Steganography is the science of hiding secret message inside another larger and harmless looking message. This is one notch above regular cryptography; which just obscures the original message. Steganography tries to conceal the fact that there is a message in the first place. Steganographic message often appears to be something else than the original (secret) message, like a picture, sound, larger text, etc.
Rascals are always sociable, and the chief sign that a man has any nobility in his character is the little pleasure he takes in others company. Arthur Schopenhauer