Secure Five-Party Computation with Private Robustness and Minimal Online Communication
摘要
Multi-Party Computation (MPC) is a cryptographic technology that enables multiple parties to compute an arbitrary function represented as a circuit while revealing only the function’s output. Secret-Sharing-based MPC (SS-MPC) is the most popular MPC scheme. SS-MPC protocols that achieve high performance and strong security simultaneously are attracting much attention. In particular, both communication efficiency and strong security during the online phase, i.e., the computation with actual inputs, are desired for SS-MPC protocols with a small number of parties. Private Robustness (PR) is one of the strongest security notions, ensuring that honest parties learn the correct outputs without aborting the protocol or revealing the parties’ inputs regardless of the adversary’s behavior. To the best of our knowledge, the SS-MPC protocol with PR proposed by Dalskov et al. (CCS’22) represents the current state-of-the-art in terms of communication efficiency for protocols with PR. In this paper, we propose a novel Five-Party Computation (5PC) protocol with a single malicious corruption that achieves PR. Our 5PC protocol is more efficient than the current state-of-the-art SS-MPC protocol with PR in terms of communication efficiency during the online phase.