Foundations of Blockchain

Linking blocks

As we know, blocks are linked in a blockchain using references, just like in a linked list, but here the blocks are linked by referencing the hash value (identifier) of the previous block. Each full node in a blockchain network will maintain a complete blockchain and append a new block whenever it has one to append. Due to the decentralized nature of the blockchain, each node will verify the block before linking it to the local blockchain record.

The computed hash value of each block is the combination of the hash of the previous block and its own block data. This results in a dependency between neighboring blocks and nearly unbreakable links:

Figure 1.5: Linking blocks using hashes, from Bitcoin: A Peer-to-Peer Electronic ...