STEGANO

C programm for LSB steganography

Installation

1. Install FreeImage
2. Clone this repository
3. [For Windows only] copy FreeImage.dll in the cloned folder. Adapt LDFLAGS (see Makefile)
4. Execute make

Description

Stegano conceals any file in any other file using LSB (Last Significant Bit) steganography.

Stegano stores at the end of the file, in order to prevent header corruption making the resulting file unreadable.

Information about file extension and size of the covered filed is also stored in the covering file. This ensures more efficient subsequent extraction from this file.

In case the covering file is a jpeg or a png image, it is possible to have an intermediary bitmap (bmp) conversion. In this case, the file to covert will be inserted in the intermediary bmp image. Then this bmp file will be converted into png format exclusively (because bmp -> jpg -> bmp conversions generate losses in the last bmp file, making the original file unrecoverable).

size(covering file) >= 8 * size(file to cover) + 96 (in bytes), because 96 bytes are used to store size and extension of the original file, and each byte of the covering file can cover only one bit of the file to cover (lsb approach). Basically, any file can be covered in any other file as long as this condition applies. NB: in case of intermediary bmp conversion, this condition must apply for the bmp conversion of the covering image, not to the covering image itself.

Usage

For example

./stegano -a insertion -t data/message.txt -c data/fractal_2.jpg -b -o data/f2.png

will insert data/message.txt into data/fractal_2.jpg with intermediary bitmap conversion, and the result will be stored in data/f2.png.

On the other hand,

./stegano -a extraction -c data/f2.png -b -o data/message_extracted

will extract the file encoded in data/f2.png with intermediary bitmap conversion and store the result in data/message_extracted.ext, where ext is the extension of the original file.

For more details:

./stegano --help