A new black and white visual cryptographic scheme for general access structures

Abstract

In this paper we introduce a new construction of a black and white visual cryptographic scheme for general access structure. We prove that our scheme gives a strong access structure. We find out the conditions for which our scheme gives less pixel expansion compared to the schemes given in Section 4.2 of [1]. We also propose a modified algorithm giving better result from the pixel expansion's point of view. As a particular case of general access structure, we get (k, n)-VTS with 2 ≤ k ≤ n. The (n, n)-VTS obtained from our scheme attains the optimal pixel expansion and the relative contrast. We compare the (k, n)-VTS obtained from the schemes mentioned in Section 4.1 and Section 4.2 of [1] with the (k,n)-VTS obtained from our method and it has been shown that in almost all the cases our pixel expansion is less compared to the other two schemes. © Springer-Verlag 2004.