Blockchain technology is a decentralized, distributed digital ledger that records and stores data in a secure, immutable, and transparent manner. It is used to securely store and transfer data between two or more parties without the need for a third-party intermediary. It is a distributed database that is maintained by a network of computers, and it is secured through cryptography and consensus algorithms. Blockchain technology is used in a variety of applications, including cryptocurrency, smart contracts, and distributed applications.