
+	makedepends = python-hatchling
+	depends = python>=3.11
+	optdepends = libjpeg-turbo: jpegtran for lossless JPEG rotation (DCT-safe)
+	provides = stegasoo-cli
+	conflicts = stegasoo-cli
+	conflicts = stegasoo
+	conflicts = stegasoo-git
+	source = stegasoo-cli-git::git+https://github.com/adlee-was-taken/stegasoo.git#branch=main
+	sha256sums = SKIP
+
+pkgname = stegasoo-cli-git

aur-cli/PKGBUILD

@@ -0,0 +1,69 @@
+# Maintainer: Aaron D. Lee <your-email@example.com>
+pkgname=stegasoo-cli-git
+pkgver=4.2.1
+pkgrel=1
+pkgdesc="Secure steganography CLI with hybrid photo + passphrase + PIN authentication"
+arch=('x86_64')
+url="https://github.com/adlee-was-taken/stegasoo"
+license=('MIT')
+
+# Python 3.11-3.14 supported (uses jpeglib for modern Python compatibility)
+depends=(
+    'python>=3.11'
+)
+makedepends=(
+    'git'
+    'python'
+    'python-build'
+    'python-hatchling'
+)
+optdepends=(
+    'libjpeg-turbo: jpegtran for lossless JPEG rotation (DCT-safe)'
+)
+provides=('stegasoo-cli')
+conflicts=('stegasoo-cli' 'stegasoo' 'stegasoo-git')
+install=stegasoo-cli-git.install
+source=("${pkgname}::git+https://github.com/adlee-was-taken/stegasoo.git#branch=main")
+sha256sums=('SKIP')
+
+pkgver() {
+    cd "$pkgname"
+    git describe --long --tags 2>/dev/null | sed 's/^v//;s/\([^-]*-g\)/r\1/;s/-/./g' || \
+    printf "%s.r%s.g%s" "4.2.1" "$(git rev-list --count HEAD)" "$(git rev-parse --short HEAD)"
+}
+
+build() {
+    cd "$pkgname"
+    python -m build --wheel --no-isolation
+}
+
+package() {
+    cd "$pkgname"
+
+    # Install to /opt/stegasoo-cli with dedicated venv
+    install -dm755 "$pkgdir/opt/stegasoo-cli"
+
+    # Create fresh venv in package
+    python -m venv "$pkgdir/opt/stegasoo-cli/venv"
+
+    # Install the wheel with CLI + DCT + compression extras (no web/api)
+    local wheel=$(ls dist/*.whl | head -1)
+    "$pkgdir/opt/stegasoo-cli/venv/bin/pip" install --no-cache-dir "${wheel}[cli,dct,compression]"
+
+    # Fix shebangs - replace build-time paths with installed paths
+    find "$pkgdir/opt/stegasoo-cli/venv/bin" -type f -exec \
+        sed -i "s|$pkgdir/opt/stegasoo-cli/venv|/opt/stegasoo-cli/venv|g" {} \;
+
+    # Fix pyvenv.cfg
+    sed -i "s|$pkgdir||g" "$pkgdir/opt/stegasoo-cli/venv/pyvenv.cfg"
+
+    # Create symlink to /usr/bin
+    install -dm755 "$pkgdir/usr/bin"
+    ln -s /opt/stegasoo-cli/venv/bin/stegasoo "$pkgdir/usr/bin/stegasoo"
+
+    # Install license
+    install -Dm644 LICENSE "$pkgdir/usr/share/licenses/$pkgname/LICENSE"
+
+    # Install docs
+    install -Dm644 README.md "$pkgdir/usr/share/doc/$pkgname/README.md"
+}

aur-cli/README.md

@@ -0,0 +1,62 @@
+# Stegasoo CLI AUR Package
+
+Lightweight CLI-only package for steganography operations. No web UI or API server.
+
+## Installation
+
+### From AUR (once published)
+```bash
+yay -S stegasoo-cli-git
+# or
+paru -S stegasoo-cli-git
+```
+
+### Manual build
+```bash
+git clone https://aur.archlinux.org/stegasoo-cli-git.git
+cd stegasoo-cli-git
+makepkg -si
+```
+
+## What Gets Installed
+
+- `/opt/stegasoo-cli/venv/` - Self-contained Python venv with CLI dependencies only
+- `/usr/bin/stegasoo` - CLI executable
+
+## Usage
+
+```bash
+# Show all commands
+stegasoo --help
+
+# Generate credentials (passphrase + PIN)
+stegasoo generate
+stegasoo generate --words 5 --pin-length 8
+
+# Generate with RSA keys and QR codes
+stegasoo generate --rsa --qr-ascii
+
+# Encode a message
+stegasoo encode -i carrier.jpg -r reference.jpg -m "secret message" \
+    -P "word1 word2 word3 word4" -p 123456
+
+# Decode a message
+stegasoo decode -i encoded.png -r reference.jpg \
+    -P "word1 word2 word3 word4" -p 123456
+
+# Image tools
+stegasoo tools --help
+stegasoo tools compress image.png
+stegasoo tools rotate image.jpg 90
+```
+
+## For Web UI or REST API
+
+Install the full package instead:
+```bash
+yay -S stegasoo-git
+```
+
+## Maintainer
+
+Aaron D. Lee

aur-cli/stegasoo-cli-git.install

@@ -0,0 +1,20 @@
+post_install() {
+    echo ""
+    echo "==============================================="
+    echo "  Stegasoo CLI installed successfully!"
+    echo "==============================================="
+    echo ""
+    echo "Usage:"
+    echo "  stegasoo --help          # Show all commands"
+    echo "  stegasoo generate        # Generate passphrase + PIN"
+    echo "  stegasoo encode ...      # Hide data in an image"
+    echo "  stegasoo decode ...      # Extract hidden data"
+    echo "  stegasoo tools --help    # Image tools (compress, etc.)"
+    echo ""
+    echo "For web UI or REST API, install stegasoo-git instead."
+    echo ""
+}
+
+post_upgrade() {
+    post_install
+}

aur-cli/test-build.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+# Test build the AUR CLI package locally
+
+set -e
+
+cd "$(dirname "$0")"
+
+echo "=== Cleaning previous builds ==="
+rm -rf stegasoo-cli-git pkg src *.pkg.tar.zst *.whl 2>/dev/null || true
+
+echo "=== Generating .SRCINFO ==="
+makepkg --printsrcinfo > .SRCINFO
+
+echo "=== Building package ==="
+makepkg -sf
+
+echo "=== Package built ==="
+ls -la *.pkg.tar.zst
+
+echo ""
+echo "To install: sudo pacman -U stegasoo-cli-git-*.pkg.tar.zst"
+echo "To test:    makepkg -si"

aur/PKGBUILD

@@ -0,0 +1,120 @@
+# Maintainer: Aaron D. Lee <your-email@example.com>
+pkgname=stegasoo-git
+pkgver=4.2.1
+pkgrel=1
+pkgdesc="Secure steganography with hybrid photo + passphrase + PIN authentication"
+arch=('x86_64')
+url="https://github.com/adlee-was-taken/stegasoo"
+license=('MIT')
+
+# Python 3.11-3.14 supported (uses jpeglib for modern Python compatibility)
+depends=(
+    'python>=3.11'
+    'zbar'  # QR code reading for Web UI
+)
+makedepends=(
+    'git'
+    'python'
+    'python-build'
+    'python-hatchling'
+)
+provides=('stegasoo')
+conflicts=('stegasoo')
+install=stegasoo-git.install
+source=("${pkgname}::git+https://github.com/adlee-was-taken/stegasoo.git#branch=main")
+sha256sums=('SKIP')
+
+pkgver() {
+    cd "$pkgname"
+    git describe --long --tags 2>/dev/null | sed 's/^v//;s/\([^-]*-g\)/r\1/;s/-/./g' || \
+    printf "%s.r%s.g%s" "4.2.1" "$(git rev-list --count HEAD)" "$(git rev-parse --short HEAD)"
+}
+
+build() {
+    cd "$pkgname"
+    python -m build --wheel --no-isolation
+}
+
+package() {
+    cd "$pkgname"
+
+    # Detect Python version for site-packages path
+    local pyver=$(python -c 'import sys; print(f"{sys.version_info.major}.{sys.version_info.minor}")')
+
+    # Install to /opt/stegasoo with dedicated venv
+    install -dm755 "$pkgdir/opt/stegasoo"
+
+    # Create fresh venv in package
+    python -m venv "$pkgdir/opt/stegasoo/venv"
+
+    # Install the wheel with all extras
+    local wheel=$(ls dist/*.whl | head -1)
+    "$pkgdir/opt/stegasoo/venv/bin/pip" install --no-cache-dir "${wheel}[all]"
+
+    # Install frontends (not included in wheel)
+    local site_packages="$pkgdir/opt/stegasoo/venv/lib/python${pyver}/site-packages"
+    cp -r frontends "$site_packages/"
+
+    # Create writable directories for stegasoo user
+    install -dm755 "$pkgdir/opt/stegasoo/venv/var/app-instance"
+    install -dm755 "$site_packages/frontends/web/temp_files"
+    install -dm755 "$site_packages/frontends/api/temp_files"
+
+    # Fix shebangs - replace build-time paths with installed paths
+    find "$pkgdir/opt/stegasoo/venv/bin" -type f -exec \
+        sed -i "s|$pkgdir/opt/stegasoo/venv|/opt/stegasoo/venv|g" {} \;
+
+    # Fix pyvenv.cfg
+    sed -i "s|$pkgdir||g" "$pkgdir/opt/stegasoo/venv/pyvenv.cfg"
+
+    # Create symlinks to /usr/bin
+    install -dm755 "$pkgdir/usr/bin"
+    ln -s /opt/stegasoo/venv/bin/stegasoo "$pkgdir/usr/bin/stegasoo"
+
+    # Install license
+    install -Dm644 LICENSE "$pkgdir/usr/share/licenses/$pkgname/LICENSE"
+
+    # Install docs
+    install -Dm644 README.md "$pkgdir/usr/share/doc/$pkgname/README.md"
+
+    # Install systemd service files
+    install -Dm644 /dev/stdin "$pkgdir/usr/lib/systemd/system/stegasoo-web.service" <<EOF
+[Unit]
+Description=Stegasoo Web UI
+After=network.target
+
+[Service]
+Type=simple
+User=stegasoo
+WorkingDirectory=/opt/stegasoo/venv/lib/python${pyver}/site-packages/frontends/web
+Environment="PATH=/opt/stegasoo/venv/bin"
+ExecStart=/opt/stegasoo/venv/bin/gunicorn -b 127.0.0.1:5000 app:app
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target
+EOF
+
+    install -Dm644 /dev/stdin "$pkgdir/usr/lib/systemd/system/stegasoo-api.service" <<EOF
+[Unit]
+Description=Stegasoo REST API (HTTPS)
+After=network.target
+
+[Service]
+Type=simple
+User=stegasoo
+WorkingDirectory=/opt/stegasoo/venv/lib/python${pyver}/site-packages/frontends/api
+Environment="PATH=/opt/stegasoo/venv/bin"
+Environment="HOME=/opt/stegasoo"
+# TLS enabled by default - certs auto-generated on first run
+# Use stegasoo api tls generate to pre-generate certs
+# Use stegasoo api keys create <name> to create API keys
+ExecStart=/opt/stegasoo/venv/bin/stegasoo api serve --host 127.0.0.1 --port 8000
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target
+EOF
+}

aur/README.md

@@ -0,0 +1,90 @@
+# Stegasoo AUR Package
+
+Full package with CLI, Web UI, and REST API. Supports Python 3.11-3.14.
+
+## Installation
+
+### From AUR (once published)
+```bash
+yay -S stegasoo-git
+# or
+paru -S stegasoo-git
+```
+
+### Manual build
+```bash
+git clone https://aur.archlinux.org/stegasoo-git.git
+cd stegasoo-git
+makepkg -si
+```
+
+## What Gets Installed
+
+- `/opt/stegasoo/venv/` - Self-contained Python venv with all dependencies
+- `/usr/bin/stegasoo` - CLI symlink
+- `/usr/lib/systemd/system/stegasoo-web.service` - Web UI service (port 5000)
+- `/usr/lib/systemd/system/stegasoo-api.service` - REST API service (port 8000, HTTPS)
+
+## Optional Dependencies
+
+```bash
+# QR code reading from webcam/images (recommended)
+sudo pacman -S zbar
+```
+
+All other dependencies are bundled in the venv.
+
+## Usage
+
+### CLI
+```bash
+stegasoo --help
+stegasoo generate                    # Generate passphrase + PIN
+stegasoo generate --rsa --qr-ascii   # With RSA keys and QR codes
+stegasoo encode -i carrier.jpg -r reference.jpg -m "secret" -P "word1 word2 word3 word4" -p 123456
+stegasoo decode -i encoded.png -r reference.jpg -P "word1 word2 word3 word4" -p 123456
+```
+
+### Web UI
+```bash
+# Start service (user created automatically on install)
+sudo systemctl enable --now stegasoo-web
+
+# Access at http://localhost:5000
+```
+
+### REST API
+```bash
+# Create an API key first
+sudo -u stegasoo stegasoo api keys create mykey
+
+# Start service (HTTPS with auto-generated self-signed cert)
+sudo systemctl enable --now stegasoo-api
+
+# Access docs at https://localhost:8000/docs
+curl -k -H "X-API-Key: YOUR_KEY" https://localhost:8000/
+```
+
+### HTTPS Configuration
+
+The API uses HTTPS by default with auto-generated self-signed certificates.
+
+```bash
+# View certificate info
+stegasoo api tls info
+
+# Generate new self-signed cert
+sudo -u stegasoo stegasoo api tls generate
+
+# Use custom certs (edit service file)
+sudo systemctl edit stegasoo-api
+```
+
+## Alternative Packages
+
+- `stegasoo-cli-git` - CLI only, minimal dependencies
+- `stegasoo-api-git` - CLI + REST API, no web UI
+
+## Maintainer
+
+Aaron D. Lee

aur/stegasoo-git.install

@@ -0,0 +1,75 @@
+post_install() {
+    # Create stegasoo system user if it doesn't exist
+    if ! getent passwd stegasoo >/dev/null; then
+        useradd -r -s /usr/bin/nologin -d /opt/stegasoo stegasoo
+        echo "Created system user 'stegasoo'"
+    fi
+
+    # Set ownership of instance directory for Flask
+    chown -R stegasoo:stegasoo /opt/stegasoo/venv/var/app-instance 2>/dev/null || true
+
+    echo ""
+    echo "==============================================="
+    echo "  Stegasoo installed successfully!"
+    echo "==============================================="
+    echo ""
+    echo "CLI usage:"
+    echo "  stegasoo --help"
+    echo "  stegasoo generate        # Generate credentials"
+    echo "  stegasoo encode          # Encode a message"
+    echo "  stegasoo decode          # Decode a message"
+    echo ""
+    echo "-----------------------------------------------"
+    echo "  Web UI Service"
+    echo "-----------------------------------------------"
+    echo "  Port: 5000 (HTTP)"
+    echo "  Start:   sudo systemctl start stegasoo-web"
+    echo "  Enable:  sudo systemctl enable stegasoo-web"
+    echo "  Status:  sudo systemctl status stegasoo-web"
+    echo "  Access:  http://localhost:5000"
+    echo ""
+    echo "-----------------------------------------------"
+    echo "  REST API Service"
+    echo "-----------------------------------------------"
+    echo "  Port: 8000 (HTTPS by default)"
+    echo "  Start:   sudo systemctl start stegasoo-api"
+    echo "  Enable:  sudo systemctl enable stegasoo-api"
+    echo "  Status:  sudo systemctl status stegasoo-api"
+    echo "  Access:  https://localhost:8000"
+    echo ""
+    echo "-----------------------------------------------"
+    echo "  HTTPS Configuration"
+    echo "-----------------------------------------------"
+    echo "  The API generates self-signed certs on first run."
+    echo "  To pre-generate or use custom certificates:"
+    echo ""
+    echo "  # Generate self-signed certs"
+    echo "  sudo -u stegasoo stegasoo api tls generate"
+    echo ""
+    echo "  # Use custom certs (edit the service file)"
+    echo "  sudo systemctl edit stegasoo-api"
+    echo "  # Add: ExecStart= with --cert and --key flags"
+    echo ""
+    echo "  # Create API keys for authentication"
+    echo "  sudo -u stegasoo stegasoo api keys create <name>"
+    echo ""
+    echo "==============================================="
+    echo ""
+}
+
+post_upgrade() {
+    post_install
+}
+
+pre_remove() {
+    # Stop services if running
+    systemctl stop stegasoo-web 2>/dev/null || true
+    systemctl stop stegasoo-api 2>/dev/null || true
+}
+
+post_remove() {
+    # Optionally remove the stegasoo user
+    # userdel stegasoo 2>/dev/null || true
+    echo "Stegasoo removed. User 'stegasoo' was not removed."
+    echo "To remove: userdel stegasoo"
+}

aur/test-build.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+# Test build the AUR package locally
+
+set -e
+
+cd "$(dirname "$0")"
+
+echo "=== Cleaning previous builds ==="
+rm -rf stegasoo-git pkg src *.pkg.tar.zst *.whl 2>/dev/null || true
+
+echo "=== Generating .SRCINFO ==="
+makepkg --printsrcinfo > .SRCINFO
+
+echo "=== Building package ==="
+makepkg -sf
+
+echo "=== Package built ==="
+ls -la *.pkg.tar.zst
+
+echo ""
+echo "To install: sudo pacman -U stegasoo-git-*.pkg.tar.zst"
+echo "To test:    makepkg -si"

docker/Dockerfile.base

@@ -33,7 +33,8 @@ RUN pip install --no-cache-dir \
     argon2-cffi>=23.0.0 \
     pillow>=10.0.0 \
     cryptography>=41.0.0 \
-    reedsolo>=1.7.0
+    reedsolo>=1.7.0 \
+    zstandard>=0.22.0
 
 # Install web/api framework packages (also stable)
 RUN pip install --no-cache-dir \
@@ -48,9 +49,9 @@ RUN pip install --no-cache-dir \
     lz4>=4.0.0
 
 # Verify key packages work
-RUN python -c "import jpegio; import scipy; import numpy; print('jpegio + scipy + numpy OK')"
+RUN python -c "import jpegio; import scipy; import numpy; import zstandard; print('jpegio + scipy + numpy + zstd 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"
+LABEL org.opencontainers.image.version="4.2.1"

docs/TEMPLATES.md

@@ -126,7 +126,7 @@ Quick reference for all Jinja2 templates in `frontends/web/templates/`.
 - `use_pin` - checkbox
 - `pin_length` - PIN digits (6-9)
 - `use_rsa` - checkbox
-- `rsa_bits` - key size (2048/3072/4096)
+- `rsa_bits` - key size (2048/3072)
 
 **Output panels:**
 - Passphrase display

frontends/api/auth.py

@@ -0,0 +1,256 @@
+"""
+API Key Authentication for Stegasoo REST API.
+
+Provides simple API key authentication with hashed key storage.
+Keys can be stored in user config (~/.stegasoo/) or project config (./config/).
+
+Usage:
+    from .auth import require_api_key, get_api_key_status
+
+    @app.get("/protected")
+    async def protected_endpoint(api_key: str = Depends(require_api_key)):
+        return {"status": "authenticated"}
+"""
+
+import hashlib
+import json
+import os
+import secrets
+from pathlib import Path
+from typing import Optional
+
+from fastapi import Depends, HTTPException, Security
+from fastapi.security import APIKeyHeader
+
+# API key header name
+API_KEY_HEADER = APIKeyHeader(name="X-API-Key", auto_error=False)
+
+# Config locations
+USER_CONFIG_DIR = Path.home() / ".stegasoo"
+PROJECT_CONFIG_DIR = Path("./config")
+
+# Key file name
+API_KEYS_FILE = "api_keys.json"
+
+# Environment variable for API key (alternative to file)
+API_KEY_ENV_VAR = "STEGASOO_API_KEY"
+
+
+def _hash_key(key: str) -> str:
+    """Hash an API key for storage."""
+    return hashlib.sha256(key.encode()).hexdigest()
+
+
+def _get_keys_file(location: str = "user") -> Path:
+    """Get path to API keys file."""
+    if location == "project":
+        return PROJECT_CONFIG_DIR / API_KEYS_FILE
+    return USER_CONFIG_DIR / API_KEYS_FILE
+
+
+def _load_keys(location: str = "user") -> dict:
+    """Load API keys from config file."""
+    keys_file = _get_keys_file(location)
+    if keys_file.exists():
+        try:
+            with open(keys_file) as f:
+                return json.load(f)
+        except (json.JSONDecodeError, IOError):
+            return {"keys": [], "enabled": True}
+    return {"keys": [], "enabled": True}
+
+
+def _save_keys(data: dict, location: str = "user") -> None:
+    """Save API keys to config file."""
+    keys_file = _get_keys_file(location)
+    keys_file.parent.mkdir(parents=True, exist_ok=True)
+
+    with open(keys_file, "w") as f:
+        json.dump(data, f, indent=2)
+
+    # Secure permissions (owner read/write only)
+    os.chmod(keys_file, 0o600)
+
+
+def generate_api_key() -> str:
+    """Generate a new API key."""
+    # Format: stegasoo_XXXX_XXXXXXXXXXXXXXXXXXXXXXXXXXXX
+    # 32 bytes = 256 bits of entropy
+    random_part = secrets.token_hex(16)
+    return f"stegasoo_{random_part[:4]}_{random_part[4:]}"
+
+
+def add_api_key(name: str, location: str = "user") -> str:
+    """
+    Generate and store a new API key.
+
+    Args:
+        name: Descriptive name for the key (e.g., "laptop", "automation")
+        location: "user" or "project"
+
+    Returns:
+        The generated API key (only shown once!)
+    """
+    key = generate_api_key()
+    key_hash = _hash_key(key)
+
+    data = _load_keys(location)
+
+    # Check for duplicate name
+    for existing in data["keys"]:
+        if existing["name"] == name:
+            raise ValueError(f"Key with name '{name}' already exists")
+
+    data["keys"].append({
+        "name": name,
+        "hash": key_hash,
+        "created": __import__("datetime").datetime.now().isoformat(),
+    })
+
+    _save_keys(data, location)
+
+    return key
+
+
+def remove_api_key(name: str, location: str = "user") -> bool:
+    """
+    Remove an API key by name.
+
+    Returns:
+        True if key was found and removed, False otherwise
+    """
+    data = _load_keys(location)
+    original_count = len(data["keys"])
+
+    data["keys"] = [k for k in data["keys"] if k["name"] != name]
+
+    if len(data["keys"]) < original_count:
+        _save_keys(data, location)
+        return True
+    return False
+
+
+def list_api_keys(location: str = "user") -> list[dict]:
+    """
+    List all API keys (names and creation dates, not actual keys).
+    """
+    data = _load_keys(location)
+    return [{"name": k["name"], "created": k.get("created", "unknown")} for k in data["keys"]]
+
+
+def set_auth_enabled(enabled: bool, location: str = "user") -> None:
+    """Enable or disable API key authentication."""
+    data = _load_keys(location)
+    data["enabled"] = enabled
+    _save_keys(data, location)
+
+
+def is_auth_enabled() -> bool:
+    """Check if API key authentication is enabled."""
+    # Check project config first, then user config
+    for location in ["project", "user"]:
+        data = _load_keys(location)
+        if "enabled" in data:
+            return data["enabled"]
+
+    # Default: enabled if any keys exist
+    return bool(get_all_key_hashes())
+
+
+def get_all_key_hashes() -> set[str]:
+    """Get all valid API key hashes from all sources."""
+    hashes = set()
+
+    # Check environment variable first
+    env_key = os.environ.get(API_KEY_ENV_VAR)
+    if env_key:
+        hashes.add(_hash_key(env_key))
+
+    # Check project and user configs
+    for location in ["project", "user"]:
+        data = _load_keys(location)
+        for key_entry in data.get("keys", []):
+            if "hash" in key_entry:
+                hashes.add(key_entry["hash"])
+
+    return hashes
+
+
+def validate_api_key(key: str) -> bool:
+    """Validate an API key against stored hashes."""
+    if not key:
+        return False
+
+    key_hash = _hash_key(key)
+    valid_hashes = get_all_key_hashes()
+
+    return key_hash in valid_hashes
+
+
+def get_api_key_status() -> dict:
+    """Get current API key authentication status."""
+    user_keys = list_api_keys("user")
+    project_keys = list_api_keys("project")
+    env_configured = bool(os.environ.get(API_KEY_ENV_VAR))
+
+    total_keys = len(user_keys) + len(project_keys) + (1 if env_configured else 0)
+
+    return {
+        "enabled": is_auth_enabled(),
+        "total_keys": total_keys,
+        "user_keys": len(user_keys),
+        "project_keys": len(project_keys),
+        "env_configured": env_configured,
+        "keys": {
+            "user": user_keys,
+            "project": project_keys,
+        }
+    }
+
+
+# FastAPI dependency for API key authentication
+async def require_api_key(api_key: Optional[str] = Security(API_KEY_HEADER)) -> str:
+    """
+    FastAPI dependency that requires a valid API key.
+
+    Usage:
+        @app.get("/protected")
+        async def endpoint(key: str = Depends(require_api_key)):
+            ...
+    """
+    # Check if auth is enabled
+    if not is_auth_enabled():
+        return "auth_disabled"
+
+    # No keys configured = auth disabled
+    if not get_all_key_hashes():
+        return "no_keys_configured"
+
+    # Validate the provided key
+    if not api_key:
+        raise HTTPException(
+            status_code=401,
+            detail="API key required. Provide X-API-Key header.",
+            headers={"WWW-Authenticate": "ApiKey"},
+        )
+
+    if not validate_api_key(api_key):
+        raise HTTPException(
+            status_code=403,
+            detail="Invalid API key.",
+        )
+
+    return api_key
+
+
+async def optional_api_key(api_key: Optional[str] = Security(API_KEY_HEADER)) -> Optional[str]:
+    """
+    FastAPI dependency that optionally validates API key.
+
+    Returns the key if valid, None if not provided or invalid.
+    Doesn't raise exceptions - useful for endpoints that work
+    with or without auth.
+    """
+    if api_key and validate_api_key(api_key):
+        return api_key
+    return None

frontends/api/main.py

@@ -1,10 +1,19 @@
 #!/usr/bin/env python3
 """
-Stegasoo REST API (v4.0.0)
+Stegasoo REST API (v4.2.1)
 
 FastAPI-based REST API for steganography operations.
 Supports both text messages and file embedding.
 
+CHANGES in v4.2.1:
+- API key authentication (X-API-Key header)
+- TLS support with self-signed certificates
+- /auth/* endpoints for key management
+
+CHANGES in v4.2.0:
+- Async encode/decode operations (run in thread pool)
+- Server can handle concurrent requests without blocking
+
 CHANGES in v4.0.0:
 - Added channel key support for deployment/group isolation
 - New /channel endpoints for key management
@@ -21,15 +30,38 @@ NEW in v3.0: LSB and DCT embedding modes.
 NEW in v3.0.1: DCT color mode and JPEG output format.
 """
 
+import asyncio
 import base64
 import sys
+from functools import partial
 from pathlib import Path
 from typing import Literal
 
-from fastapi import FastAPI, File, Form, HTTPException, Query, UploadFile
+from fastapi import Depends, FastAPI, File, Form, HTTPException, Query, UploadFile
 from fastapi.responses import JSONResponse, Response
 from pydantic import BaseModel, Field
 
+# API Key Authentication
+try:
+    from .auth import (
+        require_api_key,
+        get_api_key_status,
+        add_api_key,
+        remove_api_key,
+        list_api_keys,
+        is_auth_enabled,
+    )
+except ImportError:
+    # When running directly (not as package)
+    from auth import (
+        require_api_key,
+        get_api_key_status,
+        add_api_key,
+        remove_api_key,
+        list_api_keys,
+        is_auth_enabled,
+    )
+
 # Add parent to path for development
 sys.path.insert(0, str(Path(__file__).parent.parent.parent / "src"))
 
@@ -68,13 +100,20 @@ from stegasoo.constants import (
 try:
     from stegasoo.qr_utils import (
         extract_key_from_qr,
+        generate_qr_ascii,
+        generate_qr_code,
         has_qr_read,
+        has_qr_write,
     )
 
     HAS_QR_READ = has_qr_read()
+    HAS_QR_WRITE = has_qr_write()
 except ImportError:
     HAS_QR_READ = False
+    HAS_QR_WRITE = False
     extract_key_from_qr = None
+    generate_qr_code = None
+    generate_qr_ascii = None
 
 
 # ============================================================================
@@ -344,6 +383,23 @@ class ChannelSetRequest(BaseModel):
     location: str = Field(default="user", description="'user' or 'project'")
 
 
+class AuthStatusResponse(BaseModel):
+    """Response for API key authentication status."""
+
+    enabled: bool = Field(description="Whether API key auth is enabled")
+    total_keys: int = Field(description="Total number of configured API keys")
+    user_keys: int = Field(description="Keys in user config")
+    project_keys: int = Field(description="Keys in project config")
+    env_configured: bool = Field(description="Whether env var key is set")
+
+
+class AuthKeyInfo(BaseModel):
+    """Info about a single API key (not the actual key)."""
+
+    name: str
+    created: str
+
+
 class ModesResponse(BaseModel):
     """Response showing available embedding modes."""
 
