Improved steganographic method preserving the pixel-value differencing histogram for the security and practicality

Abstract

A specific steganalysis scheme to defeat the Wang et al.’s method using pixel-value differencing(PVD) and modulus function is proposed. The Wang et al.’s method provides the high capacity and the good image quality with keeping the advantage of the PVD based steganography such as the security under the RS-analysis because the modulus function is adapted to embed the secret data. Although the Wang et al.’s method gains more flexibility and derives the least distortion, it makes severe modifications of the PVD histogram: fluctuations of the histogram, asymmetry of the 1 and .1 histogram values, and abnormal increasing of the 0 histogram value. New steganalytic measures using these modifications of the PVD histogram are proposed. Since the embedding process remarkably increases the value of the steganalytic measures, stego images embedded by the Wang et al.’s method are clearly separated with cover images statistically. A support vector machine with these steganalytic measures is adapted to discriminate between cover and stego images. Also, the length of the hidden messages is estimated by computing the original 0 histogram value reversely without the cover image through two novel schemes: curve-fitting method and histogram reverse-tracing method. Experimental results verify that the proposed steganalysis successfully detects the Wang et al.’s method with high detection accuracy. Based on the analysis of the Wang et al.’s method, a secure data hiding algorithm that uses a turnover policy and a novel adjusting process is proposed. In order to enhance the security of the steganographic algorithm, a turnover policy is used that prevents abnormal increases in the histogram values and a novel adjusting process is devised to remove the fluctuations at the border of the subrange in the PVD histogram. The proposed algorithm therefore eliminates all the weaknesses of the PVD based steganographic methods thus far proposed and guarantees secure communication. In the experime...