Precise Concurrent Zero Knowledge

Precise zero knowledge introduced by Micali and Pass (STOC'06) guarantees that the view of any verifier V can be simulated in time closely related to the actual (as opposed to worstcase) time spent by V in the generated view. We provide the first constructions of precise concurrent zero-knowledge protocols. Our constructions have essentially optimal precision; consequently this improves also upon the previously tightest non-precise concurrent zero-knowledge protocols by Kilian and Petrank (STOC'01) and Prabhakaran, Rosen and Sahai (FOCS'02) whose simulators have a quadratic worst-case overhead. Additionally, we achieve a statisticallyprecise concurrent zero-knowledge property--which requires simulation of unbounded verifiers participating in an unbounded number of concurrent executions; as such we obtain the first (even non-precise) concurrent zero-knowledge protocols which handle verifiers participating in a super-polynomial number of concurrent executions.

• Type: Conference
• Year: 2008
• Where: EUROCRYPT
• Authors: Omkant Pandey, Rafael Pass, Amit Sahai, Wei-Lung Dustin Tseng, Muthuramakrishnan Venkitasubramaniam
• Keywords: Concurrent Executions, Concurrent Zero-knowledge Protocols, Cryptology, EUROCRYPT 2008, Precise Zero Knowledge