Consensus with Byzantine Failures and Little System Synchrony

Abstract

We study consensus in a message-passing system where only some of the n2 links exhibit some synchrony. This problem was previously studied for systems with process crashes; we now consider Byzantine failures. We show that consensus can be solved in a system where there is at least one non-faulty process whose links are eventually timely; all other links can be arbitrarily slow. We also show that, in terms of problem solvability, such a system is strictly weaker than one where all links are eventually timely