Optimistically Terminating Consensus: All Asynchronous Consensus Protocols in One Framework

Optimistically Terminating Consensus (OTC) is a variant of Consensus that decides if all correct processes propose the same value. It is surprisingly easy to implement: processes broadcast their proposals and decide if sufficiently many processes report the same proposal. This paper shows an OTC-based framework which can reconstruct all major asynchronous Consensus algorithms, even in Byzantine settings, with no overhead in latency or the required number of processes. This result does not only deepen our understanding of Consensus, but also reduces the problem of designing new, modular distributed agreement protocols to choosing the parameters of OTC.