Quantum Proofs of Knowledge

Abstract

We motivate, define and construct quantum proofs of knowledge, proofs of knowledge secure against quantum adversaries. Our constructions are based on a new quantum rewinding technique that allows us to extract witnesses in many classical proofs of knowledge. We give criteria under which a classical proof of knowledge is a quantum proof of knowledge. Combining our results with Watrous’ results on quantum zeroknowledge, we show that there are zero-knowledge quantum proofs of knowledge for all languages in NP.