Attestation

An attestation is a validator's signed vote about the state of a proof-of-stake chain, typically declaring which block it sees as the head and which checkpoints it considers justified. Validators are assigned to attest on a regular schedule, and the aggregated votes are what give a block its weight under the fork-choice rule and eventually make it final. Most of a validator's income comes from producing timely, correct attestations rather than from the rarer job of proposing blocks, so reliable uptime and an in-sync node matter more than raw hardware power. Missing attestations because a node is offline costs rewards, while signing contradictory attestations is a slashable offence that can destroy part of the stake.