Merkle Tree

A hash tree or Merkle tree is a tree structure where each leaf node is a hash of a block of data, and each non-leaf node is a hash of its child nodes.

• It uses a hash-based tree structures to store the children (just like in a trie)

• Only the leaf nodes actually contain the data, the rest is just hashes of data or hashes of hashes

Usage

• Using a Merkle tree provides integrity and validity of your data using a small amount of data that a trusted authority has to maintain
• It's used to verify that a message is actually legit. For that you need to get hash values for all nodes until the root node $O(log(n))$
• Merkle tree is used in blockchain to efficiently verify the consistency and integrity of large datasets.