Blockchains are decentralized protocols which means that they depend on various types of consensus models. This article takes a comparative view of the Proof-of-Authority and Proof-of-Stake models.
What is Proof-of-Authority (PoA)?
Proof-of-Authority is a type of decentralized public ledger on Bitcoin. It is now used for federation and integration by commercial entities. PoA is a type of consensus model that appoints validators on a blockchain.
These validators reserve the right to update the distributed ledger. This type of algorithm architecture depends on the validators to create new blocks that are referenced to obtain distributed consensus. It is scalable since it depends on a small number of validators.
Working Mechanism of Proof-of-Authority
PoA designates preapproved validators that use software to list transaction records in blocks. The validators do not need to actively monitor their computers but they have to keep their computational devices in good state of order. Here are some of the terms that validators must comply with in order to get appointed:
Validators must have a clean record without any criminal charges or legal violations. Validators must have verified accounts on the network with necessary information available on the public domain. In this manner, validators can be trusted and checked by all blockchain participants.
Validators should be willing to invest their funds and stake their reputation. The validators must also pass all the strict scrutiny requirements set by the network.
Validators are encouraged to maintain a consistent transaction volume to secure their reputation and maintain trust of network participants.
All validators on the network must comply with the same standardized rules of the forum in order to maintain the reliability and integrity of the network.
What is Proof-of-Stake (PoS)?
The Proof-of-Stake or PoS is a progression of Proof-of-Work consensus model. In PoW, the miners have to increase their computational power in comparison to their competitors in order to verify a new block. This can take a lot of energy.
However, in Proof-of-Stake (PoS), the validators are appointed based on their invested stakes in a blockchain network rather than processing power. The more tokens a validators can commit the greater their chances of getting appointed as a validator.
Proof-of-Authority Vs Proof-of-Stake
Here are some important parameters that determine the differences between PoA and PoS consensus mechanism:
Basis of Consensus
PoA blockchains disclose verified information about validators that are available on public domain. In this manner, all network participants can view and validate the moderators who are building new blocks.
On the contrary, in a PoS network validators remain unknown but they are selected based on the total number of staked coins.
Validators do not require any specified type of hardware to interact with the network. Meanwhile, validators in PoS may need to employ three software tools to participate in Ethereum network.
PoA are secured against 51% attack since they depend on a very concentrated amount of blockchain administrators. On the other side, PoS validators are vulnerable to 51% attacks if the counterparty is able to acquire the majority stake in the network.
PoA blockchains are permissioned networks which mean that they are only open to a few approved participants whereas, PoS blockchains are permission-less.
PoA is usually preferred for cost effectiveness. It simplifies consensus process for validators, and ensures more independence for validators. At the same time, it is also used for bringing greater security for the nodes.
On the other side of the spectrum, PoS is ideal for decentralized applications, scalability, and anti-spam systems.
Byzantine Fault Tolerance (BFT)
BFT is the measure of a distributed ledger to continue to operate regardless of a few nodes acting maliciously or failing. PoA ensures BFT by concentrating the validating power among a few select nodes that are appointed after a rigorous scrutiny.
In this manner, if a few nodes act rouge, the overall integrity of the distributed ledger is not compromised. However, PoS ensure BFT by the way of continuous appointment of new validators and block generation at regular intervals.
PoA was introduced by Gavin Wood in 2017, one of the Ethereum co-founders as a way to improve performance of the protocols based on this blockchain. PoS ensure economic transactions while increasing network efficiency.
However, the practical utility of PoS in various jurisdictions makes it a more worthy choice for blockchain integration.