What Is a Merkle Tree?
A Merkle tree is a cryptographic data structure used in Bitcoin to efficiently summarize and verify all transactions in a block. It organizes transaction data into a tree of hashes, with the "Merkle root" at the top representing all transactions in the block.
How It Works
Transactions are hashed in pairs repeatedly until a single hash remains - the Merkle root. This root is included in the block header, allowing anyone to verify that a specific transaction is included in a block without downloading all transaction data.
Key Benefits
Efficient Verification
Light clients can verify transactions using only the block headers and a small proof path, without needing to download the entire blockchain. This is called Simplified Payment Verification (SPV).
Data Integrity
Any change to a single transaction will completely alter the Merkle root, making tampering immediately detectable. This provides strong cryptographic proof of data integrity.
Merkle trees are a fundamental component of Bitcoin's design, enabling efficient and secure transaction verification without requiring full nodes to share every detail with lightweight clients. This innovation allows Bitcoin to scale while maintaining security.
Quick Facts
- •Binary tree of transaction hashes
- •Merkle root stored in block header
- •Enables SPV wallets to verify transactions