Continuity: A deterministic Byzantine fault tolerant asynchronous consensus algorithm

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In 1985, Fischer, Lynch, and Patterson presented the FLP Impossibility Theorem which states that it is impossible for an asynchronous system to reach consensus if at least one node fails; asynchrony prevents distinguishing between process crashes and delays. Traditionally, asynchronous consensus algorithms implement protocol adaptations to handle delays and prevent indefinite runs (e.g. coordination protocols in the form of ordered rounds). In this paper, we present a deterministic Byzantine fault tolerant asynchronous consensus algorithm called Continuity. Within this system, processes do not begin by supporting a possible decision value. Instead, Continuity utilizes logical monotonicity to build an initial configuration that is necessarily univalent, thus eliminating the assumed initial conditions of the FLP Impossibility Theorem. As such, Continuity achieves consensus in a wait-free manner.



FLP, Byzantine fault tolerant, Asynchronous consensus