Prove to me that you know a secret without revealing anything else (including the secret).
Definition
An interactive proof is complete if, given an honest prover
and honest verifier, the protocol succeeds with overwhelming
probability (the verifier accepts the prover's claim).
Definition An interactive proof is sound if there
exists an expected polynomial time algorithm M with the property
tat if a dishonest prover can fool the verifier, then the algorithm
M can be used to extract information from the prover that allows
further successful executions of the protocol.