A reference to or a description of a secret message that is hidden in an image, an audio, or a video file.

It is used instead of an encryption (secret code) and it takes advantage of unused bits within a computer file structure or secret bits which are mostly undetectable if altered.

A steganographic message can go secretly to its destination, unlike encrypted messages, which although they may be undecipherable without the decryption key, they can be identified as being encrypted or some kind of a coded secret message.