Cheating And Anti-Cheating In Visual Cryptography Scheme

Visual cryptography scheme (VCS) is an important branch of modern cryptography. Itapplies in modern information technology well. Since Naor and Shamir proposed the conceptof secret sharing independently in1979, visual cryptography is improved and developed. Andit takes an important position in information security. The research directions of visualcryptography are about the discussion of parameters, the expansion scheme for Naor andShamir's scheme, the meaning of secret sharing, cheating or anti-cheating problem and itsapplication.In this paper we focus on cheating and anti-cheating problem. From the original(k,n)-VCS, we analysis the hidden unsafe problems and try to find out the possible existenceof cheatings. One innovation of this paper is to take the Dealer's cheating into account. Weproposed a scheme by introducing the verification image and combine the scheme with thecredible arbiter. Our scheme can verify behavior of not only the internal and externalparticipants but also the Dealer. In short, the safety of original scheme is improved.