KEY TAKEAWAYS

Blockchain is a type of shared database that differs from a typical database in the way it stores information; blockchains store data in blocks linked together via cryptography.

Different types of information can be stored on a blockchain, but the most common use for transactions has been as a ledger.

In Bitcoin’s case, blockchain is decentralized so that no single person or group has control—instead, all users collectively retain control.

Decentralized blockchains are immutable, which means that the data entered is irreversible. For Bitcoin, transactions are permanently recorded and viewable to anyone.