<human>:  Can you explain the concept of block chain and how it works?
<bot>: Blockchain is a form of distributed ledger technology. It is a secure system that records and stores information such as transactions, contracts, and other data in a distributed and decentralized way. This means that instead of having it stored on a single server or in a central database, there is no single point of failure. The records are stored on multiple computers and the network of computers then verifies the records against each other. This ensures that all the copies of the data are the same and that no one can tamper with it. The records are linked together in a chain-like structure, hence the name. Transactions are encrypted and added to the chain, which permanently stores the data, making it difficult to alter the data. This makes it a secure method of storing data and records, and it is often used for secure financial transactions.