This paper proposes a novel reversible data-hiding scheme utilizing two steganographic images. The proposed method is able to hide more secret messages than other messages by studying the characters of embedded messages. We transformed the form of the secret message byte from 8 binary bits to 7-base digits, which was departed to 3-digit planes to allow for hiding more secret messages through use of an extensional key matrix M∗. The horizontal and vertical coordinate of the key matrix M∗ ranges are from 0 to 255. Therefore, we use the pixel pairs in a cover image to help hide secret message bytes in the method proposed. In key matrix M∗, a point can be located by a horizontal coordinate and a vertical coordinate, which are the exact paired pixels. After embedding data by using the coordinates in the key matrix and then obtaining two stego images, we can recover the cover image after extracting the embedded data. Experiments show that the method proposed can hide more pixels in an image and recover the image accurately with only a tiny decrease in image quality.
['Youjing Lu', 'Wan-Li Lyu']
A novel high-capacity reversible data-hiding scheme using two steganographic images