Why is multi-factor authentication more secure than single-factor authentication?

• A. It uses only passwords
• B. It is more expensive to implement
• C. It requires two or more independent factors
• D. It eliminates all risk of compromise

Answer: (C)

Requiring two or more independent credentials from different categories to verify identity makes multi-factor authentication more secure than relying on a single factor. When only a password is used, a stolen or guessed password can unlock the account. Adding a second factor—such as a code from a hardware token or authenticator app, a push approval, or a biometric check—means an attacker would need access to multiple, independent proofs, which is much harder to achieve. Because the factors are independent, compromising one credential doesn’t automatically grant access. This layered approach reduces the likelihood of unauthorized entry, even if one factor is compromised. It doesn’t guarantee perfect security, and some second-factor methods have vulnerabilities, but the core benefit is the requirement for multiple factors. The other statements don’t explain why MFA is more secure: one-factor use, potential cost, or the claim that all risk is eliminated are not accurate explanations.