International Journal of Engineering Associates
Visual cryptography is a perfectly secure encryption mechanism, and the decryption process is done by the human visual system. The cipher-text is a printed page, and the key is a printed transparency of the same size. When the two are stacked and aligned together the plain text is revealed. Knowing just one of these two shares does not reveal any new information about the plaintext. This encryption scheme can be also considered as 2-out-of-2 secret sharing scheme (the two shares being the cipher-text and the key), and it can be generalized to a k out of n secret sharing scheme.