International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Efficient Constant-Round MPC with Identifiable Abort and Public Verifiability

Carsten Baum , Aarhus University
Emmanuela Orsini , KU Leuven
Peter Scholl , Aarhus University
Eduardo Soria-vazquez , Aarhus University
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Conference: CRYPTO 2020
Abstract: Recent years have seen a tremendous growth in the interest in se- cure multiparty computation (MPC) and its applications. While much progress has been made concerning its efficiency, many current, state-of-the-art protocols are vulnerable to Denial of Service attacks, where a cheating party may prevent the honest parties from learning the output of the computation, whilst remaining anonymous. The security model of identifiable abort aims to prevent these at- tacks, by allowing honest parties to agree upon the identity of a cheating party, who can then be excluded in the future. Several existing MPC protocols offer security with identifiable abort against a dishonest majority of corrupted parties. However, all of these protocols have a round complexity that scales linearly with the depth of the circuit (and are therefore unsuitable for use in high latency net- works) or use cryptographic primitives or techniques that have a high computa- tional overhead. In this work, we present the first efficient MPC protocols with identifiable abort in the dishonest majority setting, which run in a constant number of rounds and make only black-box use of cryptographic primitives. Our main construction is built from highly efficient primitives in a careful way to achieve identifiability at a low cost. In particular, we avoid the use of public-key operations outside of a setup phase, incurring a relatively low overhead on top of the fastest currently known constant-round MPC protocols based on garbled circuits. Our construction also avoids the use of adaptively secure primitives and heavy zero-knowledge machinery, which was inherent in previous works. In addition, we show how to upgrade our protocol to achieve public verifiability using a public bulletin board, allowing any external party to verify correctness of the computation or identify a cheating party.
Video from CRYPTO 2020
  title={Efficient Constant-Round MPC with Identifiable Abort and Public Verifiability},
  author={Carsten Baum and Emmanuela Orsini and Peter Scholl and Eduardo Soria-vazquez},