Proof-of-Authority (PoA)

Proof of Authority is a consensus mechanism in which a small, pre-approved set of validators — whose real-world identities are known and verified — are given the authority to create new blocks and confirm transactions. Unlike Proof of Work or Proof of Stake, which are open to anyone willing to commit resources or capital, Proof of Authority relies on reputation and trust. Validators are vetted in advance and their standing is tied to their real identity, creating accountability through social and legal consequences rather than purely economic penalties.

Because PoA networks have a small number of known validators, they can process transactions extremely quickly and cheaply — a handful of trusted nodes simply take turns producing blocks in a predetermined order. This makes PoA well-suited for private enterprise blockchains, development testnets, or supply chain networks where all parties are known and trusted. The obvious trade-off is centralization — a small group of known validators is fundamentally more centralized than most public blockchains aim for, making PoA inappropriate for fully public, permissionless systems.

Example: Think of a homeowners’ association where a small elected board makes all the official decisions. Every board member’s name and address is public knowledge, and their reputation is on the line with every vote. Proof of Authority blockchains work the same way: a known, accountable group is trusted to run things efficiently, in exchange for giving up the anonymity and openness of a fully public system.