Multiple messages embedding using DCT-based Mod4 steganographic method

This paper proposes a Multiple Messages Embedding (MME) scheme for achieving plausible deniability with DCT-based Mod4 steganography. To implement MME, we utilize the structural feature of vGQC (Valid Group of 2 X 2 adjacent quantized DCT Coefficients) in Mod4 as message carrier. vGQC's can be partitioned into several disjoint sets by differentiating the parameters where each set could serve as an individual secret communication channel. A maximum number of 14 independent messages can be embedded into a cover image without interfering one message and another. We can generate stego images with image quality no worse than the conventional Mod4 when embedding at the same rate. Results for blind steganalysis are also shown.