Throughput of Byzantine Broadcast

Abstract

Byzantine broadcast is a classic problem in distributed computing, with a wide variety of target applications. This work is motivated by the emerging new application of byzantine broadcast in blockchains, which has prompted us to consider the throughput of byzantine broadcast protocols. To our knowledge, this work is the very first to investigate the throughput of byzantine broadcast. We first show that the throughput of existing byzantine broadcast protocols are all far from ideal. We then obtain a simple upper bound on the throughput of byzantine broadcast protocols, showing that no protocol can do better than this upper bound. As the central contribution of this work, we propose a novel byzantine broadcast protocol called OverlayBB. OverlayBB achieves the optimal throughput, and is the very first protocol that can do so. Our protocol does not sacrifice other aspects of the performance.