DCT Steganography

A Python tool for hiding and extracting messages in images using DCT (Discrete Cosine Transform) steganography. My implementation modifies DCT coefficients in the frequency domain to embed data with minimal visual impact on the image.

What is DCT Steganography?

DCT (Discrete Cosine Transform) steganography is a technique that hides information within the frequency components of an image rather than directly manipulating pixel values.

Features

Secure Message Hiding: Embed text messages within images with minimal visual changes
Extraction: Recover hidden messages from steganographic images
Configurable Strength: Adjust embedding strength to balance between robustness and visual quality
Command-Line Interface: Easy-to-use CLI for both embedding and extraction operations
Grayscale Image Support: Works with grayscale images (can be extended to color)
Null Termination: Messages are automatically null-terminated for reliable extraction

Requirements

Python 3.6+
NumPy
OpenCV (cv2)
SciPy

Installation

Clone this repository:

git clone https://github.com/murugnn/dct-steganography.git
cd dct-steganography

Install the required dependencies:

pip install numpy opencv-python scipy

Usage

Embedding a Message

To hide a message in an image:

python dct_steganography.py embed --image path/to/cover.png --message "Your secret message or flag{hidden_data}" --output path/to/output.png

Optional parameters:

--alpha or -a: Embedding strength (default: 0.1). Higher values make the embedding more robust but potentially more visible.

Extracting a Message

To extract a hidden message from an image:

python dct_steganography.py extract --image path/to/stego.png

Optional parameters:

--length or -l: Specify the message length in bits if known (usually not needed as messages are null-terminated)

Applications

CTF Challenges: Hide flags within images for capture-the-flag competitions
Digital Watermarking: Embed copyright information in images
Covert Communication: Exchange hidden messages within innocuous-looking images
Data Authentication: Verify the integrity of images

Future Improvements

Color image support (applying DCT to each color channel)
Adaptive embedding strength based on image content
Error correction codes for more robust recovery
Encryption of the message before embedding
Spread spectrum techniques for increased security

License

This project is licensed under the MIT License

License

orozcodiaz/dct-steganography

ErrorLooks like something went wrong!

About

Resources

License

Uh oh!

Stars

Watchers

Forks

Releases

Packages 0

Languages

Error
Looks like something went wrong!

Packages