Foundations of Blockchain

Block header

The block header, as stated before, consists of the metadata of the block. This holds the information that's needed to link the blocks in the blockchain:

Figure 1.4: Structure of a block header

Each block header will have the components outlined in Figure 1.4. These are the minimum fields required in a permissionless blockchain, such as Bitcoin, to efficiently create a block that can be appended to an immutable blockchain. The Previous Block Hash field is a reference to the last block created. The Merkle Root is the value of the Merkle hash tree; it summarizes all the transactions in the block. Timestamp, Difficulty Target, and ...