Efficient Secure Multiparty Computation with Identifiable Abort

We study secure multiparty computation (MPC) in the dishonest majority setting providing security with identifiable abort, where if the protocol aborts, the honest parties can agree upon the identity of a corrupt party. All known constructions that achieve this notion require expensive zeroknowledge techniques to obtain active security, so are not practical. In this work, we present the first efficient MPC protocol with identifiable abort. Our protocol has an information-theoretic online phase, with roughly the same performance as the SPDZ protocol (Damg̊ard et al., Crypto 2012), requiring O(n) messages to be broadcast for each secure multiplication. A key component of our protocol is a linearly homomorphic information-theoretic signature scheme, for which we provide the first definitions and construction based on a previous non-homomorphic scheme. We then show how to implement the preprocessing for our protocol using somewhat homomorphic encryption, similarly to the SPDZ protocol and other recent works with applicable efficiency improvements.