@@ -357,6 +413,7 @@ class StatusResponse(BaseModel):
     version: str
     has_argon2: bool
     has_qrcode_read: bool
+    has_qrcode_write: bool  # v4.2.0: QR generation capability
     has_dct: bool
     max_payload_kb: int
     available_modes: list[str]
@@ -372,6 +429,32 @@ class QrExtractResponse(BaseModel):
     error: str | None = None
 
 
+class QrGenerateRequest(BaseModel):
+    """Request to generate QR code from RSA key."""
+
+    key_pem: str = Field(..., description="RSA private key in PEM format")
+    output_format: str = Field(
+        default="png",
+        description="Output format: 'png', 'jpg', or 'ascii'",
+    )
+    compress: bool = Field(
+        default=True,
+        description="Compress key data with zstd (recommended for larger keys)",
+    )
+
+
+class QrGenerateResponse(BaseModel):
+    """Response containing generated QR code."""
+
+    success: bool
+    format: str | None = None
+    qr_data: str | None = Field(
+        default=None,
+        description="Base64-encoded image data (for png/jpg) or ASCII string",
+    )
+    error: str | None = None
+
+
 class WillFitRequest(BaseModel):
     """Request to check if payload will fit."""
 
@@ -436,6 +519,27 @@ def _get_channel_info(channel_key: str | None) -> tuple[str, str | None]:
     return info["mode"], info.get("fingerprint")
 
 
+# ============================================================================
+# HELPER: ASYNC EXECUTION
+# ============================================================================
+
+
+async def run_in_thread(func, *args, **kwargs):
+    """
+    Run a CPU-bound function in a thread pool.
+
+    This allows the FastAPI server to handle other requests while
+    encode/decode operations are running. Essential for Pi deployments
+    where operations can take several seconds.
+
+    Usage:
+        result = await run_in_thread(encode, message=msg, carrier_image=carrier, ...)
+    """
+    if kwargs:
+        func = partial(func, **kwargs)
+    return await asyncio.to_thread(func, *args)
+
+
 # ============================================================================
 # ROUTES - STATUS & INFO
 # ============================================================================
@@ -469,6 +573,7 @@ async def root():
         version=__version__,
         has_argon2=has_argon2(),
         has_qrcode_read=HAS_QR_READ,
+        has_qrcode_write=HAS_QR_WRITE,
         has_dct=has_dct_support(),
         max_payload_kb=MAX_FILE_PAYLOAD_SIZE // 1024,
         available_modes=available_modes,
@@ -552,6 +657,7 @@ async def api_channel_status(
 
 @app.post("/channel/generate", response_model=ChannelGenerateResponse)
 async def api_channel_generate(
+    _: str = Depends(require_api_key),
     save: bool = Query(False, description="Save to user config"),
     save_project: bool = Query(False, description="Save to project config"),
 ):
@@ -590,7 +696,7 @@ async def api_channel_generate(
 
 
 @app.post("/channel/set")
-async def api_channel_set(request: ChannelSetRequest):
+async def api_channel_set(request: ChannelSetRequest, _: str = Depends(require_api_key)):
     """
     Set/save a channel key to config.
 
@@ -616,6 +722,7 @@ async def api_channel_set(request: ChannelSetRequest):
 
 @app.delete("/channel")
 async def api_channel_clear(
+    _: str = Depends(require_api_key),
     location: str = Query("user", description="'user', 'project', or 'all'")
 ):
     """
@@ -642,8 +749,98 @@ async def api_channel_clear(
     }
 
 
+# ============================================================================
+# ROUTES - AUTHENTICATION (v4.2.1)
+# ============================================================================
+
+
+@app.get("/auth/status", response_model=AuthStatusResponse)
+async def api_auth_status():
+    """
+    Get API key authentication status.
+
+    v4.2.1: New endpoint for auth status.
+    Returns whether auth is enabled and key counts.
+    """
+    status = get_api_key_status()
+    return AuthStatusResponse(
+        enabled=status["enabled"],
+        total_keys=status["total_keys"],
+        user_keys=status["user_keys"],
+        project_keys=status["project_keys"],
+        env_configured=status["env_configured"],
+    )
+
+
+@app.get("/auth/keys", response_model=list[AuthKeyInfo])
+async def api_auth_list_keys(
+    location: str = Query("user", description="'user' or 'project'"),
+    _: str = Depends(require_api_key),
+):
+    """
+    List configured API keys (names only, not actual keys).
+
+    v4.2.1: New endpoint for auth management.
+    Requires authentication.
+    """
+    if location not in ("user", "project"):
+        raise HTTPException(400, "location must be 'user' or 'project'")
+
+    keys = list_api_keys(location)
+    return [AuthKeyInfo(name=k["name"], created=k["created"]) for k in keys]
+
+
+@app.post("/auth/keys")
+async def api_auth_create_key(
+    name: str = Query(..., description="Name for the new API key"),
+    location: str = Query("user", description="'user' or 'project'"),
+    _: str = Depends(require_api_key),
+):
+    """
+    Create a new API key.
+
+    v4.2.1: New endpoint for auth management.
+    Returns the key ONCE - it cannot be retrieved again!
+    Requires authentication (or no keys configured yet).
+    """
+    if location not in ("user", "project"):
+        raise HTTPException(400, "location must be 'user' or 'project'")
+
+    try:
+        key = add_api_key(name, location)
+        return {
+            "success": True,
+            "name": name,
+            "key": key,
+            "warning": "Save this key now! It cannot be retrieved again.",
+        }
+    except ValueError as e:
+        raise HTTPException(400, str(e))
+
+
+@app.delete("/auth/keys")
+async def api_auth_delete_key(
+    name: str = Query(..., description="Name of key to delete"),
+    location: str = Query("user", description="'user' or 'project'"),
+    _: str = Depends(require_api_key),
+):
+    """
+    Delete an API key by name.
+
+    v4.2.1: New endpoint for auth management.
+    Requires authentication.
+    """
+    if location not in ("user", "project"):
+        raise HTTPException(400, "location must be 'user' or 'project'")
+
+    if remove_api_key(name, location):
+        return {"success": True, "deleted": name}
+    else:
+        raise HTTPException(404, f"Key '{name}' not found in {location} config")
+
+
 @app.post("/compare", response_model=CompareModesResponse)
-async def api_compare_modes(request: CompareModesRequest):
+async def api_compare_modes(request: CompareModesRequest, _: str = Depends(require_api_key)):
     """
     Compare LSB and DCT embedding modes for a carrier image.
 
@@ -701,7 +898,7 @@ async def api_compare_modes(request: CompareModesRequest):
 
 
 @app.post("/will-fit", response_model=WillFitResponse)
-async def api_will_fit(request: WillFitRequest):
+async def api_will_fit(request: WillFitRequest, _: str = Depends(require_api_key)):
     """
     Check if a payload of given size will fit in the carrier image.
 
@@ -737,6 +934,7 @@ async def api_will_fit(request: WillFitRequest):
 
 @app.post("/extract-key-from-qr", response_model=QrExtractResponse)
 async def api_extract_key_from_qr(
+    _: str = Depends(require_api_key),
     qr_image: UploadFile = File(..., description="QR code image containing RSA key")
 ):
     """
@@ -760,13 +958,58 @@ async def api_extract_key_from_qr(
         return QrExtractResponse(success=False, error=str(e))
 
 
+@app.post("/generate-key-qr", response_model=QrGenerateResponse)
+async def api_generate_key_qr(request: QrGenerateRequest, _: str = Depends(require_api_key)):
+    """
+    Generate QR code from an RSA private key.
+
+    Supports PNG, JPG, and ASCII output formats.
+    Uses zstd compression by default for better QR code density.
+    """
+    if not HAS_QR_WRITE:
+        raise HTTPException(501, "QR code generation not available. Install qrcode library.")
+
+    try:
+        fmt = request.output_format.lower()
+
+        if fmt == "ascii":
+            ascii_qr = generate_qr_ascii(
+                request.key_pem,
+                compress=request.compress,
+                invert=False,
+            )
+            return QrGenerateResponse(success=True, format="ascii", qr_data=ascii_qr)
+
+        elif fmt in ("png", "jpg", "jpeg"):
+            import base64
+
+            qr_bytes = generate_qr_code(
+                request.key_pem,
+                compress=request.compress,
+                output_format=fmt,
+            )
+            qr_b64 = base64.b64encode(qr_bytes).decode("ascii")
+            return QrGenerateResponse(success=True, format=fmt, qr_data=qr_b64)
+
+        else:
+            return QrGenerateResponse(
+                success=False,
+                error=f"Unsupported format: {fmt}. Use 'png', 'jpg', or 'ascii'",
+            )
+
+    except ValueError as e:
+        return QrGenerateResponse(success=False, error=str(e))
+    except Exception as e:
+        return QrGenerateResponse(success=False, error=f"QR generation failed: {e}")
+
+
 # ============================================================================
 # ROUTES - GENERATE
 # ============================================================================
 
 
 @app.post("/generate", response_model=GenerateResponse)
-async def api_generate(request: GenerateRequest):
+async def api_generate(request: GenerateRequest, _: str = Depends(require_api_key)):
     """
     Generate credentials for encoding/decoding.
 
@@ -848,7 +1091,7 @@ def _get_output_info(embed_mode: str, dct_output_format: str, dct_color_mode: st
 
 
 @app.post("/encode", response_model=EncodeResponse)
-async def api_encode(request: EncodeRequest):
+async def api_encode(request: EncodeRequest, _: str = Depends(require_api_key)):
     """
     Encode a text message into an image.
 
@@ -874,8 +1117,9 @@ async def api_encode(request: EncodeRequest):
             request.embed_mode, request.dct_output_format, request.dct_color_mode
         )
 
-        # v4.0.0: Include channel_key
-        result = encode(
+        # v4.2.0: Run CPU-bound encode in thread pool
+        result = await run_in_thread(
+            encode,
             message=request.message,
             reference_photo=ref_photo,
             carrier_image=carrier,
@@ -919,7 +1163,7 @@ async def api_encode(request: EncodeRequest):
 
 
 @app.post("/encode/file", response_model=EncodeResponse)
-async def api_encode_file(request: EncodeFileRequest):
+async def api_encode_file(request: EncodeFileRequest, _: str = Depends(require_api_key)):
     """
     Encode a file into an image (JSON with base64).
 
@@ -950,8 +1194,9 @@ async def api_encode_file(request: EncodeFileRequest):
             request.embed_mode, request.dct_output_format, request.dct_color_mode
         )
 
-        # v4.0.0: Include channel_key
-        result = encode(
+        # v4.2.0: Run CPU-bound encode in thread pool
+        result = await run_in_thread(
+            encode,
             message=payload,
             reference_photo=ref_photo,
             carrier_image=carrier,
@@ -1000,7 +1245,7 @@ async def api_encode_file(request: EncodeFileRequest):
 
 
 @app.post("/decode", response_model=DecodeResponse)
-async def api_decode(request: DecodeRequest):
+async def api_decode(request: DecodeRequest, _: str = Depends(require_api_key)):
     """
     Decode a message or file from a stego image.
 
@@ -1021,8 +1266,9 @@ async def api_decode(request: DecodeRequest):
         ref_photo = base64.b64decode(request.reference_photo_base64)
         rsa_key = base64.b64decode(request.rsa_key_base64) if request.rsa_key_base64 else None
 
-        # v4.0.0: Include channel_key
-        result = decode(
+        # v4.2.0: Run CPU-bound decode in thread pool
+        result = await run_in_thread(
+            decode,
             stego_image=stego,
             reference_photo=ref_photo,
             passphrase=request.passphrase,
@@ -1062,6 +1308,7 @@ async def api_decode(request: DecodeRequest):
 
 @app.post("/encode/multipart")
 async def api_encode_multipart(
+    _: str = Depends(require_api_key),
     passphrase: str = Form(..., description="Passphrase (v3.2.0: renamed from day_phrase)"),
     reference_photo: UploadFile = File(...),
     carrier: UploadFile = File(...),
@@ -1150,8 +1397,9 @@ async def api_encode_multipart(
         # Get DCT parameters
         dct_params = _get_dct_params(embed_mode, dct_output_format, dct_color_mode)
 
-        # v4.0.0: Include channel_key
-        result = encode(
+        # v4.2.0: Run CPU-bound encode in thread pool
+        result = await run_in_thread(
+            encode,
             message=payload,
             reference_photo=ref_data,
             carrier_image=carrier_data,
@@ -1202,6 +1450,7 @@ async def api_encode_multipart(
 
 @app.post("/decode/multipart", response_model=DecodeResponse)
 async def api_decode_multipart(
+    _: str = Depends(require_api_key),
     passphrase: str = Form(..., description="Passphrase (v3.2.0: renamed from day_phrase)"),
     reference_photo: UploadFile = File(...),
     stego_image: UploadFile = File(...),
@@ -1264,8 +1513,9 @@ async def api_decode_multipart(
         # QR code keys are never password-protected
         effective_password = None if rsa_key_from_qr else (rsa_password if rsa_password else None)
 
-        # v4.0.0: Include channel_key
-        result = decode(
+        # v4.2.0: Run CPU-bound decode in thread pool
+        result = await run_in_thread(
+            decode,
             stego_image=stego_data,
             reference_photo=ref_data,
             passphrase=passphrase,
@@ -1306,6 +1556,7 @@ async def api_decode_multipart(
 
 @app.post("/image/info", response_model=ImageInfoResponse)
 async def api_image_info(
+    _: str = Depends(require_api_key),
     image: UploadFile = File(...),
     include_modes: bool = Query(True, description="Include capacity by mode (v3.0+)"),
 ):

frontends/cli/main.py

@@ -120,6 +120,7 @@ try:
     from stegasoo.qr_utils import (  # noqa: F401
         can_fit_in_qr,
         extract_key_from_qr_file,
+        generate_qr_ascii,
         generate_qr_code,
         has_qr_read,
         has_qr_write,
@@ -136,6 +137,9 @@ except ImportError:
     def has_qr_write() -> bool:
         return False
 
+    def generate_qr_ascii(*args, **kwargs):
+        raise RuntimeError("QR code generation not available")
+
 
 # ============================================================================
 # CLI SETUP
@@ -236,7 +240,7 @@ def format_channel_status_line(quiet: bool = False) -> str | None:
     help=f"PIN length (6-9, default: {DEFAULT_PIN_LENGTH})",
 )
 @click.option(
-    "--rsa-bits", type=click.Choice(["2048", "3072", "4096"]), default="2048", help="RSA key size"
+    "--rsa-bits", type=click.Choice(["2048", "3072"]), default="2048", help="RSA key size"
 )
 @click.option(
     "--words",
@@ -247,7 +251,13 @@ def format_channel_status_line(quiet: bool = False) -> str | None:
 @click.option("--output", "-o", type=click.Path(), help="Save RSA key to file (requires password)")
 @click.option("--password", "-p", help="Password for RSA key file")
 @click.option("--json", "as_json", is_flag=True, help="Output as JSON")
-def generate(pin, rsa, pin_length, rsa_bits, words, output, password, as_json):
+@click.option(
+    "--qr",
+    type=click.Path(),
+    help="Save RSA key QR code to file (png/jpg, uses zstd compression)",
+)
+@click.option("--qr-ascii", is_flag=True, help="Print RSA key as ASCII QR code to terminal")
+def generate(pin, rsa, pin_length, rsa_bits, words, output, password, as_json, qr, qr_ascii):
     """
     Generate credentials for encoding/decoding.
 
@@ -261,13 +271,18 @@ def generate(pin, rsa, pin_length, rsa_bits, words, output, password, as_json):
     Examples:
         stegasoo generate
         stegasoo generate --words 5
-        stegasoo generate --rsa --rsa-bits 4096
+        stegasoo generate --rsa --rsa-bits 3072
         stegasoo generate --rsa -o mykey.pem -p "secretpassword"
+        stegasoo generate --rsa --qr key.png
+        stegasoo generate --rsa --qr-ascii
         stegasoo generate --no-pin --rsa
     """
     if not pin and not rsa:
         raise click.UsageError("Must enable at least one of --pin or --rsa")
 
+    if (qr or qr_ascii) and not rsa:
+        raise click.UsageError("QR output requires --rsa to generate an RSA key")
+
     if output and not password:
         raise click.UsageError("--password is required when saving RSA key to file")
 
@@ -334,6 +349,33 @@ def generate(pin, rsa, pin_length, rsa_bits, words, output, password, as_json):
                 click.echo(creds.rsa_key_pem)
             click.echo()
 
+            # QR code output (v4.2.0)
+            if qr:
+                if not HAS_QR:
+                    click.secho("    ⚠️  QR code library not available", fg="yellow")
+                else:
+                    # Determine format from extension
+                    qr_path = Path(qr)
+                    ext = qr_path.suffix.lower()
+                    fmt = "jpeg" if ext in (".jpg", ".jpeg") else "png"
+
+                    qr_bytes = generate_qr_code(creds.rsa_key_pem, compress=True, output_format=fmt)
+                    qr_path.write_bytes(qr_bytes)
+                    click.secho(f"─── RSA KEY QR CODE ───", fg="green")
+                    click.secho(f"    Saved to: {qr}", fg="bright_white")
+                    click.secho("    ⚠️  Contains unencrypted private key!", fg="yellow")
+                    click.echo()
+
+            if qr_ascii:
+                if not HAS_QR:
+                    click.secho("    ⚠️  QR code library not available", fg="yellow")
+                else:
+                    click.secho("─── RSA KEY QR CODE (ASCII) ───", fg="green")
+                    click.secho("    ⚠️  Contains unencrypted private key!", fg="yellow")
+                    click.echo()
+                    ascii_qr = generate_qr_ascii(creds.rsa_key_pem, compress=True, invert=True)
+                    click.echo(ascii_qr)
+
         click.secho("─── SECURITY ───", fg="green")
         click.echo(f"    Passphrase entropy: {creds.passphrase_entropy} bits ({words} words)")
         if creds.pin:

frontends/web/app.py

@@ -31,7 +31,7 @@ KEY PATTERNS
 ============
 
 1. SUBPROCESS ISOLATION
-   Stegasoo's DCT mode uses scipy/jpegio which can crash on malformed input.
+   Stegasoo's DCT mode uses scipy/jpeglib which can crash on malformed input.
    We run encode/decode in subprocesses so crashes don't take down the server:
 
        subprocess_stego = SubprocessStego(timeout=180)
@@ -213,7 +213,7 @@ except ImportError:
 #
 # This is a critical reliability pattern. Here's the problem:
 #
-# scipy's DCT and jpegio can crash (segfault) on:
+# scipy's DCT and jpeglib can crash (segfault) on:
 # - Malformed JPEG files
 # - Very large images that exhaust memory
 # - Certain edge cases in coefficient manipulation
@@ -253,6 +253,7 @@ from stegasoo.qr_utils import (
     detect_and_crop_qr,
     extract_key_from_qr,
     generate_qr_code,
+    is_compressed,
 )
 
 # Initialize subprocess wrapper (worker script must be in same directory)
@@ -1116,6 +1117,13 @@ def encode_page():
         # Check if async mode requested
         is_async = request.form.get("async") == "true" or request.headers.get("X-Async") == "true"
 
+        def _error_response(msg):
+            """Return error as JSON (async) or HTML flash (sync)."""
+            if is_async:
+                return jsonify({"error": msg}), 400
+            flash(msg, "error")
+            return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+
         try:
             # Get files
             ref_photo = request.files.get("reference_photo")
@@ -1124,12 +1132,10 @@ def encode_page():
             payload_file = request.files.get("payload_file")
 
             if not ref_photo or not carrier:
-                flash("Both reference photo and carrier image are required", "error")
-                return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                return _error_response("Both reference photo and carrier image are required")
 
             if not allowed_image(ref_photo.filename) or not allowed_image(carrier.filename):
-                flash("Invalid file type. Use PNG, JPG, or BMP", "error")
-                return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                return _error_response("Invalid file type. Use PNG, JPG, or BMP")
 
             # Get form data - v3.2.0: renamed from day_phrase to passphrase
             message = request.form.get("message", "")
@@ -1158,8 +1164,7 @@ def encode_page():
 
             # Check DCT availability
             if embed_mode == "dct" and not has_dct_support():
-                flash("DCT mode requires scipy. Install with: pip install scipy", "error")
-                return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                return _error_response("DCT mode requires scipy. Install with: pip install scipy")
 
             # Determine payload
             if payload_type == "file" and payload_file and payload_file.filename:
@@ -1168,8 +1173,7 @@ def encode_page():
 
                 result = validate_file_payload(file_data, payload_file.filename)
                 if not result.is_valid:
-                    flash(result.error_message, "error")
-                    return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                    return _error_response(result.error_message)
 
                 mime_type, _ = mimetypes.guess_type(payload_file.filename)
                 payload = FilePayload(
@@ -1179,20 +1183,17 @@ def encode_page():
                 # Text message
                 result = validate_message(message)
                 if not result.is_valid:
-                    flash(result.error_message, "error")
-                    return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                    return _error_response(result.error_message)
                 payload = message
 
             # v3.2.0: Renamed from day_phrase
             if not passphrase:
-                flash("Passphrase is required", "error")
-                return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                return _error_response("Passphrase is required")
 
             # v3.2.0: Validate passphrase
             result = validate_passphrase(passphrase)
             if not result.is_valid:
-                flash(result.error_message, "error")
-                return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                return _error_response(result.error_message)
 
             # Show warning if passphrase is short
             if result.warning:
@@ -1209,8 +1210,8 @@ def encode_page():
             rsa_key_from_qr = False
 
             if rsa_key_pem:
-                # Webcam-scanned PEM key (v4.1.5) - may be compressed
-                if rsa_key_pem.startswith("STEGASOO-Z:"):
+                # Webcam-scanned PEM key (v4.1.5+) - may be compressed (zlib or zstd)
+                if is_compressed(rsa_key_pem):
                     rsa_key_pem = decompress_data(rsa_key_pem)
                 rsa_key_data = rsa_key_pem.encode("utf-8")
                 rsa_key_from_qr = True
@@ -1223,21 +1224,18 @@ def encode_page():
                     rsa_key_data = key_pem.encode("utf-8")
                     rsa_key_from_qr = True
                 else:
-                    flash("Could not extract RSA key from QR code image.", "error")
-                    return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                    return _error_response("Could not extract RSA key from QR code image.")
 
             # Validate security factors
             result = validate_security_factors(pin, rsa_key_data)
             if not result.is_valid:
-                flash(result.error_message, "error")
-                return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                return _error_response(result.error_message)
 
             # Validate PIN if provided
             if pin:
                 result = validate_pin(pin)
                 if not result.is_valid:
-                    flash(result.error_message, "error")
-                    return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                    return _error_response(result.error_message)
 
             # Determine key password
             key_password = None if rsa_key_from_qr else (rsa_password if rsa_password else None)
@@ -1246,14 +1244,12 @@ def encode_page():
             if rsa_key_data:
                 result = validate_rsa_key(rsa_key_data, key_password)
                 if not result.is_valid:
-                    flash(result.error_message, "error")
-                    return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                    return _error_response(result.error_message)
 
             # Validate carrier image
             result = validate_image(carrier_data, "Carrier image")
             if not result.is_valid:
-                flash(result.error_message, "error")
-                return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                return _error_response(result.error_message)
 
             # Pre-check payload capacity BEFORE encode (fail fast)
             from stegasoo.steganography import will_fit_by_mode
@@ -1273,8 +1269,7 @@ def encode_page():
                     alt_check = will_fit_by_mode(payload_size, carrier_data, embed_mode="lsb")
                     if alt_check.get("fits"):
                         error_msg += " - Try LSB mode instead."
-                flash(error_msg, "error")
-                return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+                return _error_response(error_msg)
 
             # Build encode params for either sync or async
             encode_params = {
@@ -1375,14 +1370,11 @@ def encode_page():
             return redirect(url_for("encode_result", file_id=file_id))
 
         except CapacityError as e:
-            flash(str(e), "error")
-            return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+            return _error_response(str(e))
         except StegasooError as e:
-            flash(str(e), "error")
-            return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+            return _error_response(str(e))
         except Exception as e:
-            flash(f"Error: {e}", "error")
-            return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
+            return _error_response(f"Error: {e}")
 
     return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
 
@@ -1657,8 +1649,8 @@ def decode_page():
             rsa_key_from_qr = False
 
             if rsa_key_pem:
-                # Webcam-scanned PEM key (v4.1.5) - may be compressed
-                if rsa_key_pem.startswith("STEGASOO-Z:"):
+                # Webcam-scanned PEM key (v4.1.5+) - may be compressed (zlib or zstd)
+                if is_compressed(rsa_key_pem):
                     rsa_key_pem = decompress_data(rsa_key_pem)
                 rsa_key_data = rsa_key_pem.encode("utf-8")
                 rsa_key_from_qr = True
@@ -2108,8 +2100,11 @@ def api_tools_exif_clear():
 @app.route("/api/tools/rotate", methods=["POST"])
 @login_required
 def api_tools_rotate():
-    """Rotate and/or flip an image."""
+    """Rotate and/or flip an image, using lossless jpegtran for JPEGs."""
     from PIL import Image
+    import shutil
+    import subprocess
+    import tempfile
 
     image_file = request.files.get("image")
     if not image_file:
@@ -2120,22 +2115,115 @@ def api_tools_rotate():
     flip_v = request.form.get("flip_v", "false").lower() == "true"
 
     try:
-        img = Image.open(io.BytesIO(image_file.read()))
+        image_data = image_file.read()
+        img = Image.open(io.BytesIO(image_data))
+        original_format = img.format  # JPEG, PNG, etc.
+        img.close()
 
-        # Apply rotation (PIL rotates counter-clockwise, so negate)
-        if rotation:
-            img = img.rotate(-rotation, expand=True)
+        # For JPEGs, use jpegtran for lossless rotation/flip (preserves DCT stego)
+        has_jpegtran = shutil.which("jpegtran") is not None
+        use_jpegtran = original_format == "JPEG" and has_jpegtran and (rotation or flip_h or flip_v)
 
-        # Apply flips
-        if flip_h:
-            img = img.transpose(Image.FLIP_LEFT_RIGHT)
-        if flip_v:
-            img = img.transpose(Image.FLIP_TOP_BOTTOM)
+        if use_jpegtran:
+            # Chain jpegtran operations for lossless transformation
+            current_data = image_data
 
