Two Kinds of Ideal Contrast Visual Cryptography Schemes

The (k, n) visual cryptography schemes (VCS) is a perfect secure method that encrypts a secret image by breaking it into shadow images. A Visual Crypto (VC) system based on the polarisation of light which has good resolution, contrast and color properties is introduced. Mathematically, the VC system is described by the XOR operation, which just mean modulo two addition and is equivalence of addition in the finite field GF(2). In this paper, we investigate threshold visual secret sharing schemes mixed XOR and OR operation with reversing and based on binary linear error-correcting code. Firstly, we show that 2 out of 2 schemes mixed on XOR and OR operation with reversing where the reconstruction of both black and white pixels is perfect. It turns out that scheme have much better resolution than their OR-based counterparts. Secondly, we provide one construction for general k out of n schemes based on binary linear error-correcting code. And we show these two schemes are ideal contrast.