Cryptology ePrint Archive: Report 2003/265

Concurrent/Resettable Zero-Knowledge With Concurrent Soundness in the Bare Public-Key Model and Its Applications

Yunlei ZHAO

Abstract: In this work, we investigate concurrent knowledge-extraction (CKE) and concurrent non-malleability (CNM) for concurrent (and stronger, resettable) ZK protocols in the bare public-key model.

We formulate, driven by concrete attacks, and achieve CKE for constant-round concurrent/resettable arguments in the BPK model under standard polynomial assumptions. We get both generic and practical implementations. Here, CKE is a new concurrent verifier security that is strictly stronger than concurrent soundness in public-key model.

We investigate, driven by concrete attacks, and clarify the subtleties in formulating CNM in the public-key model. We then give a new (augmented) CNM formulation in the public-key model and a construction of CNMZK in the public-key model satisfying the new CNM formulation.

Category / Keywords: concurrent knowledge-extraction, concurrent non-malleability, concurrent/resettable zero-knowledge, bare public-key model

Publication Info: A new result that has not been published and has not been submitted to other places.

Date: received 1 Jan 2004, last revised 7 Mar 2007

Contact author: ylzhao at fudan edu cn

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Version: 20070307:104425 (All versions of this report)

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