# PBFT Proof of Authority (PoA)

**What is Proof of Authority (PoA)?**

PoA for Proof of Authority is a reputation-based consensus algorithm that brings a practical and efficient solution to blockchains. The term was coined by Ethereum co-founder and former CTO Gavin Wood in 2017. Proof of Authority is a variation of the Proof of Stake consensus mechanism, in which the algorithm upholds identity value & the reputation of the participants, not based on the token value they hold. The Proof of Authority model is based on a limited number of validators, making it an easily scalable model. Blocks and transactions are validated by approved participants who act as the system's moderators

**How Proof of Authority (PoA) Works**

PoA is an automated process, validators are not required to monitor their computers constantly, but they will need a device capable of running around  the clock. Validators must run software that allows them to include transactions in the block. The authenticator's identity is always kept anonymous by encryption and cryptographically secure and is only revealed when the validator processes a fraudulent or malicious transaction. Validators are paid an incentive in the form of transaction fees in the event of a 'good' validation job, however, if a validator handles a malicious or fraudulent transaction, his node can be deleted, and the validator's identity will be revealed, discrediting him

**What Problem Does Proof of Authority (PoA) Solve For Blockchain?**

Proof of Work is so profitable and expensive, Proof of Stake algorithms emerged as one of the popular alternatives to PoW. The strengths of PoS and PoA are clear:

* Provides a more substantial financial incentive for validators to operate.
* Does not require much computational effort and specialized equipment.
* Opens the door for sharding, making the blockchain network more scalable in the future

**PoA and Sea Network**

For Sea Network the validator is responsible for generating blocks and adding them sequentially to the blockchain. All validators create a dynamic set of validators where validators can be added or removed from the cluster using a decentralized voting mechanism. Block Verifier Proposer Authority List Round/Epoch Leader ID / Nodes IDs transactions Selected? No Yes What Problem Does Proof of Authority (PoA) Solve For Blockchain? This means that validators can be included or excluded from the validator pool if a majority (51%) of validator nodes voted to add/remove a particular validator from the set. So malicious validators can be detected and removed from the network anytime, and new trusted validators can be added to the network. All validators, in turn, propose the following block (by selecting the leader in a circle). Since a block is validated/added to the blockchain, the majority of validators (i.e., more than 2/3) have to approve the block. In addition to validators, some non-validators are not directly involved in the block generation but participate in the validator block. PBFT PoA is the default consensus mechanism of the system framework
