Merkle Trees

A Merkle tree is a clever way to combine lots of data (like transactions) into a single fingerprint (the Merkle root). Blockchains use Merkle trees to make sure all transactions in a block are valid and haven’t been tampered with.

Why is this important?

• Merkle trees let you prove a transaction is in a block without downloading the whole block.
• They make blockchains efficient and secure.
• Used in Bitcoin, Ethereum, and many other blockchains.