Improving side-informed JPEG steganography using two-dimensional decomposition embedding method

Abstract

Side-informed JPEG steganography is a renowned technology of concealing information for the high resistance to blind detection. The existed popular side-informed JPEG steganographic algorithms use binary embedding method with the corresponding binary distortion function. Then, the embedding methods and binary distortion functions of popular side-informed JPEG steganographic algorithms are analyzed and the wasted secure capacity by using the binary embedding operation is pointed out. Thus, the detection resistance of the side-informed JPEG steganographic algorithms can be improved if the embedding operation is changed to ternary mode which causes less changes than binary embedding at same payload. The problem of using ternary embedding is to define a suitable ternary distortion function. To solve this, a two-dimensional decomposition embedding method is proposed in this paper. The proposed ternary distortion function is defined by transforming the problem into two different binary distortion functions of two layers that based on the ternary entropy decomposition. Meanwhile, the proposed method ensures the minimal value of the distortion function on each layer can be reached in theory. Several popular side-inform JPEG steganographic algorithms (NPQ, EBS, and SI-UNIWARD) are improved through defining ternary distortion function by the proposed method. The experimental results on parameters, blind detection and processing time show that the proposed method increases the blind detection resistance of side-informed steganographic algorithm with acceptable computation complexity.