Visual cryptography is a cryptographic technique which allows visual information (pictures, text, etc.) to be encrypted in such a way that decryption becomes a mechanical operation that does not require a computer.
One of the best-known techniques has been credited to Moni Naor and Adi Shamir, who developed it in 1994. They demonstrated a visual secret sharing scheme, where an image was broken up into n shares so that only someone with all n shares could decrypt the image, while any n-1 shares revealed no information about the original image. Each share was printed on a separate transparency, and decryption was performed by overlaying the shares. When all n shares were overlaid, the original image would appear.
Using a similar idea, transparencies can be used to implement a one-time pad encryption, where one transparency is a shared random pad, and another transparency acts as the ciphertext.
Read more about Visual Cryptography: Example, (2, N) Visual Cryptography Sharing Case, Cheating The (2,N) Visual Secret Sharing Scheme
Famous quotes containing the word visual:
“To write well, to have style ... is to paint. The master faculty of style is therefore the visual memory. If a writer does not see what he describes—countrysides and figures, movements and gestures—how could he have a style, that is originality?”
—Rémy De Gourmont (1858–1915)