A model of adversary that does not commit in advance to which validators it will corrupt. Instead it watches the network, sees which validator has been elected for the next slot, and targets that specific validator for compromise or denial-of-service moments before its turn.
Ouroboros Praos blocks this by keeping each slot's leader hidden until the block is published. Validators learn privately, via a verifiable random function, whether they have won the current slot, and the adversary discovers it only after the block has been broadcast. By then the leader has already done its job.
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
- VRFA cryptographic function that produces a verifiably random output; Cardano uses it inside Ouroboros as a private per-slot lottery, letting each pool check whether it won the right to produce a block, fairly and unpredictably.View term