smoke52ru / stegopy

LSB steganoraphy with Python3

StegoPy

Русская версия

Статья со скриншотами на Habrahabr - https://habr.com/ru/post/497420/

English version

Theory

StegoPy - Steganography with Python3 LSB algorithm with some improvements. The cryptography algorithm can choose the balance itself. The brightest channel of an each pixel is used for encoding. Pixels are used, from x|y = 0 and from left to right.

Balance - the number of least significant bits of the pixel that are involved in the encoding. The maximum is 4, the minimum is 1. With increasing cryptographic strength and the number of pixels involved decreases. Therefore, I advise you to use 1. And if the text does not fit, but you still want to cram the large text into a small image, then you can use 2 or 3.

The peculiarity of the balance system is that for a certain text, balance 3 can be more stable than 1. I also examine balances on the same text, I noticed that often the pixels do not even change, mainly with a balance of 1. But it also depends on the text.

When encoding text in an image, it is pre-encrypted with the DES algorithm, so no matter how you try, you cannot encode the same text with the same key.

After encoding, the key will be saved in the key.dat file, the image with the text in the file out.png The key consists of three parts, for example: 2$400$KJhkiGlGKkghk/FffdD=

Shared by the character '$'. First - 2 is the balance. The second - 400 is the number of pixels involved and at the end is the key to the DES cipher. Over time, pixel randomization will be added, which will make the algorithm even more stable, as well as change the structure of the key.

Linux installation

Make sure > which python3 gives a /usr/bin/python3

> git clone https://github.com/securityhigh/StegoPy
> cd StegoPy
> sudo ./install.sh

Start in any folders:

> stegopy [arguments]

Windows installation (not tested!):

Download from https://github.com/securityhigh/StegoPy Unpack archive. Open cmd.exe (Win + R and write cmd.exe)

> python3 stegopy.py [arguments]

Encoding

> stegopy -e in.jpg data.txt

-e - action type, encoding in.jpg - target image data.txt - file with your text

Enter a need balance. Out image out.png, key in key.dat

Deconding

> stegopy -d out.png

-d - action type, decoding out.png - encoded image

Enter a key. Decoded data saved in out.txt