Proof of Authority (PoA) Explained
Proof of Authority (PoA) is a reputation-based consensus algorithm used in blockchain networks, particularly private ones, to maintain integrity and security
1. Unlike Proof of Work (PoW) and Proof of Stake (PoS), which rely on computational capacity or staked cryptocurrency, PoA leverages the value of identities
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The term Proof of Authority was proposed in 2017 by Ethereum co-founder and former CTO Gavin Wood
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How PoA Works
The PoA consensus mechanism relies on authorized entities to validate blockchain transactions
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- Validation Requirement: Instead of staking currency, block validators stake their own reputation 1.
- Validator Selection: PoA blockchains are secured by validating nodes that are arbitrarily designated as dependable entities 1.
- Scalability: PoA is considered a highly scalable system because it operates with a small number of pre-approved participants who verify blocks and transactions 1.
- Efficiency: PoA is designed to be a scalable and efficient alternative for constructing private blockchain networks 1.
Use Cases and Examples
PoA is a versatile consensus algorithm that is regarded as a valuable option for logistical applications, such as supply chains, where it allows businesses to maintain privacy while utilizing the benefits of blockchain technology
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Examples of PoA implementation include:
- Microsoft Azure: The Azure platform provides solutions for private networks using a PoA system that does not require a native currency (like Ether's 'gas') because mining is unnecessary 1.
- Chiliz Sidechain: The Chiliz sidechain uses a PoA consensus mechanism where the identity of each individual node is staked instead of monetary value . Chiliz only allows whitelisted entities to operate a node and process transactions, and every Fan Token partner operates a node .
- Rails Network: The Rails Network, an EVM-compatible blockchain solution, is powered by Proof of Work by Authority (PoWbA) 3.
It is important to note that while the Chiliz sidechain initially used PoA, the newer Chiliz Chain 2.0 uses a Proof of Staked Authority (PoSA) consensus mechanism, which is run by a maximum of 11 validators who stake CHZ tokens to participate in network security .