Foundations of Blockchain

Merkle trees

A Bitcoin header has metadata that summarizes all the transactions present in the block. This is achieved by creating a digest using a special type of tree called a Merkle hash tree. As mentioned in Chapter 2, A Bit of Cryptography, a Merkle hash tree is a binary hash tree that is used to summarize large sets of data. Merkle trees are used to summarize all the transactions in Bitcoin and thus ensure the integrity of the transactions. They provide an efficient way to verify whether a transaction is included in the block.

Merkle trees recursively hash the nodes, starting from the leaves, which are hashes of transactions, until there is only one hash. This hash value summarizes all the transactions in the block and is called the ...