Construction of a (k, n)-visual cryptography scheme

In this paper we give an explicit construction of basis matrices for a ( k , n )-visual cryptography scheme ( k , n ) - VCS for integers k and n with 2 ≤ k ≤ n . In balanced VCS every set of participants with equal cardinality has same relative contrast. The VCS constructed in this paper is a balanced ( k , n ) - VCS for general k . Also we obtain a formula for pixel expansion and relative contrast. We also prove that our construction gives optimal contrast and minimum pixel expansion when k = n and n - 1 .