-        # Output as PNG (lossless)
-        buffer = io.BytesIO()
-        img.save(buffer, format="PNG")
-        buffer.seek(0)
+            # Apply rotation first
+            if rotation in (90, 180, 270):
+                with tempfile.NamedTemporaryFile(suffix=".jpg", delete=False) as f:
+                    f.write(current_data)
+                    input_path = f.name
+                output_path = tempfile.mktemp(suffix=".jpg")
+                try:
+                    result = subprocess.run(
+                        ["jpegtran", "-rotate", str(rotation), "-copy", "all",
+                         "-outfile", output_path, input_path],
+                        capture_output=True, timeout=30
+                    )
+                    if result.returncode == 0:
+                        with open(output_path, "rb") as f:
+                            current_data = f.read()
+                finally:
+                    for p in [input_path, output_path]:
+                        try:
+                            os.unlink(p)
+                        except OSError:
+                            pass
+
+            # Apply horizontal flip
+            if flip_h:
+                with tempfile.NamedTemporaryFile(suffix=".jpg", delete=False) as f:
+                    f.write(current_data)
+                    input_path = f.name
+                output_path = tempfile.mktemp(suffix=".jpg")
+                try:
+                    result = subprocess.run(
+                        ["jpegtran", "-flip", "horizontal", "-copy", "all",
+                         "-outfile", output_path, input_path],
+                        capture_output=True, timeout=30
+                    )
+                    if result.returncode == 0:
+                        with open(output_path, "rb") as f:
+                            current_data = f.read()
+                finally:
+                    for p in [input_path, output_path]:
+                        try:
+                            os.unlink(p)
+                        except OSError:
+                            pass
+
+            # Apply vertical flip
+            if flip_v:
+                with tempfile.NamedTemporaryFile(suffix=".jpg", delete=False) as f:
+                    f.write(current_data)
+                    input_path = f.name
+                output_path = tempfile.mktemp(suffix=".jpg")
+                try:
+                    result = subprocess.run(
+                        ["jpegtran", "-flip", "vertical", "-copy", "all",
+                         "-outfile", output_path, input_path],
+                        capture_output=True, timeout=30
+                    )
+                    if result.returncode == 0:
+                        with open(output_path, "rb") as f:
+                            current_data = f.read()
+                finally:
+                    for p in [input_path, output_path]:
+                        try:
+                            os.unlink(p)
+                        except OSError:
+                            pass
+
+            buffer = io.BytesIO(current_data)
+            mimetype = "image/jpeg"
+            ext = "jpg"
+        else:
+            # Fallback to PIL for non-JPEGs or when jpegtran unavailable
+            img = Image.open(io.BytesIO(image_data))
+
+            # Apply rotation (PIL rotates counter-clockwise, so negate)
+            if rotation:
+                img = img.rotate(-rotation, expand=True)
+
+            # Apply flips
+            if flip_h:
+                img = img.transpose(Image.FLIP_LEFT_RIGHT)
+            if flip_v:
+                img = img.transpose(Image.FLIP_TOP_BOTTOM)
+
+            # Preserve original format
+            buffer = io.BytesIO()
+            if original_format == "JPEG":
+                if img.mode in ("RGBA", "P"):
+                    img = img.convert("RGB")
+                img.save(buffer, format="JPEG", quality=95)
+                mimetype = "image/jpeg"
+                ext = "jpg"
+            else:
+                img.save(buffer, format="PNG")
+                mimetype = "image/png"
+                ext = "png"
+            buffer.seek(0)
 
         stem = (
             image_file.filename.rsplit(".", 1)[0]
@@ -2144,9 +2232,9 @@ def api_tools_rotate():
         )
         return send_file(
             buffer,
-            mimetype="image/png",
+            mimetype=mimetype,
             as_attachment=True,
-            download_name=f"{stem}_transformed.png",
+            download_name=f"{stem}_transformed.{ext}",
         )
     except Exception as e:
         return jsonify({"success": False, "error": str(e)}), 500

frontends/web/static/js/stegasoo.js

@@ -1009,7 +1009,9 @@ const Stegasoo = {
                 const percent = progressData.percent || 0;
                 const phase = progressData.phase || 'processing';
 
-                this.updateProgress(percent, this.formatPhase(phase));
+                // Use indeterminate mode for initializing/starting phases
+                const isIndeterminate = (phase === 'initializing' || phase === 'starting');
+                this.updateProgress(percent, this.formatPhase(phase), isIndeterminate);
 
                 // Continue polling
                 setTimeout(poll, 500);
@@ -1029,7 +1031,7 @@ const Stegasoo = {
     formatPhase(phase) {
         const phases = {
             'starting': 'Starting...',
-            'initializing': 'Initializing...',
+            'initializing': 'Deriving keys (may take a moment)...',
             'embedding': 'Embedding data...',
             'saving': 'Saving image...',
             'finalizing': 'Finalizing...',
@@ -1070,8 +1072,9 @@ const Stegasoo = {
             document.body.appendChild(modal);
         }
 
-        // Reset progress
-        this.updateProgress(0, 'Initializing...');
+        // Reset progress tracking and start with indeterminate state
+        this.resetProgressTracking();
+        this.updateProgress(0, 'Initializing...', true);
 
         // Show modal
         const bsModal = new bootstrap.Modal(modal);
@@ -1090,16 +1093,47 @@ const Stegasoo = {
     },
 
     /**
-     * Update progress bar and text
+     * Track max progress to prevent backwards jumps
      */
-    updateProgress(percent, phase) {
+    _maxProgress: 0,
+
+    /**
+     * Reset progress tracking (call when starting new operation)
+     */
+    resetProgressTracking() {
+        this._maxProgress = 0;
+    },
+
+    /**
+     * Update progress bar and text
+     * Supports indeterminate mode for initializing phase (barber pole at full width)
+     */
+    updateProgress(percent, phase, indeterminate = false) {
         const progressBar = document.getElementById('progressBar');
         const progressText = document.getElementById('progressText');
         const phaseText = document.getElementById('progressPhase');
 
-        if (progressBar) progressBar.style.width = percent + '%';
-        if (progressText) progressText.textContent = Math.round(percent) + '%';
-        if (phaseText) phaseText.textContent = phase;
+        if (indeterminate) {
+            // Barber pole animation at full width, no percentage
+            if (progressBar) {
+                progressBar.style.width = '100%';
+                progressBar.classList.add('progress-bar-striped', 'progress-bar-animated');
+            }
+            if (progressText) progressText.textContent = '';
+            if (phaseText) phaseText.textContent = phase;
+        } else {
+            // Determinate progress - never go backwards
+            const safePercent = Math.max(percent, this._maxProgress);
+            this._maxProgress = safePercent;
+
+            if (progressBar) {
+                progressBar.style.width = safePercent + '%';
+                // Keep animation but show actual progress
+                progressBar.classList.add('progress-bar-striped', 'progress-bar-animated');
+            }
+            if (progressText) progressText.textContent = Math.round(safePercent) + '%';
+            if (phaseText) phaseText.textContent = phase;
+        }
     },
 
     // ========================================================================
@@ -1187,7 +1221,9 @@ const Stegasoo = {
                 const percent = progressData.percent || 0;
                 const phase = progressData.phase || 'processing';
 
-                this.updateProgress(percent, this.formatDecodePhase(phase));
+                // Use indeterminate mode for initializing/starting/loading phases
+                const isIndeterminate = (phase === 'initializing' || phase === 'starting' || phase === 'loading');
+                this.updateProgress(percent, this.formatDecodePhase(phase), isIndeterminate);
 
                 // Continue polling
                 setTimeout(poll, 500);
@@ -1207,8 +1243,11 @@ const Stegasoo = {
     formatDecodePhase(phase) {
         const phases = {
             'starting': 'Starting...',
+            'initializing': 'Deriving keys (may take a moment)...',
+            'loading': 'Deriving keys (may take a moment)...',
             'reading': 'Reading image...',
             'extracting': 'Extracting data...',
+            'decoding': 'Decoding data...',
             'decrypting': 'Decrypting...',
             'verifying': 'Verifying...',
             'finalizing': 'Finalizing...',

frontends/web/static/style.css

@@ -2247,7 +2247,7 @@ footer {
     display: none;
     width: 100%;
     flex: 1;
-    padding: 1.25rem;
+    padding: 0.5rem;
 }
 
 .tool-section.active {
@@ -2255,33 +2255,92 @@ footer {
     flex-direction: column;
 }
 
-/* EXIF Table in Results */
-.tool-exif-table {
-    font-size: 0.8rem;
-    max-height: 250px;
+/* EXIF Grid Layout */
+.exif-grid {
+    display: grid;
+    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
+    gap: 0.3rem;
+    max-height: 280px;
     overflow-y: auto;
+    padding: 0.15rem;
 }
 
-.tool-exif-table table {
-    width: 100%;
+.exif-card {
+    background: rgba(255, 255, 255, 0.03);
+    border: 1px solid rgba(255, 255, 255, 0.06);
+    border-radius: 4px;
+    padding: 0.25rem 0.4rem;
 }
 
-.tool-exif-table th,
-.tool-exif-table td {
-    padding: 0.35rem 0.5rem;
-    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
+.exif-card:hover {
+    background: rgba(255, 255, 255, 0.06);
 }
 
-.tool-exif-table th {
+.exif-card-label {
+    font-size: 0.55rem;
     font-weight: 500;
-    color: rgba(255, 255, 255, 0.5);
-    text-align: left;
-    width: 40%;
+    color: rgba(255, 255, 255, 0.4);
+    text-transform: uppercase;
+    letter-spacing: 0.02em;
+    margin-bottom: 0.1rem;
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
 }
 
-.tool-exif-table td {
+.exif-card-value {
+    font-size: 0.7rem;
     font-family: 'SF Mono', 'Consolas', monospace;
-    word-break: break-all;
+    color: rgba(255, 255, 255, 0.85);
+    word-break: break-word;
+    line-height: 1.2;
+}
+
+.exif-card-value.truncated {
+    max-height: 2.4em;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    display: -webkit-box;
+    -webkit-line-clamp: 2;
+    -webkit-box-orient: vertical;
+}
+
+/* Category headers */
+.exif-category {
+    grid-column: 1 / -1;
+    font-size: 0.6rem;
+    font-weight: 600;
+    color: var(--bs-primary);
+    text-transform: uppercase;
+    letter-spacing: 0.04em;
+    padding: 0.35rem 0 0.15rem;
+    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
+    margin-top: 0.15rem;
+}
+
+.exif-category:first-child {
+    margin-top: 0;
+    padding-top: 0;
+}
+
+/* Compact tool headers and actions */
+.tool-results-header {
+    padding-bottom: 0.35rem;
+    margin-bottom: 0.35rem;
+}
+
+.tool-results-header h6 {
+    font-size: 0.8rem;
+    margin-bottom: 0;
+}
+
+.tool-results-header small {
+    font-size: 0.65rem;
+}
+
+.tool-results-actions {
+    padding-top: 0.35rem;
+    margin-top: 0.35rem;
 }
 
 /* Loading State */

frontends/web/stego_worker.py

@@ -3,7 +3,7 @@
 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.
+If it crashes due to jpeglib/scipy issues, the parent Flask process survives.
 
 CHANGES in v4.0.0:
 - Added channel_key support for encode/decode operations
@@ -171,8 +171,7 @@ def decode_operation(params: dict) -> dict:
     # Resolve channel key (v4.0.0)
     resolved_channel_key = _resolve_channel_key(params.get("channel_key", "auto"))
 
-    _write_decode_progress(progress_file, 25, "extracting")
-
+    # Library handles progress internally via progress_file parameter
     # Call decode with correct parameter names
     result = decode(
         stego_image=stego_data,
@@ -183,9 +182,9 @@ def decode_operation(params: dict) -> dict:
         rsa_password=params.get("rsa_password"),
         embed_mode=params.get("embed_mode", "auto"),
         channel_key=resolved_channel_key,  # v4.0.0
+        progress_file=progress_file,  # v4.2.0: pass through for real-time progress
     )
-
-    _write_decode_progress(progress_file, 90, "finalizing")
+    # Library writes 100% "complete" - no need for worker to write again
 
     if result.is_file:
         return {

frontends/web/subprocess_stego.py

@@ -132,7 +132,7 @@ class SubprocessStego:
     """
     Subprocess-isolated steganography operations.
 
-    All operations run in a separate Python process. If jpegio or scipy
+    All operations run in a separate Python process. If jpeglib or scipy
     crashes, only the subprocess dies - Flask keeps running.
     """
 

frontends/web/templates/about.html

@@ -340,11 +340,13 @@
                 <!-- 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>
+                        <span class="badge bg-success fs-6 me-3">v4.2.1</span>
                         <div>
-                            <strong>Progress bars</strong> for encode operations,
-                            <strong>mobile-responsive polish</strong>,
-                            DCT decode bug fix, release validation script
+                            <strong>Security & API improvements:</strong>
+                            API key authentication,
+                            TLS with self-signed certs,
+                            CLI tools (compress, rotate, convert),
+                            jpegtran lossless JPEG rotation
                         </div>
                     </div>
                 </div>
@@ -362,6 +364,10 @@
                             <div class="accordion-body p-0">
                                 <table class="table table-dark table-sm small mb-0">
                                     <tbody>
+                                        <tr>
+                                            <td width="80"><strong>4.1.7</strong></td>
+                                            <td>Progress bars for encode, mobile polish, release validation</td>
+                                        </tr>
                                         <tr>
                                             <td width="80"><strong>4.1.1</strong></td>
                                             <td>DCT RS format stability, Docker cleanup, first-boot wizard</td>
@@ -559,7 +565,7 @@
                                         </tr>
                                         <tr>
                                             <td><i class="bi bi-clock me-2"></i>File expiry</td>
-                                            <td><strong>5 min</strong></td>
+                                            <td><strong>10 min</strong></td>
                                         </tr>
                                         <tr>
                                             <td><i class="bi bi-key me-2"></i>PIN</td>
@@ -567,7 +573,7 @@
                                         </tr>
                                         <tr>
                                             <td><i class="bi bi-shield me-2"></i>RSA keys</td>
-                                            <td><strong>2048, 3072, 4096 bit</strong></td>
+                                            <td><strong>2048, 3072 bit</strong></td>
                                         </tr>
                                         <tr>
                                             <td><i class="bi bi-chat-quote me-2"></i>Passphrase</td>

frontends/web/templates/base.html

@@ -16,11 +16,11 @@
                 <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 }}">
+            <span class="badge bg-success bg-opacity-25 small me-auto" 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.">
+            <span class="badge bg-secondary bg-opacity-25 small text-muted me-auto" 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 %}

frontends/web/templates/decode.html

@@ -158,7 +158,7 @@
 
                 <div class="alert alert-warning small">
                     <i class="bi bi-clock me-1"></i>
-                    <strong>File expires in 5 minutes.</strong> Download now.
+                    <strong>File expires in 10 minutes.</strong> Download now.
                 </div>
 
                 <a href="/decode" class="btn btn-outline-light w-100">

frontends/web/templates/encode_result.html

@@ -128,7 +128,7 @@
                     <i class="bi bi-exclamation-triangle me-1"></i>
                     <strong>Important:</strong>
                     <ul class="mb-0 mt-2">
-                        <li>This file expires in <strong>5 minutes</strong></li>
+                        <li>This file expires in <strong>10 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>

frontends/web/templates/generate.html

@@ -65,11 +65,7 @@
                                 <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>
@@ -286,12 +282,6 @@
                                     <i class="bi bi-shield-exclamation me-1"></i>
                                     <strong>Security note:</strong> The QR code contains your unencrypted private key.
                                     Only scan in a secure environment. Consider using the password-protected download instead.
-                                    {% if rsa_bits >= 4096 %}
-                                    <br><br>
-                                    <i class="bi bi-exclamation-triangle me-1"></i>
-                                    <strong>4096-bit keys</strong> produce very dense QR codes. If scanning fails, 
-                                    use the PEM text or download options instead.
-                                    {% endif %}
                                 </div>
                             </div>
                         </div>

frontends/web/templates/tools.html

@@ -22,17 +22,17 @@
                 <div class="tools-ribbon-divider"></div>
 
                 <div class="tools-ribbon-group">
-                    <button class="tool-icon-btn" data-tool="strip" title="Strip Metadata">
-                        <i class="bi bi-eraser"></i>
-                        <span>Strip</span>
+                    <button class="tool-icon-btn" data-tool="compress" title="JPEG Compression">
+                        <i class="bi bi-file-zip"></i>
+                        <span>Compress</span>
                     </button>
                     <button class="tool-icon-btn" data-tool="rotate" title="Rotate / Flip">
                         <i class="bi bi-arrow-repeat"></i>
                         <span>Rotate</span>
                     </button>
-                    <button class="tool-icon-btn" data-tool="compress" title="JPEG Compression">
-                        <i class="bi bi-file-zip"></i>
-                        <span>Compress</span>
+                    <button class="tool-icon-btn" data-tool="strip" title="Strip Metadata">
+                        <i class="bi bi-eraser"></i>
+                        <span>Strip</span>
                     </button>
                     <button class="tool-icon-btn" data-tool="convert" title="Format Convert">
                         <i class="bi bi-arrow-left-right"></i>
@@ -283,10 +283,8 @@
                                 <span>Drop an image to view metadata</span>
                             </div>
                             <div id="exifData" class="d-none">
-                                <div class="tool-exif-table">
-                                    <table>
-                                        <tbody id="exifTable"></tbody>
-                                    </table>
+                                <div class="exif-grid" id="exifGrid">
+                                    <!-- Cards populated by JS -->
                                 </div>
                                 <div id="exifNoData" class="text-muted text-center py-3 d-none">
                                     <i class="bi bi-inbox d-block mb-2"></i>
@@ -368,6 +366,14 @@
                                     <span class="tool-result-label">Flipped</span>
                                     <span class="tool-result-value" id="rotateFlip">None</span>
                                 </div>
+                                <div class="alert alert-success small mt-3 mb-0" id="rotateJpegSafe" style="display: none;">
+                                    <i class="bi bi-check-circle me-1"></i>
+                                    <strong>DCT Safe:</strong> Uses jpegtran for lossless JPEG rotation. Your stego data will be preserved.
+                                </div>
+                                <div class="alert alert-warning small mt-3 mb-0" id="rotateNonJpegWarn" style="display: none;">
+                                    <i class="bi bi-exclamation-triangle me-1"></i>
+                                    <strong>Note:</strong> Non-JPEG images are re-encoded during rotation.
+                                </div>
                             </div>
                         </div>
                         <div class="tool-results-actions d-none" id="rotateActions">
@@ -634,30 +640,104 @@ setupDropZone('exifZone', 'exifFile', async (file) => {
 
     try {
         const res = await fetch('/api/tools/exif', { method: 'POST', body: formData });
+
+        // Check for auth redirect or non-JSON response
+        const contentType = res.headers.get('content-type') || '';
+        if (!contentType.includes('application/json')) {
+            console.error('EXIF API returned non-JSON:', res.status, contentType);
+            document.getElementById('exifNoData').classList.remove('d-none');
+            document.getElementById('exifNoData').innerHTML = '<i class="bi bi-exclamation-triangle d-block mb-2"></i>Session expired - please refresh';
+            document.getElementById('exifEmpty').classList.add('d-none');
+            document.getElementById('exifData').classList.remove('d-none');
+            return;
+        }
+
         const data = await res.json();
 
         if (data.success) {
-            const tbody = document.getElementById('exifTable');
-            const entries = Object.entries(data.exif).sort((a, b) => a[0].localeCompare(b[0]));
+            const grid = document.getElementById('exifGrid');
+            const entries = Object.entries(data.exif);
 
             if (entries.length === 0) {
-                tbody.innerHTML = '';
+                grid.innerHTML = '';
                 document.getElementById('exifNoData').classList.remove('d-none');
+                document.getElementById('exifNoData').innerHTML = '<i class="bi bi-inbox d-block mb-2"></i>No metadata found';
             } else {
                 document.getElementById('exifNoData').classList.add('d-none');
-                tbody.innerHTML = entries.map(([key, value]) => {
+
+                // Categorize EXIF fields
+                const categories = {
+                    'Camera': ['Make', 'Model', 'Software', 'LensMake', 'LensModel', 'BodySerialNumber'],
+                    'Image': ['ImageWidth', 'ImageLength', 'Orientation', 'ResolutionUnit', 'XResolution', 'YResolution', 'ColorSpace', 'ExifImageWidth', 'ExifImageHeight'],
+                    'Date/Time': ['DateTime', 'DateTimeOriginal', 'DateTimeDigitized', 'SubsecTime', 'SubsecTimeOriginal', 'SubsecTimeDigitized', 'OffsetTime', 'OffsetTimeOriginal'],
+                    'Exposure': ['ExposureTime', 'FNumber', 'ExposureProgram', 'ISOSpeedRatings', 'ExposureBiasValue', 'MaxApertureValue', 'MeteringMode', 'Flash', 'FocalLength', 'FocalLengthIn35mmFilm', 'WhiteBalance', 'ExposureMode', 'DigitalZoomRatio', 'SceneCaptureType', 'Contrast', 'Saturation', 'Sharpness'],
+                    'GPS': ['GPSInfo', 'GPSLatitude', 'GPSLatitudeRef', 'GPSLongitude', 'GPSLongitudeRef', 'GPSAltitude', 'GPSAltitudeRef', 'GPSTimeStamp', 'GPSDateStamp'],
+                };
+
+                const categorized = {};
+                const other = [];
+                const allCategoryFields = new Set(Object.values(categories).flat());
+
+                entries.forEach(([key, value]) => {
+                    let found = false;
+                    for (const [cat, fields] of Object.entries(categories)) {
+                        if (fields.includes(key)) {
+                            if (!categorized[cat]) categorized[cat] = [];
+                            categorized[cat].push([key, value]);
+                            found = true;
+                            break;
+                        }
+                    }
+                    if (!found) other.push([key, value]);
+                });
+
+                // Render cards
+                let html = '';
+                const renderCard = ([key, value]) => {
                     let displayVal = typeof value === 'object' ? JSON.stringify(value) : String(value);
-                    if (displayVal.length > 40) displayVal = displayVal.substring(0, 37) + '...';
-                    return `<tr><th>${key}</th><td title="${String(value)}">${displayVal}</td></tr>`;
-                }).join('');
+                    const needsTruncate = displayVal.length > 60;
+                    if (needsTruncate) displayVal = displayVal.substring(0, 57) + '...';
+                    const fullVal = typeof value === 'object' ? JSON.stringify(value) : String(value);
+                    return `<div class="exif-card" title="${fullVal.replace(/"/g, '&quot;')}">
+                        <div class="exif-card-label">${key}</div>
+                        <div class="exif-card-value${needsTruncate ? ' truncated' : ''}">${displayVal}</div>
+                    </div>`;
+                };
+
+                // Render each category
+                for (const [cat, fields] of Object.entries(categories)) {
+                    if (categorized[cat] && categorized[cat].length > 0) {
+                        html += `<div class="exif-category"><i class="bi bi-${cat === 'Camera' ? 'camera' : cat === 'Image' ? 'image' : cat === 'Date/Time' ? 'clock' : cat === 'Exposure' ? 'aperture' : cat === 'GPS' ? 'geo-alt' : 'tag'} me-1"></i>${cat}</div>`;
+                        html += categorized[cat].map(renderCard).join('');
+                    }
+                }
+
+                // Render other fields
+                if (other.length > 0) {
+                    html += `<div class="exif-category"><i class="bi bi-three-dots me-1"></i>Other</div>`;
+                    html += other.map(renderCard).join('');
+                }
+
+                grid.innerHTML = html;
             }
 
             document.getElementById('exifEmpty').classList.add('d-none');
             document.getElementById('exifData').classList.remove('d-none');
             document.getElementById('exifActions').classList.remove('d-none');
+        } else {
+            // API returned success: false
+            console.error('EXIF API error:', data.error);
+            document.getElementById('exifNoData').classList.remove('d-none');
+            document.getElementById('exifNoData').innerHTML = `<i class="bi bi-exclamation-triangle d-block mb-2"></i>${data.error || 'Error reading metadata'}`;
+            document.getElementById('exifEmpty').classList.add('d-none');
+            document.getElementById('exifData').classList.remove('d-none');
         }
     } catch (err) {
-        console.error(err);
+        console.error('EXIF fetch error:', err);
+        document.getElementById('exifNoData').classList.remove('d-none');
+        document.getElementById('exifNoData').innerHTML = '<i class="bi bi-exclamation-triangle d-block mb-2"></i>Error loading metadata';
+        document.getElementById('exifEmpty').classList.add('d-none');
+        document.getElementById('exifData').classList.remove('d-none');
     }
 });
 
@@ -796,6 +876,11 @@ setupDropZone('rotateZone', 'rotateFile', async (file) => {
     document.getElementById('rotateData').classList.remove('d-none');
     document.getElementById('rotateActions').classList.remove('d-none');
 
+    // Show appropriate DCT warning based on file type
+    const isJpeg = file.type === 'image/jpeg' || file.name.toLowerCase().match(/\.jpe?g$/);
+    document.getElementById('rotateJpegSafe').style.display = isJpeg ? 'block' : 'none';
+    document.getElementById('rotateNonJpegWarn').style.display = isJpeg ? 'none' : 'block';
+
     // Load image to get dimensions, then show preview
     const thumb = document.getElementById('rotateThumb');
     const objectUrl = URL.createObjectURL(file);
@@ -889,6 +974,8 @@ function clearRotate() {
         document.getElementById('rotateData').classList.add('d-none');
         document.getElementById('rotateActions').classList.add('d-none');
         document.getElementById('rotateFileInfo').classList.add('d-none');
+        document.getElementById('rotateJpegSafe').style.display = 'none';
+        document.getElementById('rotateNonJpegWarn').style.display = 'none';
         const thumb = document.getElementById('rotateThumb');
         thumb.style.transform = '';
         thumb.style.width = '';
@@ -920,8 +1007,7 @@ document.getElementById('rotateDownload')?.addEventListener('click', async funct
             const url = URL.createObjectURL(blob);
             const a = document.createElement('a');
             a.href = url;
-            const baseName = rotateCurrentFile?.name?.replace(/\.[^.]+$/, '') || 'rotated';
-            a.download = `${baseName}_transformed.png`;
+            a.download = res.headers.get('Content-Disposition')?.split('filename=')[1]?.replace(/"/g, '') || 'rotated.jpg';
             document.body.appendChild(a);
             a.click();
             document.body.removeChild(a);

pyproject.toml

@@ -4,11 +4,11 @@ build-backend = "hatchling.build"
 
 [project]
 name = "stegasoo"
-version = "4.1.5"
+version = "4.2.1"
 description = "Secure steganography with hybrid photo + passphrase + PIN authentication"
 readme = "README.md"
 license = "MIT"
-requires-python = ">=3.10"
+requires-python = ">=3.11"
 authors = [
     { name = "Aaron D. Lee" }
 ]
@@ -29,9 +29,10 @@ classifiers = [
     "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
     "Topic :: Security :: Cryptography",
     "Topic :: Multimedia :: Graphics",
 ]
@@ -40,6 +41,7 @@ dependencies = [
     "pillow>=10.0.0",
     "cryptography>=41.0.0",
     "argon2-cffi>=23.0.0",
+    "zstandard>=0.22.0",  # v4.2.0: Default compression algorithm
 ]
 
 [project.optional-dependencies]
@@ -47,7 +49,7 @@ dependencies = [
 dct = [
     "numpy>=2.0.0",
     "scipy>=1.10.0",
-    "jpegio>=0.2.0",
+    "jpeglib>=1.0.0",
     "reedsolo>=1.7.0",
 ]
 cli = [
@@ -57,7 +59,7 @@ cli = [
     "rich>=13.0.0",
 ]
 compression = [
-    "lz4>=4.0.0",
+    "lz4>=4.0.0",  # Optional: faster but slightly worse ratio than zstd
 ]
 web = [
     "flask>=3.0.0",
@@ -68,7 +70,7 @@ web = [
     # Include DCT support for web UI
     "numpy>=2.0.0",
     "scipy>=1.10.0",
-    "jpegio>=0.2.0",
+    "jpeglib>=1.0.0",
     "reedsolo>=1.7.0",
 ]
 api = [
@@ -80,7 +82,7 @@ api = [
     # Include DCT support for API
     "numpy>=2.0.0",
     "scipy>=1.10.0",
-    "jpegio>=0.2.0",
+    "jpeglib>=1.0.0",
     "reedsolo>=1.7.0",
 ]
 all = [
@@ -110,7 +112,14 @@ include = [
 ]
 
 [tool.hatch.build.targets.wheel]
-packages = ["src/stegasoo"]
+packages = ["src/stegasoo", "frontends"]
+
+[tool.hatch.build.targets.wheel.sources]
+"src" = ""
+
+# Include data files in the wheel
+[tool.hatch.build.targets.wheel.force-include]
+"src/stegasoo/data/bip39-words.txt" = "stegasoo/data/bip39-words.txt"
 
 [tool.pytest.ini_options]
 testpaths = ["tests"]
@@ -119,7 +128,7 @@ addopts = "-v --cov=stegasoo --cov-report=term-missing"
 
 [tool.black]
 line-length = 100
-target-version = ["py310", "py311", "py312"]
+target-version = ["py311", "py312", "py313"]
 
 [tool.ruff]
 line-length = 100
@@ -136,7 +145,7 @@ ignore = ["E501"]
 "src/stegasoo/__init__.py" = ["E402"]
 
 [tool.mypy]
-python_version = "3.10"
+python_version = "3.11"
 warn_return_any = true
 warn_unused_configs = true
 ignore_missing_imports = true

rpi/BUILD_IMAGE.md

@@ -26,51 +26,50 @@ ssh admin@stegasoo.local
 ## Step 3: Pre-Setup
 
 ```bash
-# Take ownership of /opt (for pyenv, jpegio builds)
+# Take ownership of /opt
 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
+# Install git (not included in Lite image)
+sudo apt-get update && sudo apt-get install -y git
 ```
 
 ## Step 4: Clone Repo
 
 ```bash
 cd /opt
-git clone -b 4.1 https://github.com/adlee-was-taken/stegasoo.git stegasoo
+git clone -b 4.2 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
+## Step 5: Run Setup
 
 ```bash
 cd /opt/stegasoo
-./rpi/setup.sh  # Detects local tarball, skips download
+./rpi/setup.sh
 ```
 
-### From-Source Build (optional)
+The setup script:
+- Verifies Python 3.11+ (system Python, no pyenv needed)
+- Installs dependencies via apt and pip
+- jpeglib installs cleanly (no ARM patching like jpegio)
+- Creates and enables systemd service
+
+Install time: **5-10 minutes** (from source)
+
+### Pre-built Venv (optional)
+
+For faster installs, you can provide a pre-built venv tarball:
 
-To build without the pre-built tarball:
 ```bash
-./rpi/setup.sh --no-prebuilt  # Takes 15-20 minutes
+# On your host machine:
+scp rpi/stegasoo-rpi-venv-arm64.tar.zst admin@stegasoo.local:/opt/stegasoo/rpi/
+
+# Then on Pi:
+cd /opt/stegasoo && ./rpi/setup.sh  # Detects local tarball, skips pip build
 ```
 
-## Step 7: Test It Works
+Install time with pre-built: **~2 minutes**
+
+## Step 6: Test It Works
 
 ```bash
 sudo systemctl start stegasoo
@@ -78,7 +77,7 @@ curl -k https://localhost:5000
 # Should return HTML
 ```
 
-## Step 8: Sanitize for Distribution
+## Step 7: Sanitize for Distribution
 
 ```bash
 # Full sanitize (for final image - removes WiFi, shuts down)
@@ -98,7 +97,7 @@ This removes:
 
 The script validates all cleanup steps before finishing.
 
