New Steganography Scheme in Halftone Images

A so-called DHCED (Data Hiding by Conjugate Error Diffusion) method was proposed to hide a binary visual secret into halftone images such that the watermarked halftone image still has good visual quality. When decoding, the secret can be visually revealed by directly superimposing the halftone images. The authors claimed that the DHCED scheme reduced the boundary artifacts around the hidden visual secret in the watermarked halftone image than the previous schemes. However, the DHCED scheme does not achieve the perfect secrecy like the steganography scheme and is still compromised by the gradient-attack In this paper, by combining the halftoning technique and the visual cryptography technique, we introduce a new steganography scheme for halftone images. Our new scheme has the perfect secrecy that one cannot gain any information from the watermarked halftone image by either the human visual system or the computer program.