Proof of Authority (PoA) is a consensus mechanism where a limited number of pre-approved validators are responsible for verifying transactions and creating new blocks. Validators are selected based on their identity and reputation rather than computational power or stake.
How It Works
Validators are known, vetted entities who stake their reputation on honest behavior. If a validator acts maliciously, they are publicly identified and removed. This creates accountability through identity rather than anonymous economic incentives.
Advantages
Speed: Very fast block times and high throughput since there's no mining competition or stake-weighted selection.
Efficiency: Minimal computational overhead.
Predictability: Block production is consistent and reliable.
Disadvantages
Centralized: A small number of validators means less decentralization.
Permissioned: Not anyone can become a validator.
Use Cases
PoA is commonly used in private/enterprise blockchains and testnets where decentralization is less critical than performance. VeChain uses a PoA-based consensus for its supply chain-focused blockchain.