Date Added: Jul 2010
This paper is presenting a betterment steganographic method for covert channel communication. Two distinct methods are combined to achieve possibly high data hiding capability with high visual quality. The proposed method shifts the last n nonzero AC coefficients from S JPEG block, and changes the magnitude values of the first n nonzero AC coefficients from T JPEG blocks. S and T blocks are determined by the number of nonzero JPEG coefficients in the block. Zero run-length modification method improves the robustness against statistical attack based on magnitude histogram. Magnitude modification method improves the visual quality. This combination complements each other.