cryptography is study of transforming information in order to make it secure from unintended
recipients. Visual Cryptography Scheme (VCS) is a cryptography method that encrypts
any information [picture, printed text, etc]
such that decryption can be perform
ed using human visual system. The
goal of this survey paper is to give
the readers an overview of the basic visual cryptography schemes constructions,as well as the new techniques
derived from VCS.We also review some applications that take advantage of such secure schemes.