Consensus is the process through which distributed participants in a blockchain network reach agreement about valid state and the accepted sequence of blocks.

Without a consensus process, independent nodes could maintain permanently different versions of the blockchain history. Consensus rules determine which blocks are valid, how competing branches are resolved, and how new state changes are accepted.

Consensus and protocol rules

The consensus process is part of a broader protocol design. In Proof-of-Work systems, participants use computational work as part of the security model. In Proof-of-Stake systems, block production and validation are connected to staking and economic incentives.

Consensus does not necessarily mean that every node literally votes on every block. The exact process is determined by the network consensus mechanism.