Steganography Using Sudoku Revisited

In this paper, we propose a revised version of information hiding scheme using Sudoku. The original work was proposed by Chang et al. in 2008, and their work was inspired by Zhang and Wang´s method and Sudoku solutions. Chang et al. successfully used Sudoku solutions to guide cover pixels to modify pixel values so that secret messages can be embedded. However, all possible embedding positions for smaller image distortions in Chang et al.´s method are not fully explored. The proposed method modified Chang et al.´s embedding rules by allowing candidate pairs falling into more suitable regions in the reference matrix, so that a better position for data embedding can be selected to minimize image distortions. The experimental results show that, in average, the visual quality of stego image is 0.81 dB higher than that of Chang et al.´s method without sacrificing any embedding capacity.