Revisiting the Efficiency of Asynchronous Multi Party Computation Against General Adversaries

TL;DR

This paper introduces the first asynchronous multi-party computation protocols secure against general adversaries with optimal resilience, achieving novel communication complexities previously known only in synchronous settings.

Contribution

It presents new asynchronous MPC protocols with optimal resilience against unbounded malicious adversaries, featuring the first known communication complexities in this setting.

Findings

Protocols achieve $ ext{O}(| ext{Z}|^2)$ communication for perfect security.

Protocols achieve $ ext{O}(| ext{Z}|)$ communication for statistical security.

First protocols with these complexities in asynchronous MPC against general adversaries.

Abstract

In this paper, we design secure multi-party computation (MPC) protocols in the asynchronous communication setting with optimal resilience. Our protocols are secure against a computationally-unbounded malicious adversary, characterized by an adversary structure $\mathcal{Z}$, which enumerates all possible subsets of potentially corrupt parties. Our protocols incur a communication of $\mathcal{O}(|\mathcal{Z}|^2)$ and $\mathcal{O}(|\mathcal{Z}|)$ bits per multiplication for perfect and statistical security respectively. These are the first protocols with this communication complexity, as such protocols were known only in the synchronous communication setting (Hirt and Tschudi, ASIACRYPT 2013).