Bitcoin and other cryptocurrencies operate on a technology called “blockchain.” You may have heard of blockchain referred to as a “distributed, decentralized, public ledger,” but the technology is actually easier to understand than that definition sounds. At its most basic level, blockchain is literally a chain of blocks — only not in the traditional sense of those words. When we say the words “block” and “chain” in this context, we are actually talking about digital information (the “block”) stored in an online database (the “chain”). Here’s how it works.

You have all these people, all over the world, who have bitcoin. According to a 2017 study by the Cambridge Centre for Alternative Finance, the number may be as many as 5.9 million. Let’s say one of those 5.9 million people wants to spend one or many of their Bitcoin. This is where blockchain comes in.

With other public recorders of information, like the Securities Exchange Commission (SEC), Wikipedia, or your local library, there’s someone in charge of vetting new data entries. With blockchain, however, that job is left up to a network of computers. These networks often consist of thousands (or in the case of Bitcoin, about 5 million) computers spread across the globe. When you go to make a purchase using bitcoin, that network of computers rushes to check that your transaction happened in the way you said it did. They confirm the details of the purchase, including the transaction’s time, dollar amount, and participants.

When consumers make purchases using the U.S. dollar, banks and credit card companies verify the accuracy of those transactions. Bitcoin performs this same function without these institutions using a system called “hashing.” When one person pays another for goods using bitcoin, computers on the bitcoin blockchain rush to check that your transaction is accurate. In order to add new transactions to the blockchain, a computer must solve a complex mathematical problem, called a “hash.”

Solving a hash takes computers, and even supercomputers, an average of 10 minutes. During that time, computers also check the accuracy of new transactions on the bitcoin blockchain. If a computer is the first to solve a hash, they store newly-made transactions as a block on the blockchain, at which point they become unalterable.