A blockchain is an online network composed of immutable blocks of data that are recorded chronologically. A blockchain network links all of these blocks together and secures them with cryptographic proofs.
Blockchain technology is at the core of most cryptocurrency networks and enables the transfer of funds around the globe. Millions of computers simultaneously control blockchain processes, and anyone with an internet connection can check records in a blockchain. Meanwhile, the decentralized approach protects records from unauthorized changes. It’s technically impossible to cancel or change a blockchain operation (a crypto transaction) that has been approved.