Byzantine Agreement is a key component in many distributed systems. While Dolev and Reischuk have proven a long time ago that quadratic communication complexity is necessary for worst-case runs, the question of what can be done in practically common runs with fewer failures remained open. In this paper we present the first Byzantine Broadcast algorithm with O(n(f+1)) communication complexity, where 0≤f≤t is the actual number of process failures in a run. And for BA with strong unanimity, we present the first optimal-resilience algorithm that has linear communication complexity in the failure-free case and a quadratic cost otherwise.
@article{arxiv.2202.09123,
title = {Make Every Word Count: Adaptive BA with Fewer Words},
author = {Shir Cohen and Idit Keidar and Alexander Spiegelman},
journal= {arXiv preprint arXiv:2202.09123},
year = {2024}
}