Steganography is another term for a type of covert communication. It works by concealing messages within some “cover medium” that are then sent to the intended recipients in such a way that a message being sent at all is difficult to detect, hard to prove, and recovery of any such message even harder. The most important requirement of any stenographic system is that it should be impossible to distinguish between ordinary objects and objects that contain secret data. Steganography aims at sending a message through a cover - medium, in an undetectable way. Undetectable means that nobody, except the intended receiver of the message, should be able to tell if the medium is carrying a message or not.