💡Key Ideas:

Merkle Trees are probably THE most important data structure (imo) in blockchain and in the ZK world.

It's a binary tree filled with cryptographic hashes. Data is separated into leafs (bottom row). Leafs are hashed into branches (second row), branches/nodes are hashed continuously (third row) until the very top (top row) known as the tree root.

This structure enables efficient and secure verification of the contents of large data structures. To understand more about Merkle trees, read the suggested links.

• Extra: there are variants of Merkle Trees that implement improvements for specific use cases. For example:

• IMT - Incremental Merkle Tree is a type of data structure used in cryptography and computer science for efficiently verifying the integrity of a large set of data, especially in situations where new data is added over time.

• LeanIMT - Lean Incremental Merkle Tree is an optimized binary version of the IMT into binary-focused model, eliminating the need for zero values and allowing dynamic depth adjustment.

• SMT - Sparse Merkle Tree is a data structure useful for storing a key/value map where every leaf node of the tree contains the cryptographic hash of a key/value pair and every non leaf node contains the concatenated hashes of its child nodes.

• Merkle-Patricia Trie is a data structure modofied from Merkle Tree where the whole state of Ethereum (the totality of all accounts, balances, and smart contracts), is encoded into.

• Verkle Tree: similar to Merkle Patricia Trees (MPT) with , a key difference is each node uses a special type of hash (called a vector commitment) to commit to children nodes. These vector commitments provide several important, long-term benefits, and help pave the way for statelessness in Ethereum.

• Reckle Tree: recursive zk proofs tree.

🔗 Links:

How Merkle Trees Enable the Decentralized Web!

Merkle Trees and Merkle Roots Explained

Visualizing Efficient Merkle Trees for Zero-Knowledge Proofs

The Ultimate Merkle Tree Guide in Solidity

🛠️ Build and Practice:

Try writing a Merkle Tree using a language of your choice.

Can you describe the structure of a Merkle tree?

How are Merkle trees used within the blockchain context?

Why are Merkle trees useful for efficient and secure verification of large data structures?