We present a simple and efficient Byzantine Agreement protocol in the mixed fault model where up to $t$ parties can be Byzantine, up to $s$ parties can be send-omission, and up to $r$ parties can be receive-omission such that $2t+s+r<n$. Our synchronous protocol greatly improves over the efficiency of the state-of-the-art solution due to Loss and Stern [TCC '23]. Specifically, our protocol incurs an expected communication complexity of $O(n^2)$ instead of $O(n^5)$ in their construction, while maintaining the same resilience. Our protocol terminates in an expected constant number of rounds, provided that a constant fraction of parties are non-faulty.
Financial Cryptography and Data Security (FC)
2026-03-08
2026-06-25