definition
The full name of PoA is "Proof Of Authority".
The earliest proposal was made by Gavin Wood, a former Ethereum technical expert in 2017.
PoA is a consensus algorithm based on reputation (or reputation), which is most suitable for use in private chains. In this algorithm, miners are selected as validators of blocks by virtue of their personal reputation rather than mortgaged cryptocurrencies. The verifier of the block has the authority to produce the block, sign and upload it to the chain.
principle
In the PoA algorithm, there are no longer ordinary miners, and miners (that is, authorities) who have the authority to generate blocks, sign and upload to the chain are elected by ordinary nodes (that is to say, every ordinary node may become an authority , get more than 50% of the votes of ordinary nodes), the authority will attach a reputation (or reputation) information, once there is a problem with the reputation (or reputation), other authorities can vote for it Kicked out of the ranks of authority.
Miners under the PoA mechanism do not earn rewards through mining like PoW miners. Recognized and influential miners (authorities) can participate in verifying transactions and blocks, and participating in verification miners (authorities) can verify transactions. All operations are verified and rewarded.
Participation must meet the following conditions to become an authority:
1. The identity must be formally verified on the Internet, and the identity information can be found in the public domain;
2. Participants must have some qualifications to obtain the authority to verify transactions, blocks and obtain income from them;
3. It is necessary to ensure that the verification process is normal and consistent with other authorities.
process
Here is mainly to explain how the transaction is on the chain
features
advantage
1. The performance is good, the time for verifying transactions is significantly shortened, and the time for generating blocks is accelerated.
2. Energy saving.
3. Functions such as review and blacklist are relatively easy to implement.
shortcoming
1. Tend to centralization.
2. Usually used in private chains and permissioned blockchains.
3. Due to the relatively large degree of information disclosure of authoritative nodes, authoritative nodes are more likely to become the target of hackers.