Understand consensus with plain language and practical tradeoffs.
Core idea
Consensus is how a network agrees on one shared history. Different designs trade energy, hardware, and security assumptions.
Proof of Work
Miners compete to solve a computational puzzle. The winner proposes the next block and earns rewards. Attacking the chain requires large ongoing cost in hardware and electricity.
Proof of Stake
Validators lock capital as stake. The network selects validators to propose and attest to blocks. If validators break rules, their stake can be reduced. Attacks require large capital and face penalties.
Tradeoffs
- Energy. PoW uses more energy. PoS uses less.
- Participation. PoW needs mining gear. PoS needs capital and uptime.
- Attack cost. PoW attacks burn resources. PoS attacks risk losing stake.
How to use this
Ask who can participate in consensus. Wider participation usually means better decentralization.
Warning
No consensus is perfect. Security depends on incentives and real-world economics.
Quick quiz
- In PoW, what resource is spent?
- In PoS, what is at risk?
- Name one tradeoff between them.