Multisig, short for multi-signature, is a wallet or approval scheme that requires more than one private key or authorized signer before a transaction can be executed. Instead of one person or device being able to move funds alone, the system enforces a threshold such as 2-of-3 or 3-of-5 approvals.
In cyber security, multisig matters because it reduces the damage from stolen credentials, malware, or a compromised admin account. Attackers often try to steal a single signer’s key, phish approvals, or manipulate a user interface so a legitimate signer authorizes the wrong transaction. Defenders use multisig for treasury control, exchange custody, and incident response, because it adds friction and creates a second check before assets can move. However, multisig is only as strong as its signers, policies, and signing workflow.