What is Nakamoto consensus?
- Author
- CRYPTO PORT Editorial
- Published
- Updated
- Reading time
- 6 min
In short
Nakamoto consensus reaches agreement on an open, permissionless network by substituting proof of computation for voting. Needing no roster of participants is what set it apart from earlier consensus work. Finality is not explicit here: a block simply becomes progressively harder to reverse over time.
Key points
- Reaches agreement without a roster of participants
- Weights proof of computation instead of votes
- Finality is probabilistic and strengthens over time
- Reward design makes honest behaviour the rational choice
Definition
The method that combines proof of work, the longest-chain rule and reward design to achieve agreement among participants who are not identified in advance. It originated with Bitcoin.
Classical Byzantine fault tolerance assumes every participant knows who the others are. On a network anyone can join, one person can claim many identities, so voting by head count collapses.
Nakamoto consensus sidesteps this by tying voting weight to computation rather than identity. Creating extra identities does not create extra hash power, so faking a majority costs real resources — and no one needs to maintain a participant list.
Which chain is correct follows from choosing the branch with the greatest cumulative work. Agreement emerges not from a prior vote but from the accumulated choices of which branch to extend. Consequently no block is ever absolutely final; each additional block raises the cost of reversing it.
The second pillar is economic design. As long as mining honestly for rewards pays better than spending the resources to attack, the majority stays honest. The case where that stops holding is discussed as the 51% attack.
Watch out for
- · Because finality is probabilistic, settling a large receipt after few confirmations is risky
- · If most hash power concentrates in a few operators, the decentralisation premise weakens
- · The long-run shift from block subsidy to fee income remains an unresolved question