Merkle Tree Verification & Tamper Detection

Merkle Trees allow the blockchain to efficiently verify that a specific transaction is part of a block without needing the entire list of transactions.

• Integrity check: If any transaction changes, its hash changes, propagating up the tree and changing the Merkle Root.
• Tamper detection: Even a single-bit modification in Tx3 changes H3, then H34, and finally the root. Nodes can instantly detect tampering.

Example: Tamper Detection

• Original Tx3 hash: H3 = SHA256(Tx3)
• Modified transaction Tx3’ → H3’
• New root = SHA256(H12 || H34’) ≠ original Merkle Root

This ensures immutability and integrity of the block’s transactions.