Block header

Block header is a crucial component of a blockchain block. It contains metadata necessary for verifying block integrity and linking blocks. Key elements include the block version, timestamp, previous block hash, Merkle root, difficulty target, and nonce. The block header ensures the block's validity and continuity in the blockchain. It allows nodes to efficiently verify transactions and maintain a secure, tamper-resistant ledger. By changing even a small part of a block, the entire header hash changes, ensuring the blockchain's immutability and security.