Stegtool - Simple steganography tool

Encode and decode text hidden in bmp files

After enjoying the Filter problem in the CS50X I decided to make my own program to manipulate bmp image files.

⚠️ Warning: This tool is not encryption, don't use for sensitive data!

This project was good practice working with pointers and learning to read data from a file.

Requires 24-bit uncompressed bmp files

This is a learning project and is currently under development. It is a working tool, but some bugs remain. Bug reports / Issues welcomed.

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Using the tool

To build

git clone https://github.com/dotpeedeeeff/stegtool.git

cd stegtool

make steg

To encode:

Arguments:

1. Program name
2. Input image
3. String to encode

./steg ./images/test.bmp "hello world"

The program will produce output file: output.bmp Note that all text is converted to upper case and only very limited punctuation is supported.

To decode:

Arguments:

1. Program name
2. Input image

./steg output.bmp

The program will decode any hidden message. If the output is less than 500 characters, the output will be displayed in the terminal. Output larger than 500 chars will be written to output.txt.

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Screenshots

An example of "Hello World." encoded on a tiny 16 x 16 pixel image.

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To do

• expanded punctuation set
• improved argument parsing
• selectable encoding density
• txt file message input
• support for different image types