Generic and practical resettable zero-knowledge in the bare public-key model

Abstract

We present a generic construction for constant-round concurrently sound resettable zero-knowledge (rZK-CS) arguments for NP in the bare public-key (BPK) model under any (sub-exponentially strong) one-way function (OWF), which is a traditional assumption in this area. The generic construction in turn allows round-optimal implementation for NP still under general assumptions, and can be converted into a highly practical instantiation (under specific number-theoretic assumptions) for any language admitting Σ-protocols. Further, the rZK-CS arguments developed in this work also satisfy a weak (black-box) concurrent knowledge-extractability property as proofs of knowledge, in which case some super-polynomial-time assumption is intrinsic. © International Association for Cryptology Research 2007.