A polarisation based Visual Crypto System and its Secret Sharing Schemes
In this paper, we present a new visual crypto system based on the polarisation of light and investigate the existence and structure of the associated threshold visual secret sharing schemes. It is shown that very efficient $(n,n)$ schemes exist and that $(2,n)$ schemes are equivalent to binary codes. The existence of $(k,n)$ schemes is shown in general by two explicit constructions. Finally, bounds on the physical properties as contrast and resolution are derived.
An addition to the paper: A polarisation based visual crypto system and its secret sharing schemes
An (n,k) pair is a pair of binary nxm matrices (A,B), such that the weight of the modulo-two sum of any i rows, 1\leq i \leq k, from A or B is equal to a_i or b_i, respectively, and moreover, a_i=b_i, for 1\leq i < k, while a_k \neq b_k. In this note we first show how to construct an (n,k) Threshold Visual Secret Sharing Scheme from an (n,k) pair. Then, we explicitly construct an (n,k)-pair for all n and k with 1 \leq k <n.