Steganography is the art of embedding secret messages into cover data sets (such as images, video, audio files, text, and computer programs). The presence of hidden information should be undetectable to everyone except the intended recipient of the message. Conversely, steganalysis is the art of discovering the presence of hidden data.
Steganography has been used by revolutionaries, spies, the military, and perhaps terrorists. Recently sophisticated methods have been developed for steganalysis, aiming at identifying small changes in statistics in cover data. This has led to a new generation of steganographic techniques that can resist steganalysis. Where does the cat and mouse game stop?
In this talk we'll present some fundamental limits for steganography, by defining ground rules and maximizing rate of reliable transmission subject to a statistical undetectability constraint (analogous to Shannon's notion of perfect secrecy). The applicability of this theory to practical steganographic problems will be discussed.