Date Added: Oct 2010
The basic principle of Visual Cryptography Scheme (VCS) was first introduced by Naor and Shamir. The idea of the visual cryptography model proposed in  is to split an image into two random shares (printed on transparencies) which separately reveal no information about the original secret image other than the size of the secret image. The image is composed of black and white pixels. The original image can be reconstructed visually by superimposing the two shares. The underlying operation of such scheme is OR. Similar model of visual cryptography with different underlying operation has been proposed.