PoA (Proof of Authority)

Proof of Authority replaces mining power or staked capital with something simpler: a validator's real-world identity and reputation. A small, pre-approved set of nodes takes turns producing blocks in a fixed rotation, each one signing what it creates with its own private key. Because every validator is a known, vetted entity rather than an anonymous address, misbehavior such as approving fraudulent transactions can be traced directly back to them and punished with removal from the validator set.

This design trades decentralization for speed. With no puzzle-solving or stake-locking involved, PoA networks typically confirm blocks in seconds and handle far higher throughput than Proof of Work chains, while using a fraction of the energy. That efficiency made PoA a popular consensus choice for Ethereum's early public test networks, Rinkeby and Goerli, both of which ran on the Clique PoA protocol before Ethereum's testnets moved to proof-of-stake designs.

PoA also suits private, enterprise, and consortium chains where participants already know and trust one another, and it remains common on sidechains and appchains that prioritize speed over openness. VeChain ran one of the best-known public examples, requiring its KYC-verified Authority Masternodes to validate blocks, before shifting the network to a delegated proof-of-stake model in its December 2025 Hayabusa upgrade. Binance Smart Chain uses a related hybrid, Proof of Staked Authority, pairing validator identity with staking.

PoA's core weakness is that it is not trustless: concentrating block production in a handful of known validators creates a single point of censorship, collusion, or regulatory pressure. That trade-off makes it a poor fit for a fully open, adversarial public network, but a practical choice anywhere participants already trust an identifiable authority, such as a permissioned blockchain run by a consortium of known companies.