An attack that exploits the fact that producing old blocks in a proof-of-stake system costs essentially nothing. An adversary collects old signing keys (or buys them), rebuilds a long alternate chain starting far behind the current tip, and presents it to bootstrapping nodes as the "real" history.
Cardano mitigates the attack via Ouroboros Genesis, whose chain-selection rule lets a fresh or rejoining node compare chain density at the point of divergence and pick the honest branch without trusting any external checkpoint.
Explore next
- Proof-of-Stake AttacksThe set of known attack categories against proof-of-stake blockchains and how Cardano's Ouroboros family defends against each.View term
- Proof of StakeA consensus mechanism where validators are selected to create blocks based on the amount of cryptocurrency they hold and stake (commit) to the network.View term
- OuroborosThe family of proof-of-stake consensus protocols that power Cardano, designed with formal security proofs against the known attack catalogue against PoS chains.View term
- Posterior CorruptionAn attack where the adversary buys or steals signing keys from people who held large stake in the past but no longer do.View term
- Grinding AttackAn attack on the randomness used to pick proof-of-stake block leaders, where the adversary tries to bias the lottery in its own favour.View term