Which authentication practice requires two or more verification factors?

Which authentication practice requires two or more verification factors?

• A. Passwordless authentication
• B. Biometric authentication
• C. Multi-factor authentication
• D. Single-factor authentication

Answer: (C)

The strength of an authentication method is determined by how many verification factors it uses. When two or more verification factors are required, the method is multi-factor authentication. Verification factors come in three broad types: something you know (like a password), something you have (such as a hardware token or a phone for a one-time code), and something you are (a biometric like a fingerprint). Multi-factor authentication deliberately combines at least two of these independent factors to prove identity, which makes it much harder for someone to gain unauthorized access if one factor is compromised. For example, entering a password (something you know) and then approving a push notification on your phone (something you have) requires two factors. In contrast, passwordless or biometric methods, taken alone, rely on a single factor, and single-factor authentication uses only one factor at a time.

The strength of an authentication method is determined by how many verification factors it uses. When two or more verification factors are required, the method is multi-factor authentication. Verification factors come in three broad types: something you know (like a password), something you have (such as a hardware token or a phone for a one-time code), and something you are (a biometric like a fingerprint). Multi-factor authentication deliberately combines at least two of these independent factors to prove identity, which makes it much harder for someone to gain unauthorized access if one factor is compromised. For example, entering a password (something you know) and then approving a push notification on your phone (something you have) requires two factors. In contrast, passwordless or biometric methods, taken alone, rely on a single factor, and single-factor authentication uses only one factor at a time.