Double Signing

Double signing is a malicious or erroneous act where a validator signs two different blocks at the same block height, potentially leading to a blockchain fork. This is considered a severe violation of consensus rules because it attempts to create conflicting versions of history.

Most modern protocols detect double signing automatically and immediately slash the offender's stake. This serves as a critical defense against attacks that aim to reorganize the chain or perform double-spending.

It ensures that there is only one source of truth in the distributed ledger. Validators must implement robust key management to prevent accidental double signing, as the consequences are usually irreversible.

This represents a key intersection of cryptography and game theory in blockchain security.