⚖️ Two Ways to Secure a Network

Agreeing without a referee

Every blockchain needs a way to agree on what's true, without a referee.

Two approaches dominate — and they work in fundamentally different ways.

Proof of Work (PoW)

Miners compete using real-world computing power and electricity to earn the right to add the next block.

This is the model Bitcoin uses — the one you met in Pillar 3.

Proof of Stake (PoS)

Instead of competing with hardware and energy, "validators" lock up ("stake") a portion of the network's own coins as collateral.

The protocol selects who proposes blocks partly based on stake size, and validators can lose — "get slashed" — their staked coins for misbehaving.

The threat isn't wasted electricity. It's losing the collateral you put down.

The structural difference

PoW security is anchored in something external and physical — real energy, real hardware.

PoS security is anchored in something internal to the network — the coin's own value, staked back into the system.

That's the split everything else in this course turns on. Hold onto it.

Try it: Match the mechanism

Four features, two buckets. Sort them and watch the split appear.

Electricity and hardware on one side, locked-up coins on the other. Fill both buckets and the structural split shows up on its own: one model spends something the network cannot create, the other spends something it can. Open the Match the Mechanism tool →

Quick check: What resource secures a Proof of Work network?

1. Real-world computing power and electricity ✓
2. Coins locked up by validators
3. A reputation score assigned by the protocol

Something the network itself cannot create — it has to be bought from the physical world.

Quick check: What do Proof of Stake validators risk losing if they misbehave?

1. Their hardware
2. Their staked coins ("slashing") ✓
3. Nothing — misbehaviour is simply ignored

The collateral is the deterrent. Break the rules and the protocol destroys part of what you put up.

Next up

So which one actually holds up better under pressure?

Bitcoiners have a strong opinion — here's the case.