Improving Image Data Hiding Capacity Scheme using Sudoku Puzzle in Color Images

-Steganography is a skill to convey the secret data in the digital images without getting any unexpected notices to attackers. LSB replacement, the simplest method, directly replaces the secret bits with LSB bit plane. Unfortunately, it is insecure because it cannot resist against the visual attacks and statistic detection. The original work was proposed by Chang et al. in 2010, 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. The main idea of our scheme is to use a Sudoku puzzle, in which every value corresponds to a pixel pair (red, blue) of image mapped with the secret digit by replacing a pair of one pixel of two colors. Experimental results show that the proposed scheme can improve the visual quality of stego-images. In addition, the average of hiding capacity is 4 bpp (bits per pixel). Therefore, it confirms that our proposed scheme provides higher hiding capacity than that of existed Scheme (Chang et al). Furthermore, our method shows the positive results to resist against the visual attacks. Moreover, the proposed scheme provides a large capacity for embedded secret data. The earlier version is for a grayscale image but the proposed method is for a colored image. KeywordsData hiding, Steganography, Sudoku, Reference Matrix, Secret data, Sudoku