A Byzantine fault is a failure in which a component of a distributed system does not simply stop, but behaves arbitrarily: it may send wrong or conflicting messages, lie, or act in coordination with attackers. The name comes from the Byzantine Generals Problem described by Lamport, Shostak and Pease in 1982. A system that keeps working correctly despite such faults is said to have Byzantine fault tolerance (BFT), explained in full on its own page.