Block header

The block header of a block in Bitcoin comprises of metadata about the block. Consider the following:

  • Bitcoin version: This field contains the Bitcoin version number.
  • Previous block hash: The previous block's hash is required to create the new block's hash.
  • Merkle root: This is the hash of the root of the Merkle tree of the current block's transactions.
  • Timestamp: This is the timestamp of the block in UNIX.
  • Mining difficulty: Mining is a crucial part of the blockchain ecosystem in Bitcoin. There is a difficulty target for mining, which is mentioned in the header.
  • Nonce: Blockchain adds deviations in each block; these are known as nonce. Take a look at this diagram:
The formation of block headers and what comprises the Merkle root and the Merkle tree