Capacity of steganographic channels

Abstract

An information-theoretic approach is used to determine the amount of information that may be safely transferred over a steganographic channel with a passive adversary. A steganographic channel, or stego-channel is a pair consisting of the channel transition probabilities and a detection function. When a message is sent, it first encounters a distortion (due to the channel), then is subject to inspection by a passive adversary (using the detection function). This paper presents results on the amount of information that may be transferred over an arbitrary stego-channel with vanishing probabilities of error and detection.