-## Step 9: Pull the Image
+## Step 8: Pull the Image
 
 Remove SD card, insert into your Linux machine:
 
@@ -107,12 +106,12 @@ Remove SD card, insert into your Linux machine:
 lsblk
 
 # Pull image (auto-resizes to 16GB, compresses with zstd)
-sudo ./rpi/pull-image.sh /dev/sdX stegasoo-rpi-4.1.5.img.zst
+sudo ./rpi/pull-image.sh /dev/sdX stegasoo-rpi-4.2.1.img.zst
 ```
 
 The script automatically resizes rootfs to 16GB (for smaller download), preserves auto-expand, and compresses.
 
-## Step 10: Distribute
+## Step 9: Distribute
 
 Upload `.img.zst` to GitHub Releases.
 
@@ -130,36 +129,31 @@ zstdcat stegasoo-rpi-*.img.zst | sudo dd of=/dev/sdX bs=4M status=progress
 
 ---
 
-## Creating the Pre-built Tarball
+## Creating the Pre-built Venv Tarball
 
 After a successful from-source build, create the pre-built tarball for future installs:
 
 ```bash
 # On the Pi after successful setup:
-cd ~
+cd /opt/stegasoo
 
-# 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
+# Strip caches and tests from venv (saves ~100MB)
+find venv/ -type d -name '__pycache__' -exec rm -rf {} + 2>/dev/null
+find venv/ -type d -name 'tests' -exec rm -rf {} + 2>/dev/null
+find 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
+tar -cf - venv/ | zstd -19 -T0 > /tmp/stegasoo-rpi-venv-arm64.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
+# Check size (should be ~40-50MB)
+ls -lh /tmp/stegasoo-rpi-venv-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
+scp admin@stegasoo.local:/tmp/stegasoo-rpi-venv-arm64.tar.zst ./rpi/
+# Upload to GitHub releases as stegasoo-rpi-venv-arm64.tar.zst
 ```
 
 ---
@@ -169,18 +163,15 @@ scp admin@stegasoo.local:/tmp/stegasoo-rpi-runtime-env-arm64.tar.zst ./
 ```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
+sudo apt-get update && sudo apt-get install -y git
+cd /opt && git clone -b 4.2 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):
+# 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
+sudo ./rpi/pull-image.sh /dev/sdX stegasoo-rpi-4.2.1.img.zst
 ```

rpi/README.md

@@ -4,7 +4,7 @@ Scripts and resources for deploying Stegasoo on Raspberry Pi.
 
 ## Quick Install
 
-On a fresh Raspberry Pi OS Lite (64-bit) installation:
+On a fresh Raspberry Pi OS (64-bit) installation:
 
 ```bash
 # Pre-setup (git not included in Lite image)
@@ -13,16 +13,16 @@ 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
+git clone -b 4.2 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
+1. **Verifies Python 3.11+** - uses system Python (no pyenv needed)
+2. **Installs system dependencies** - build tools, libraries
+3. **Installs jpeglib** - DCT steganography (Python 3.11-3.14 compatible)
 4. **Installs Stegasoo** - with web UI and all dependencies
 5. **Creates systemd service** - auto-starts on boot
 6. **Enables the service** - ready to start
@@ -30,11 +30,18 @@ cd stegasoo
 ## Requirements
 
 - Raspberry Pi 4 or 5
-- Raspberry Pi OS Lite (64-bit) - Bookworm or later
+- Raspberry Pi OS (64-bit) - Bookworm (Python 3.11) or Trixie (Python 3.13)
 - 4GB+ RAM recommended (2GB minimum)
 - 16GB+ SD card (pre-built images are 16GB)
 - Internet connection
 
+### Python Compatibility
+
+| Raspberry Pi OS | Python | Supported |
+|-----------------|--------|-----------|
+| Bookworm        | 3.11   | Yes       |
+| Trixie          | 3.13   | Yes       |
+
 ### 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).
@@ -159,7 +166,7 @@ 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
+git clone -b 4.2 https://github.com/adlee-was-taken/stegasoo.git stegasoo
 cd stegasoo
 ./rpi/setup.sh
 ```
@@ -200,7 +207,7 @@ After Pi shuts down, remove SD card and on another Linux machine:
 lsblk
 
 # Pull image (auto-resizes to 16GB, compresses with zstd)
-sudo ./rpi/pull-image.sh /dev/sdX stegasoo-rpi-4.1.5.img.zst
+sudo ./rpi/pull-image.sh /dev/sdX stegasoo-rpi-4.2.1.img.zst
 ```
 
 The `pull-image.sh` script automatically:

rpi/build-runtime-tarball.sh

@@ -1,10 +1,10 @@
 #!/bin/bash
 #
-# Build Stegasoo Pi Runtime Environment Tarball
+# Build Stegasoo Pi venv Tarball
 # Run this ON THE PI after a successful from-source build
 #
-# Creates: stegasoo-rpi-runtime-env-arm64.tar.zst (~50-60MB)
-# Contains: pyenv + Python 3.12 + venv with all dependencies
+# Creates: stegasoo-rpi-venv-arm64.tar.zst (~40-50MB)
+# Contains: venv with all dependencies (uses system Python 3.11+)
 #
 
 set -e
@@ -16,11 +16,10 @@ YELLOW='\033[1;33m'
 NC='\033[0m'
 
 INSTALL_DIR="${INSTALL_DIR:-/opt/stegasoo}"
-OUTPUT_DIR="${OUTPUT_DIR:-/tmp}"
-OUTPUT_FILE="$OUTPUT_DIR/stegasoo-rpi-runtime-env-arm64.tar.zst"
+OUTPUT_FILE="${1:-$HOME/stegasoo-rpi-venv-arm64.tar.zst}"
 
 echo -e "${GREEN}╔═══════════════════════════════════════════════════════════════╗${NC}"
-echo -e "${GREEN}║         Stegasoo Pi Runtime Tarball Builder                   ║${NC}"
+echo -e "${GREEN}║         Stegasoo Pi venv Tarball Builder                      ║${NC}"
 echo -e "${GREEN}╚═══════════════════════════════════════════════════════════════╝${NC}"
 echo ""
 
@@ -32,13 +31,6 @@ if [[ "$ARCH" != "aarch64" ]]; then
     exit 1
 fi
 
-# Verify pyenv exists
-if [[ ! -d "$HOME/.pyenv" ]]; then
-    echo -e "${RED}Error: pyenv not found at ~/.pyenv${NC}"
-    echo "Run a from-source build first: ./rpi/setup.sh --no-prebuilt"
-    exit 1
-fi
-
 # Verify venv exists
 if [[ ! -d "$INSTALL_DIR/venv" ]]; then
     echo -e "${RED}Error: venv not found at $INSTALL_DIR/venv${NC}"
@@ -47,33 +39,22 @@ if [[ ! -d "$INSTALL_DIR/venv" ]]; then
 fi
 
 # Step 1: Clean caches from venv
-echo -e "${GREEN}[1/4]${NC} Cleaning caches from venv..."
+echo -e "${GREEN}[1/2]${NC} Cleaning caches from venv..."
 VENV_SIZE_BEFORE=$(du -sh "$INSTALL_DIR/venv" | cut -f1)
 find "$INSTALL_DIR/venv/" -type d -name '__pycache__' -exec rm -rf {} + 2>/dev/null || true
 find "$INSTALL_DIR/venv/" -type d -name 'tests' -exec rm -rf {} + 2>/dev/null || true
 find "$INSTALL_DIR/venv/" -type d -name 'test' -exec rm -rf {} + 2>/dev/null || true
 find "$INSTALL_DIR/venv/" -type f -name '*.pyc' -delete 2>/dev/null || true
 VENV_SIZE_AFTER=$(du -sh "$INSTALL_DIR/venv" | cut -f1)
-echo "  venv: $VENV_SIZE_BEFORE → $VENV_SIZE_AFTER"
+echo "  venv: $VENV_SIZE_BEFORE -> $VENV_SIZE_AFTER"
 
-# Step 2: Create venv tarball
-echo -e "${GREEN}[2/4]${NC} Creating venv tarball..."
+# Step 2: Create tarball
+echo -e "${GREEN}[2/2]${NC} Creating tarball..."
 cd "$INSTALL_DIR"
-tar -cf - venv/ | zstd -19 -T0 > "$HOME/stegasoo-venv.tar.zst"
-VENV_TAR_SIZE=$(ls -lh "$HOME/stegasoo-venv.tar.zst" | awk '{print $5}')
-echo "  Created: ~/stegasoo-venv.tar.zst ($VENV_TAR_SIZE)"
+tar -cf - venv/ | zstd -19 -T0 > "$OUTPUT_FILE"
 
-# Step 3: Create combined tarball
-echo -e "${GREEN}[3/4]${NC} Creating combined runtime tarball..."
-cd "$HOME"
-tar -cf - .pyenv stegasoo-venv.tar.zst | zstd -19 -T0 > "$OUTPUT_FILE"
-
-# Cleanup intermediate file
-rm "$HOME/stegasoo-venv.tar.zst"
-
-# Step 4: Summary
+# Summary
 FINAL_SIZE=$(ls -lh "$OUTPUT_FILE" | awk '{print $5}')
-echo -e "${GREEN}[4/4]${NC} Done!"
 echo ""
 echo -e "${GREEN}════════════════════════════════════════════════════════════════${NC}"
 echo -e "  Output: ${YELLOW}$OUTPUT_FILE${NC}"
@@ -83,7 +64,7 @@ echo ""
 echo "To pull to your host machine:"
 echo "  scp $(whoami)@$(hostname).local:$OUTPUT_FILE ./"
 echo ""
-echo "To use in setup.sh, copy to:"
-echo "  rpi/stegasoo-rpi-runtime-env-arm64.tar.zst"
+echo "To use in setup.sh, place at:"
+echo "  rpi/stegasoo-rpi-venv-arm64.tar.zst"
 echo ""
 echo "Or upload to GitHub releases for automatic download."

rpi/flash-image.sh

@@ -80,9 +80,9 @@ if [ -z "$1" ]; then
     echo "Supported formats: .img, .img.zst, .img.xz, .img.gz, .img.zst.zip"
     echo ""
     echo "Examples:"
-    echo "  $0 stegasoo-rpi-4.1.1.img.zst             # auto-detect SD card"
-    echo "  $0 stegasoo-rpi-4.1.1.img.zst.zip         # from GitHub release"
-    echo "  $0 stegasoo-rpi-4.1.1.img.zst /dev/sdb    # specify device"
+    echo "  $0 stegasoo-rpi-4.2.1.img.zst             # auto-detect SD card"
+    echo "  $0 stegasoo-rpi-4.2.1.img.zst.zip         # from GitHub release"
+    echo "  $0 stegasoo-rpi-4.2.1.img.zst /dev/sdb    # specify device"
     exit 1
 fi
 

rpi/patches/README.md

@@ -2,56 +2,39 @@
 
 This directory contains patches for dependencies that need modifications to build on ARM64.
 
+## Current Status (v4.2+)
+
+As of Stegasoo 4.2, we use **jpeglib** instead of jpegio. The jpeglib build process is handled inline in `setup.sh` and includes:
+
+- Cloning from GitHub (PyPI tarball missing headers)
+- Downloading libjpeg headers for each version (6b through 9f)
+- Patching setup.py to skip turbo/mozjpeg (need cmake-generated headers)
+
+See `setup.sh` for the full implementation.
+
+## Legacy: jpegio Patches (v4.1 and earlier)
+
+The `jpegio/` directory contains patches for the old jpegio dependency, which required removing x86-specific `-m64` compiler flags. These are no longer used but kept for reference.
+
+## jpeglib Helper Script
+
+The `jpeglib/install-jpeglib-arm64.sh` script is a standalone version of the jpeglib build process. It's not used by setup.sh (which has the logic inline) but can be useful for manual testing or debugging.
+
 ## Structure
 
 ```
 patches/
-  <package>/
-    arm64.patch       # Standard unified diff patch file
-    apply-patch.sh    # Script with fallback strategies
+  jpegio/           # Legacy (v4.1) - not used in v4.2+
+    arm64.patch
+    apply-patch.sh
+  jpeglib/          # Reference script for manual builds
+    install-jpeglib-arm64.sh
 ```
 
-## How It Works
+## Adding New Patches
 
-The `apply-patch.sh` script tries multiple strategies in order:
-
-1. **Patch file** - Apply the `.patch` file using `patch -p1`
-2. **Sed fallback** - Use sed for simple string replacements
-3. **Python fallback** - Use regex for flexible pattern matching
-
-This layered approach handles:
-- Exact matches (patch file works)
-- Minor upstream changes (sed catches variations)
-- Significant changes (Python regex is most flexible)
-- Already patched files (detected and skipped)
-
-## Adding a New Patch
+If a new dependency needs ARM64 patches:
 
 1. Create a directory: `patches/<package>/`
-2. Create the patch file: `git diff > arm64.patch`
-3. Create `apply-patch.sh` with appropriate fallback logic
-4. Update `setup.sh` to call the patch script
-
-## jpegio Patch
-
-The jpegio library includes x86-specific `-m64` compiler flags that fail on ARM64.
-The patch removes these flags by replacing:
-
-```python
-cargs.append('-m64')
-```
-
-with:
-
-```python
-pass  # ARM64: removed x86-specific -m64 flag
-```
-
-## Updating Patches
-
-When upstream changes break a patch:
-
-1. Clone the new version
-2. Make the necessary modifications
-3. Generate a new patch: `diff -u original modified > arm64.patch`
-4. Test on a fresh Pi install
+2. Add patch files or helper scripts
+3. Update `setup.sh` to apply the patch during installation

rpi/patches/jpeglib/install-jpeglib-arm64.sh

@@ -0,0 +1,57 @@
+#!/bin/bash
+#
+# Install jpeglib on ARM64 Linux (Raspberry Pi)
+# Works around missing headers in the source tarball
+#
+# Usage: ./install-jpeglib-arm64.sh
+#
+
+set -e
+
+echo "Installing jpeglib for ARM64..."
+
+# Create temp directory
+WORKDIR=$(mktemp -d)
+cd "$WORKDIR"
+
+# Download jpeglib source
+echo "  Downloading jpeglib source..."
+pip download jpeglib==1.0.2 --no-binary :all: --no-deps -d . -q
+tar -xzf jpeglib-1.0.2.tar.gz
+cd jpeglib-1.0.2
+
+# Download official libjpeg sources and copy headers
+echo "  Downloading libjpeg headers..."
+CJPEGLIB="src/jpeglib/cjpeglib"
+
+# libjpeg 6b
+curl -sL "https://www.ijg.org/files/jpegsrc.v6b.tar.gz" | tar -xzf -
+cp jpeg-6b/*.h "$CJPEGLIB/6b/"
+
+# libjpeg 7-9f (all use similar headers from 9e)
+curl -sL "https://www.ijg.org/files/jpegsrc.v9f.tar.gz" | tar -xzf -
+for v in 7 8 8a 8b 8c 8d 9 9a 9b 9c 9d 9e 9f; do
+    cp jpeg-9f/*.h "$CJPEGLIB/$v/"
+done
+
+# libjpeg-turbo versions
+curl -sL "https://github.com/libjpeg-turbo/libjpeg-turbo/archive/refs/tags/2.1.0.tar.gz" | tar -xzf -
+for v in turbo120 turbo130 turbo140 turbo150 turbo200 turbo210; do
+    cp libjpeg-turbo-2.1.0/*.h "$CJPEGLIB/$v/" 2>/dev/null || true
+done
+
+# mozjpeg versions
+curl -sL "https://github.com/mozilla/mozjpeg/archive/refs/tags/v4.0.3.tar.gz" | tar -xzf -
+for v in mozjpeg101 mozjpeg201 mozjpeg300 mozjpeg403; do
+    cp mozjpeg-4.0.3/*.h "$CJPEGLIB/$v/" 2>/dev/null || true
+done
+
+# Build and install
+echo "  Building jpeglib..."
+pip install . -q
+
+# Cleanup
+cd /
+rm -rf "$WORKDIR"
+
+echo "  Done! jpeglib installed successfully."

rpi/pull-image.sh

@@ -3,7 +3,7 @@
 # Resizes rootfs to 16GB for consistent image size, then pulls
 #
 # Usage: ./pull-image.sh <device> <output.img.zst>
-# Example: ./pull-image.sh /dev/sdb stegasoo-rpi-4.1.5.img.zst
+# Example: ./pull-image.sh /dev/sdb stegasoo-rpi-4.2.1.img.zst
 
 set -e
 
@@ -15,7 +15,7 @@ NC='\033[0m'
 
 if [ $# -ne 2 ]; then
     echo "Usage: $0 <device> <output.img.zst>"
-    echo "Example: $0 /dev/sdb stegasoo-rpi-4.1.5.img.zst"
+    echo "Example: $0 /dev/sdb stegasoo-rpi-4.2.1.img.zst"
     exit 1
 fi
 

rpi/remote-build-pi.sh

@@ -105,7 +105,7 @@ echo ""
 echo -e "${GREEN}[4/6]${NC} Copying pre-built tarball to Pi..."
 echo ""
 
-TARBALL="$SCRIPT_DIR/stegasoo-rpi-runtime-env-arm64.tar.zst"
+TARBALL="$SCRIPT_DIR/stegasoo-rpi-venv-arm64.tar.zst"
 if [[ -f "$TARBALL" ]]; then
     scp_to_pi "$TARBALL" "/opt/stegasoo/rpi/"
     echo -e "  ${GREEN}✓${NC} Tarball copied"

rpi/sanitize-for-image.sh

@@ -264,49 +264,25 @@ if [ -n "$STEGASOO_DIR" ] && [ -d "$STEGASOO_DIR/venv" ]; then
         echo "  Venv broken or stegasoo not installed, rebuilding..."
         rm -rf "$STEGASOO_DIR/venv"
 
-        # Find Python 3.12 (prefer pyenv, fall back to system)
-        USER_HOME=$(eval echo "~$STEGASOO_USER")
-        PYENV_PYTHON="$USER_HOME/.pyenv/versions/3.12*/bin/python"
-        if compgen -G "$PYENV_PYTHON" > /dev/null 2>&1; then
-            PYTHON_BIN=$(ls $PYENV_PYTHON 2>/dev/null | head -1)
-            echo "  Using pyenv Python: $PYTHON_BIN"
-        elif command -v python3.12 &>/dev/null; then
-            PYTHON_BIN="python3.12"
-            echo "  Using system Python 3.12"
-        else
-            PYTHON_BIN="python3"
-            echo "  Warning: Python 3.12 not found, using $($PYTHON_BIN --version)"
-        fi
-
-        sudo -u "$STEGASOO_USER" "$PYTHON_BIN" -m venv "$STEGASOO_DIR/venv"
-        sudo -u "$STEGASOO_USER" "$STEGASOO_DIR/venv/bin/pip" install --quiet --upgrade pip setuptools wheel
-
-        # On ARM64, jpegio needs patching before install
-        ARCH=$(uname -m)
-        if [[ "$ARCH" == "aarch64" || "$ARCH" == "arm64" ]]; then
-            echo "  Building jpegio for ARM64 (this may take a minute)..."
-            # Install build deps
-            sudo -u "$STEGASOO_USER" "$STEGASOO_DIR/venv/bin/pip" install --quiet cython numpy
-            JPEGIO_DIR="/tmp/jpegio-build-$$"
-            rm -rf "$JPEGIO_DIR"
-            if git clone https://github.com/dwgoon/jpegio.git "$JPEGIO_DIR" 2>/dev/null; then
-                # Apply patch to remove -m64 flag
-                if [ -f "$STEGASOO_DIR/rpi/patches/jpegio/apply-patch.sh" ]; then
-                    bash "$STEGASOO_DIR/rpi/patches/jpegio/apply-patch.sh" "$JPEGIO_DIR"
-                else
-                    sed -i "s/cargs.append('-m64')/pass  # ARM64 fix/g" "$JPEGIO_DIR/setup.py"
-                fi
-                # Change ownership so user can build
-                chown -R "$STEGASOO_USER:$STEGASOO_USER" "$JPEGIO_DIR"
-                sudo -u "$STEGASOO_USER" "$STEGASOO_DIR/venv/bin/pip" install "$JPEGIO_DIR"
-                rm -rf "$JPEGIO_DIR"
-            else
-                echo "  Warning: Failed to clone jpegio, DCT mode may not work"
+        # Find system Python 3.11+ (no pyenv needed)
+        PYTHON_BIN=""
+        for py in python3.14 python3.13 python3.12 python3.11 python3; do
+            if command -v "$py" &>/dev/null; then
+                PYTHON_BIN=$(command -v "$py")
+                break
             fi
-        fi
+        done
 
-        sudo -u "$STEGASOO_USER" "$STEGASOO_DIR/venv/bin/pip" install --quiet -e "$STEGASOO_DIR[web]"
-        echo "  Venv rebuilt and stegasoo installed"
+        if [ -z "$PYTHON_BIN" ]; then
+            echo "  Error: Python 3.11+ not found"
+            VALIDATION_ERRORS=$((VALIDATION_ERRORS + 1))
+        else
+            echo "  Using: $PYTHON_BIN ($($PYTHON_BIN --version 2>&1))"
+            sudo -u "$STEGASOO_USER" "$PYTHON_BIN" -m venv "$STEGASOO_DIR/venv"
+            sudo -u "$STEGASOO_USER" "$STEGASOO_DIR/venv/bin/pip" install --quiet --upgrade pip setuptools wheel
+            sudo -u "$STEGASOO_USER" "$STEGASOO_DIR/venv/bin/pip" install --quiet -e "$STEGASOO_DIR[web]"
+            echo "  Venv rebuilt and stegasoo installed"
+        fi
     else
         echo "  Venv OK"
     fi

rpi/setup.sh

@@ -4,14 +4,14 @@
 # Tested on: Raspberry Pi 4/5 with Raspberry Pi OS (64-bit)
 #
 # Usage:
-#   curl -sSL https://raw.githubusercontent.com/adlee-was-taken/stegasoo/4.1/rpi/setup.sh | bash
+#   curl -sSL https://raw.githubusercontent.com/adlee-was-taken/stegasoo/4.2/rpi/setup.sh | bash
 #   # or
-#   wget -qO- https://raw.githubusercontent.com/adlee-was-taken/stegasoo/4.1/rpi/setup.sh | bash
+#   wget -qO- https://raw.githubusercontent.com/adlee-was-taken/stegasoo/4.2/rpi/setup.sh | bash
 #
 # What this script does:
 #   1. Installs system dependencies
-#   2. Installs Python 3.12 via pyenv (Pi OS ships with 3.13 which is incompatible)
-#   3. Patches and builds jpegio for ARM
+#   2. Verifies Python 3.11+ (uses system Python)
+#   3. Installs jpeglib for DCT steganography (Python 3.11-3.14 compatible)
 #   4. Installs Stegasoo with web UI
 #   5. Creates systemd service for auto-start
 #   6. Enables the service
@@ -75,9 +75,8 @@ show_help() {
     echo ""
     echo "  Available variables:"
     echo "    INSTALL_DIR       Install location (default: /opt/stegasoo)"
-    echo "    PYTHON_VERSION    Python version (default: 3.12)"
     echo "    STEGASOO_REPO     Git repo URL"
-    echo "    STEGASOO_BRANCH   Git branch (default: 4.1)"
+    echo "    STEGASOO_BRANCH   Git branch (default: 4.2)"
     echo ""
     echo "  Example:"
     echo "    export INSTALL_DIR=\"/home/pi/stegasoo\""
@@ -95,10 +94,8 @@ done
 
 # Default configuration
 INSTALL_DIR="${INSTALL_DIR:-/opt/stegasoo}"
-PYTHON_VERSION="${PYTHON_VERSION:-3.12}"
 STEGASOO_REPO="${STEGASOO_REPO:-https://github.com/adlee-was-taken/stegasoo.git}"
-STEGASOO_BRANCH="${STEGASOO_BRANCH:-4.1}"
-JPEGIO_REPO="https://github.com/dwgoon/jpegio.git"
+STEGASOO_BRANCH="${STEGASOO_BRANCH:-4.2}"
 
 # Load config files (system, then user - user overrides system)
 for config_file in "/etc/stegasoo.conf" "$HOME/.config/stegasoo/stegasoo.conf"; do
@@ -112,7 +109,7 @@ clear
 print_banner "Raspberry Pi Setup"
 echo ""
 echo "  This will install Stegasoo with full DCT support"
-echo "  Estimated time: ~2 minutes (pre-built) or 15-20 min (from source)"
+echo "  Estimated time: ~2 minutes (pre-built) or 5-10 min (from source)"
 echo ""
 
