Asymmetric Orientation Combination for Reversible and Authenticable Data Hiding of Dual Stego-images

Abstract

A dual-image-based reversible data hiding (RDH) scheme can conceal secret data into a cover image by creating two steganographic images. These two stego-images can cooperate to extract secret data and restore the cover image. This paper describes a generalization of the orientation combination technology for dual-image-based RDH. We first propose a full search algorithm to find the optimal set of the reversible orientation combinations. Based on the algorithm, the modification range of pixel values can be dynamically enlarged, and thus the embedding capacity becomes adjustable. In addition, an authentication algorithm is provided to detect tampered shadows based on a faithful one. Experimental results confirm that the proposed scheme can produce dual stego-images with a good visual quality. Furthermore, our method provides an adjustable payload. A lot more secret data can be embedded than with state-of-the-art methods, with a satisfactory image quality. Two steganalysis tools are applied to demonstrate the security level of the proposed scheme.