Practical Byzantine Fault Tolerance
Practical Byzantine Fault Tolerance (PBFT) is a consensus algorithm designed to achieve fault tolerance in distributed systems, even when some nodes (replicas) behave maliciously or arbitrarily (Byzantine faults). It enables a network of nodes to agree on a state or transaction order without relying on proof-of-work, making it efficient for permissioned blockchain systems and critical distributed applications. PBFT ensures safety (all non-faulty nodes agree on the same sequence of operations) and liveness (the system continues to make progress) under the assumption that less than one-third of the nodes are faulty.
Developers should learn PBFT when building or working with high-assurance distributed systems, such as permissioned blockchains (e.g., Hyperledger Fabric), financial transaction systems, or any application requiring consensus in adversarial environments. It's particularly useful in scenarios where low latency and high throughput are critical, as it avoids the energy-intensive mining of proof-of-work algorithms, making it suitable for enterprise and consortium settings where participants are known and trusted to some degree.