Enhanced fault-tolerance through Byzantine failure detection

Abstract

We consider a variant of the Byzantine failure model in which Byzantine processes are eventually detected and silenced, and investigate the fault-tolerance of the classical broadcast and agreement problems. We show that if all Byzantine processes are eventually detected, then it is possible to solve the broadcast problem in the presence of any number of Byzantine processes. If only a fraction of the Byzantine processes can be detected, then we show that it is possible to solve consensus (and broadcast) if the total number of processes is N ≥ 2f + 3F + 1, where f is the number of Byzantine processes that are eventually detected and F is the number of those that are never detected. We show that 2f + 3F + 1 is a lower bound to solve the consensus and broadcast problems. © 2009 Springer-Verlag.