Consensus Layer

The consensus layer is the part of a blockchain that decides which blocks are valid and in what order they belong — the agreement machinery that keeps thousands of independent nodes on one shared history. It defines how block producers are selected (proof of work, proof of stake or another mechanism), how votes or attestations are counted, and when a block can be treated as final. On Ethereum the consensus layer runs validators and attestations while the execution layer processes transactions, and the two communicate over a defined interface. This layer is the source of a network's security budget: attacking the chain means overpowering consensus, which is why a broad, decentralised validator set and honest-majority assumptions matter so much.