Cryptology ePrint Archive: Report 2019/705

Commodity-Based 2PC for Arithmetic Circuits

Ivan Damgård and Helene Haagh and Michael Nielsen and Claudio Orlandi

Abstract: We revisit the framework of Commodity-based Cryptography presented by Beaver (STOC'97) with a focus on updating the framework to fit with modern multiparty computation (MPC) protocols. We study the possibility of replacing the well-known preprocessing model with a commodity-based setting, where a set of independent servers (some of which may be corrupt) provide clients with correlated randomness. From this, the clients then distill correct and secure correlated randomness that they can use during the online phase of the MPC protocol. Beaver showed how to do OT with semi-honest security in the commodity setting. We improve on Beaver's result as follows: In a model where one of two clients and a constant fraction of the servers may be maliciously corrupted, we obtain unconditionally secure multiplication triples and oblivious linear evaluations (OLEs) such that the amortized communication cost of one triple/OLE is a constant number of field elements (when the field is sufficiently large). We also report on results from an implementation of the OLE protocol. Finally, we suggest an approach to practical realization of a commodity based system where servers need no memory and can be accessed asynchronously by clients, but still a maliciously corrupt client cannot get data he should not have access to.

Category / Keywords: cryptographic protocols / Secure Two-Party Computation, Information Theoretic Security, Oblivious Linear Evaluation, Commodity-based Cryptography

Date: received 14 Jun 2019

Contact author: orlandi at cs au dk

Available format(s): PDF | BibTeX Citation

Version: 20190618:103309 (All versions of this report)

Short URL: ia.cr/2019/705


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