Stego

A steganography tool that hides data in PNG images using LSB (Least Significant Bit) technique.

Features

• Hide files or text in PNG images
• Extract hidden data from images
• Extract from PNG URLs
• Data compression
• Optional ChaCha20-Poly1305 encryption
• Uses 2 LSBs per channel
• Automatic image sizing

Building

make

Requires:

• libcurl (for URLs)
• zlib
• gcc/clang

On macOS:

brew install curl

Usage

Hide a file:

stego hide input.txt output.png [-p password]

Hide text directly:

stego hide -t "Hello World" output.png [-p password]

Extract from file:

stego extract input.png output.txt [-p password]

Extract from URL:

stego -u https://example.com/secret.png -o output.txt [-p password]

How it Works

Basic steganography implementation:

• Uses 2 LSBs from each RGB channel
• Requires 2 pixels per byte of data
• Compresses data before embedding
• Optional ChaCha20-Poly1305 encryption
• Creates or reuses PNG images as needed

Storage

Storage characteristics:

• Compression typically reduces input size
• Uses 2 bits per color channel
• Requires 2 pixels per byte
• Image size scales with data size

License

MIT License - see LICENSE file for details