Zero-knowledge proof

Summary

A zero-knowledge proof is an interactive proof in which the verifier becomes convinced that a statement is true but learns nothing else. "Nothing else" is made precise by a simulator. Whatever the verifier sees could have been produced by an efficient algorithm that never talked to the prover. The notion was introduced by Goldwasser, Micali and Rackoff in the 1980s. It is a basic tool of cryptography, used for identification schemes and for protocols that must stay secure against cheating parties.