A high capacity steganographic method based on quantization table modification

For the traditional steganographic method of Jsteg, the emmbedment of secret message is completed by dividing cover-image into nonoverlapping blocks of 8×8 pixels, discrete cosine transform (DCT) transforming, and using the standard 8×8 quantization table to quantize. In this paper, a novel steganographic method based on the JPEG quantization table modification is presented. Instead of dividing cover-image into 8×8 blocks, nonoverlapping blocks of 16×16 pixels is used. Both theoretical anlysis and experiment results show that the new methods has larger steganography capacity and better stego-image quality, compared with the method of Jsteg and Chang’s.