What is Steganography

Steganography - concealing information within something else so that it is not visible to anyone except those that have the key and know where to look. Often this will be seen as embedding data into images, and to uncover that information there are a number of tools we can use.

Tools to uncover information

To install stegosuite and steghide reference my resources page.

To start the GUI for stegosuite, simply enter stegosuite in the terminal. From there you can select a file and enter a key to try and identify embedded files.

Another tool you can use is called binwalk, for more details on how it works enter binwalk -h or reference this site from Kali Linux.
Example usage of this would be binwalk -e file.bin, where the -e flag indicates to extract known file types.

A companion tool to stegosuite is steghide can be used to both embed and extract data, for the various flags / uses on that reference man steghide.

A Challenge

If you want a challenge with decryption reference here for a go at a cipher I wrote a while back. This was well before I had done any reading at all about cryptography, steganography, ciphers, etc. but I had fun making it. I have a full break down on how this works here.