Merkle Tree Hash Calculator

What is a Merkle Tree?

A Merkle tree is a hash-based data structure where each leaf node represents a transaction, and each non-leaf node is the hash of its child nodes. The top hash (Merkle root) represents all transactions in the block.

How It Works:

1. Hash each transaction (leaf nodes)
2. Pair adjacent hashes and hash them together
3. Repeat until only one hash remains (root)
4. If odd number of nodes, duplicate the last one

Example (4 transactions):

                    Root
                   /    \
                 H12    H34
                /  \   /  \
               H1  H2 H3  H4
               |   |  |   |
              tx1 tx2 tx3 tx4
              

Why Blockchains Use Merkle Trees:

• Efficiency: Only root hash stored in block header
• Proof of Inclusion: Verify transaction with log(n) hashes
• SPV (Simple Payment Verification): Light clients can verify without full blockchain
• Tamper Detection: Any change to a transaction changes the root

Merkle Proof:

To prove a transaction is in a block, you only need:

• The transaction itself
• Sibling hashes along the path to root
• The Merkle root (from block header)

For 1000 transactions, you only need ~10 hashes to prove inclusion!

Cryptocurrency Usage:

• Bitcoin: Merkle root in every block header
• Ethereum: Uses modified Merkle-Patricia trees
• Filecoin: Merkle proofs for storage verification
• IPFS: Content addressing with Merkle DAG