Overview
Byzantine fault tolerance (BFT) is a system's ability to reach agreement despite some participants behaving maliciously or failing. It is the theoretical foundation of blockchain consensus. BFT systems can tolerate a fraction of faulty nodes and still agree.
How It Works
BFT algorithms, such as Practical BFT (PBFT), use message exchange and voting among nodes to agree on state. They often require a quorum, such as two-thirds of nodes, to make progress. Many proof-of-stake protocols are BFT-inspired.
Why It Matters
BFT guarantees underpin the safety of blockchain networks: without it, malicious validators could create conflicting histories. It directly informs the design of Consensus mechanisms and their fault tolerances.
Related Concepts
BFT is the foundation of Consensus and Proof of Stake. It relates to Validator sets and finality guarantees.