Proof of Work vs Proof of Stake
The two dominant consensus mechanisms have fundamental differences that affect security, scalability, and sustainability.
Proof of Work
How It Works
Miners use computational power to solve puzzlesThe first miner to solve adds the next blockDifficulty adjusts to maintain block timeAdvantages
Battle-tested security (Bitcoin since 2009)Truly permissionless participationHigh cost of attackDisadvantages
Enormous energy consumptionExpensive hardware requirementsCentralization through mining poolsProof of Stake
How It Works
Validators lock tokens as stakeRandom selection weighted by stake amountRewards proportional to stakeAdvantages
99.9% less energy than PoWLower barrier to entryReduced hardware needsDisadvantages
"Rich get richer" concernsComplex implementationLess battle-testedThe Ethereum Merge
In September 2022, Ethereum switched from PoW to PoS:
Reduced energy consumption by ~99.95%Changed mining to stakingRequired 32 ETH minimum to run a validator