Block Headers
Also known as: Block Metadata, Header Hash, Block Summary
Metadata at the start of a blockchain block containing crucial information like hashes, timestamps, and Merkle roots.
A block header is a compact piece of metadata at the beginning of each blockchain block. It includes essential fields such as the previous block hash, timestamp, Merkle root, difficulty target, and nonce. These components allow nodes to link blocks securely, validate proof of work, and verify the integrity of transactions. Block headers are especially important in lightweight clients (SPV) and for generating succinct cryptographic proofs. They also form the foundation for mining and consensus by providing the inputs for hash-based calculations.