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proof-of-authority

id: proof-of-authority title: Proof of Authority sidebar_label: Proof of Authority​

Proof of Authority (PoA) is a blockchain consensus mechanism where a limited set of pre-approved validators (sometimes called “authorities”) are responsible for producing blocks and validating transactions. Unlike Proof of Work (PoW) or Proof of Stake (PoS), which rely on computational power or token holdings, PoA relies on the identity and reputation of validators.

🔹 How It Works​

  1. Validator Selection

    • Validators are chosen based on their real-world identity, reputation, or stake in the project (often institutions, companies, or trusted community members).
    • Their authority is publicly verifiable.

  2. Block Production

    • Validators take turns creating blocks.
    • Since the validator set is small and known, block times are predictable and fast.

  3. Finality

    • Blocks are considered valid as soon as they are produced by an authority, which reduces the chance of forks.

🔹 Advantages​

  • ⚡ High throughput & low latency – fewer validators = faster block confirmation.
  • 💰 Low resource cost – no mining or large staking hardware required.
  • 🔒 Sybil resistance – hard to create many fake validators because each validator must be approved/known.
  • 🛠 Simplicity – easier to set up for private or consortium blockchains.

🔹 Disadvantages​

  • 🏛 Centralization – only a handful of validators have control, which can reduce trustlessness.
  • 🚨 Censorship risk – validators could exclude transactions they don’t like.
  • 🕵️ Trust in identity – security relies on the honesty and reputation of validators, not just cryptography.

🔹 Real-World Examples​

  • VeChain – runs on a PoA network where authority nodes are approved by the foundation.
  • Ethereum testnets – some past Ethereum testnets (like Kovan) used PoA.
  • Private/consortium chains – enterprises often choose PoA because they value control and efficiency over decentralization.

✅ In short: Proof of Authority = fast, efficient, reputation-based consensus. It’s often used where trust is placed in known entities rather than in open, permissionless participation.