Talk by Michael Nielsen on Commodity-based 2PC for Arithmetic Circuits

2018.04.26 | Malene Bisgaard Blaabjerg Andersen

Date Wed 25 Apr
Time 13:00 14:00
Location Nygaard 295

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 set- ting, where a set of 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. In this paper we show how to produce unconditionally secure random Beaver triples and oblivious linear evaluations (OLE) in a commodity setting, in a model where one of two clients and almost half the servers may be maliciously corrupted, improving on Beaver’s result. This is essentially the optimal corruption tolerance. We also report on results from an imple- mentation 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.

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