What Is the Purpose of a “Block Header” in a Blockchain?

The block header is a small section of data that summarizes the contents of the entire block and is essential for the Proof-of-Work mechanism. It contains key metadata, including the hash of the previous block, the Merkle Root of all transactions, the timestamp, the difficulty target, and the nonce.

The header is the only part of the block that is hashed repeatedly by miners to find a valid solution, securing the chain and validating the transactions.

Does the Timestamp Affect the Hash of the Merkle Root?
What Is a “Nonce” in the Context of Proof-of-Work Mining?
Why Is the Nonce Typically Incremented Sequentially by Miners?
What Is the Role of the Merkle Root in a Block Header?
What Is the Purpose of the ‘Nonce’ Field in a Cryptocurrency Block Header?
What Is a Nonce in the Context of PoW?
What Is the Significance of the “Nonce” in the Process of Finding a Valid Block Solution?
If the Nonce Space Is Exhausted, What Is the Miner’s Next Step?

Glossar