Journal of Cryptology

, Volume 19, Issue 2, pp 169–209

Strengthening Zero-Knowledge Protocols Using Signatures

Authors

    • Bell Labs – Lucent Technologies, 600 Mountain Avenue, Murray Hill, NJ 07974
    • DoCoMo USA Laboratories, 181 Metro Drive, Suite 300, San Jose, CA 95110
    • Google Inc., 1600 Amphitheatre Parkway, Mountain View, CA 94043
Article

DOI: 10.1007/s00145-005-0307-3

Cite this article as:
Garay, J., MacKenzie, P. & Yang, K. J Cryptology (2006) 19: 169. doi:10.1007/s00145-005-0307-3

Abstract

Recently there has been an interest in zero-knowledge protocols with stronger properties, such as concurrency, simulation soundness, non-malleability, and universal composability. In this paper we show a novel technique to convert a large class of existing honest-verifier zero-knowledge protocols into ones with these stronger properties in the common reference string model. More precisely, our technique utilizes a signature scheme existentially unforgeable against adaptive chosen-message attacks, and transforms any Σ-protocol (which is honest-verifier zero-knowledge) into a simulation sound concurrent zero-knowledge protocol. We also introduce Ω-protocols, a variant of Σ-protocols for which our technique further achieves the properties of non-malleability and/or universal composability. In addition to its conceptual simplicity, a main advantage of this new technique over previous ones is that it avoids the Cook-Levin theorem, which tends to be rather inefficient. Indeed, our technique allows for very efficient instantiation based on the security of some efficient signature schemes and standard number-theoretic assumptions. For instance, one instantiation of our technique yields a universally composable zero-knowledge protocol under the Strong RSA assumption, incurring an overhead of a small constant number of exponentiations, plus the generation of two signatures.

Zero knowledgeSignaturesSimulation soundnessNon-malleability

Copyright information

© International Association for Cryptologic Research 2005