 # Check if running on ARM
@@ -123,6 +120,63 @@ if [[ "$ARCH" != "aarch64" && "$ARCH" != "arm64" ]]; then
     exit 1
 fi
 
+# =============================================================================
+# Python Version Check
+# =============================================================================
+echo -e "${GREEN}Checking Python version...${NC}"
+
+# Find system Python
+SYSTEM_PYTHON=""
+for py in python3.14 python3.13 python3.12 python3.11 python3; do
+    if command -v "$py" &>/dev/null; then
+        SYSTEM_PYTHON=$(command -v "$py")
+        break
+    fi
+done
+
+if [ -z "$SYSTEM_PYTHON" ]; then
+    echo -e "${RED}Error: Python 3 not found.${NC}"
+    echo "Please install Python 3.11 or later:"
+    echo "  sudo apt-get install python3"
+    exit 1
+fi
+
+# Get version numbers
+PY_VERSION=$("$SYSTEM_PYTHON" -c 'import sys; print(f"{sys.version_info.major}.{sys.version_info.minor}")')
+PY_MAJOR=$("$SYSTEM_PYTHON" -c 'import sys; print(sys.version_info.major)')
+PY_MINOR=$("$SYSTEM_PYTHON" -c 'import sys; print(sys.version_info.minor)')
+
+echo "  Found: $SYSTEM_PYTHON (Python $PY_VERSION)"
+
+# Check version range (3.11 <= version <= 3.14)
+if [ "$PY_MAJOR" -ne 3 ]; then
+    echo -e "${RED}Error: Python 3 required, found Python $PY_MAJOR${NC}"
+    exit 1
+fi
+
+if [ "$PY_MINOR" -lt 11 ]; then
+    echo -e "${RED}Error: Python 3.11+ required, found Python $PY_VERSION${NC}"
+    echo ""
+    echo "Raspberry Pi OS Bookworm ships with Python 3.11."
+    echo "Raspberry Pi OS Trixie ships with Python 3.13."
+    echo ""
+    echo "Please upgrade your Raspberry Pi OS or install Python 3.11+."
+    exit 1
+fi
+
+if [ "$PY_MINOR" -gt 14 ]; then
+    echo -e "${YELLOW}Warning: Python $PY_VERSION detected.${NC}"
+    echo "Stegasoo is tested with Python 3.11-3.14."
+    echo "Newer versions may work but are not officially supported."
+    read -p "Continue anyway? [y/N] " -n 1 -r
+    echo
+    if [[ ! $REPLY =~ ^[Yy]$ ]]; then
+        exit 1
+    fi
+fi
+
+echo -e "  ${GREEN}✓${NC} Python $PY_VERSION supported"
+
 # Check available memory
 TOTAL_MEM=$(free -m | awk '/^Mem:/{print $2}')
 if [ "$TOTAL_MEM" -lt 2000 ]; then
@@ -136,8 +190,11 @@ if [ "$TOTAL_MEM" -lt 2000 ]; then
     fi
 fi
 
-# Create /opt/stegasoo with proper permissions
-echo -e "${GREEN}[1/12]${NC} Setting up install directory..."
+# =============================================================================
+# Installation
+# =============================================================================
+
+echo -e "${GREEN}[1/9]${NC} Setting up install directory..."
 if [ ! -d "$INSTALL_DIR" ]; then
     sudo mkdir -p "$INSTALL_DIR"
     sudo chown "$USER:$USER" "$INSTALL_DIR"
@@ -148,7 +205,7 @@ else
     echo "  $INSTALL_DIR exists, updated ownership"
 fi
 
-echo -e "${GREEN}[2/12]${NC} Installing system dependencies..."
+echo -e "${GREEN}[2/9]${NC} Installing system dependencies..."
 sudo apt-get update
 sudo apt-get install -y \
     build-essential \
@@ -170,9 +227,11 @@ sudo apt-get install -y \
     libzbar0 \
     libjpeg-dev \
     python3-dev \
+    python3-venv \
+    python3-pip \
     btop
 
-echo -e "${GREEN}[3/12]${NC} Installing gum (TUI toolkit)..."
+echo -e "${GREEN}[3/9]${NC} Installing gum (TUI toolkit)..."
 # Add Charm repo for gum
 if ! command -v gum &>/dev/null; then
     sudo mkdir -p /etc/apt/keyrings
@@ -198,7 +257,7 @@ else
     echo "  mkcert already installed"
 fi
 
-echo -e "${GREEN}[4/12]${NC} Cloning Stegasoo..."
+echo -e "${GREEN}[4/9]${NC} Cloning Stegasoo..."
 
 # Clone Stegasoo first (needed to check for pre-built tarball)
 if [ -d "$INSTALL_DIR/.git" ]; then
@@ -212,17 +271,16 @@ else
     cd "$INSTALL_DIR"
 fi
 
-# Pre-built environment tarball (skips 20+ min compile time)
-# Includes both pyenv Python 3.12 AND venv with all dependencies
-PREBUILT_TARBALL="$INSTALL_DIR/rpi/stegasoo-rpi-runtime-env-arm64.tar.zst"
-PREBUILT_URL="${PREBUILT_URL:-https://github.com/adlee-was-taken/stegasoo/releases/download/v4.1.5/stegasoo-rpi-runtime-env-arm64.tar.zst}"
+# Pre-built venv tarball (skips pip compile time)
+PREBUILT_TARBALL="$INSTALL_DIR/rpi/stegasoo-rpi-venv-arm64.tar.zst"
+PREBUILT_URL="${PREBUILT_URL:-https://github.com/adlee-was-taken/stegasoo/releases/download/v4.2.1/stegasoo-rpi-venv-arm64.tar.zst}"
 USE_PREBUILT=true
 
 # Use local tarball if present, otherwise will download
 if [ -f "$PREBUILT_TARBALL" ]; then
-    echo -e "${GREEN}Found local pre-built environment - fast install mode${NC}"
+    echo -e "${GREEN}Found local pre-built venv - fast install mode${NC}"
 else
-    echo -e "${GREEN}Will download pre-built environment - fast install mode${NC}"
+    echo -e "${GREEN}Will download pre-built venv - fast install mode${NC}"
 fi
 
 # Allow --no-prebuilt flag to force from-source build
@@ -231,44 +289,30 @@ if [[ " $* " =~ " --no-prebuilt " ]] || [[ " $* " =~ " --from-source " ]]; then
     echo -e "${YELLOW}Building from source (--no-prebuilt specified)${NC}"
 fi
 
-# Fast path: use pre-built environment if available
+echo -e "${GREEN}[5/9]${NC} Setting up Python environment..."
+
 if [ "$USE_PREBUILT" = true ]; then
-    echo -e "${GREEN}[5/8]${NC} Installing pre-built Python environment..."
+    # Fast path: use pre-built venv
 
     # Download if local file doesn't exist
     if [ ! -f "$PREBUILT_TARBALL" ]; then
-        echo "  Downloading pre-built environment (~50MB)..."
+        echo "  Downloading pre-built venv (~50MB)..."
         curl -L -o "$PREBUILT_TARBALL" "$PREBUILT_URL"
     fi
 
-    # Extract pre-built environment (includes pyenv Python + venv)
-    echo "  Extracting pre-built environment..."
-    zstd -d "$PREBUILT_TARBALL" --stdout | tar -xf - -C "$HOME"
+    # Extract pre-built venv
+    echo "  Extracting pre-built venv..."
+    zstd -d "$PREBUILT_TARBALL" --stdout | tar -xf - -C "$INSTALL_DIR"
 
-    # Setup pyenv in current shell
-    export PYENV_ROOT="$HOME/.pyenv"
-    export PATH="$PYENV_ROOT/bin:$PATH"
-    eval "$(pyenv init -)"
-    pyenv global $PYTHON_VERSION
+    # Fix venv Python symlinks to point to system Python
+    echo "  Updating venv to use system Python..."
+    rm -f "$INSTALL_DIR/venv/bin/python" "$INSTALL_DIR/venv/bin/python3"
+    ln -s "$SYSTEM_PYTHON" "$INSTALL_DIR/venv/bin/python"
+    ln -s "$SYSTEM_PYTHON" "$INSTALL_DIR/venv/bin/python3"
 
-    # Add to .bashrc if not already there
-    if ! grep -q 'PYENV_ROOT' ~/.bashrc; then
-        echo '' >> ~/.bashrc
-        echo '# pyenv' >> ~/.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
-    fi
-
-    # Verify Python
-    INSTALLED_PY=$(python --version 2>&1 | cut -d' ' -f2 | cut -d'.' -f1,2)
-    echo -e "  ${GREEN}✓${NC} Python: $INSTALLED_PY"
-
-    # Extract venv to install dir
-    echo -e "${GREEN}[6/8]${NC} Setting up virtual environment..."
-    if [ -f "$HOME/stegasoo-venv.tar.zst" ]; then
-        zstd -d "$HOME/stegasoo-venv.tar.zst" --stdout | tar -xf - -C "$INSTALL_DIR"
-        rm "$HOME/stegasoo-venv.tar.zst"
+    # Update pip shebang if needed
+    if [ -f "$INSTALL_DIR/venv/bin/pip" ]; then
+        sed -i "1s|^#!.*|#!$INSTALL_DIR/venv/bin/python|" "$INSTALL_DIR/venv/bin/pip" 2>/dev/null || true
     fi
 
     # Activate and verify
@@ -277,105 +321,87 @@ if [ "$USE_PREBUILT" = true ]; then
     echo -e "  ${GREEN}✓${NC} venv Python: $VENV_PY"
 
     # Install stegasoo package in editable mode (quick, no compile)
-    echo -e "${GREEN}[7/8]${NC} Installing Stegasoo package..."
+    echo "  Installing Stegasoo package..."
     pip install -e "." --quiet
-
-    # Adjust step numbers for rest of script
-    STEP_OFFSET=-4
 else
-    echo -e "${GREEN}[5/12]${NC} Installing pyenv and Python $PYTHON_VERSION..."
+    # Build from source
+    echo -e "  ${YELLOW}Building from source (this takes 5-10 minutes)${NC}"
 
-    # Install pyenv if not present
-    if [ ! -d "$HOME/.pyenv" ]; then
-        curl https://pyenv.run | bash
-
-        # Add pyenv to current shell
-        export PYENV_ROOT="$HOME/.pyenv"
-        export PATH="$PYENV_ROOT/bin:$PATH"
-        eval "$(pyenv init -)"
-
-        # Add to .bashrc if not already there
-        if ! grep -q 'PYENV_ROOT' ~/.bashrc; then
-            echo '' >> ~/.bashrc
-            echo '# pyenv' >> ~/.bashrc
-            echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
-            echo '[[ -d $PYENV_ROOT/bin ]] && export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bashrc
-            echo 'eval "$(pyenv init - bash)"' >> ~/.bashrc
-        fi
-    else
-        echo "  pyenv already installed"
-        export PYENV_ROOT="$HOME/.pyenv"
-        export PATH="$PYENV_ROOT/bin:$PATH"
-        eval "$(pyenv init -)"
+    # Create venv with system Python
+    if [ ! -d "$INSTALL_DIR/venv" ]; then
+        "$SYSTEM_PYTHON" -m venv "$INSTALL_DIR/venv"
     fi
-
-    # Install Python 3.12 if not present
-    if ! pyenv versions | grep -q "$PYTHON_VERSION"; then
-        echo "  Building Python $PYTHON_VERSION (this takes ~10 minutes)..."
-        pyenv install $PYTHON_VERSION
-    else
-        echo "  Python $PYTHON_VERSION already installed"
-    fi
-    pyenv global $PYTHON_VERSION
-
-    # Verify Python version
-    INSTALLED_PY=$(python --version 2>&1 | cut -d' ' -f2 | cut -d'.' -f1,2)
-    if [ "$INSTALLED_PY" != "$PYTHON_VERSION" ]; then
-        echo -e "${RED}Error: Python $PYTHON_VERSION not active. Got: $INSTALLED_PY${NC}"
-        exit 1
-    fi
-    echo -e "${GREEN}[6/12]${NC} Creating Python virtual environment..."
-    echo -e "  ${YELLOW}Note: No pre-built venv found. Building from source (20+ min)${NC}"
-    echo -e "  ${YELLOW}To speed up future installs, add stegasoo-venv-pi-arm64.tar.gz to rpi/${NC}"
-
-    # Create venv with pyenv Python (not system Python)
-    # Use pyenv which to get actual path (handles 3.12 -> 3.12.12 mapping)
-    PYENV_PYTHON=$(pyenv which python)
-    echo "  Using Python: $PYENV_PYTHON"
-    if [ ! -d "venv" ]; then
-        "$PYENV_PYTHON" -m venv venv
-    fi
-    source venv/bin/activate
+    source "$INSTALL_DIR/venv/bin/activate"
 
     # Verify we're using the right Python
     VENV_PY=$(python --version 2>&1 | cut -d' ' -f2 | cut -d'.' -f1,2)
     echo "  venv Python: $VENV_PY"
 
-    echo -e "${GREEN}[7/12]${NC} Building jpegio for ARM..."
+    # Upgrade pip and install build tools
+    pip install --upgrade pip setuptools wheel
 
-    # Clone jpegio
-    JPEGIO_DIR="/tmp/jpegio-build"
-    rm -rf "$JPEGIO_DIR"
-    git clone "$JPEGIO_REPO" "$JPEGIO_DIR"
+    # Install jpeglib (no ARM64 wheel, PyPI tarball missing headers - use GitHub)
+    echo "  Installing jpeglib for ARM64..."
+    JPEGLIB_WORKDIR=$(mktemp -d)
+    cd "$JPEGLIB_WORKDIR"
 
-    # Apply ARM64 patch
-    if [ -f "$INSTALL_DIR/rpi/patches/jpegio/apply-patch.sh" ]; then
-        bash "$INSTALL_DIR/rpi/patches/jpegio/apply-patch.sh" "$JPEGIO_DIR"
-    else
-        echo "  Applying inline ARM64 patch..."
-        sed -i "s/cargs.append('-m64')/pass  # ARM64 fix/g" "$JPEGIO_DIR/setup.py"
-    fi
+    # Clone from GitHub (PyPI source tarball is missing .h files)
+    echo "    Cloning jpeglib from GitHub..."
+    git clone --depth 1 --branch 1.0.2 https://github.com/martinbenes1996/jpeglib.git
+    cd jpeglib
+    CJPEGLIB="src/jpeglib/cjpeglib"
 
-    cd "$JPEGIO_DIR"
+    # Fix broken include paths in setup.py (uses jpeglib/ but files are in src/jpeglib/)
+    ln -s src/jpeglib jpeglib
 
-    # Build jpegio into venv
-    pip install --upgrade pip setuptools wheel cython numpy
+    # Download libjpeg headers (not included in repo either)
+    # Each version needs EXACT matching headers (APIs differ between versions)
+    echo "    Downloading libjpeg headers (all versions)..."
+
+    # Download each version separately (APIs are incompatible between versions)
+    for v in 6b 7 8 8a 8b 8c 8d 9 9a 9b 9c 9d 9e 9f; do
+        echo "      libjpeg $v..."
+        curl -sL "https://www.ijg.org/files/jpegsrc.v${v}.tar.gz" | tar -xzf -
+        cp jpeg-${v}/*.h "$CJPEGLIB/$v/" 2>/dev/null || cp jpeg-${v//.}/*.h "$CJPEGLIB/$v/" 2>/dev/null || true
+    done
+
+    # Skip turbo/mozjpeg - they need cmake-generated headers
+    # Only remove dict entries (lines 49-59), keep if blocks (they're safe when is_turbo=False)
+    echo "    Patching setup.py to skip turbo/mozjpeg (need cmake)..."
+    python3 << 'PYPATCH'
+with open('setup.py', 'r') as f:
+    lines = f.readlines()
+filtered = []
+for line in lines:
+    # Only skip dict entries like "'turbo120': ..." or "'mozjpeg101': ..."
+    stripped = line.strip()
+    if stripped.startswith("'turbo") and ':' in stripped:
+        continue
+    if stripped.startswith("'mozjpeg") and ':' in stripped:
+        continue
+    if stripped.startswith("# 'turbo"):  # commented turbo line
+        continue
+    filtered.append(line)
+with open('setup.py', 'w') as f:
+    f.writelines(filtered)
+PYPATCH
+
+    # Build and install
+    echo "    Building jpeglib (this takes a few minutes)..."
     pip install .
-
     cd "$INSTALL_DIR"
-    rm -rf "$JPEGIO_DIR"
+    rm -rf "$JPEGLIB_WORKDIR"
 
-    echo -e "${GREEN}[8/12]${NC} Installing Stegasoo..."
-
-    # Install dependencies (jpegio already in venv, won't re-download)
+    # Install remaining dependencies
+    echo "  Installing remaining dependencies..."
     pip install -e ".[web]"
-
-    STEP_OFFSET=0
 fi
 
-echo -e "${GREEN}[9/12]${NC} Creating systemd service..."
+echo -e "  ${GREEN}✓${NC} Stegasoo installed"
 
-# Create systemd service file
+echo -e "${GREEN}[6/9]${NC} Creating systemd services..."
+
+# Create systemd service file for Web UI
 sudo tee /etc/systemd/system/stegasoo.service > /dev/null <<EOF
 [Unit]
 Description=Stegasoo Web UI
@@ -397,12 +423,53 @@ RestartSec=5
 WantedBy=multi-user.target
 EOF
 
-echo -e "${GREEN}[10/12]${NC} Enabling service..."
+# Create systemd service file for REST API (optional)
+sudo tee /etc/systemd/system/stegasoo-api.service > /dev/null <<EOF
+[Unit]
+Description=Stegasoo REST API
+After=network.target
+
+[Service]
+Type=simple
+User=$USER
+WorkingDirectory=$INSTALL_DIR/frontends/api
+Environment="PATH=$INSTALL_DIR/venv/bin:/usr/bin"
+Environment="PYTHONPATH=$INSTALL_DIR/src"
+ExecStart=$INSTALL_DIR/venv/bin/uvicorn main:app --host 0.0.0.0 --port 8000
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target
+EOF
+
+echo -e "${GREEN}[7/9]${NC} Enabling services..."
 
 sudo systemctl daemon-reload
 sudo systemctl enable stegasoo.service
 
-echo -e "${GREEN}[11/12]${NC} Setting up user environment..."
+# Prompt for REST API service (optional, with security warning)
+echo ""
+echo -e "${CYAN}Would you like to enable the REST API service? (port 8000)${NC}"
+echo ""
+echo -e "  ${RED}⚠ WARNING: The REST API has NO AUTHENTICATION${NC}"
+echo "  Anyone on your network can use it to encode/decode messages."
+echo "  Only enable if you understand the security implications."
+echo ""
+echo "  The Web UI (port 5000) has authentication and works independently."
+echo ""
+read -p "Enable REST API (no auth)? [y/N]: " ENABLE_API
+if [[ "$ENABLE_API" =~ ^[Yy]$ ]]; then
+    sudo systemctl enable stegasoo-api.service
+    STEGASOO_API_ENABLED=true
+    echo -e "  ${YELLOW}⚠${NC} REST API enabled on port 8000 ${RED}(no authentication)${NC}"
+else
+    STEGASOO_API_ENABLED=false
+    echo -e "  ${GREEN}✓${NC} REST API not enabled (recommended)"
+    echo "    Can enable later with: sudo systemctl enable --now stegasoo-api"
+fi
+
+echo -e "${GREEN}[8/9]${NC} Setting up user environment..."
 
 # Add stegasoo venv and rpi scripts to PATH for all users
 sudo tee /etc/profile.d/stegasoo-path.sh > /dev/null <<'PATHEOF'
@@ -436,7 +503,7 @@ if [ -f "$INSTALL_DIR/docs/stegasoo.1" ]; then
     echo "  Installed man page (man stegasoo)"
 fi
 
-echo -e "${GREEN}[12/12]${NC} Setting up login banner..."
+echo -e "${GREEN}[9/9]${NC} Setting up login banner..."
 
 # Create dynamic MOTD script
 sudo tee /etc/profile.d/stegasoo-motd.sh > /dev/null <<'MOTDEOF'
@@ -727,6 +794,14 @@ echo "  Start:   sudo systemctl start stegasoo"
 echo "  Stop:    sudo systemctl stop stegasoo"
 echo "  Status:  sudo systemctl status stegasoo"
 echo "  Logs:    journalctl -u stegasoo -f"
+if [ "$STEGASOO_API_ENABLED" = "true" ]; then
+    echo ""
+    echo -e "${GREEN}REST API Commands:${NC}"
+    echo "  Start:   sudo systemctl start stegasoo-api"
+    echo "  Stop:    sudo systemctl stop stegasoo-api"
+    echo "  Status:  sudo systemctl status stegasoo-api"
+    echo "  Logs:    journalctl -u stegasoo-api -f"
+fi
 echo ""
 
 # Offer to start now
@@ -734,9 +809,12 @@ read -p "Start Stegasoo now? [Y/n] " -n 1 -r
 echo
 if [[ ! $REPLY =~ ^[Nn]$ ]]; then
     sudo systemctl start stegasoo
+    if [ "$STEGASOO_API_ENABLED" = "true" ]; then
+        sudo systemctl start stegasoo-api
+    fi
     sleep 2
     if systemctl is-active --quiet stegasoo; then
-        echo -e "${GREEN}✓ Stegasoo is running!${NC}"
+        echo -e "${GREEN}✓ Stegasoo Web UI is running!${NC}"
         if [ "$ENABLE_HTTPS" = "true" ]; then
             if [ "$USE_PORT_443" = "true" ]; then
                 echo -e "  Create admin: ${YELLOW}https://$PI_HOST.local/setup${NC} or ${YELLOW}https://$PI_IP/setup${NC}"
@@ -746,6 +824,13 @@ if [[ ! $REPLY =~ ^[Nn]$ ]]; then
         else
             echo -e "  Create admin: ${YELLOW}http://$PI_HOST.local:5000/setup${NC} or ${YELLOW}http://$PI_IP:5000/setup${NC}"
         fi
+        if [ "$STEGASOO_API_ENABLED" = "true" ]; then
+            if systemctl is-active --quiet stegasoo-api; then
+                echo -e "${GREEN}✓ Stegasoo REST API is running on port 8000${NC}"
+            else
+                echo -e "${YELLOW}⚠ REST API failed to start. Check logs:${NC} journalctl -u stegasoo-api -f"
+            fi
+        fi
     else
         echo -e "${RED}✗ Failed to start. Check logs:${NC} journalctl -u stegasoo -f"
     fi

scripts/build.sh

@@ -68,20 +68,31 @@ case "${1:-fast}" in
         echo -e "${GREEN}Cleaned!${NC}"
         ;;
 
+    rebuild)
+        echo -e "${YELLOW}Full rebuild from scratch (no cache)...${NC}"
+        $SUDO $COMPOSE_CMD -f "$COMPOSE_FILE" down --rmi local -v 2>/dev/null || true
+        $SUDO docker rmi stegasoo-base:latest 2>/dev/null || true
+        $SUDO docker build --no-cache -f "$DOCKER_DIR/Dockerfile.base" -t stegasoo-base:latest .
+        $SUDO $COMPOSE_CMD -f "$COMPOSE_FILE" build --no-cache
+        echo -e "${GREEN}Done! Start with: $COMPOSE_CMD -f docker/docker-compose.yml up -d${NC}"
+        ;;
+
     *)
         echo -e "${CYAN}Stegasoo Build Script${NC}"
         echo ""
         echo "Usage: $0 [command]"
         echo ""
         echo "Commands:"
-        echo "  base   Build the base image (one-time, 5-10 min)"
-        echo "  fast   Fast build using base image (default, ~10 sec)"
-        echo "  full   Full rebuild from scratch (slow, no base needed)"
-        echo "  clean  Remove all images and volumes"
+        echo "  base    Build the base image (one-time, 5-10 min)"
+        echo "  fast    Fast build using base image (default, ~10 sec)"
+        echo "  full    Rebuild services without cache (uses existing base)"
+        echo "  rebuild Complete rebuild with no cache (base + services)"
+        echo "  clean   Remove all images and volumes"
         echo ""
         echo "Typical workflow:"
-        echo "  1. First time:  $0 base"
-        echo "  2. Daily dev:   $0 fast"
-        echo "  3. Deps change: $0 base"
+        echo "  1. First time:   $0 base"
+        echo "  2. Daily dev:    $0 fast"
+        echo "  3. Deps change:  $0 base"
+        echo "  4. Nuclear:      $0 rebuild"
         ;;
 esac

scripts/screenshots.sh

@@ -33,8 +33,8 @@ for cmd in chromium magick curl; do
     fi
 done
 
-# Check if server is running
-if ! curl -s "$BASE_URL" > /dev/null 2>&1; then
+# Check if server is running (-k for self-signed certs)
+if ! curl -sk "$BASE_URL" > /dev/null 2>&1; then
     echo "Error: Server not responding at $BASE_URL"
     echo "Start with: STEGASOO_AUTH_ENABLED=false python frontends/web/app.py"
     exit 1
@@ -49,7 +49,7 @@ capture() {
     printf "  %-20s <- %s\n" "$name" "$route"
     chromium --headless --screenshot="$OUTPUT_DIR/$name.png" \
         --window-size="$WINDOW_SIZE" --hide-scrollbars \
-        --disable-gpu --no-sandbox \
+        --disable-gpu --no-sandbox --ignore-certificate-errors \
         "$url" 2>/dev/null
 }
 

src/stegasoo/__init__.py

@@ -7,7 +7,7 @@ Changes in v4.0.0:
 - encode() and decode() now accept channel_key parameter
 """
 
-__version__ = "4.1.7"
+__version__ = "4.2.1"
 
 # Core functionality
 # Channel key management (v4.0.0)

src/stegasoo/cli.py

@@ -241,8 +241,20 @@ def encode(
     with open(carrier, "rb") as f:
         carrier_data = f.read()
 
-    # Determine output path
-    output = output or f"{Path(carrier).stem}_encoded.png"
+    # Determine output path and format
+    # Default to JPEG for JPEG carriers (preserves DCT mode benefits)
+    carrier_ext = Path(carrier).suffix.lower()
+    if not output:
+        if carrier_ext in ('.jpg', '.jpeg'):
+            output = f"{Path(carrier).stem}_encoded.jpg"
+        else:
+            output = f"{Path(carrier).stem}_encoded.png"
+
+    # Detect output format from extension
+    output_ext = Path(output).suffix.lower()
+    use_dct = output_ext in ('.jpg', '.jpeg')
+
+    from .steganography import EMBED_MODE_DCT, EMBED_MODE_LSB
 
     try:
         if file_payload:
@@ -253,6 +265,8 @@ def encode(
                 carrier_image=carrier_data,
                 passphrase=passphrase,
                 pin=pin,
+                embed_mode=EMBED_MODE_DCT if use_dct else EMBED_MODE_LSB,
+                dct_output_format="jpeg" if use_dct else "png",
             )
         else:
             # Encode message
@@ -262,6 +276,8 @@ def encode(
                 carrier_image=carrier_data,
                 passphrase=passphrase,
                 pin=pin,
+                embed_mode=EMBED_MODE_DCT if use_dct else EMBED_MODE_LSB,
+                dct_output_format="jpeg" if use_dct else "png",
             )
 
         # Write output
@@ -1297,6 +1313,203 @@ def tools_exif(image, clear, set_fields, output, as_json):
             raise click.UsageError(str(e))
 
