Merkle Root

Definition

A Merkle root is the single hash at the top of a Merkle tree, summarizing all data in the tree. In blockchains, the Merkle root of transactions allows efficient verification that a specific transaction is included in a block without downloading all transactions.

Technical Explanation

Construction: hash each transaction, pair hashes and hash again, repeat until one hash remains. Verification: provide sibling hashes along the path (Merkle proof)—O(log n) hashes verify inclusion in n transactions.

Quantum resistance: Merkle trees using SHA-256 or similar maintain security. 256-bit hashes provide 128-bit post-quantum security. Modifying any transaction changes the root—tampering is immediately detectable.

SynX Relevance

SynX blocks contain Merkle roots of all transactions. Light clients verify transaction inclusion using Merkle proofs without full blocks. The hash-based structure resists quantum attacks—no quantum algorithm efficiently finds collisions in properly-sized hash functions.

Frequently Asked Questions

Why not just hash all transactions together?: Merkle trees enable efficient proofs. You can prove one transaction's inclusion without revealing others.
How big is a Merkle proof?: O(log n)—for 1000 transactions, about 10 hashes (320 bytes with SHA-256).
Are Merkle roots quantum-resistant?: Yes—they rely on hash function security, which remains strong against quantum attacks.

Efficient transaction verification. Merkle-based integrity with SynX