Abstract: Aiming at the problem of mutual authentication among three participants, we  proposed a (3,3) visual cryptography scheme with mutual authentication capability. According to the different proportions of black and white pixels in the black and white regions of the original image,  the basic matrix was constructed  in this scheme.  The white region of the original image had more white than the black region, so that the black and white region of the restored image could be distinguished. At the same time, the scheme also ensured that the overlapping of shared images could restore the verification images and realize mutual verification among participants. The scheme involved three different verification images and a secret image, in which any two shared images could be superimposed to produce a verification image, and superposition of three shared images could finally  restore the secret image. The experimental results demonstrated the effectiveness of the proposed scheme.

Key words: visual cryptography, shared image, authentication image, secret image