Feature	Description
DCT Mode	Frequency-domain embedding survives JPEG recompression
JPEG Output	Native JPEG output using jpegio library
Color Preservation	DCT color mode preserves carrier image colors
Auto-Detection	Decoder automatically detects LSB vs DCT mode

Embedding Mode Comparison

Mode	Capacity (1080p)	JPEG Resilient	Best For
LSB (default)	~770 KB	❌ No	Email, file transfer
DCT (experimental)	~65 KB	✅ Yes	Social media, messaging apps

WebUI Preview

Front Page	Encode	Decode	Generate

Quick Start

# Install with all features
pip install -e ".[all]"

# Generate credentials (memorize these!)
stegasoo generate --pin --words 3

# Encode a message (LSB mode - default)
stegasoo encode \
  --ref photo.jpg \
  --carrier meme.png \
  --phrase "apple forest thunder" \
  --pin 123456 \
  --message "Secret message"

# Encode for social media (DCT mode)
stegasoo encode \
  --ref photo.jpg \
  --carrier meme.png \
  --phrase "apple forest thunder" \
  --pin 123456 \
  --message "Secret message" \
  --mode dct \
  --format jpeg

# Decode (auto-detects mode)
stegasoo decode \
  --ref photo.jpg \
  --stego stego.png \
  --phrase "apple forest thunder" \
  --pin 123456

For detailed installation instructions, see INSTALL.md.

Security Model

Stegasoo uses multiple authentication factors combined with strong cryptography:

┌─────────────────────────────────────────────────────────────────┐
│                    AUTHENTICATION LAYERS                         │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│   Reference Photo ──┐                                           │
│   (~80-256 bits)    │                                           │
│                     ├──► Argon2id KDF ──► AES-256-GCM Key       │
│   Day Phrase ───────┤    (256MB RAM)                            │
│   (~33-132 bits)    │                                           │
│                     │                                           │
│   Static PIN ───────┤                                           │
│   (~20-30 bits)     │                                           │
│                     │                                           │
│   RSA Key ──────────┘                                           │
│   (~128 bits)       (optional, adds another factor)             │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

Entropy Summary

Component	Entropy	Purpose
Reference Photo	~80-256 bits	Something you have
Day Phrase (3-12 words)	~33-132 bits	Something you know (rotates daily)
PIN (6-9 digits)	~20-30 bits	Something you know (static)
RSA Key (2048-4096 bit)	~112-128 bits	Something you have (optional)
Combined	133-400+ bits	Beyond brute force

Attack Resistance

Attack	Protection
Brute force	2^133+ combinations minimum
Rainbow tables	Random 16-byte salt per message
Steganalysis	Pseudo-random pixel/coefficient selection
GPU cracking	Argon2id requires 256MB RAM per attempt
Side-channel	Constant-time operations in cryptography library
JPEG recompression	DCT mode embeds in frequency domain (v3.0+)

Security Configurations

Configuration	Entropy	Use Case
3-word phrase + 6-digit PIN	~133 bits	Casual private messaging
6-word phrase + 9-digit PIN	~176 bits	Standard security
3-word phrase + RSA 2048	~241 bits	File-based authentication
6-word phrase + PIN + RSA 4096	~304 bits	Maximum security

Interfaces

Command-Line Interface (CLI)

Full-featured CLI with piping support:

# Generate with RSA key
stegasoo generate --rsa --rsa-bits 4096 -o mykey.pem -p "password"

# Encode from file
stegasoo encode -r ref.jpg -c carrier.png -p "phrase" --pin 123456 -f secret.txt

# Encode for social media (DCT + JPEG)
stegasoo encode -r ref.jpg -c carrier.png -p "phrase" --pin 123456 \
  -m "Message" --mode dct --format jpeg

# Decode to stdout (quiet mode)
stegasoo decode -r ref.jpg -s stego.png -p "phrase" --pin 123456 -q

# Check image capacity (shows both LSB and DCT)
stegasoo info carrier.png

📖 Full documentation: CLI.md

Web UI

Browser-based interface with drag-and-drop uploads:

