Paper 2015/1235

Constant-round Leakage-resilient Zero-knowledge from Collision Resistance

Susumu Kiyoshima

Abstract

We construct a constant-round leakage-resilient zero-knowledge argument system under the existence of collision-resistant hash function family. That is, using collision-resistant hash functions, we construct a constant-round zero-knowledge argument system such that for any cheating verifier that obtains arbitrary amount of leakage of the prover's state, there exists a simulator that can simulate the adversary's view by obtaining at most the same amount of leakage of the witness. Previously, leakage-resilient zero-knowledge protocols were constructed only under a relaxed security definition (Garg-Jain-Sahai, CRYPTO'11) or under the DDH assumption (Pandey, TCC'14). Our leakage-resilient zero-knowledge argument system satisfies an additional property that it is simultaneously leakage-resilient zero-knowledge, meaning that both zero-knowledgeness and soundness hold in the presence of leakage.