 
+@tools.command("compress")
+@click.argument("image", type=click.Path(exists=True))
+@click.option("-q", "--quality", type=int, default=75, help="JPEG quality (1-100, default: 75)")
+@click.option("-o", "--output", type=click.Path(), help="Output file (default: <name>_q<quality>.jpg)")
+def tools_compress(image, quality, output):
+    """Compress a JPEG image.
+
+    DCT steganography survives JPEG compression! Use this to reduce file size
+    while preserving hidden data.
+
+    Examples:
+
+        stegasoo tools compress photo.jpg -q 60
+        stegasoo tools compress photo.jpg -q 80 -o smaller.jpg
+    """
+    from PIL import Image
+    import io
+
+    if not 1 <= quality <= 100:
+        raise click.UsageError("Quality must be between 1 and 100")
+
+    with open(image, "rb") as f:
+        image_data = f.read()
+
+    img = Image.open(io.BytesIO(image_data))
+
+    # Convert to RGB if needed (JPEG doesn't support alpha)
+    if img.mode in ("RGBA", "P"):
+        img = img.convert("RGB")
+
+    buffer = io.BytesIO()
+    img.save(buffer, format="JPEG", quality=quality)
+    compressed_data = buffer.getvalue()
+
+    if not output:
+        stem = Path(image).stem
+        output = f"{stem}_q{quality}.jpg"
+
+    with open(output, "wb") as f:
+        f.write(compressed_data)
+
+    orig_size = len(image_data)
+    new_size = len(compressed_data)
+    reduction = (1 - new_size / orig_size) * 100
+
+    click.echo(f"Compressed to: {output}")
+    click.echo(f"  Original: {orig_size:,} bytes")
+    click.echo(f"  Compressed: {new_size:,} bytes ({reduction:.1f}% smaller)")
+
+
+@tools.command("rotate")
+@click.argument("image", type=click.Path(exists=True))
+@click.option("-r", "--rotation", type=click.Choice(["90", "180", "270"]), help="Rotation degrees clockwise")
+@click.option("--flip-h", is_flag=True, help="Flip horizontally")
+@click.option("--flip-v", is_flag=True, help="Flip vertically")
+@click.option("-o", "--output", type=click.Path(), help="Output file")
+def tools_rotate(image, rotation, flip_h, flip_v, output):
+    """Rotate and/or flip an image.
+
+    For JPEGs, uses lossless jpegtran rotation which preserves DCT steganography.
+    For other formats, uses PIL (re-encodes the image).
+
+    Examples:
+
+        stegasoo tools rotate photo.jpg -r 90
+        stegasoo tools rotate photo.jpg -r 180 --flip-h -o rotated.jpg
+    """
+    from PIL import Image
+    import io
+    import shutil
+
+    with open(image, "rb") as f:
+        image_data = f.read()
+
+    # Must have rotation or flip
+    if not rotation and not flip_h and not flip_v:
+        raise click.UsageError("Must specify at least one of -r/--rotation, --flip-h, or --flip-v")
+
+    img = Image.open(io.BytesIO(image_data))
+    is_jpeg = img.format == "JPEG"
+    img.close()
+
+    rotation_deg = int(rotation) if rotation else 0
+
+    # For JPEGs, use lossless jpegtran
+    if is_jpeg and shutil.which("jpegtran"):
+        from .dct_steganography import _jpegtran_rotate
+
+        result_data = image_data
+
+        # Apply rotation
+        if rotation_deg in (90, 180, 270):
+            result_data = _jpegtran_rotate(result_data, rotation_deg)
+
+        # Apply flips using jpegtran
+        if flip_h or flip_v:
+            import subprocess
+            import tempfile
+            import os
+
+            for flip_type in (["horizontal"] if flip_h else []) + (["vertical"] if flip_v else []):
+                with tempfile.NamedTemporaryFile(suffix=".jpg", delete=False) as f:
+                    f.write(result_data)
+                    input_path = f.name
+                output_path = tempfile.mktemp(suffix=".jpg")
+                try:
+                    subprocess.run(
+                        ["jpegtran", "-flip", flip_type, "-copy", "all",
+                         "-outfile", output_path, input_path],
+                        capture_output=True, timeout=30, check=True
+                    )
+                    with open(output_path, "rb") as f:
+                        result_data = f.read()
+                finally:
+                    for p in [input_path, output_path]:
+                        try:
+                            os.unlink(p)
+                        except OSError:
+                            pass
+
+        ext = "jpg"
+        click.echo("  (Used lossless jpegtran - DCT stego preserved)")
+    else:
+        # Use PIL for non-JPEGs
+        img = Image.open(io.BytesIO(image_data))
+
+        # PIL rotation is counter-clockwise, we want clockwise
+        if rotation_deg:
+            pil_rotation = {90: 270, 180: 180, 270: 90}[rotation_deg]
+            img = img.rotate(pil_rotation, expand=True)
+
+        if flip_h:
+            img = img.transpose(Image.FLIP_LEFT_RIGHT)
+        if flip_v:
+            img = img.transpose(Image.FLIP_TOP_BOTTOM)
+
+        buffer = io.BytesIO()
+        img.save(buffer, format="PNG")
+        result_data = buffer.getvalue()
+        ext = "png"
+
+    if not output:
+        stem = Path(image).stem
+        suffix = "rotated" if rotation_deg else "flipped"
+        output = f"{stem}_{suffix}.{ext}"
+
+    with open(output, "wb") as f:
+        f.write(result_data)
+
+    click.echo(f"Saved to: {output}")
+
+
+@tools.command("convert")
+@click.argument("image", type=click.Path(exists=True))
+@click.option("-f", "--format", "fmt", type=click.Choice(["png", "jpg", "bmp", "webp"]), required=True, help="Output format")
+@click.option("-q", "--quality", type=int, default=95, help="Quality for lossy formats (default: 95)")
+@click.option("-o", "--output", type=click.Path(), help="Output file")
+def tools_convert(image, fmt, quality, output):
+    """Convert image to a different format.
+
+    Examples:
+
+        stegasoo tools convert photo.png -f jpg
+        stegasoo tools convert photo.jpg -f png -o lossless.png
+    """
+    from PIL import Image
+    import io
+
+    with open(image, "rb") as f:
+        image_data = f.read()
+
+    img = Image.open(io.BytesIO(image_data))
+
+    # Handle format-specific conversions
+    save_format = {"jpg": "JPEG", "png": "PNG", "bmp": "BMP", "webp": "WEBP"}[fmt]
+
+    if save_format == "JPEG" and img.mode in ("RGBA", "P"):
+        img = img.convert("RGB")
+
+    buffer = io.BytesIO()
+    if save_format in ("JPEG", "WEBP"):
+        img.save(buffer, format=save_format, quality=quality)
+    else:
+        img.save(buffer, format=save_format)
+
+    result_data = buffer.getvalue()
+
+    if not output:
+        stem = Path(image).stem
+        output = f"{stem}.{fmt}"
+
+    with open(output, "wb") as f:
+        f.write(result_data)
+
+    click.echo(f"Converted to: {output}")
+
+
 # =============================================================================
 # ADMIN COMMANDS (Web UI administration)
 # =============================================================================
@@ -1455,6 +1668,301 @@ def admin_generate_key(show_qr):
     click.echo("go to Account > Recovery Key > Regenerate")
 
 
+# =============================================================================
+# API COMMANDS (REST API management)
+# =============================================================================
+
+
+def _setup_frontends_path():
+    """Add frontends directory to sys.path for importing API/web modules."""
+    import sys
+
+    # Try multiple possible locations
+    possible_paths = [
+        # Development: stegasoo/frontends
+        Path(__file__).parent.parent.parent / "frontends",
+        # Installed package: site-packages/frontends
+        Path(__file__).parent.parent / "frontends",
+    ]
+
+    for path in possible_paths:
+        if path.exists() and str(path) not in sys.path:
+            sys.path.insert(0, str(path))
+            return True
+
+    return False
+
+
+@cli.group()
+@click.pass_context
+def api(ctx):
+    """REST API management commands."""
+    pass
+
+
+@api.group("keys")
+def api_keys():
+    """Manage API keys for authentication."""
+    pass
+
+
+@api_keys.command("list")
+@click.option("--location", type=click.Choice(["user", "project", "all"]), default="all",
+              help="Config location to list keys from")
+def api_keys_list(location):
+    """List configured API keys.
+
+    Shows key names and creation dates (not actual keys).
+
+    Examples:
+
+        stegasoo api keys list
+        stegasoo api keys list --location user
+    """
+    _setup_frontends_path()
+
+    try:
+        from api.auth import list_api_keys, get_api_key_status
+    except ImportError:
+        raise click.ClickException("API frontend not available")
+
+    status = get_api_key_status()
+
+    click.echo(f"\nAPI Key Authentication: {'Enabled' if status['enabled'] else 'Disabled'}")
+    click.echo(f"Total keys: {status['total_keys']}")
+    click.echo(f"Environment variable: {'Set' if status['env_configured'] else 'Not set'}")
+
+    locations = ["user", "project"] if location == "all" else [location]
+
+    for loc in locations:
+        keys = list_api_keys(loc)
+        click.echo(f"\n{loc.title()} keys ({len(keys)}):")
+        if keys:
+            for k in keys:
+                click.echo(f"  - {k['name']} (created: {k['created'][:10]})")
+        else:
+            click.echo("  (none)")
+
+
+@api_keys.command("create")
+@click.argument("name")
+@click.option("--location", type=click.Choice(["user", "project"]), default="user",
+              help="Where to store the key")
+def api_keys_create(name, location):
+    """Create a new API key.
+
+    The key is shown ONCE and cannot be retrieved again.
+    Save it immediately!
+
+    Examples:
+
+        stegasoo api keys create laptop
+        stegasoo api keys create automation --location project
+    """
+    _setup_frontends_path()
+
+    try:
+        from api.auth import add_api_key
+    except ImportError:
+        raise click.ClickException("API frontend not available")
+
+    try:
+        key = add_api_key(name, location)
+        click.echo(f"\nAPI Key created: {name}")
+        click.echo("─" * 60)
+        click.echo(f"  {key}")
+        click.echo("─" * 60)
+        click.echo("\nSave this key NOW! It cannot be retrieved again.")
+        click.echo(f"Stored in: {location} config")
+    except ValueError as e:
+        raise click.ClickException(str(e))
+
+
+@api_keys.command("delete")
+@click.argument("name")
+@click.option("--location", type=click.Choice(["user", "project"]), default="user",
+              help="Config location")
+def api_keys_delete(name, location):
+    """Delete an API key by name.
+
+    Examples:
+
+        stegasoo api keys delete laptop
+        stegasoo api keys delete automation --location project
+    """
+    _setup_frontends_path()
+
+    try:
+        from api.auth import remove_api_key
+    except ImportError:
+        raise click.ClickException("API frontend not available")
+
+    if remove_api_key(name, location):
+        click.echo(f"Deleted API key: {name}")
+    else:
+        raise click.ClickException(f"Key '{name}' not found in {location} config")
+
+
+@api.group("tls")
+def api_tls():
+    """Manage TLS certificates for HTTPS."""
+    pass
+
+
+@api_tls.command("generate")
+@click.option("--hostname", default="localhost", help="Server hostname for certificate")
+@click.option("--days", default=365, help="Certificate validity in days")
+@click.option("--output", "-o", type=click.Path(), help="Output directory (default: ~/.stegasoo/certs)")
+def api_tls_generate(hostname, days, output):
+    """Generate self-signed TLS certificate.
+
+    Creates a certificate valid for:
+    - The specified hostname
+    - localhost / 127.0.0.1
+    - hostname.local (for mDNS)
+    - All detected local network IPs
+
+    Examples:
+
+        stegasoo api tls generate
+        stegasoo api tls generate --hostname myserver --days 730
+        stegasoo api tls generate -o /etc/stegasoo/certs
+    """
+    _setup_frontends_path()
+
+    try:
+        from web.ssl_utils import generate_self_signed_cert, get_cert_paths
+    except ImportError:
+        raise click.ClickException("Web frontend not available (ssl_utils required)")
+
+    if output:
+        base_dir = Path(output)
+    else:
+        base_dir = Path.home() / ".stegasoo"
+
+    click.echo(f"Generating TLS certificate for: {hostname}")
+    click.echo(f"Validity: {days} days")
+
+    cert_path, key_path = generate_self_signed_cert(base_dir, hostname, days)
+
+    click.echo(f"\nCertificate: {cert_path}")
+    click.echo(f"Private Key: {key_path}")
+    click.echo("\nTo use with the API:")
+    click.echo(f"  uvicorn main:app --ssl-certfile {cert_path} --ssl-keyfile {key_path}")
+
+
+@api_tls.command("info")
+@click.option("--cert", "-c", type=click.Path(exists=True), help="Certificate file (default: ~/.stegasoo/certs/server.crt)")
+def api_tls_info(cert):
+    """Show information about a TLS certificate.
+
+    Examples:
+
+        stegasoo api tls info
+        stegasoo api tls info --cert /path/to/server.crt
+    """
+    from cryptography import x509
+    from cryptography.hazmat.primitives import serialization
+
+    if not cert:
+        cert = Path.home() / ".stegasoo" / "certs" / "server.crt"
+        if not cert.exists():
+            raise click.ClickException(f"No certificate found at {cert}. Generate one with: stegasoo api tls generate")
+
+    cert_data = Path(cert).read_bytes()
+    certificate = x509.load_pem_x509_certificate(cert_data)
+
+    click.echo(f"\nCertificate: {cert}")
+    click.echo("─" * 50)
+    click.echo(f"Subject: {certificate.subject.rfc4514_string()}")
+    click.echo(f"Issuer: {certificate.issuer.rfc4514_string()}")
+    click.echo(f"Serial: {certificate.serial_number}")
+    click.echo(f"Valid from: {certificate.not_valid_before_utc}")
+    click.echo(f"Valid until: {certificate.not_valid_after_utc}")
+
+    # Check expiry
+    import datetime
+    now = datetime.datetime.now(datetime.timezone.utc)
+    if certificate.not_valid_after_utc < now:
+        click.echo("\nStatus: EXPIRED")
+    elif certificate.not_valid_after_utc < now + datetime.timedelta(days=30):
+        days_left = (certificate.not_valid_after_utc - now).days
+        click.echo(f"\nStatus: Expires in {days_left} days (consider renewal)")
+    else:
+        days_left = (certificate.not_valid_after_utc - now).days
+        click.echo(f"\nStatus: Valid ({days_left} days remaining)")
+
+    # Show SANs
+    try:
+        san_ext = certificate.extensions.get_extension_for_class(x509.SubjectAlternativeName)
+        click.echo("\nSubject Alternative Names:")
+        for name in san_ext.value:
+            click.echo(f"  - {name.value}")
+    except x509.ExtensionNotFound:
+        pass
+
+
+@api.command("serve")
+@click.option("--host", default="127.0.0.1", help="Host to bind to")
+@click.option("--port", default=8000, help="Port to bind to")
+@click.option("--ssl/--no-ssl", default=True, help="Enable/disable TLS")
+@click.option("--cert", type=click.Path(exists=True), help="TLS certificate file")
+@click.option("--key", type=click.Path(exists=True), help="TLS private key file")
+@click.option("--reload", "do_reload", is_flag=True, help="Enable auto-reload for development")
+def api_serve(host, port, ssl, cert, key, do_reload):
+    """Start the REST API server.
+
+    By default starts with TLS using certificates from ~/.stegasoo/certs/.
+    If no certificates exist, they are generated automatically.
+
+    Examples:
+
+        stegasoo api serve
+        stegasoo api serve --host 0.0.0.0 --port 8443
+        stegasoo api serve --no-ssl
+        stegasoo api serve --cert /path/to/cert.pem --key /path/to/key.pem
+    """
+    _setup_frontends_path()
+
+    # Determine cert paths
+    if ssl:
+        if cert and key:
+            cert_path, key_path = cert, key
+        else:
+            try:
+                from web.ssl_utils import ensure_certs
+                base_dir = Path.home() / ".stegasoo"
+                cert_path, key_path = ensure_certs(base_dir, host if host != "0.0.0.0" else "localhost")
+            except ImportError:
+                raise click.ClickException("ssl_utils not available")
+
+        click.echo(f"Starting API server with TLS on https://{host}:{port}")
+        click.echo(f"Certificate: {cert_path}")
+    else:
+        cert_path = key_path = None
+        click.echo(f"Starting API server on http://{host}:{port}")
+        click.echo("WARNING: TLS disabled - connections are not encrypted!")
+
+    # Import and run uvicorn
+    try:
+        import uvicorn
+    except ImportError:
+        raise click.ClickException("uvicorn not installed. Install with: pip install uvicorn")
+
+    uvicorn_kwargs = {
+        "app": "api.main:app",
+        "host": host,
+        "port": port,
+        "reload": do_reload,
+    }
+
+    if ssl and cert_path and key_path:
+        uvicorn_kwargs["ssl_certfile"] = str(cert_path)
+        uvicorn_kwargs["ssl_keyfile"] = str(key_path)
+
+    uvicorn.run(**uvicorn_kwargs)
+
+
 def main():
     """Entry point for CLI."""
     cli(obj={})

src/stegasoo/compression.py

@@ -17,6 +17,14 @@ try:
 except ImportError:
     HAS_LZ4 = False
 
+# Optional ZSTD support (best ratio, fast)
+try:
+    import zstandard as zstd
+
+    HAS_ZSTD = True
+except ImportError:
+    HAS_ZSTD = False
+
 
 class CompressionAlgorithm(IntEnum):
     """Supported compression algorithms."""
@@ -24,6 +32,7 @@ class CompressionAlgorithm(IntEnum):
     NONE = 0
     ZLIB = 1
     LZ4 = 2
+    ZSTD = 3  # v4.2.0: Best ratio, fast compression
 
 
 # Magic bytes for compressed payloads
@@ -72,6 +81,15 @@ def compress(data: bytes, algorithm: CompressionAlgorithm = CompressionAlgorithm
             algorithm = CompressionAlgorithm.ZLIB
         else:
             compressed = lz4.frame.compress(data)
+
+    elif algorithm == CompressionAlgorithm.ZSTD:
+        if not HAS_ZSTD:
+            # Fall back to zlib if ZSTD not available
+            compressed = zlib.compress(data, level=ZLIB_LEVEL)
+            algorithm = CompressionAlgorithm.ZLIB
+        else:
+            cctx = zstd.ZstdCompressor(level=19)  # High compression level
+            compressed = cctx.compress(data)
     else:
         raise CompressionError(f"Unknown compression algorithm: {algorithm}")
 
@@ -123,6 +141,15 @@ def decompress(data: bytes) -> bytes:
             result = lz4.frame.decompress(compressed_data)
         except Exception as e:
             raise CompressionError(f"LZ4 decompression failed: {e}")
+
+    elif algorithm == CompressionAlgorithm.ZSTD:
+        if not HAS_ZSTD:
+            raise CompressionError("ZSTD compression used but zstandard package not installed")
+        try:
+            dctx = zstd.ZstdDecompressor()
+            result = dctx.decompress(compressed_data)
+        except Exception as e:
+            raise CompressionError(f"ZSTD decompression failed: {e}")
     else:
         raise CompressionError(f"Unknown compression algorithm: {algorithm}")
 
@@ -181,6 +208,9 @@ def estimate_compressed_size(
         compressed_sample = zlib.compress(sample, level=ZLIB_LEVEL)
     elif algorithm == CompressionAlgorithm.LZ4 and HAS_LZ4:
         compressed_sample = lz4.frame.compress(sample)
+    elif algorithm == CompressionAlgorithm.ZSTD and HAS_ZSTD:
+        cctx = zstd.ZstdCompressor(level=19)
+        compressed_sample = cctx.compress(sample)
     else:
         compressed_sample = zlib.compress(sample, level=ZLIB_LEVEL)
 
@@ -195,14 +225,24 @@ def get_available_algorithms() -> list[CompressionAlgorithm]:
     algorithms = [CompressionAlgorithm.NONE, CompressionAlgorithm.ZLIB]
     if HAS_LZ4:
         algorithms.append(CompressionAlgorithm.LZ4)
+    if HAS_ZSTD:
+        algorithms.append(CompressionAlgorithm.ZSTD)
     return algorithms
 
 
+def get_best_algorithm() -> CompressionAlgorithm:
+    """Get the best available compression algorithm (prefer ZSTD > ZLIB > LZ4)."""
+    if HAS_ZSTD:
+        return CompressionAlgorithm.ZSTD
+    return CompressionAlgorithm.ZLIB
+
+
 def algorithm_name(algo: CompressionAlgorithm) -> str:
     """Get human-readable algorithm name."""
     names = {
         CompressionAlgorithm.NONE: "None",
         CompressionAlgorithm.ZLIB: "Zlib (deflate)",
         CompressionAlgorithm.LZ4: "LZ4 (fast)",
+        CompressionAlgorithm.ZSTD: "Zstd (best)",
     }
     return names.get(algo, "Unknown")

src/stegasoo/constants.py

@@ -1,9 +1,15 @@
 """
-Stegasoo Constants and Configuration (v4.0.2 - Web UI Authentication)
+Stegasoo Constants and Configuration (v4.2.0 - Performance & Compression)
 
 Central location for all magic numbers, limits, and crypto parameters.
 All version numbers, limits, and configuration values should be defined here.
 
+CHANGES in v4.2.0:
+- Added zstd compression for QR codes (better ratio than zlib)
+- RSA key size capped at 3072 bits (4096 too large for QR codes)
+- Progress bar improvements for encode/decode operations
+- File auto-expire increased to 10 minutes
+
 CHANGES in v4.0.2:
 - Added Web UI authentication with SQLite3 user storage
 - Added optional HTTPS with auto-generated self-signed certificates
@@ -19,13 +25,14 @@ BREAKING CHANGES in v3.2.0:
 - Renamed day_phrase → passphrase throughout codebase
 """
 
+import importlib.resources
 from pathlib import Path
 
 # ============================================================================
 # VERSION
 # ============================================================================
 
-__version__ = "4.1.5"
+__version__ = "4.2.1"
 
 # ============================================================================
 # FILE FORMAT
@@ -98,7 +105,7 @@ DEFAULT_PHRASE_WORDS = DEFAULT_PASSPHRASE_WORDS
 
 # RSA configuration
 MIN_RSA_BITS = 2048
-VALID_RSA_SIZES = (2048, 3072, 4096)
+VALID_RSA_SIZES = (2048, 3072)  # 4096 removed - too large for QR codes
 DEFAULT_RSA_BITS = 2048
 
 MIN_KEY_PASSWORD_LENGTH = 8
@@ -108,8 +115,8 @@ MIN_KEY_PASSWORD_LENGTH = 8
 # ============================================================================
 
 # Temporary file storage
-TEMP_FILE_EXPIRY = 300  # 5 minutes in seconds
-TEMP_FILE_EXPIRY_MINUTES = 5
+TEMP_FILE_EXPIRY = 600  # 10 minutes in seconds
+TEMP_FILE_EXPIRY_MINUTES = 10
 
 # Thumbnail settings
 THUMBNAIL_SIZE = (250, 250)  # Maximum dimensions for thumbnails
@@ -171,15 +178,32 @@ BATCH_OUTPUT_SUFFIX = "_encoded"
 
 
 def get_data_dir() -> Path:
-    """Get the data directory path."""
-    # Check multiple locations
+    """Get the data directory path.
+
+    Checks locations in order:
+    1. Package data (installed via pip/wheel) using importlib.resources
+    2. Development layout (src/stegasoo -> project root/data)
+    3. Docker container (/app/data)
+    4. Current working directory fallbacks
+    """
+    # Try package data first (works when installed via pip)
+    try:
+        pkg_data = importlib.resources.files("stegasoo.data")
+        # Check if the package data directory exists and has our files
+        if (pkg_data / "bip39-words.txt").is_file():
+            # Return as Path - importlib.resources.files returns a Traversable
+            return Path(str(pkg_data))
+    except (ModuleNotFoundError, TypeError):
+        pass
+
+    # Fallback to file-based locations
     # From src/stegasoo/constants.py:
     #   .parent = src/stegasoo/
     #   .parent.parent = src/
     #   .parent.parent.parent = project root (where data/ lives)
     candidates = [
+        Path(__file__).parent / "data",  # Installed package (stegasoo/data/)
         Path(__file__).parent.parent.parent / "data",  # Development: src/stegasoo -> project root
-        Path(__file__).parent / "data",  # Installed package
         Path("/app/data"),  # Docker
         Path.cwd() / "data",  # Current directory
         Path.cwd().parent / "data",  # One level up from cwd
@@ -190,8 +214,8 @@ def get_data_dir() -> Path:
         if path.exists():
             return path
 
-    # Default to first candidate
-    return candidates[0]
+    # Default to package data path for clearer error messages
+    return Path(__file__).parent / "data"
 
 
 def get_bip39_words() -> list[str]:

src/stegasoo/data/__init__.py

@@ -0,0 +1 @@
+# Package data directory for stegasoo

src/stegasoo/dct_steganography.py

@@ -12,7 +12,7 @@ Why is this cool?
 
 Two approaches depending on what you want:
 1. PNG output: We do our own DCT math via scipy (works on any image)
-2. JPEG output: We use jpegio to directly tweak the coefficients (chef's kiss)
+2. JPEG output: We use jpeglib to directly tweak the coefficients (chef's kiss)
 
 v4.1.0 - The "please stop corrupting my data" release:
 - Reed-Solomon error correction (can fix up to 16 byte errors per chunk)
@@ -24,7 +24,7 @@ v3.2.0-patch2 - The "scipy why are you like this" release:
 - Process blocks one at a time with fresh arrays
 - Yes, it's slower. No, I don't care. Correctness > speed.
 
