Halftone Visual Cryptography with Complementary Cover Images
By the addition of halftone techniques, halftone visual cryptography scheme (HVCS) embeds a secret image into halftone shares taking meaningful visual information. In this paper, we propose a (k, n)-HVCS using complementary cover images. Before the halftone processing of the cover images by error diffusion, secret information pixels (SIPs) are prefixed based on the underlying (k, n)-VCS. In the halftone processing, several pairs of complementary cover images are adopted and two halftone methods on the cover images are designed for different (k, n) threshold access structures. The proposed scheme removes the share’s cross interference from other shares and obtains better visual quality. Furthermore, the proposed scheme eliminates the burden that each participant may carry multiple shares.
KeywordsVisual cryptography Visual secret sharing Extended visual cryptography Halftone visual cryptography Meaningful shares
We would like to thank the anonymous reviewers for their important and helpful comments. This work was supported by the National Natural Science Foundation of China with No. 61602513 and No. 61671448, the Strategic Priority Research Program of the Chinese Academy of Sciences with No. XDA06010701, and the National Key R&D Program of China with No. 2016YFB0800100.
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