A Steganography Preserving the Property of the Histogram for JPEG Images

Traditional steganographic techniques for JPEG images always suffer from histogram-based attacks because they change the DCT coefficient histogram of the cover image, or from the reduced hiding capacity due to the correction of the change of the histogram. A new steganography preserving the property of the histogram is proposed in this paper. When the secret message is embedded, an adjust_info table is built to memorize the alteration of the histogram. Then the modification direction of the coefficient is adjusted according to the table. In this way, the change of the histogram is compensated and the hiding capacity is not reduced yet. Several experimental results demonstrate that the algorithm can attain a high hiding capacity of 13% (the quality factor is 75). Furthermore the average distortion rate of the general DCT coefficient histograms on stego-images is 0.81%, the maximal distortion rate of the histograms on low frequency coefficients is 3.83% obtained from the stego-images generated by the improved algorithm and the average distortion rate of them is only 1.98%. The property of the histogram is fine changed; therefore, various histogram-based attacks can be effectively resisted and secure steganorgraphy can be insured.