Glossary · Security and access
Two-factor authentication
Authentication that requires evidence from more than one independent factor category.
Also called: 2FA, multifactor authentication, MFA
Definition
Two-factor authentication combines factors such as something known, something possessed, or something inherent. A security key or authenticator app can add protection beyond a password alone.
Why it matters
Important ownership accounts are harder to take over when a stolen password is not sufficient by itself.
Common misunderstanding
Two passwords are still one factor category, and not all second-factor methods resist phishing equally well.
Related terms
Related system family: Secure Integrations & Custom Tools
Sources
- Authentication (opens in a new tab) · NIST Computer Security Resource Center
Last reviewed July 16, 2026