What is Visual Secret Sharing(VSS) Scheme ? (The Basic VSS Scheme Model)
Let CW and CB be two collections of n„em Boolean matrices. The dealer randomly chooses one of the matrices in CW(resp. CB) to share a white(resp. black) pixel; a (k, n) VSS scheme satisfies the following conditions where Condition C1 is called contrast and Condition C2 is called security :
(C1) : For any S in CW(resp. CB), the ¡§OR¡¨ of any k of the n rows has a Hamming weight of at most d-ƒÑm(resp. at least d).
(C2) : For any subset {i1, i2, ¡K, iq} of {1, 2, ¡K, n} with q < k, the two collections of q„em matrices obtained by restricting each n„em matrices in Ci , i{W, B}, to rows i1, i2, ¡K, iq are not visual in the sense that they contain the same matrices with the same frequencies.
The Formal required conditions of basic (k, n) VSS scheme :