Byzantine Fault Tolerance (BFT) is a property of computer systems, particularly important in distributed networks and blockchain technology, that allows them to reach consensus and continue operating effectively even in the presence of faulty or malicious nodes. This term originates from the Byzantine Generals' Problem, a theoretical situation in computer science illustrating the difficulties decentralized systems face in achieving reliable consensus in the presence of disloyal or unreliable units.
In a BFT system, even if some nodes fail or act maliciously (like providing false or misleading information), the system is designed to withstand such faults and maintain its core functions. This is crucial for blockchain networks, where trust and reliability are paramount, and the system must reach a consensus on the state of the ledger even when some participants are untrustworthy or compromised.
BFT mechanisms are integral to many blockchain protocols, especially in Proof of Stake (PoS) systems. They ensure that as long as a certain percentage of the network's nodes are honest and reliable, the network can validate transactions and add new blocks to the blockchain accurately. This threshold varies between different blockchain implementations. A blockchain with strong BFT characteristics is less susceptible to manipulation and errors, ensuring more reliable and secure transactions.