Cox: a reliable runtime switching protocol for BFT consensus algorithms

Abstract

Different Byzantine fault tolerance (BFT) consensus algorithms have distinct characteristics and optimal use cases. Rarely does a single protocol demonstrate outstanding performance across different environments. Sometimes, systems need to switch consensus algorithms to adapt to different environments. This paper aims to investigate how to achieve seamless consensus algorithm switching without system downtime or compromising the security and consistency of the original consensus module. To address this issue, we propose Cox, a reliable online switching protocol for BFT consensus algorithms, and design a corresponding recovery sub-protocol for lagging nodes. Experimental results indicate that, under the assumption of a partially synchronous network, Cox ensures both the liveness and safety of the consensus module and achieves reliable switching in milliseconds.