At its core, a blockchain is a method of storing and transferring information. It can be considered a kind of database, albeit one that differs from traditional databases. Information on a blockchain is stored in a continuous chain of blocks with each block containing essential information (for example, transactions) and the cryptographic hash of the previous block. To change the information in any block, you have to make changes to all subsequent blocks.

A blockchain is also a distributed database, which means it isn’t stored on any single computer. Instead, many identical copies of it are stored on a network of different computers called nodes. The content of the blocks is verified by the consensus of all nodes in the network. This makes it very difficult to alter any information already included in the blocks, and this difficulty increases with the number of nodes in the network.