Efficient Visual Cryptography
Visual Cryptography Scheme (VCS) is a secret-sharing scheme which allows the encryption of a secret image into n shares that are distributed to n participants. The beauty of such a scheme is that, the decryption of the secret image requires neither the knowledge of cryptography nor complex computation. Colour visual cryptography becomes an interesting research topic after the formal introduction of visual cryptography by Naor and Shamir in 1995. It is a powerful technique which combines the notions of perfect ciphers and secret sharing in cryptography with that of raster graphics.