Proof of Stake (PoS)
Consensus secured by validators' locked capital: honest work earns yield, cheating gets your stake destroyed.
Proof of Stake selects validators to propose and attest blocks in proportion to coins they lock as collateral. Honesty earns staking rewards; provable misbehavior triggers slashing — the network burns part of the offender’s stake. Security rests on capital-at-risk instead of energy spent. Ethereum’s 2022 Merge — cutting its energy use ~99.95% — made PoS the dominant design outside Bitcoin.
Trade-offs debated ever since: PoS enables cheap participation and fee-burning economics, but critics point to rich-get-richer compounding, and liquid-staking concentration creating de facto gatekeepers. The Bitcoin–Ethereum split is thus philosophical: physics-anchored security versus capital-anchored efficiency.