## Cryptology ePrint Archive: Report 2021/1138

Optimal Good-case Latency for Rotating Leader Synchronous BFT

Ittai Abraham and Kartik Nayak and Nibesh Shrestha

Abstract: This paper explores the good-case latency of synchronous Byzantine Fault Tolerant (BFT) consensus protocols in the rotating leader setting. We first present a lower bound that relates the latency of a broadcast when the sender is honest and the latency of switching to the next sender. We then present a matching upper bound with a latency of $2\Delta$ ($\Delta$ is the pessimistic synchronous delay) with an optimistically responsive change to the next sender. The results imply that both our lower and upper bounds are tight. We implement and evaluate our protocol and show that our protocol obtains similar latency compared to state-of-the-art stable-leader protocol Sync~HotStuff while allowing optimistically responsive leader rotation.

Category / Keywords: foundations / Distributed computing, blockchains, consensus protocols, SMR, Synchrony, optimistic responsiveness

Date: received 7 Sep 2021

Contact author: nxs4564 at rit edu

Available format(s): PDF | BibTeX Citation

Short URL: ia.cr/2021/1138

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