Steganography

Steganography is the art of hiding data inside a file that looks ordinary, such as an image or an audio clip, so that no one notices it is there. It differs from encryption: encryption makes a message unreadable, while steganography makes its very presence unnoticeable. In CTF challenges you face a file that looks innocent and must detect what was hidden in it and extract it, whether in the least significant bits of an image’s pixels, in metadata, or in an audio spectrum. The link to the encoding lesson holds because what you extract is often encoded. This lesson introduces the common hiding methods and the tools that reveal them.