Validators are specialized nodes in a blockchain network that are responsible for verifying and validating the transactions within the network. Validators play an integral role in ensuring the security and scalability of distributed networks by preventing malicious activity, such as double-spending, while also providing a secure platform for users to make trustless payments.
In public blockchains such as Bitcoin and Ethereum, validators are known as miners or full nodes. Miners compete with each other to determine which one can produce the next “block” of validated transactions first. The miner who successfully solves a cryptographic puzzle is rewarded with cryptocurrency tokens (e.g., BTC).
In private or permissioned blockchains, however, there is no competition among miners; instead, certain pre-selected servers have been designated as validators by their creators or operators. In this case, these trusted nodes must reach consensus before any new blocks can be added to the chain – otherwise all participants will reject them if they conflict with existing rules set out by their creator/operator. This ensures that only legitimate changes are accepted into the ledger; for example it prevents someone from transferring money out of another user’s account without authorization from both parties involved in the transaction.
Additionally, it is important to note that there may be differences between how consensus algorithms work on different types of blockchain networks: proof-of-work (PoW) requires miners/validators to solve difficult mathematical problems; meanwhile proof-of-stake (PoS) relies on validators stake coins in order to receive rewards based off their contributions towards maintaining network integrity & security. Ultimately though both methods serve similar functions – namely preventing malicious actors from manipulating data stored within distributed ledgers!