Part II — Consensus
How trustless nodes agree on block ordering while resisting cheaters. The heart of every blockchain — and the innovation Bitcoin brought.
| # | Section | What it covers |
|---|---|---|
| 1 | The problem and Proof of Work | Sybil + Byzantine faults, PoW (mining, difficulty, heaviest chain), strengths and the energy cost. |
| 2 | Proof of Stake and BFT | PoS (stake, slashing, the Merge), BFT consensus with instant finality, PoW vs PoS. |
| 3 | Finality and attacks | Probabilistic vs deterministic finality, fork-choice, attacks (51%, nothing-at-stake, long-range), MEV. |
Previous part: I — Fundamentals. Next: III — L1 and L2 — Bitcoin, Ethereum, and the rollups.
For dense reference, see Part VIII — Reference.