Block sealer refers to a mechanism used to finalize blocks in a blockchain. In a blockchain, blocks are groups of transactions that are added to the chain. However, before they are considered complete, they need to be sealed or confirmed to ensure that the transactions are valid and irreversible.

This process often involves consensus algorithms, where network participants agree on the state of the blockchain. Different protocols have different methods for sealing blocks, such as Proof of Work, where miners solve complex mathematical puzzles, or Proof of Stake, where validators are chosen based on the number of coins they hold and are willing to “stake” as collateral.

Block sealing adds a layer of security, making it difficult for malicious actors to alter the blockchain. Once a block is sealed, it becomes part of the permanent record, contributing to the overall integrity and trustworthiness of the system. Thus, block sealers play a crucial role in maintaining the stability and security of blockchain networks.