The Blockchain industry is continuously progressing since its inception. The consensus mechanism is the core of a decentralized ecosystem that helps it to achieve consensus in the network. Till now, many consensus methods have been invented and implemented to achieve consensus within a blockchain system. I am writing a series of articles on different consensus mechanisms with a detailed explanation of their advantages and disadvantages over each other. I have already covered PoW and PoS, so here in this article, I will focus on PoA.
The PoW consensus algorithm used by Bitcoin is considered a reliable and secure consensus mechanism but it doesn’t support scalability. As a result, it restricts the performance of the Bitcoin network along with its transaction speed. The major disadvantage of this method is that it requires high energy consumption and system resources which are needed to solve the complex mathematical puzzles.
With some more features, Proof of Stake came into existence which offers better performance than PoW. There are several PoS projects which are still under development so what new features it can offer and how much it can deal with the drawback of the existing consensus mechanism is depends on the success rate of future projects.
Then there is another consensus mechanism called Proof of Authority which is the enhanced version of PoS. It supports better performance by allowing more transactions per second. Now let’s discuss it in detail.
What is Proof of Authority?
The Proof-Of-Authority (PoA) is a consensus method where a group of validators is already chosen as the authority. Their task is to check and validate all the newly added identities, validate transactions, and blocks to add to the network. To ensure efficiency and security in the network the validator group is usually kept small (~25 or less).
Proof of Authority (PoA) is an enhanced version of Proof of Stake (PoS) where the validator’s identity is used as a stake in the network.
A node needs to complete a mandatory process to authenticate itself to receive the right to generate new blocks. Validators need to register themselves in the public notary database using government-issued documents with the same identity that they have on the platform. Thus, Blocks and transactions are verified by participants, whose identity is already verified and acts as an authority of the system.
With the power under a limited number of users, PoA consensus can be adopted as a solution for private networks rather than public blockchains.
PoA was proposed by a group of developers in March 2017 (coined by Gavin Wood) as a blockchain-based on the Ethereum protocol. It was developed with the idea to solve the problem of spam attacks on Ethereum’s Ropsten test network. The new network was named Kovan, the main test network that all Ethereum users use today.
Pre-Requisites for Proof of Authority Consensus
The PoA consensus algorithm is usually based upon the following criteria:
- Validators need to disclose and confirm their identities by giving government-issued documents.
- The standard procedure for verifying the identity of validators.
- Complex and robust criteria to define a validator so that they can put his reputation at stake and commit to a long-term alliance.
Advantages of PoA consensus
As compared to other consensus methods, PoA offers the following advantages:
- High transaction rate.
- High-performance hardware is not required.
- PoA networks are very scalable as compare to PoW blockchains
- Less power extensive.
- Low transaction fees.
- Sequentially block generation with fixed time interval by authorized network nodes. This increases transaction validity speed.
- No communication is required to reach the consensus between the nodes.
- Network operation is independent of the number of the available genuine nodes.
- The chance of a node to become a forge depends upon both on their stake and overall holding.
Drawback
- Proof-of-Authority based networks lack in decentralization.
- PoA validator's identities are visible in the network.
- PoA does not guarantee censorship resistance.
Practical Implementation
PoA consensus algorithm can be applied in various fields and industries to achieve high throughput ranging from supply chains to banking sectors. PoA is considered as an effective and reasonable solution along with cost-saving benefit.
Below is the list of projects which has adopted PoA :
- Ethereum’s test net Kovan built on the Parity's PoA Protocol
- PoA Network by the Proof of Authority, LLC. (an Ethereum sidechain)
- The VeChainThor platform.
Conclusion
Every consensus method, be it PoW, PoS or PoA has its own set of advantages and disadvantages. But if we talk about PoA particularly, it somehow compromises in the decentralization area to achieve scalability and throughput.
Proof-Of-Authority can, therefore, be treated as a better option for a centralized solution because of its efficiency and less power consumption property.
Read More: Atomic Wallet’s Roadmap to success
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