steganography definition security
Hiding a secret message within a larger one in such a way that others can not discern the presence or contents of the hidden message. For example, a message might be hidden within an image
by changing the least significant bits to be the message bits.
[Chaffing and Winnowing: Confidentiality without Encryption, Ronald L. Rivest, MIT Lab for Computer Science, 1998-03-22 (http://theory.lcs.mit.edu/~rivest/chaffing.txt)].