-Requires: scipy (PNG mode), optionally jpegio (JPEG mode), reedsolo (error correction)
+Requires: scipy (PNG mode), optionally jpeglib (JPEG mode), reedsolo (error correction)
 """
 
 import gc
@@ -35,32 +35,35 @@ from dataclasses import dataclass
 from enum import Enum
 
 import numpy as np
-from PIL import Image
+from PIL import Image, ImageOps
 
 # Check for scipy availability (for PNG/DCT mode)
 # Prefer scipy.fft (newer, more stable) over scipy.fftpack
 try:
-    from scipy.fft import dct, idct
+    from scipy.fft import dct, idct, dctn, idctn
 
     HAS_SCIPY = True
 except ImportError:
     try:
-        from scipy.fftpack import dct, idct
+        from scipy.fftpack import dct, idct, dctn, idctn
 
         HAS_SCIPY = True
     except ImportError:
         HAS_SCIPY = False
         dct = None
         idct = None
+        dctn = None
+        idctn = None
 
-# Check for jpegio availability (for proper JPEG mode)
+# Check for jpeglib availability (for proper JPEG mode)
+# jpeglib replaces jpegio for Python 3.13+ compatibility
 try:
-    import jpegio as jio
+    import jpeglib
 
-    HAS_JPEGIO = True
+    HAS_JPEGIO = True  # Keep variable name for compatibility
 except ImportError:
     HAS_JPEGIO = False
-    jio = None
+    jpeglib = None
 
 # Import custom exceptions
 from .exceptions import InvalidMagicBytesError
@@ -403,31 +406,72 @@ def _safe_idct2(block: np.ndarray) -> np.ndarray:
 # ============================================================================
 
 
+def _apply_exif_orientation(image_data: bytes) -> bytes:
+    """
+    Apply EXIF orientation to image and return corrected bytes.
+
+    Portrait photos from cameras often have EXIF orientation metadata that
+    tells viewers to rotate the image for display. However, the raw pixel
+    data is stored in landscape orientation. This function applies that
+    rotation to the pixel data so the output matches what users expect.
+
+    Without this, a portrait photo encoded with DCT would come out rotated
+    90 degrees because we'd embed in the raw (landscape) orientation.
+    """
+    img = Image.open(io.BytesIO(image_data))
+    original_format = img.format or "JPEG"
+
+    # Apply EXIF orientation (rotates/flips pixels to match EXIF tag)
+    # This also removes the EXIF orientation tag since it's now baked in
+    corrected = ImageOps.exif_transpose(img)
+
+    # If no change was needed, return original data unchanged
+    if corrected is img:
+        img.close()
+        return image_data
+
+    # Save corrected image back to bytes
+    output = io.BytesIO()
+    if original_format == "JPEG":
+        if corrected.mode in ("RGBA", "P"):
+            corrected = corrected.convert("RGB")
+        corrected.save(output, format="JPEG", quality=95)
+    else:
+        corrected.save(output, format="PNG")
+
+    img.close()
+    corrected.close()
+    output.seek(0)
+    return output.getvalue()
+
+
 def _to_grayscale(image_data: bytes) -> np.ndarray:
     img = Image.open(io.BytesIO(image_data))
     gray = img.convert("L")
-    return np.array(gray, dtype=np.float64, copy=True, order="C")
+    return np.array(gray, dtype=np.float32, copy=True, order="C")
 
 
 def _extract_y_channel(image_data: bytes) -> np.ndarray:
+    """Extract Y (luminance) channel - float32 for memory efficiency."""
     img = Image.open(io.BytesIO(image_data))
     if img.mode != "RGB":
         img = img.convert("RGB")
 
-    rgb = np.array(img, dtype=np.float64, copy=True, order="C")
+    rgb = np.array(img, dtype=np.float32, copy=True, order="C")
     Y = 0.299 * rgb[:, :, 0] + 0.587 * rgb[:, :, 1] + 0.114 * rgb[:, :, 2]
-    return np.array(Y, dtype=np.float64, copy=True, order="C")
+    return np.array(Y, dtype=np.float32, copy=True, order="C")
 
 
 def _pad_to_blocks(image: np.ndarray) -> tuple[np.ndarray, tuple[int, int]]:
+    """Pad image to block boundaries - uses float32 for memory efficiency."""
     h, w = image.shape
     new_h = ((h + BLOCK_SIZE - 1) // BLOCK_SIZE) * BLOCK_SIZE
     new_w = ((w + BLOCK_SIZE - 1) // BLOCK_SIZE) * BLOCK_SIZE
 
     if new_h == h and new_w == w:
-        return np.array(image, dtype=np.float64, copy=True, order="C"), (h, w)
+        return np.array(image, dtype=np.float32, copy=True, order="C"), (h, w)
 
-    padded = np.zeros((new_h, new_w), dtype=np.float64, order="C")
+    padded = np.zeros((new_h, new_w), dtype=np.float32, order="C")
     padded[:h, :w] = image
 
     # Simple edge replication for padding
@@ -444,8 +488,9 @@ def _pad_to_blocks(image: np.ndarray) -> tuple[np.ndarray, tuple[int, int]]:
 
 
 def _unpad_image(image: np.ndarray, original_size: tuple[int, int]) -> np.ndarray:
+    """Remove padding - uses float32 for memory efficiency."""
     h, w = original_size
-    return np.array(image[:h, :w], dtype=np.float64, copy=True, order="C")
+    return np.array(image[:h, :w], dtype=np.float32, copy=True, order="C")
 
 
 def _embed_bit_in_coeff(coef: float, bit: int, quant_step: int = QUANT_STEP) -> float:
@@ -543,20 +588,23 @@ def _rgb_to_ycbcr(rgb: np.ndarray) -> tuple[np.ndarray, np.ndarray, np.ndarray]:
     - Cb/Cr are often subsampled (4:2:0) so Y has more capacity anyway
 
     The coefficients here are from ITU-R BT.601 - the standard for video.
+
+    Uses float32 to reduce memory usage (~50% savings vs float64).
     """
-    R = rgb[:, :, 0].astype(np.float64)
-    G = rgb[:, :, 1].astype(np.float64)
-    B = rgb[:, :, 2].astype(np.float64)
+    # Use float32 - sufficient precision for 8-bit images, halves memory
+    R = rgb[:, :, 0].astype(np.float32)
+    G = rgb[:, :, 1].astype(np.float32)
+    B = rgb[:, :, 2].astype(np.float32)
 
     # Y = luminance (brightness). Green contributes most because eyes are most sensitive to it.
-    Y = np.array(0.299 * R + 0.587 * G + 0.114 * B, dtype=np.float64, copy=True, order="C")
+    Y = np.array(0.299 * R + 0.587 * G + 0.114 * B, dtype=np.float32, copy=True, order="C")
     # Cb = blue-difference chroma (centered at 128)
     Cb = np.array(
-        128 - 0.168736 * R - 0.331264 * G + 0.5 * B, dtype=np.float64, copy=True, order="C"
+        128 - 0.168736 * R - 0.331264 * G + 0.5 * B, dtype=np.float32, copy=True, order="C"
     )
     # Cr = red-difference chroma (centered at 128)
     Cr = np.array(
-        128 + 0.5 * R - 0.418688 * G - 0.081312 * B, dtype=np.float64, copy=True, order="C"
+        128 + 0.5 * R - 0.418688 * G - 0.081312 * B, dtype=np.float32, copy=True, order="C"
     )
 
     return Y, Cb, Cr
@@ -569,11 +617,12 @@ def _ycbcr_to_rgb(Y: np.ndarray, Cb: np.ndarray, Cr: np.ndarray) -> np.ndarray:
     After embedding in the Y channel, we need to reconstruct RGB for display.
     The Cb/Cr channels are unchanged - we only touched luminance.
     """
+    # Use float32 for memory efficiency
     R = Y + 1.402 * (Cr - 128)
     G = Y - 0.344136 * (Cb - 128) - 0.714136 * (Cr - 128)
     B = Y + 1.772 * (Cb - 128)
 
-    rgb = np.zeros((Y.shape[0], Y.shape[1], 3), dtype=np.float64, order="C")
+    rgb = np.zeros((Y.shape[0], Y.shape[1], 3), dtype=np.float32, order="C")
     rgb[:, :, 0] = R
     rgb[:, :, 1] = G
     rgb[:, :, 2] = B
@@ -733,7 +782,7 @@ def estimate_capacity_comparison(image_data: bytes) -> dict:
         },
         "jpeg_native": {
             "available": HAS_JPEGIO,
-            "note": "Uses jpegio for proper JPEG coefficient embedding",
+            "note": "Uses jpeglib for proper JPEG coefficient embedding",
         },
     }
 
@@ -753,6 +802,10 @@ def embed_in_dct(
     if color_mode not in ("color", "grayscale"):
         color_mode = "color"
 
+    # Apply EXIF orientation to carrier image before embedding
+    # This ensures portrait photos are embedded in their correct visual orientation
+    carrier_image = _apply_exif_orientation(carrier_image)
+
     if output_format == OUTPUT_FORMAT_JPEG and HAS_JPEGIO:
         return _embed_jpegio(data, carrier_image, seed, color_mode, progress_file)
 
@@ -818,8 +871,8 @@ def _embed_scipy_dct_safe(
         if img.mode == "RGBA":
             img = img.convert("RGB")
 
-        # Process color image
-        rgb = np.array(img, dtype=np.float64, copy=True, order="C")
+        # Process color image (float32 for memory efficiency)
+        rgb = np.array(img, dtype=np.float32, copy=True, order="C")
         img.close()
 
         Y, Cb, Cr = _rgb_to_ycbcr(rgb)
@@ -891,61 +944,105 @@ def _embed_in_channel_safe(
     progress_file: str | None = None,
 ) -> np.ndarray:
     """
-    Embed bits in channel using safe DCT operations.
+    Embed bits in channel using vectorized DCT operations.
 
-    Processes one block at a time with fresh array allocations.
+    Processes blocks in batches for ~10x speedup over sequential processing.
     """
     h, w = channel.shape
 
-    # Create result with explicit new memory
-    result = np.array(channel, dtype=np.float64, copy=True, order="C")
+    # Create result with explicit new memory (float32 for memory efficiency)
+    result = np.array(channel, dtype=np.float32, copy=True, order="C")
 
+    # Pre-compute embed positions as numpy indices
+    embed_rows = np.array([pos[0] for pos in DEFAULT_EMBED_POSITIONS])
+    embed_cols = np.array([pos[1] for pos in DEFAULT_EMBED_POSITIONS])
+    bits_per_block = len(DEFAULT_EMBED_POSITIONS)
+
+    # Calculate how many blocks we need
+    total_bits = len(bits)
+    blocks_needed = (total_bits + bits_per_block - 1) // bits_per_block
+    blocks_to_process = min(blocks_needed, len(block_order))
+
+    # Initial progress write - signals Argon2/prep is done, embedding starting
+    if progress_file:
+        _write_progress(progress_file, 5, 100, "embedding")
+
+    # Vectorized embedding: process blocks in batches
+    BATCH_SIZE = 500
     bit_idx = 0
-    total_blocks = len(block_order)
+    block_idx = 0
 
-    for block_idx, block_num in enumerate(block_order):
-        if bit_idx >= len(bits):
-            break
+    while block_idx < blocks_to_process and bit_idx < total_bits:
+        # Determine batch size
+        batch_end = min(block_idx + BATCH_SIZE, blocks_to_process)
+        batch_order = block_order[block_idx:batch_end]
+        batch_count = len(batch_order)
 
-        by = (block_num // blocks_x) * BLOCK_SIZE
-        bx = (block_num % blocks_x) * BLOCK_SIZE
+        # Extract blocks into 3D array (float32 for memory efficiency)
+        blocks = np.zeros((batch_count, BLOCK_SIZE, BLOCK_SIZE), dtype=np.float32)
+        block_positions = []
+        for i, block_num in enumerate(batch_order):
+            by = (block_num // blocks_x) * BLOCK_SIZE
+            bx = (block_num % blocks_x) * BLOCK_SIZE
+            blocks[i] = result[by : by + BLOCK_SIZE, bx : bx + BLOCK_SIZE]
+            block_positions.append((by, bx))
 
-        # Extract block - create brand new array
-        block = np.array(
-            result[by : by + BLOCK_SIZE, bx : bx + BLOCK_SIZE],
-            dtype=np.float64,
-            copy=True,
-            order="C",
-        )
+        # Vectorized 2D DCT on all blocks at once
+        dct_blocks = dctn(blocks, axes=(1, 2), norm="ortho")
 
-        # Apply safe DCT (row-by-row)
-        dct_block = _safe_dct2(block)
-
-        # Embed bits
-        for pos in DEFAULT_EMBED_POSITIONS:
-            if bit_idx >= len(bits):
+        # Embed bits in each block (vectorized where possible)
+        for i in range(batch_count):
+            if bit_idx >= total_bits:
                 break
-            dct_block[pos[0], pos[1]] = _embed_bit_in_coeff(
-                float(dct_block[pos[0], pos[1]]), bits[bit_idx]
-            )
-            bit_idx += 1
 
-        # Apply safe inverse DCT
-        modified_block = _safe_idct2(dct_block)
+            # Get bits for this block
+            block_bits = bits[bit_idx : bit_idx + bits_per_block]
+            num_bits = len(block_bits)
 
-        # Copy back
-        result[by : by + BLOCK_SIZE, bx : bx + BLOCK_SIZE] = modified_block
+            if num_bits == bits_per_block:
+                # Full block - vectorized embedding
+                coeffs = dct_blocks[i, embed_rows, embed_cols]
+                bit_array = np.array(block_bits)
+                # QIM embedding: round to grid, adjust for bit
+                quantized = np.round(coeffs / QUANT_STEP).astype(int)
+                # If quantized % 2 != bit, nudge coefficient
+                needs_adjust = (quantized % 2) != bit_array
+                # Determine direction to nudge
+                dct_blocks[i, embed_rows[needs_adjust], embed_cols[needs_adjust]] = (
+                    (quantized[needs_adjust] + (1 - 2 * (quantized[needs_adjust] % 2 == 1))) * QUANT_STEP
+                ).astype(np.float64)
+                # For bits that already match, just quantize
+                dct_blocks[i, embed_rows[~needs_adjust], embed_cols[~needs_adjust]] = (
+                    quantized[~needs_adjust] * QUANT_STEP
+                ).astype(np.float64)
+            else:
+                # Partial block - process remaining bits individually
+                for j, bit in enumerate(block_bits):
+                    row, col = embed_rows[j], embed_cols[j]
+                    dct_blocks[i, row, col] = _embed_bit_in_coeff(
+                        float(dct_blocks[i, row, col]), bit
+                    )
 
-        # Clean up this iteration
-        del block, dct_block, modified_block
+            bit_idx += num_bits
+
+        # Vectorized inverse DCT
+        modified_blocks = idctn(dct_blocks, axes=(1, 2), norm="ortho")
+
+        # Copy modified blocks back to result
+        for i, (by, bx) in enumerate(block_positions):
+            result[by : by + BLOCK_SIZE, bx : bx + BLOCK_SIZE] = modified_blocks[i]
+
+        # Cleanup
+        del blocks, dct_blocks, modified_blocks
+        block_idx = batch_end
 
         # Report progress periodically
         if progress_file and block_idx % PROGRESS_INTERVAL == 0:
-            _write_progress(progress_file, block_idx, total_blocks, "embedding")
+            _write_progress(progress_file, block_idx, blocks_to_process, "embedding")
 
     # Final progress update
     if progress_file:
-        _write_progress(progress_file, total_blocks, total_blocks, "finalizing")
+        _write_progress(progress_file, blocks_to_process, blocks_to_process, "finalizing")
 
     # Force garbage collection
     gc.collect()
@@ -1029,7 +1126,7 @@ def _embed_jpegio(
     flags = FLAG_COLOR_MODE if color_mode == "color" else 0
 
     try:
-        jpeg = jio.read(input_path)
+        jpeg = jpeglib.to_jpegio(jpeglib.read_dct(input_path))
         coef_array = jpeg.coef_arrays[JPEGIO_EMBED_CHANNEL]
 
         all_positions = _jpegio_get_usable_positions(coef_array)
@@ -1064,6 +1161,10 @@ def _embed_jpegio(
         total_bits = len(bits)
         progress_interval = max(total_bits // 20, 100)  # Report ~20 times or every 100 bits
 
+        # Initial progress write - signals prep is done, embedding starting
+        if progress_file:
+            _write_progress(progress_file, 5, 100, "embedding")
+
         for bit_idx, pos_idx in enumerate(order):
             if bit_idx >= len(bits):
                 break
@@ -1087,7 +1188,7 @@ def _embed_jpegio(
         if progress_file:
             _write_progress(progress_file, total_bits, total_bits, "saving")
 
-        jio.write(jpeg, output_path)
+        jpeg.write(output_path)
 
         with open(output_path, "rb") as f:
             stego_bytes = f.read()
@@ -1115,24 +1216,261 @@ def _embed_jpegio(
                 pass
 
 
-def extract_from_dct(stego_image: bytes, seed: bytes) -> bytes:
-    """Extract data from DCT stego image."""
-    img = Image.open(io.BytesIO(stego_image))
-    fmt = img.format
+def _jpegtran_available() -> bool:
+    """Check if jpegtran is available on the system."""
+    import shutil
+    return shutil.which("jpegtran") is not None
+
+
+def _jpegtran_rotate(image_data: bytes, rotation: int) -> bytes:
+    """
+    Losslessly rotate a JPEG using jpegtran.
+
+    This preserves DCT coefficients by rearranging blocks rather than
+    re-encoding. Essential for rotating stego images without destroying
+    the hidden data.
+
+    Args:
+        image_data: JPEG image bytes
+        rotation: Degrees clockwise (90, 180, or 270)
+
+    Returns:
+        Rotated JPEG bytes with DCT coefficients preserved
+    """
+    import subprocess
+    import tempfile
+    import os
+
+    if rotation not in (90, 180, 270):
+        raise ValueError(f"Invalid rotation: {rotation}")
+
+    # Write input to temp file
+    with tempfile.NamedTemporaryFile(suffix=".jpg", delete=False) as f:
+        f.write(image_data)
+        input_path = f.name
+
+    output_path = tempfile.mktemp(suffix=".jpg")
+
+    try:
+        # jpegtran -rotate 90|180|270 -copy all
+        # -copy all: preserve all metadata
+        # NOTE: Don't use -trim as it drops edge blocks and destroys stego data
+        # NOTE: Don't use -perfect as it fails on images with non-MCU-aligned edges
+        result = subprocess.run(
+            ["jpegtran", "-rotate", str(rotation), "-copy", "all",
+             "-outfile", output_path, input_path],
+            capture_output=True,
+            timeout=30
+        )
+
+        if result.returncode != 0:
+            raise RuntimeError(f"jpegtran failed: {result.stderr.decode()}")
+
+        with open(output_path, "rb") as f:
+            return f.read()
+    finally:
+        for path in [input_path, output_path]:
+            try:
+                os.unlink(path)
+            except OSError:
+                pass
+
+
+def _rotate_image_bytes(image_data: bytes, rotation: int, lossless: bool = True) -> bytes:
+    """
+    Rotate image by 90, 180, or 270 degrees and return as bytes.
+
+    For JPEGs with lossless=True (default), uses jpegtran to preserve DCT
+    coefficients. This is essential for rotating stego images.
+
+    For PNGs or when jpegtran is unavailable, uses PIL (which re-encodes
+    but PNGs are lossless anyway).
+    """
+    img = Image.open(io.BytesIO(image_data))
+    original_format = img.format or "PNG"
     img.close()
 
-    if fmt == "JPEG" and HAS_JPEGIO:
+    # Use jpegtran for lossless JPEG rotation
+    if lossless and original_format == "JPEG" and _jpegtran_available():
+        return _jpegtran_rotate(image_data, rotation)
+
+    # Fallback to PIL for PNGs or when jpegtran unavailable
+    img = Image.open(io.BytesIO(image_data))
+
+    # PIL rotation is counter-clockwise, we want clockwise
+    # 90 CW = 270 CCW, 180 = 180, 270 CW = 90 CCW
+    pil_rotation = {90: 270, 180: 180, 270: 90}[rotation]
+    rotated = img.rotate(pil_rotation, expand=True)
+
+    output = io.BytesIO()
+    # Save in original format if possible, fallback to PNG
+    save_format = original_format if original_format in ("JPEG", "PNG") else "PNG"
+    if save_format == "JPEG":
+        rotated.save(output, format="JPEG", quality=95)
+    else:
+        rotated.save(output, format="PNG")
+    output.seek(0)
+    return output.getvalue()
+
+
+def _quick_validate_dct_header(image_data: bytes, seed: bytes) -> bool:
+    """
+    Quick validation that only extracts enough DCT data to check magic bytes.
+    Returns True if header looks valid, False otherwise.
+
+    This is much faster than full extraction - only processes first ~8 blocks.
+    """
+    try:
+        # Convert to grayscale for quick check
+        gray = _to_grayscale(image_data)
+        height, width = gray.shape
+        padded, _ = _pad_to_blocks(gray)
+        padded_h, padded_w = padded.shape
+        blocks_x = padded_w // BLOCK_SIZE
+        num_blocks = (padded_h // BLOCK_SIZE) * blocks_x
+
+        # Generate block order
+        block_order = _generate_block_order(num_blocks, seed)
+
+        # Only extract first 8 blocks (enough for RS length prefix + header)
+        # 8 blocks * 16 bits/block = 128 bits = 16 bytes (covers RS prefix)
+        blocks_needed = min(8, len(block_order))
+
+        all_bits = []
+        for block_num in block_order[:blocks_needed]:
+            by = (block_num // blocks_x) * BLOCK_SIZE
+            bx = (block_num % blocks_x) * BLOCK_SIZE
+            block = padded[by : by + BLOCK_SIZE, bx : bx + BLOCK_SIZE].astype(np.float32)
+
+            dct_block = dctn(block, norm="ortho")
+
+            for row, col in EMBED_POSITIONS:
+                coef = dct_block[row, col]
+                bit = _extract_bit_from_coeff(coef)
+                all_bits.append(bit)
+
+        # Check RS format first (3 copies of 8-byte length header)
+        if len(all_bits) >= RS_LENGTH_PREFIX_SIZE * 8:
+            length_prefix_bits = all_bits[: RS_LENGTH_PREFIX_SIZE * 8]
+            length_prefix_bytes = bytes(
+                [
+                    sum(length_prefix_bits[i * 8 : (i + 1) * 8][j] << (7 - j) for j in range(8))
+                    for i in range(RS_LENGTH_PREFIX_SIZE)
+                ]
+            )
+
+            # Check if 2+ copies match (indicates valid RS format)
+            copies = []
+            for i in range(RS_LENGTH_COPIES):
+                start = i * RS_LENGTH_HEADER_SIZE
+                end = start + RS_LENGTH_HEADER_SIZE
+                copies.append(length_prefix_bytes[start:end])
+
+            from collections import Counter
+            counter = Counter(copies)
+            _, count = counter.most_common(1)[0]
+
+            if count >= 2:
+                return True  # Looks like valid RS format
+
+        # Check legacy format (magic bytes in first 10 bytes)
+        if len(all_bits) >= HEADER_SIZE * 8:
+            try:
+                _parse_header(all_bits[: HEADER_SIZE * 8])
+                return True  # Magic bytes matched
+            except (ValueError, InvalidMagicBytesError):
+                pass
+
+        return False
+    except Exception:
+        return False
+
+
+def extract_from_dct(
+    stego_image: bytes,
+    seed: bytes,
+    progress_file: str | None = None,
+) -> bytes:
+    """
+    Extract data from DCT stego image.
+
+    If extraction fails with InvalidMagicBytesError, automatically tries
+    90°, 180°, and 270° rotations to handle images that were rotated after
+    encoding (e.g., by external tools or EXIF orientation changes).
+
+    Uses quick header validation to skip obviously invalid rotations.
+    """
+    rotations_to_try = [0, 90, 180, 270]
+    last_error = None
+    valid_rotations = []
+
+    # Phase 1: Quick validation to find candidate rotations
+    for rotation in rotations_to_try:
+        if rotation == 0:
+            image_to_check = stego_image
+        else:
+            image_to_check = _rotate_image_bytes(stego_image, rotation)
+
+        if _quick_validate_dct_header(image_to_check, seed):
+            valid_rotations.append((rotation, image_to_check))
+
+    # If no rotations pass quick check, try all anyway (fallback)
+    if not valid_rotations:
+        # Must try all rotations - quick validation might have failed due to
+        # scipy vs jpegio differences or other edge cases
+        for rotation in rotations_to_try:
+            if rotation == 0:
+                valid_rotations.append((0, stego_image))
+            else:
+                valid_rotations.append((rotation, _rotate_image_bytes(stego_image, rotation)))
+
+    # Phase 2: Full extraction on valid candidates
+    for rotation, image_to_decode in valid_rotations:
         try:
-            return _extract_jpegio(stego_image, seed)
-        except ValueError:
-            pass
+            img = Image.open(io.BytesIO(image_to_decode))
+            fmt = img.format
+            img.close()
 
-    _check_scipy()
-    return _extract_scipy_dct_safe(stego_image, seed)
+            if fmt == "JPEG" and HAS_JPEGIO:
+                try:
+                    result = _extract_jpegio(image_to_decode, seed, progress_file)
+                    if rotation != 0:
+                        try:
+                            from . import debug
+                            debug.print(f"DCT decode succeeded after {rotation}° rotation")
+                        except Exception:
+                            pass  # Don't let debug logging break extraction
+                    return result
+                except (ValueError, InvalidMagicBytesError) as e:
+                    last_error = e if isinstance(e, InvalidMagicBytesError) else last_error
+                    continue
+
+            _check_scipy()
+            result = _extract_scipy_dct_safe(image_to_decode, seed, progress_file)
+            if rotation != 0:
+                try:
+                    from . import debug
+                    debug.print(f"DCT decode succeeded after {rotation}° rotation")
+                except Exception:
+                    pass  # Don't let debug logging break extraction
+            return result
+
+        except InvalidMagicBytesError as e:
+            last_error = e
+            continue
+
+    # All rotations failed
+    raise last_error or InvalidMagicBytesError("Not a Stegasoo image (tried all rotations)")
 
 
-def _extract_scipy_dct_safe(stego_image: bytes, seed: bytes) -> bytes:
-    """Extract using safe DCT operations."""
+def _extract_scipy_dct_safe(
+    stego_image: bytes,
+    seed: bytes,
+    progress_file: str | None = None,
+) -> bytes:
+    """Extract using safe DCT operations with vectorized processing."""
+    # Progress starts at 25% (decode.py writes 20% for Argon2, 25% before extraction)
+
     img = Image.open(io.BytesIO(stego_image))
     width, height = img.size
     mode = img.mode
@@ -1156,26 +1494,54 @@ def _extract_scipy_dct_safe(stego_image: bytes, seed: bytes) -> bytes:
 
     block_order = _generate_block_order(num_blocks, seed)
 
+    # Vectorized extraction: process blocks in batches for ~10x speedup
+    # Batch size balances memory usage vs. parallelization benefit
+    BATCH_SIZE = 500
     all_bits = []
 
-    for block_num in block_order:
-        by = (block_num // blocks_x) * BLOCK_SIZE
-        bx = (block_num % blocks_x) * BLOCK_SIZE
+    # Pre-compute embed positions as numpy indices for vectorized access
+    embed_rows = np.array([pos[0] for pos in DEFAULT_EMBED_POSITIONS])
+    embed_cols = np.array([pos[1] for pos in DEFAULT_EMBED_POSITIONS])
 
-        block = np.array(
-            padded[by : by + BLOCK_SIZE, bx : bx + BLOCK_SIZE],
-            dtype=np.float64,
-            copy=True,
-            order="C",
-        )
-        dct_block = _safe_dct2(block)
+    # Progress reporting interval - report frequently for responsive UI
+    PROGRESS_INTERVAL = 500  # Report every N blocks (matches BATCH_SIZE)
 
-        for pos in DEFAULT_EMBED_POSITIONS:
-            bit = _extract_bit_from_coeff(float(dct_block[pos[0], pos[1]]))
-            all_bits.append(bit)
+    block_idx = 0
+    while block_idx < len(block_order):
+        # Determine batch size (may be smaller at end)
+        batch_end = min(block_idx + BATCH_SIZE, len(block_order))
+        batch_order = block_order[block_idx:batch_end]
+        batch_count = len(batch_order)
 
-        del block, dct_block
+        # Extract blocks into 3D array (batch_count, 8, 8) - float32 for memory efficiency
+        blocks = np.zeros((batch_count, BLOCK_SIZE, BLOCK_SIZE), dtype=np.float32)
+        for i, block_num in enumerate(batch_order):
+            by = (block_num // blocks_x) * BLOCK_SIZE
+            bx = (block_num % blocks_x) * BLOCK_SIZE
+            blocks[i] = padded[by : by + BLOCK_SIZE, bx : bx + BLOCK_SIZE]
 
+        # Vectorized 2D DCT on all blocks at once (~10-15x faster than sequential)
+        dct_blocks = dctn(blocks, axes=(1, 2), norm="ortho")
+
+        # Extract bits from embed positions (vectorized)
+        # Shape: (batch_count, num_positions)
+        coeffs = dct_blocks[:, embed_rows, embed_cols]
+
+        # Quantize and extract bits (vectorized)
+        quantized = np.round(coeffs / QUANT_STEP).astype(int)
+        bits = (quantized % 2).flatten().tolist()
+        all_bits.extend(bits)
+
+        del blocks, dct_blocks, coeffs, quantized
+        block_idx = batch_end
+
+        # Report progress (scale to 25-70% range, RS decode gets 70-100%)
+        # Starts at 25% because decode.py writes 25% before calling extraction
+        if progress_file and block_idx % PROGRESS_INTERVAL < BATCH_SIZE:
+            extract_pct = 25 + int(45 * block_idx / num_blocks)
+            _write_progress(progress_file, extract_pct, 100, "extracting")
+
+        # Check if we have enough bits (early exit)
         if len(all_bits) >= HEADER_SIZE * 8:
             try:
                 _, flags, data_length = _parse_header(all_bits[: HEADER_SIZE * 8])
@@ -1188,6 +1554,9 @@ def _extract_scipy_dct_safe(stego_image: bytes, seed: bytes) -> bytes:
     del padded
     gc.collect()
 
+    # Extraction done, RS decode starts at 70%
+    _write_progress(progress_file, 70, 100, "decoding")
+
     # Try RS-protected format first (has 24-byte length prefix: 3 copies of 8-byte header)
     if HAS_REEDSOLO and len(all_bits) >= RS_LENGTH_PREFIX_SIZE * 8:
         # Extract length prefix (24 bytes: 3 copies of 8-byte header for majority voting)
@@ -1240,10 +1609,16 @@ def _extract_scipy_dct_safe(stego_image: bytes, seed: bytes) -> bytes:
                     ]
                 )
 
