7.3.2. Key Theft

7.3.2. Key Theft

A foundational assumption of signature-based cryptographic systems is that the signing key is not compromised by an attacker. If the keys used to sign the message are exfiltrated or stolen, the attacker will be able to generate their own signatures using those keys. As a consequence, signers have to protect any signing key material from exfiltration, capture, and use by an attacker.

To combat this, signers can rotate keys over time to limit the amount of time that stolen keys are useful. Signers can also use key escrow and storage systems to limit the attack surface against keys. Furthermore, the use of asymmetric signing algorithms exposes key material less than the use of symmetric signing algorithms (Section 7.3.3).