Contents Lossless Data Embedding
In our previous work on lossless (or invertible) data embedding,[8] we proposed an idea for a new steganalytic method for detection of LSB embedding in color and grayscale images. The method originated by analyzing the capacity for lossless data embedding in the LSBs. Randomizing the LSBs decreases the lossless capacity in the LSB plane, but it has a different influence on the capacity for embedding that isn't constrained to one bit plane. Thus, the lossless capacity became a sensitive measure for the degree of randomization of the LSB plane. Note that for most images the LSB plane is essentially random and doesn't contain any easily recognizable structure. Using classical statistical quantities constrained to the LSB plane to capture the degree of randomization is unreliable. The lossless capacity reflects the fact that the LSB plane—even though it looks random—is related nonetheless to the other bit planes. This relationship, however, is nonlinear, and the lossless capacity seems to measure this relationship fairly well. This is why we proposed it for steganography detection.
