What is BLOCKCHAIN? Understanding Blockchain: A Primer 1. What is Blockchain? Blockchain is a type of digital record-keeping system that stores information across many computers. This setup makes it very hard for anyone to change the records without everyone noticing. It was first created for Bitcoin but now has many other uses too. 2. Key Ideas 2.1. Decentralization Instead of having one central place where all data is kept, blockchain spreads it out over a network of many computers.