Block Header Chain

The block header chain is the sequence of metadata headers that link all blocks in a blockchain together. Each header contains a hash of the previous header, creating a cryptographic chain that makes it computationally infeasible to alter historical data.

Because headers are small, they are easily transmitted and stored, which is why SPV clients rely on them for verification. The chain of headers also contains information about the network difficulty, timestamp, and Merkle root of transactions.

By following the chain with the most cumulative work, nodes determine the canonical history of the network. This structure is the backbone of blockchain security, ensuring that participants agree on the order and validity of events.

It is the fundamental data structure for achieving decentralized consensus.