The popularity of permissioned blockchain systems demands BFT SMR protocols that are efficient under good network conditions (synchrony) and robust under bad network conditions (asynchrony). The state-of-the-art partially synchronous BFT SMR protocols provide optimal linear communication cost per decision under synchrony and good leaders, but lose liveness under asynchrony. On the other hand, the state-of-the-art asynchronous BFT SMR protocols are live even under asynchrony, but always pay quadratic cost even under synchrony. In this paper, we propose a BFT SMR protocol that achieves the best of both worlds -- optimal linear cost per decision under good networks and leaders, optimal quadratic cost per decision under bad networks, and remains always live.
@article{arxiv.2103.03181,
title = {Be Prepared When Network Goes Bad: An Asynchronous View-Change Protocol},
author = {Rati Gelashvili and Lefteris Kokoris-Kogias and Alexander Spiegelman and Zhuolun Xiang},
journal= {arXiv preprint arXiv:2103.03181},
year = {2021}
}