GlossaryAdvanced
Byzantine Fault Tolerance
A distributed system's ability to reach correct consensus even if some participants act dishonestly or fail unpredictably.
Byzantine Fault Tolerance (BFT) describes a distributed system's ability to reach correct, reliable consensus even when some of its participants fail, go offline, or act maliciously — including sending conflicting information to different parts of the network.
Most blockchain consensus mechanisms are designed to be Byzantine fault tolerant up to some threshold, commonly up to just under one-third of total participating power acting dishonestly, beyond which the system's guarantees can no longer be assured. See Kaavon's "Consensus Mechanisms Compared" guide for how different designs approach this.
Examples
- A consensus mechanism's Byzantine fault tolerance threshold describes the maximum proportion of dishonest or failed participants it can withstand while still functioning correctly.
- Byzantine Fault Tolerance is named after a thought experiment involving generals who must coordinate an attack despite some potentially being traitors sending false messages.