LEGO for Two-Party Secure Computation

This paper continues the recent line of work of making Yao's garbled circuit approach to two-party computation secure against an active adversary. We propose a new cut-and-choose based approach called LEGO (Large Efficient Garbled-circuit Optimization): It is specifically aimed at large circuits. Asymptotically it obtains a factor log vertical bar C vertical bar improvement in computation and communication over previous cut-and-choose based solutions, where vertical bar C vertical bar is the size of the circuit being computed. The protocol is universally composable (UC) in the OT-hybrid model against a static, active adversary.