Glossary
Byzantine Fault Tolerance (BFT)
A system's ability to keep reaching correct agreement even when some participants fail arbitrarily or act maliciously, named after the Byzantine Generals Problem.
Byzantine Fault Tolerance (BFT) is the property that lets a distributed system reach correct agreement even when some of its participants fail in arbitrary ways — crashing, sending conflicting messages, or actively lying. The name comes from the 1982 "Byzantine Generals Problem," which framed the challenge of coordinating honest actors over an unreliable network in the presence of traitors.
In blockchains, BFT is the theoretical floor every consensus design must clear: a protocol is Byzantine-fault-tolerant if honest nodes still converge on one history despite a bounded fraction of malicious validators. Classical BFT protocols such as PBFT, Tendermint, and HotStuff tolerate up to one-third faulty nodes and offer deterministic finality, while Nakamoto-style consensus achieves a probabilistic variant through proof-of-work.