Blocks and blockchain

Blocks are the main building structure of a blockchain. Ethereum blocks consist of various elements, which are described as follows:

• The list of headers of ommers or uncles
• The block header
• The transactions list

An uncle block is a block that is the child of a parent but does not have a child block. Ommers or uncles are valid but stale blocks that are not part of the main chain but contribute to the security of the chain. They also earn a reward for their participation but do not become part of the canonical truth.

Block header: Block headers are the most critical and detailed components of an Ethereum block. The header contains various elements, which are described in detail here:

• Parent hash: This is the Keccak 256-bit hash of the parent (previous) block’s header.
• Ommers hash: This is the Keccak 256-bit hash of the list of ommers (or uncle) blocks included in the block.
• The beneficiary: The beneficiary...