We’re rewarding the question askers & reputations are being recalculated! Read more.

Encrypting images so that they can be decrypted without using a computer, e.g. by superimposing two random-looking images.

Visual cryptography is a method of encrypting images so that they can be decrypted without using a computer, e.g. by superimposing two random-looking images that combine to yield (something resembling) the original image.

One of the most well known visual cryptography techniques was described by Mori Naor and Adi Shamir in 1994, in the eponymous paper "Visual Cryptography". Their method is essentially a scheme for black-and-white images that allows the original image to be reconstructed by superimposing the (semitransparent) shares.

history | excerpt history