Authenticated Garbling and Efficient Maliciously Secure Multi-Party Computation

In this paper, we extend the recent work by Wang et al., who proposed a new framework for secure two-party computation in the preprocessing model that can be instantiated efficiently using TinyOT. We show that their protocol can be generalized to the multi-party setting, where the preprocessing functionality is based on the multi-party TinyOT-like protocol. Assuming there are n parties where at most n−1 parties are corrupted, the function-dependent phase has a total communication complexity of O(κn) bits per AND gate; the online phase has a total communication complexity of O(κn) bits per input/output bit. In the second part of this paper, we propose a new multi-party TinyOT protocol. The new protocol uses a set of new techniques that allow parties to distributively check the correctness without the need for cut-and-choose. The resulting protocol is much more efficient compared to previous protocols: with statistical security parameter ρ, the complexity to generate one AND triple is O( ρ log |C|n ), where |C| is the circuit size. The best previous multi-party TinyOT protocol by Frederiksen et al. has a complexity of O( ρ 2 log2 |C|n ) per AND triple. The complexity is measured in terms of number of symmetric key operations/number of symmetric key messages. The resulting protocol enjoys extremely high efficiency, compared to the state-of-the-art protocol by Lindell et al. that combines the BMR protocol with the SPDZ protocol.