Proof of Stake Explained

Proof of stake is the main alternative to mining. Instead of competing with electricity, participants called validators lock up some of the network’s own coins as collateral. The network picks validators to propose and confirm blocks, pays them for doing it honestly, and destroys part of their collateral if they cheat.

Ethereum, the second-largest blockchain, switched from mining to proof of stake in September 2022, an upgrade known as the Merge. Ethereum’s own estimates put the reduction in its energy use at more than 99.9 percent.

How it works, step by step

1. Stake. To run a validator on Ethereum you deposit 32 ether into the network’s staking contract. That deposit is your “stake”.
2. Get selected. For each slot (every 12 seconds) the protocol pseudo-randomly picks one validator to propose a block. Groups of other validators are assigned to check it and vote (“attest”) that it is valid.
3. Earn. Validators that do their job earn rewards, paid in newly issued ether plus a share of transaction fees.
4. Get punished for misbehaving. A validator that is offline loses small amounts. One that provably cheats, for example by signing two conflicting blocks, is slashed: part of its stake is destroyed and it is forced out.

The security logic mirrors mining. To attack proof of work you need to outspend the network on electricity. To attack proof of stake you need to control a large share of all staked coins, and the protocol is designed so that an attack would destroy much of that stake.

Staking as a regular user

Most people don’t run their own validator. Instead they:

• Stake through an exchange, which runs validators and passes on part of the reward. Simple, but you are trusting the exchange with your coins.
• Use a staking pool or liquid staking service, which combines deposits from many people and often gives you a token representing your share. This adds smart-contract risk on top of everything else.

Advertised staking yields are paid in the same coin you staked. If the coin’s price falls 40 percent, a 4 percent staking reward does not help much. Staking rewards are also generally treated as taxable income.

Proof of stake versus proof of work

	Proof of work	Proof of stake
Security comes from	Electricity and hardware	Coins locked as collateral
Who adds blocks	Miners	Validators
Energy use	Very high	Low
Cheaters lose	Wasted electricity	Their stake (slashing)
Main criticism	Environmental cost	Rewards flow to those who already hold the most coins

Neither design is free of trade-offs. Proof of stake uses far less energy, but critics point out that the richest holders earn the most rewards and that large staking providers concentrate influence. Proof of work’s defenders argue that tying security to physical energy is more robust. This is a live debate, not a settled question.

The short version

Proof of stake replaces “spend electricity to earn the right to add a block” with “put up collateral you will lose if you lie”. It is cheaper to run and now secures most of the activity on Ethereum, with its own risks around concentration and complexity.

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