# Start the server
cd frontends/web
python app.py
# Visit http://localhost:5000

Features:

Drag-and-drop image uploads
Real-time entropy calculator
Native mobile sharing (Web Share API)
DCT mode with advanced options panel
Automatic day-of-week detection

📖 Full documentation: WEB_UI.md

REST API

FastAPI-powered REST API with OpenAPI documentation:

# Start the server
cd frontends/api
uvicorn main:app --host 0.0.0.0 --port 8000
# Docs at http://localhost:8000/docs

Example API calls:

# Generate credentials
curl -X POST http://localhost:8000/generate \
  -H "Content-Type: application/json" \
  -d '{"use_pin": true, "words_per_phrase": 3}'

# Encode with DCT mode
curl -X POST http://localhost:8000/encode/multipart \
  -F "message=Secret" \
  -F "day_phrase=apple forest thunder" \
  -F "pin=123456" \
  -F "embedding_mode=dct" \
  -F "output_format=jpeg" \
  -F "reference_photo=@photo.jpg" \
  -F "carrier=@meme.png" \
  --output stego.jpg

# Decode (auto-detects mode)
curl -X POST http://localhost:8000/decode/multipart \
  -F "day_phrase=apple forest thunder" \
  -F "pin=123456" \
  -F "reference_photo=@photo.jpg" \
  -F "stego_image=@stego.jpg"

📖 Full documentation: API.md

Project Structure

stegasoo/
├── src/stegasoo/           # Core library
│   ├── __init__.py         # Public API
│   ├── constants.py        # Configuration
│   ├── crypto.py           # Encryption/decryption
│   ├── steganography.py    # LSB image embedding
│   ├── dct_steganography.py # DCT embedding (v3.0+)
│   ├── keygen.py           # Credential generation
│   ├── validation.py       # Input validation
│   ├── models.py           # Data classes
│   ├── exceptions.py       # Custom exceptions
│   ├── qr_utils.py         # QR code utilities
│   └── utils.py            # Utilities
│
├── frontends/
│   ├── web/                # Flask web UI
│   ├── cli/                # Command-line interface
│   └── api/                # FastAPI REST API
│
├── data/
│   └── bip39-words.txt     # BIP-39 wordlist
│
├── pyproject.toml          # Package configuration
├── Dockerfile              # Multi-stage Docker build
├── docker-compose.yml      # Container orchestration
│
├── README.md               # This file
├── INSTALL.md              # Installation guide
├── CLI.md                  # CLI documentation
├── API.md                  # API documentation
└── WEB_UI.md               # Web UI documentation

Configuration

Limits

Limit	Value
Max image size	4 megapixels
Max message size	50 KB
Max file upload	5 MB
PIN length	6-9 digits
Phrase length	3-12 words
RSA key sizes	2048, 3072, 4096 bits

Environment Variables

Variable	Default	Description
`FLASK_ENV`	production	Flask environment
`PYTHONPATH`	-	Include `src/` for development

Development

# Install dev dependencies
pip install -e ".[dev]"

# Run tests
pytest

# Format code
black src/ frontends/
ruff check src/ frontends/

# Type checking
mypy src/

# Check DCT support
python -c "from stegasoo import has_dct_support; print(has_dct_support())"
python -c "from stegasoo.dct_steganography import has_jpegio_support; print(has_jpegio_support())"

Version History

Version	Changes
3.0.2	Fixed JPEG output with jpegio integration
3.0.1	Added DCT color mode, JPEG output (broken)
3.0.0	Added DCT steganography mode
2.2.x	QR code support, file embedding
2.0.x	Web UI, REST API, RSA keys
1.0.x	Initial release, CLI only

License

MIT License - Use responsibly.

⚠️ Disclaimer

This tool is for educational and legitimate privacy purposes only. Users are responsible for complying with applicable laws in their jurisdiction.

README.md

Stegasoo

Features

What's New in v3.0.2