$TREE

A Merkle Tree is a cryptographic data structure used for efficient and secure verification of data. It’s a binary tree where each leaf contains the hash of a data block, and each internal node contains the hash of the combination of its two child nodes.

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🔐 Why Is It Used?

Merkle Trees allow:

- ✅ Fast data integrity verification without checking the entire dataset.

- ✅ Secure data sharing – only the root hash (Merkle root) is needed.

- ✅ Space and performance efficiency during verification.

They’re used in:

- Blockchain technologies (e.g., Bitcoin, Ethereum)

- Peer-to-peer networks (e.g., BitTorrent)

- Digital certificates and file versioning systems

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🧠 How Does It Work?

1. Hashing data blocks – each block of data is hashed (e.g., using SHA-256).

2. Combining hashes – pairs of hashes are concatenated and hashed again.

3. Repeat – until only one hash remains: the Merkle root.

Example:

`

Merkle Root

/ \

Hash A Hash B

/ \ / \

H1 H2 H3 H4

`

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📌 Advantages

- Security: Hashing protects against tampering.

- Efficiency: Only part of the tree needs to be verified.

- Scalability: Works well with large datasets.