A quorum node is a specific type of node in a blockchain network that participates in the consensus process to validate transactions and maintain the integrity of the ledger. These nodes usually operate under a set of rules that require a minimum number of them to agree on the state of the network before any changes can be made.In systems like proof-of-authority or permissioned blockchains, quorum nodes play a critical role in maintaining security and ensuring that no single entity can manipulate the data. This structure helps achieve consensus efficiently while reducing the risk of forks or discrepancies in the ledger.The concept of quorum can vary, with different networks setting different thresholds for how many nodes must agree before a transaction is considered valid. By requiring agreement from multiple nodes, blockchain networks can balance efficiency with the need for trust and security, thereby ensuring a reliable and resilient system.