Technology
How does blockchain work?
Blockchain works by storing data in blocks that are cryptographically linked in a chain across many computers. Each block carries a fingerprint (hash) of the previous one, so altering any block would break the chain — making the record tamper-evident.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how blockchain works.
Step by step
- 1Transactions are grouped together into a block.
- 2Each block includes a hash of the previous block, linking them in order.
- 3The chain is copied across many computers (nodes), with no central owner.
- 4To add a block, the network must agree it's valid (consensus), making fraud extremely hard.
Frequently asked questions
- Why can't blockchain records be changed?
- Changing one block alters its hash, which breaks every block after it — and a majority of the distributed network would have to accept the change.
- What is a hash?
- A fixed-length fingerprint of data; any change to the data produces a completely different hash.
- What is consensus?
- The process by which the network's computers agree on which new block is valid before adding it to the chain.