Proof of Authority (PoA)

Proof of Authority (PoA) is a consensus algorithm used in blockchain networks to achieve consensus and validate transactions. Unlike Proof of Work (PoW) and Proof of Stake (PoS), PoA does not require miners to solve complex mathematical problems or stake cryptocurrency to validate transactions. Instead, it relies on a small number of pre-approved and publicly identified validators — known as authorities — who are granted the right to create new blocks. Because the validators' identities are known and their reputations are at stake, they are strongly incentivized to behave honestly.

PoA is most commonly used in private or consortium blockchains, where the participants are known entities such as companies or institutions that have agreed to operate within a shared network. Examples include the Ethereum-based networks used by enterprises for supply chain tracking or financial settlements. Some public testnets also use PoA because it is fast, inexpensive, and easy to operate. The Binance Smart Chain uses a variant of PoA called Proof of Staked Authority (PoSA), which combines validator staking with identity-based accountability.

The primary tradeoff of PoA is decentralization. Because consensus power is concentrated in a small group of known validators, the network is inherently less permissionless than PoW or PoS blockchains. A single colluding group of validators could theoretically censor transactions or manipulate the chain. For this reason, PoA is generally not considered suitable for fully public, trust-minimized blockchains, but it remains a practical and efficient choice for environments where some degree of centralization is acceptable in exchange for speed and low operational cost.