Chicago Journal of Theoretical Computer Science

Volume 2006

Article 1

Published by Dept. CS U. Chicago. Copyright 2006 CJTCS

Protocols for Bounded-Concurrent Secure Two-Party Computation

Yehuda Lindell
26 September 2006
(Submitted March 23 2006)

Until recently, most research on the topic of secure computation focussed on the stand-alone model, where a single protocol execution takes place. In this paper we construct protocols for the setting of bounded-concurrent self-composition, where a (single) secure protocol is run many times concurrently, and there is a predetermined bound on the number of concurrent executions. In short, we show that any two-party functionality can be securely computed unde bounded-concurrent self-composition in the plain model (where the only setup assumption made is tha the aprties communicate via authenticated channels). Our protocol provides the first feasibility result for general two-party communication in the plain model for any model of concurrency. All previous protocols assumed a trusted setup phase in order to obtain a common reference string. On the downside, the number of rounds of communication in our protocol is super-linear in the bound on the number of concurrent executions. Subsequent to this work, constant-round protocol, and protocols for the multiparty case were presented by Pass and Rosen (FOCS 2003) and by Pass (STOC 2004). We remark that this paper contains the full version of the upper-bound portion of the extended abstract presented by the author on STOC 2003 [29] (the lower bound from [29] appears in [33], together with other lower bounds from [32])

DOI: 10.4086/cjtcs.2006.001
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