Definition
A Merkle tree is a hierarchical data structure that aggregates multiple data items into a single cryptographic commitment, called the Merkle root, by recursively hashing pairs of child nodes. It organizes data as leaves and internal hash nodes in a tree topology, enabling succinct representation of a large dataset’s contents and supporting efficient, hash-based membership relations between individual elements and the overall committed set.
In Simple Terms
A Merkle tree is a structured way of arranging many pieces of data into a tree of hashes that ends in one final hash, the Merkle root. This single hash represents all the data in the tree and ties each individual piece of data to that overall representation through linked hash values.
Context and Usage
Merkle trees appear in cryptographic systems that need compact commitments to large datasets, particularly where membership relations must be tied to a single root hash. They are central to data-commitment structures in block-based ledgers, and they underpin constructions where Merkle proofs are combined with zero-knowledge proof systems, including zk-SNARK and zk-STARK schemes, to attest to properties of committed data.