Décentralisation et consensus

In Web3, decentralization means no single person or company controls the network — like swapping one boss for a whole team deciding together.

Most apps today are centralized — a company runs the servers and your data. Decentralized networks have no single point of control, staying resilient and transparent.

Decentralization pays off in resilience (no single point of failure), censorship resistance, and transparency, with rules open for anyone to inspect.

Without a central authority, how do nodes agree on one truth? That's the job of a consensus mechanism — the rules that let a distributed network agree.

A consensus mechanism is the protocol that gets all participants to agree on the current state — which transactions are valid and which block comes next.

Proof of Work (PoW) is the original, used by Bitcoin: miners solve hard puzzles, and that spent computation proves they invested real resources.

In mining, miners race to crack a cryptographic puzzle; the winner adds the next block. It's energy-hungry but makes the network very hard to attack.

Proof of Stake (PoS) is the energy-efficient successor — Ethereum switched to it. Instead of mining, you stake crypto as collateral to validate blocks.

In PoS, validators are chosen by how much they've staked and for how long. Propose a bad block and you lose your stake — so honesty pays.

PoW vs PoS: PoW burns lots of energy and leans on computing power; PoS uses far less, leans on economic stake, and generally scales better.

Consensus mechanisms are crucial for decentralized networks.

Which of the following is a key advantage of Proof of Stake (PoS) compared to Proof of Work (PoW)?

Recap: you covered decentralization and its benefits, plus how Proof of Work and Proof of Stake reach agreement across a distributed network.