Consensus in the presence of partial synchrony
Journal of the ACM (JACM)
Early stopping in Byzantine agreement
Journal of the ACM (JACM)
Shifting gears: changing algorithms on the fly to expedite Byzantine agreement
Information and Computation
An Optimal Probabilistic Protocol for Synchronous Byzantine Agreement
SIAM Journal on Computing
STOC '82 Proceedings of the fourteenth annual ACM symposium on Theory of computing
The inherent price of indulgence
Distributed Computing - Special issue: PODC 02
Round Complexity of Authenticated Broadcast with a Dishonest Majority
FOCS '07 Proceedings of the 48th Annual IEEE Symposium on Foundations of Computer Science
On expected constant-round protocols for byzantine agreement
CRYPTO'06 Proceedings of the 26th annual international conference on Advances in Cryptology
On the theoretical gap between synchronous and asynchronous MPC protocols
Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing
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Byzantine agreement is typically considered with respect to either a fully synchronous network or a fully asynchronous one. In the synchronous case, t + 1 communication rounds are necessary for deterministic protocols whereas all known probabilistic protocols require an expected large number of rounds. In this paper we examine the question of how many initial synchronous rounds are required for Byzantine agreement in the worst case if we allow to switch to asynchronous operation afterward. Let n = h + t be the number of parties where h are honest and t are corrupted. As the main result we show that, in the model with a public-key infrastructure and signatures (aka authenticated Byzantine agreement), d + O(1) deterministic synchronous rounds are sufficient where d is the minimal integer such that n - d 3(t - d). This improves over the t + 1 necessary deterministic rounds for almost all cases, and over the exact expected number of rounds in the nondeterministic case for many cases.