Visual Cryptography Schemes Using Secrete Sharing: Survey Report

Visual cryptography is a cryptographic technique which encrypt a visual information (e.g. text, handwritten notes and pictures) in such a way that the decryption done by the human visual system. It needs neither cryptography knowledge nor complex computation. For security purposs, it also ensures that hacker cannot obtain any clues about a secret image from individual sharess. Naor and Shamir proposed the basic model of visual cryptography in 1994. Visual cryptography scheme eliminates complex computation problem at the decryption the secret images can be restored by stack operation. The important issue of visual cryptography is quality of relevant image. Performance of visual cryptography scheme depends, such a number of image(single, multiple), types of image(binary, gray, color),share generation(meaningful, meaningless), security, accuracy pixel expansion, complexity,) encrypted by the scheme.