Summary
- Validators play a vital role in the functioning and security of the blockchain.
- They add new blocks and verify transactions in proposed blocks, and also store the history of transactions and confirm the validity of new transactions.
- The need for securer, more scalable and practical solutions is driving developments and breakthroughs in blockchain validation.
- For more articles like this, please visit our Explainers pages.
What’s the role of a validator in blockchain?
Validators are responsible for adding new blocks and verifying transactions in proposed blocks. They also store the history of transactions and confirm the validity of new transactions, and therefore play a vital role in the functioning of the blockchain.
A validator is crucial in validating transactions in blockchain consensus mechanisms like proof of stake and proof of authority (PoA). They check whether new transactions align with the network’s rules and ensure that the sender has adequate funds to complete the transaction.
Validators are also responsible for ensuring the security of the blockchain by monitoring the network for any nefarious activities, such as double spending. This refers to spending the same currency units twice, something that blockchains prevent by connecting the open ledger with cryptographic algorithms.
How do proof of stake (PoS) validators function?
PoS validators check if the transactions in the proposed block are valid, add the block to the blockchain, and maintain records of the ledger. For their contribution, they earn rewards in native cryptocurrency.
In PoS blockchains, validators have three major roles: validator client, node operator and stake amount. A validator client is a software application that holds and uses private keys to verify the state of the blockchain.
A single validator from the pool of validators is randomly chosen to propose a block. The proposer prepares the block and broadcasts the proposal to the entire network. The community of validators approves the transactions proposed in the block. It is important to note that only verified transactions achieve finality. The function of the validators agreeing on the state of the blockchain is termed consensus.
There are also delegated proof-of-stake (DPoS) blockchains, where network users vote to elect delegates to validate the next block. Compared to PoS, DPoS brings in better-streamlined governance and faster consensus, as the number of validators is reduced without compromising decentralization. The delegates distribute the rewards earned among the users who selected them.
How do PoA validators function?
In PoA blockchains, a group of validators chosen on the basis of their identity approves the transactions and produces the new block.
A PoA consensus mechanism consists of a small band of pre-selected validators who are entrusted with generating new blocks and maintaining the veracity of the network. It serves well in private or enterprise blockchains where trusted individuals or entities are chosen as validators and decentralization is low on priority.
If a validating node approves a malicious or fraudulent transaction, it could be penalized in the form of expulsion from the list of validating nodes for a certain duration or a complete ban.
What is the difference between miners and validators?
In PoW blockchains like Bitcoin, miners validate and add transactions to the blockchain through mining, while other nodes act as validators by verifying transactions and blocks without contributing to the mining process.
In stake-based systems, validators approve transactions and create blocks based on their stake without intensive computation.
Both miners and validators ensure the accuracy of transactions and add blocks to the blockchain. However, their responsibilities and ways of functioning differ depending on the type of blockchain they are working on.
What’s next for validation and validators?
The need for securer, more scalable and practical solutions is driving developments and breakthroughs in blockchain validation.
One trend is developing consensus methods beyond the conventional PoW and PoS models. Protocols, such as proof of burn (PoB), PoA and proof of space (PoSpace), provide distinctive validation methods focusing on user involvement, security, and energy efficiency.
Another innovation is using zero-knowledge proofs, which improve security and privacy by enabling validators to confirm transactions without disclosing underlying data. Furthermore, interoperability solutions are being developed to facilitate communication and value transfer between dissimilar blockchain platforms to promote a more integrated and effective blockchain ecosystem.
A version of this explainer first appeared on CoinTelegraph.
