Analysis of LSB based image steganography techniques

There have been many techniques for hiding messages in images in such a manner that the alterations made to the image are perceptually indiscernible However, the question whether they result in images that are statistically indistinguishable from untampered images has not been adequately explored In this paper we look at some specific image based steganography techniques and show that an observer can indeed distinguish between images carrying a hidden message and images which do not carry a message We derive a closed form expression of the probability of detection and false alarm in terms of the number of bits that are hidden This leads us to the notion of steganographic capacity, that is, how many bits can we hide in a message without causing statistically significant modification? Our results are able to provide an upper bound on the this capacity Our ongoing work relates to adaptive steganographic techniques that take explicit steps to foil the detection mechanisms In this case we hope to show that the number of bits that can be embedded increases significantly.