Proof of Stake

Proof of Work is secure but energy-hungry. Proof of Stake (PoS) seeks the same security guarantees while using a tiny fraction of the energy.

Ethereum switched from PoW to PoS in 2022 in an event called The Merge.

In Proof of Stake, the right to create a block is tied to how much cryptocurrency a participant locks up, or stakes, rather than how much computation they do.

Block creators are called validators, not miners.

A validator deposits a stake to participate in producing and attesting to blocks. On Ethereum, the required stake is 32 ETH per validator.

Validators propose blocks and vote (attest) that other blocks are valid.

Staking means locking up funds as collateral. This stake is the security deposit that keeps validators honest.

If you behave correctly you earn rewards; if you cheat, your stake is at risk.

The protocol pseudo-randomly selects one validator to propose the next block, often weighted by stake size.

Because selection is random and based on stake rather than hashing, there is no energy-intensive race.

Other validators issue attestations — signed votes confirming a proposed block is valid and is the head of the chain.

When enough attestations accumulate, the block becomes part of the canonical chain.

Validators earn rewards for proposing blocks and attesting on time. Rewards are paid in the network's native token.

This steady yield incentivizes honest, reliable participation.

Slashing is the penalty for malicious behavior, such as proposing two conflicting blocks. The protocol destroys part of the offender's stake.

Slashing makes attacks financially painful — you literally lose money for cheating.

PoS replaces PoW's energy cost with economic cost. To attack the chain, you must acquire a huge stake — and a successful attack would crash the very token you staked.

This makes attacking self-defeating.

Because validators do not race to solve puzzles, PoS uses dramatically less energy than PoW — Ethereum's consumption dropped over 99% after The Merge.

This efficiency is PoS's headline advantage.

Proof of Stake secures the chain with capital at risk instead of energy. Validators stake funds, propose and attest to blocks, earn rewards, and risk slashing for misbehavior.

Test your Proof of Stake knowledge.

You learned that:

• PoS ties block creation to staked capital, not computation
• Validators propose and attest to blocks
• Staking provides collateral; rewards pay honest behavior
• Slashing punishes misbehavior
• PoS is far more energy efficient than PoW

Next: other consensus mechanisms.