Interactive Sigma Proofs

A Sigma Protocol is an interactive zero-knowledge proof of knowledge that allows a prover to convince a verifier of the validity of a statement. It satisfies the properties of completeness, soundness, and zero-knowledge, as described in Section 3. This document describes Sigma Protocols for proving knowledge of pre- images of linear maps in prime-order elliptic curve groups. Examples include zero-knowledge proofs for discrete logarithm relations, ElGamal encryptions, Pedersen commitments, and range proofs.