dBFT

Delegated Byzantine Fault Tolerance (dBFT) is a consensus mechanism designed for blockchain networks to achieve fast, final transaction confirmations in the presence of faulty or malicious nodes. It is a variant of Byzantine fault-tolerant protocols in which a fixed, relatively small set of validators is elected by stakeholders to represent the network and run consensus on new blocks. The design aims to combine the correctness guarantees of BFT with the efficiency of delegated systems.

In a dBFT system, time proceeds in rounds. A leader or proposer for the round suggests a new block. The validators then exchange messages to verify the block and vote on its validity. Once a supermajority of validators—typically more than two-thirds in a network of N validators with up to f Byzantine nodes (N ≥ 3f+1)—has voted to commit, the block is finalized and irreversibly added to the chain. The finality is achieved quickly, often within a few seconds, and new rounds begin with either the same or a rotating leader. The protocol relies on authenticated digital signatures and point-to-point communication to preserve safety and liveness.

Compared with proof-of-work schemes, dBFT provides immediate finality and lower energy consumption, at the cost of a smaller, curated validator set and a higher degree of centralization. It is used by networks such as NEO to provide fast, deterministic finality. See also PBFT, BFT, and DPoS.