An Improved YASS Approach Using Irregular Host-Blocks and Modified Quantization Index Modulation

Yet Another Steganography Scheme (YASS) is a recently developed steganographic scheme to randomly select host blocks for data embedding. However, the randomization is not sufficient enough in the sense that some positions in an image are definitely impossible to hold host blocks, especially for the cases with high embedding rates. In view of this, an improved YASS approach is proposed in this paper to further randomize embedding locations and resist attacks upon observation features. The contributions of the proposed approach are two-fold. Firstly, an irregular constructed host block is selected using flexible of starting points and scanning modes in each cover big-block, instead of the fixed-size 8 block used in YASS. Secondly, a modified Quantization index modulation is proposed to shift zero-zones of odd and even quantizers so that the clustered coefficients can be eliminated and it is able to resist the specific steganalysis. Experimental results are provided to demonstrate the superior performance of the proposed approach.