A Review of Color Visual Cryptographic Schemes

Visual Cryptography is a special encryption technique to hide information in images in such a way that it can be decrypted by the human vision if the correct key image is used. It is a cryptographic technique which allows visual information (pictures, text, etc.) to be encrypted in such a way that the decryption can be performed by the human visual system, without the aid of computers. The technique was proposed by Naor and Shamir in 1994. This paper reviews two methods for visual cryptography of color images based on past studies in black-and-white visual cryptography, the halftone technology, and the color decomposition method.