What layer of security does two-factor authentication represent?

Two-factor authentication (2FA) represents a secondary layer of defense added to the primary layer of security. This approach strengthens security by requiring two distinct forms of verification before granting access to an account or system. Typically, this involves something the user knows (like a password) combined with something the user has (like a mobile device to receive a code) or something the user is (biometric verification).

By leveraging multiple factors, it significantly enhances the security posture, making it more difficult for unauthorized users to gain access. This layered approach is essential in modern security practices because it mitigates risks associated with compromised passwords or other vulnerabilities, thereby offering an additional layer of protection beyond what is provided by a single security measure.