Efficient Three-Party Computation from Cut-and-Choose.

With relatively few exceptions, the literature on efficient (practical) secure computation has focused on secure two-party computation (2PC). It is, in general, unclear whether the techniques used to construct practical 2PC protocols-in particular, the cut-and-choose approach-can be adapted to the multi-party setting. In this work we explore the possibility of using cut-and-choose for practical secure three-party computation. The three-party case has been studied in prior work in the semi-honest setting, and is motivated by the observation that real-world deployments of multi-party computation are likely to involve few parties. We propose a constant-round protocol for three-party computation tolerating any number of malicious parties, whose computational cost is only a small constant worse than that of state-of-the-art two-party protocols.