Posterior Corruption

Definition ∞ Posterior corruption describes a theoretical attack scenario in Proof-of-Stake blockchains where an attacker, having gained control of a significant portion of the stake, attempts to rewrite the chain’s history from a recent point in time. This differs from a long-range attack by targeting a more recent history. The attacker would try to create an alternative chain that becomes longer than the current main chain, effectively reverting recent transactions. This attack requires a substantial, active stake at the time of the attack.
Context ∞ Posterior corruption is a critical security consideration for Proof-of-Stake protocols, frequently analyzed in academic literature and protocol audits. News reports might reference this type of attack when discussing the economic security and finality guarantees of various PoS chains. The mechanisms to counter posterior corruption often involve robust slashing conditions and the rapid detection of conflicting block proposals, ensuring that honest validators can quickly penalize malicious behavior.