Validator

Overview

Since a blockchain is based on consensus mechanism, it becomes evident to have an integrated protocol on how new blocks will be committed on the blockchain. Blockchain validators are basically computer systems dedicated to maintain security and integrity of the blockchain.

Validator nodes run a program on transactions and further decide the order in which the blocks would sit on the blockchain. Each validator contributes to the consensus protocol by signing blocks containing cryptographic signatures using their private keys.

Thus, by using a distributed consensus protocol, validator nodes process transactions, run them on the blockchain, and save results on the blockchain.

PoSA and validators - a general overview

Proof of Staked Authority (PoSA) is one of the consensus mechanisms that run with the help of validators who commit new blocks on the blockchain. A validator node helps to stake your cryptocurrency on the blockchain.

A validator is selected from the pool of validators based on the amount staked or contributed. Once selected, the validator is responsible for authenticating new transactions and updating the blockchain. In return, the validator earns rewards through transaction fees and commissions.

There's a criterion for how a validator is selected. From the pool, participants who have spent considerable time and staked higher amounts are selected to validate transactions and rewarded thereafter. The validator's block must then need an attestation for the accuracy of other validators before the transaction is confirmed on the blockchain. For this job, the reward (which could be the native cryptocurrency) is then distributed amongst the validators proportionately to the amount they've pledged.

The criteria for becoming a validator:

As a volunteer validator, you must:

• dedicate a system (computer) to verify and upkeep the integrity of the blockchain.

• add a certain amount of stake to the pool.

Candidates

Candidates are a set of inactive validators that remain as a backup apart from the active validators. Candidates are also responsible for validating blocks in case the active validators go offline or are inactive.

Slashing

Becoming a validator comes with a huge responsibility as they have to pledge or contribute their crypto share to stand a chance to validate and commit blocks on the blockchain. That said, validators might lose a significant amount of stake due to the slashing process in the form of a penalty.

A validator's stake might get slashed if a bad block is committed to the blockchain. Similarly, if a validator node fails to commit blocks on time (or is offline or inactive), a node is charged with a small amount as a penalty. However, this penalty is not as severe as slashing.

Double-sign slashing

A validator is "double-sign slashed" when more than one block is committed using their validator keys at the same time.