What is AAL (Authenticator Assurance Level)?

Authenticator Assurance Level (AAL) is a standard from NIST SP 800-63-3. It shows how strong an authentication method is when checking a user’s identity. Organizations use AAL to decide what level of login security they need for different systems. Higher AAL levels mean stronger security. This can include multi-factor authentication (MFA) or cryptographic devices. They are often required for high-risk areas like finance, healthcare, or government.