An attacker pays current or former validators to misbehave: sign double blocks, censor transactions, hand over keys, vote on a controversial proposal. Bribery is the economic version of corruption attacks, and works wherever stakeholders have keys with residual value.
Cardano mitigates bribery in two directions. Present-time bribery requires corrupting a stake majority, which under Ouroboros's honest-majority assumption is economically prohibitive. Past-time bribery (buying old keys) is neutralised by key-evolving signatures, which retire old keys so they cannot be sold for malicious replay.
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
- 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
- KESKey Evolving Signatures. Block-signing keys that move forward in time to limit the damage of a key compromise.View term