+                # 75% - bits converted, starting RS decode (slow part)
+                _write_progress(progress_file, 75, 100, "decoding")
+
                 try:
                     # RS decode to get header + data
                     raw_payload = _rs_decode(rs_encoded)
 
+                    # 95% - RS decode done
+                    _write_progress(progress_file, 95, 100, "decoding")
+
                     # Parse header from decoded payload
                     _, flags, data_length = _parse_header(
                         [((raw_payload[i // 8] >> (7 - i % 8)) & 1) for i in range(HEADER_SIZE * 8)]
@@ -1251,6 +1626,7 @@ def _extract_scipy_dct_safe(stego_image: bytes, seed: bytes) -> bytes:
 
                     # Extract data
                     data = raw_payload[HEADER_SIZE : HEADER_SIZE + data_length]
+                    _write_progress(progress_file, 100, 100, "complete")
                     return data
                 except (ValueError, struct.error):
                     pass  # Fall through to legacy format
@@ -1266,13 +1642,20 @@ def _extract_scipy_dct_safe(stego_image: bytes, seed: bytes) -> bytes:
         ]
     )
 
+    _write_progress(progress_file, 100, 100, "complete")
     return data
 
 
-def _extract_jpegio(stego_image: bytes, seed: bytes) -> bytes:
+def _extract_jpegio(
+    stego_image: bytes,
+    seed: bytes,
+    progress_file: str | None = None,
+) -> bytes:
     """Extract using jpegio for JPEG images."""
     import os
 
+    # Progress starts at 25% (decode.py writes 20% for Argon2, 25% before extraction)
+
     # Normalize JPEG to avoid crashes with quality=100 images
     # (shouldn't happen with stego images, but be defensive)
     stego_image = _normalize_jpeg_for_jpegio(stego_image)
@@ -1280,12 +1663,14 @@ def _extract_jpegio(stego_image: bytes, seed: bytes) -> bytes:
     temp_path = _jpegio_bytes_to_file(stego_image, suffix=".jpg")
 
     try:
-        jpeg = jio.read(temp_path)
+        jpeg = jpeglib.to_jpegio(jpeglib.read_dct(temp_path))
         coef_array = jpeg.coef_arrays[JPEGIO_EMBED_CHANNEL]
 
         all_positions = _jpegio_get_usable_positions(coef_array)
         order = _jpegio_generate_order(len(all_positions), seed)
 
+        _write_progress(progress_file, 30, 100, "extracting")
+
         # Try RS-protected format first (has 24-byte length prefix: 3 copies for majority voting)
         if HAS_REEDSOLO and len(all_positions) >= RS_LENGTH_PREFIX_SIZE * 8:
             # Extract length prefix (24 bytes: 3 copies of 8-byte header)
@@ -1349,9 +1734,12 @@ def _extract_jpegio(stego_image: bytes, seed: bytes) -> bytes:
                     )
 
                     try:
+                        _write_progress(progress_file, 75, 100, "decoding")
                         raw_payload = _rs_decode(rs_encoded)
+                        _write_progress(progress_file, 95, 100, "decoding")
                         _, flags, data_length = _jpegio_parse_header(raw_payload[:HEADER_SIZE])
                         data = raw_payload[HEADER_SIZE : HEADER_SIZE + data_length]
+                        _write_progress(progress_file, 100, 100, "complete")
                         return data
                     except (ValueError, struct.error):
                         pass  # Fall through to legacy format
@@ -1389,6 +1777,7 @@ def _extract_jpegio(stego_image: bytes, seed: bytes) -> bytes:
             ]
         )
 
+        _write_progress(progress_file, 100, 100, "complete")
         return data
 
     finally:

src/stegasoo/decode.py

@@ -8,6 +8,7 @@ Changes in v4.0.0:
 - Improved error messages for channel key mismatches
 """
 
+import json
 from pathlib import Path
 
 from .constants import EMBED_MODE_AUTO
@@ -24,6 +25,22 @@ from .validation import (
 )
 
 
+def _write_progress(progress_file: str | None, current: int, total: int, phase: str) -> None:
+    """Write progress to file for UI polling."""
+    if progress_file is None:
+        return
+    try:
+        with open(progress_file, "w") as f:
+            json.dump({
+                "current": current,
+                "total": total,
+                "percent": (current / total * 100) if total > 0 else 0,
+                "phase": phase,
+            }, f)
+    except OSError:
+        pass
+
+
 def decode(
     stego_image: bytes,
     reference_photo: bytes,
@@ -33,6 +50,7 @@ def decode(
     rsa_password: str | None = None,
     embed_mode: str = EMBED_MODE_AUTO,
     channel_key: str | bool | None = None,
+    progress_file: str | None = None,
 ) -> DecodeResult:
     """
     Decode a message or file from a stego image.
@@ -45,6 +63,7 @@ def decode(
         rsa_key_data: Optional RSA key bytes (if used during encoding)
         rsa_password: Optional RSA key password
         embed_mode: 'auto' (default), 'lsb', or 'dct'
+        progress_file: Optional path to write progress JSON for UI polling
         channel_key: Channel key for deployment/group isolation:
             - None or "auto": Use server's configured key
             - str: Use this specific channel key
@@ -91,16 +110,23 @@ def decode(
     if rsa_key_data:
         require_valid_rsa_key(rsa_key_data, rsa_password)
 
+    # Progress: starting key derivation (Argon2 - slow on Pi)
+    _write_progress(progress_file, 20, 100, "initializing")
+
     # Derive pixel/coefficient selection key (with channel key)
     from .crypto import derive_pixel_key
 
     pixel_key = derive_pixel_key(reference_photo, passphrase, pin, rsa_key_data, channel_key)
 
+    # Progress: key derivation done, starting extraction
+    _write_progress(progress_file, 25, 100, "extracting")
+
     # Extract encrypted data
     encrypted = extract_from_image(
         stego_image,
         pixel_key,
         embed_mode=embed_mode,
+        progress_file=progress_file,
     )
 
     if not encrypted:
@@ -126,6 +152,7 @@ def decode_file(
     rsa_password: str | None = None,
     embed_mode: str = EMBED_MODE_AUTO,
     channel_key: str | bool | None = None,
+    progress_file: str | None = None,
 ) -> Path:
     """
     Decode a file from a stego image and save it.
@@ -140,6 +167,7 @@ def decode_file(
         rsa_password: Optional RSA key password
         embed_mode: 'auto', 'lsb', or 'dct'
         channel_key: Channel key parameter (see decode())
+        progress_file: Optional path to write progress JSON for UI polling
 
     Returns:
         Path where file was saved
@@ -156,6 +184,7 @@ def decode_file(
         rsa_password,
         embed_mode,
         channel_key,
+        progress_file,
     )
 
     if not result.is_file:
@@ -184,6 +213,7 @@ def decode_text(
     rsa_password: str | None = None,
     embed_mode: str = EMBED_MODE_AUTO,
     channel_key: str | bool | None = None,
+    progress_file: str | None = None,
 ) -> str:
     """
     Decode a text message from a stego image.
@@ -199,6 +229,7 @@ def decode_text(
         rsa_password: Optional RSA key password
         embed_mode: 'auto', 'lsb', or 'dct'
         channel_key: Channel key parameter (see decode())
+        progress_file: Optional path to write progress JSON for UI polling
 
     Returns:
         Decoded message string
@@ -215,6 +246,7 @@ def decode_text(
         rsa_password,
         embed_mode,
         channel_key,
+        progress_file,
     )
 
     if result.is_file:

src/stegasoo/generate.py

@@ -82,7 +82,7 @@ def generate_rsa_key(bits: int = DEFAULT_RSA_BITS, password: str | None = None)
     Generate an RSA private key in PEM format.
 
     Args:
-        bits: Key size (2048, 3072, or 4096, default 2048)
+        bits: Key size (2048 or 3072, default 2048)
         password: Optional password to encrypt the key
 
     Returns:

src/stegasoo/keygen.py

@@ -136,7 +136,7 @@ def generate_rsa_key(bits: int = DEFAULT_RSA_BITS) -> rsa.RSAPrivateKey:
     Generate an RSA private key.
 
     Args:
-        bits: Key size (2048, 3072, or 4096)
+        bits: Key size (2048 or 3072)
 
     Returns:
         RSA private key object

src/stegasoo/qr_utils.py

@@ -8,6 +8,7 @@ IMPROVEMENTS IN THIS VERSION:
 - Much more robust PEM normalization
 - Better handling of QR code extraction edge cases
 - Improved error messages
+- v4.2.0: Added zstd compression (better ratio than zlib)
 """
 
 import base64
@@ -16,6 +17,14 @@ import zlib
 
 from PIL import Image
 
+# Optional ZSTD support (better compression ratio)
+try:
+    import zstandard as zstd
+
+    HAS_ZSTD = True
+except ImportError:
+    HAS_ZSTD = False
+
 # QR code generation
 try:
     import qrcode
@@ -42,30 +51,46 @@ from .constants import (
 )
 
 # Constants
-COMPRESSION_PREFIX = "STEGASOO-Z:"
+COMPRESSION_PREFIX_ZLIB = "STEGASOO-Z:"  # Legacy zlib compression
+COMPRESSION_PREFIX_ZSTD = "STEGASOO-ZS:"  # v4.2.0: New zstd compression (better ratio)
+COMPRESSION_PREFIX = COMPRESSION_PREFIX_ZSTD if HAS_ZSTD else COMPRESSION_PREFIX_ZLIB
 
 
 def compress_data(data: str) -> str:
     """
     Compress string data for QR code storage.
 
+    Uses zstd if available (better ratio), falls back to zlib.
+
     Args:
         data: String to compress
 
     Returns:
-        Compressed string with STEGASOO-Z: prefix
+        Compressed string with STEGASOO-ZS: (zstd) or STEGASOO-Z: (zlib) prefix
     """
-    compressed = zlib.compress(data.encode("utf-8"), level=9)
-    encoded = base64.b64encode(compressed).decode("ascii")
-    return COMPRESSION_PREFIX + encoded
+    data_bytes = data.encode("utf-8")
+
+    if HAS_ZSTD:
+        # Use zstd (better compression ratio)
+        cctx = zstd.ZstdCompressor(level=19)
+        compressed = cctx.compress(data_bytes)
+        encoded = base64.b64encode(compressed).decode("ascii")
+        return COMPRESSION_PREFIX_ZSTD + encoded
+    else:
+        # Fall back to zlib
+        compressed = zlib.compress(data_bytes, level=9)
+        encoded = base64.b64encode(compressed).decode("ascii")
+        return COMPRESSION_PREFIX_ZLIB + encoded
 
 
 def decompress_data(data: str) -> str:
     """
     Decompress data from QR code.
 
+    Supports both zstd (STEGASOO-ZS:) and zlib (STEGASOO-Z:) formats.
+
     Args:
-        data: Compressed string with STEGASOO-Z: prefix
+        data: Compressed string with STEGASOO-ZS: or STEGASOO-Z: prefix
 
     Returns:
         Original uncompressed string
@@ -73,12 +98,26 @@ def decompress_data(data: str) -> str:
     Raises:
         ValueError: If data is not valid compressed format
     """
-    if not data.startswith(COMPRESSION_PREFIX):
-        raise ValueError("Data is not in compressed format")
+    if data.startswith(COMPRESSION_PREFIX_ZSTD):
+        # v4.2.0: ZSTD compression
+        if not HAS_ZSTD:
+            raise ValueError(
+                "Data compressed with zstd but zstandard package not installed. "
+                "Run: pip install zstandard"
+            )
+        encoded = data[len(COMPRESSION_PREFIX_ZSTD):]
+        compressed = base64.b64decode(encoded)
+        dctx = zstd.ZstdDecompressor()
+        return dctx.decompress(compressed).decode("utf-8")
 
-    encoded = data[len(COMPRESSION_PREFIX) :]
-    compressed = base64.b64decode(encoded)
-    return zlib.decompress(compressed).decode("utf-8")
+    elif data.startswith(COMPRESSION_PREFIX_ZLIB):
+        # Legacy zlib compression
+        encoded = data[len(COMPRESSION_PREFIX_ZLIB):]
+        compressed = base64.b64decode(encoded)
+        return zlib.decompress(compressed).decode("utf-8")
+
+    else:
+        raise ValueError("Data is not in compressed format")
 
 
 def normalize_pem(pem_data: str) -> str:
@@ -166,8 +205,8 @@ def normalize_pem(pem_data: str) -> str:
 
 
 def is_compressed(data: str) -> bool:
-    """Check if data has compression prefix."""
-    return data.startswith(COMPRESSION_PREFIX)
+    """Check if data has compression prefix (zstd or zlib)."""
+    return data.startswith(COMPRESSION_PREFIX_ZSTD) or data.startswith(COMPRESSION_PREFIX_ZLIB)
 
 
 def auto_decompress(data: str) -> str:
@@ -213,17 +252,23 @@ def needs_compression(data: str) -> bool:
     return not can_fit_in_qr(data, compress=False) and can_fit_in_qr(data, compress=True)
 
 
-def generate_qr_code(data: str, compress: bool = False, error_correction=None) -> bytes:
+def generate_qr_code(
+    data: str,
+    compress: bool = False,
+    error_correction=None,
+    output_format: str = "png",
+) -> bytes:
     """
-    Generate a QR code PNG from string data.
+    Generate a QR code image from string data.
 
     Args:
         data: String data to encode
         compress: Whether to compress data first
         error_correction: QR error correction level (default: auto)
+        output_format: Image format - 'png' or 'jpg'/'jpeg'
 
     Returns:
-        PNG image bytes
+        Image bytes in requested format
 
     Raises:
         RuntimeError: If qrcode library not available
@@ -260,11 +305,79 @@ def generate_qr_code(data: str, compress: bool = False, error_correction=None) -
     img = qr.make_image(fill_color="black", back_color="white")
 
     buf = io.BytesIO()
-    img.save(buf, format="PNG")
+    fmt = output_format.lower()
+    if fmt in ("jpg", "jpeg"):
+        # Convert to RGB for JPEG (no alpha channel)
+        img = img.convert("RGB")
+        img.save(buf, format="JPEG", quality=95)
+    else:
+        img.save(buf, format="PNG")
     buf.seek(0)
     return buf.getvalue()
 
 
+def generate_qr_ascii(
+    data: str,
+    compress: bool = False,
+    invert: bool = False,
+) -> str:
+    """
+    Generate an ASCII representation of a QR code.
+
+    Uses Unicode block characters for compact display.
+
+    Args:
+        data: String data to encode
+        compress: Whether to compress data first
+        invert: Invert colors (white on black for dark terminals)
+
+    Returns:
+        ASCII string representation of QR code
+
+    Raises:
+        RuntimeError: If qrcode library not available
+        ValueError: If data too large for QR code
+    """
+    if not HAS_QRCODE_WRITE:
+        raise RuntimeError("qrcode library not installed. Run: pip install qrcode[pil]")
+
+    qr_data = data
+
+    # Compress if requested
+    if compress:
+        qr_data = compress_data(data)
+
+    # Check size
+    if len(qr_data.encode("utf-8")) > QR_MAX_BINARY:
+        raise ValueError(
+            f"Data too large for QR code ({len(qr_data)} bytes). " f"Maximum: {QR_MAX_BINARY} bytes"
+        )
+
+    qr = qrcode.QRCode(
+        version=None,
+        error_correction=ERROR_CORRECT_L,
+        box_size=1,
+        border=2,
+    )
+    qr.add_data(qr_data)
+    qr.make(fit=True)
+
+    # Get the QR matrix
+    # Use print_ascii to a StringIO to capture output
+    import sys
+    from io import StringIO
+
+    old_stdout = sys.stdout
+    sys.stdout = StringIO()
+    try:
+        qr.print_ascii(invert=invert)
+        ascii_qr = sys.stdout.getvalue()
+    finally:
+        sys.stdout = old_stdout
+
+    return ascii_qr
+
+
 def read_qr_code(image_data: bytes) -> str | None:
     """
     Read QR code from image data.

src/stegasoo/steganography.py

@@ -156,7 +156,7 @@ def has_dct_support() -> bool:
         dct_mod = _get_dct_module()
         return dct_mod.has_dct_support()
     except (ImportError, ValueError):
-        # ValueError: numpy binary incompatibility (e.g., jpegio built against numpy 2.x)
+        # ValueError: numpy binary incompatibility (e.g., jpeglib built against numpy 2.x)
         return False
 
 
@@ -746,6 +746,10 @@ def _embed_lsb(
         modified_pixels = 0
         total_pixels_to_process = len(selected_indices)
 
+        # Initial progress write - signals prep is done, embedding starting
+        if progress_file:
+            _write_progress(progress_file, 5, 100, "embedding")
+
         for progress_idx, pixel_idx in enumerate(selected_indices):
             if bit_idx >= len(binary_data):
                 break
@@ -839,6 +843,7 @@ def extract_from_image(
     pixel_key: bytes,
     bits_per_channel: int = 1,
     embed_mode: str = EMBED_MODE_AUTO,
+    progress_file: str | None = None,
 ) -> bytes | None:
     """
     Extract hidden data from a stego image.
@@ -848,6 +853,7 @@ def extract_from_image(
         pixel_key: Key for pixel/coefficient selection (must match encoding)
         bits_per_channel: Bits per channel (LSB mode only)
         embed_mode: 'auto' (try both), 'lsb', or 'dct'
+        progress_file: Optional path to write progress JSON for UI polling
 
     Returns:
         Extracted data bytes, or None if extraction fails
@@ -863,7 +869,7 @@ def extract_from_image(
 
         if has_dct_support():
             debug.print("Auto-detect: LSB failed, trying DCT")
-            result = _extract_dct(image_data, pixel_key)
+            result = _extract_dct(image_data, pixel_key, progress_file)
             if result is not None:
                 debug.print("Auto-detect: DCT extraction succeeded")
                 return result
@@ -875,18 +881,22 @@ def extract_from_image(
     elif embed_mode == EMBED_MODE_DCT:
         if not has_dct_support():
             raise ImportError("scipy required for DCT mode")
-        return _extract_dct(image_data, pixel_key)
+        return _extract_dct(image_data, pixel_key, progress_file)
 
     # EXPLICIT LSB MODE
     else:
         return _extract_lsb(image_data, pixel_key, bits_per_channel)
 
 
-def _extract_dct(image_data: bytes, pixel_key: bytes) -> bytes | None:
+def _extract_dct(
+    image_data: bytes,
+    pixel_key: bytes,
+    progress_file: str | None = None,
+) -> bytes | None:
     """Extract using DCT mode."""
     try:
         dct_mod = _get_dct_module()
-        return dct_mod.extract_from_dct(image_data, pixel_key)
+        return dct_mod.extract_from_dct(image_data, pixel_key, progress_file)
     except Exception as e:
         debug.print(f"DCT extraction failed: {e}")
         return None
@@ -1087,7 +1097,7 @@ def peek_image(image_data: bytes) -> dict:
     except Exception:
         pass
 
-    # Try DCT extraction (requires scipy/jpegio)
+    # Try DCT extraction (requires scipy/jpeglib)
     try:
         from .dct_steganography import HAS_JPEGIO, HAS_SCIPY
 

src/stegasoo/utils.py

@@ -66,9 +66,15 @@ def read_image_exif(image_data: bytes) -> dict:
                 # Convert bytes to string if possible
                 elif isinstance(value, bytes):
                     try:
-                        result[tag] = value.decode("utf-8", errors="replace").strip("\x00")
-                    except Exception:
-                        result[tag] = f"<{len(value)} bytes>"
+                        # Try to decode as ASCII/UTF-8 text
+                        decoded = value.decode("utf-8", errors="strict").strip("\x00")
+                        # Only keep if it looks like printable text
+                        if decoded.isprintable() or all(c.isspace() or c.isprintable() for c in decoded):
+                            result[tag] = decoded
+                        else:
+                            result[tag] = f"<{len(value)} bytes binary>"
+                    except (UnicodeDecodeError, Exception):
+                        result[tag] = f"<{len(value)} bytes binary>"
                 # Handle tuples of IFDRational
                 elif isinstance(value, tuple) and value and hasattr(value[0], "numerator"):
                     result[tag] = [float(v) for v in value]

test-aur-build.sh

@@ -0,0 +1,107 @@
+#!/bin/bash
+# Test AUR package builds in a clean Arch container
+#
+# Usage: sudo ./test-aur-build.sh [package]
+#   package: all (default), full, cli, api
+
+set -e
+
+PACKAGE="${1:-all}"
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+
+echo "=== Stegasoo AUR Build Test ==="
+echo "Package: $PACKAGE"
+echo ""
+
+# Create a test script to run inside container
+cat > /tmp/aur-build-test.sh << 'INNERSCRIPT'
+#!/bin/bash
+set -e
+
+# Update system
+pacman -Syu --noconfirm
+
+# Install build dependencies
+pacman -S --noconfirm --needed \
+    base-devel git python python-build python-hatchling \
+    zbar
+
+# Create build user (makepkg won't run as root)
+useradd -m builder
+echo "builder ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers
+
+# Copy source to build location
+cp -r /src /home/builder/stegasoo
+chown -R builder:builder /home/builder/stegasoo
+
+build_package() {
+    local pkg_dir="$1"
+    local pkg_name="$2"
+
+    echo ""
+    echo "=========================================="
+    echo "Building: $pkg_name"
+    echo "=========================================="
+
+    cd "/home/builder/stegasoo/$pkg_dir"
+
+    # Build as non-root user
+    sudo -u builder makepkg -sf --noconfirm
+
+    # Show result
+    ls -lh *.pkg.tar.zst
+
+    # Test install
+    echo "Installing $pkg_name..."
+    pacman -U --noconfirm *.pkg.tar.zst
+
+    # Quick test
+    echo "Testing $pkg_name..."
+    stegasoo --version
+    stegasoo --help | head -20
+
+    # Uninstall for next test
+    pacman -R --noconfirm "${pkg_name%-git}" 2>/dev/null || pacman -R --noconfirm "$pkg_name" 2>/dev/null || true
+
+    echo "$pkg_name: SUCCESS"
+}
+
+case "$1" in
+    full)
+        build_package "aur" "stegasoo-git"
+        ;;
+    cli)
+        build_package "aur-cli" "stegasoo-cli-git"
+        ;;
+    api)
+        build_package "aur-api" "stegasoo-api-git"
+        ;;
+    all)
+        build_package "aur" "stegasoo-git"
+        build_package "aur-cli" "stegasoo-cli-git"
+        build_package "aur-api" "stegasoo-api-git"
+        ;;
+    *)
+        echo "Unknown package: $1"
+        exit 1
+        ;;
+esac
+
+echo ""
+echo "=========================================="
+echo "All builds completed successfully!"
+echo "=========================================="
+INNERSCRIPT
+
+chmod +x /tmp/aur-build-test.sh
+
+# Run in Arch container
+echo "Starting Arch container..."
+docker run --rm -it \
+    -v "$SCRIPT_DIR:/src:ro" \
+    -v "/tmp/aur-build-test.sh:/build.sh:ro" \
+    archlinux:latest \
+    /bin/bash -c "chmod +x /build.sh && /build.sh $PACKAGE"
+
+echo ""
+echo "=== Build test complete ==="

test-aur-nspawn.sh

@@ -0,0 +1,130 @@
+#!/bin/bash
+# Test AUR package builds using systemd-nspawn
+#
+# Usage: sudo ./test-aur-nspawn.sh [package]
+#   package: all (default), full, cli, api
+#
+# First run creates Arch root at /tmp/arch-build-root
+
+set -e
+
+PACKAGE="${1:-all}"
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+ARCH_ROOT="/tmp/arch-build-root"
+
+echo "=== Stegasoo AUR Build Test (nspawn) ==="
+echo "Package: $PACKAGE"
+echo "Arch root: $ARCH_ROOT"
+echo ""
+
+# Check for root
+if [ "$EUID" -ne 0 ]; then
+    echo "Please run as root (sudo)"
+    exit 1
+fi
+
+# Create Arch root if it doesn't exist
+if [ ! -d "$ARCH_ROOT/usr" ]; then
+    echo "Creating Arch root (first time setup)..."
+    mkdir -p "$ARCH_ROOT"
+    pacstrap -c "$ARCH_ROOT" base base-devel git python python-build python-hatchling zbar
+    echo "Arch root created."
+else
+    echo "Using existing Arch root."
+    # Update packages
+    arch-chroot "$ARCH_ROOT" pacman -Syu --noconfirm
+fi
+
+# Create build user if needed
+if ! arch-chroot "$ARCH_ROOT" id builder &>/dev/null; then
+    arch-chroot "$ARCH_ROOT" useradd -m builder
+    echo "builder ALL=(ALL) NOPASSWD: ALL" >> "$ARCH_ROOT/etc/sudoers"
+fi
+
+# Copy source
+rm -rf "$ARCH_ROOT/home/builder/stegasoo"
+cp -r "$SCRIPT_DIR" "$ARCH_ROOT/home/builder/stegasoo"
+arch-chroot "$ARCH_ROOT" chown -R builder:builder /home/builder/stegasoo
+
+# Create build script
+cat > "$ARCH_ROOT/tmp/build.sh" << 'BUILDSCRIPT'
+#!/bin/bash
+set -e
+
+build_package() {
+    local pkg_dir="$1"
+    local pkg_name="$2"
+
+    echo ""
+    echo "=========================================="
+    echo "Building: $pkg_name"
+    echo "=========================================="
+
+    cd "/home/builder/stegasoo/$pkg_dir"
+
+    # Clean previous builds
+    rm -rf src pkg *.pkg.tar.zst "${pkg_name}" 2>/dev/null || true
+
+    # Build as non-root user
+    sudo -u builder makepkg -sf --noconfirm
+
+    # Show result
+    ls -lh *.pkg.tar.zst
+
+    # Test install
+    echo "Installing $pkg_name..."
+    pacman -U --noconfirm *.pkg.tar.zst
+
+    # Quick test
+    echo "Testing $pkg_name..."
+    /usr/bin/stegasoo --version
+
+    # More tests for API package
+    if [[ "$pkg_name" == *"api"* ]]; then
+        /usr/bin/stegasoo api --help
+        /usr/bin/stegasoo api keys list
+    fi
+
+    # Uninstall for next test
+    pacman -Rns --noconfirm $(pacman -Qq | grep stegasoo) 2>/dev/null || true
+
+    echo "$pkg_name: SUCCESS"
+}
+
+case "$1" in
+    full)
+        build_package "aur" "stegasoo-git"
+        ;;
+    cli)
+        build_package "aur-cli" "stegasoo-cli-git"
+        ;;
+    api)
+        build_package "aur-api" "stegasoo-api-git"
+        ;;
+    all)
+        build_package "aur-cli" "stegasoo-cli-git"
+        build_package "aur-api" "stegasoo-api-git"
+        build_package "aur" "stegasoo-git"
+        ;;
+    *)
+        echo "Unknown package: $1"
+        exit 1
+        ;;
+esac
+
+echo ""
+echo "=========================================="
+echo "All builds completed successfully!"
+echo "=========================================="
+BUILDSCRIPT
+
+chmod +x "$ARCH_ROOT/tmp/build.sh"
+
+# Run build in nspawn container
+echo "Starting nspawn container..."
+systemd-nspawn -D "$ARCH_ROOT" --bind-ro="$SCRIPT_DIR:/home/builder/stegasoo" /tmp/build.sh "$PACKAGE"
+
+echo ""
+echo "=== Build test complete ==="
+echo "Arch root preserved at: $ARCH_ROOT"
+echo "To clean up: sudo rm -rf $ARCH_ROOT"

test_data/phonebooth.pem

@@ -0,0 +1,30 @@
+-----BEGIN ENCRYPTED PRIVATE KEY-----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+-----END ENCRYPTED PRIVATE KEY-----