MFA uses three common authentication methods to verify a user’s identity.
Knowledge: This is the factor users are most familiar with. The user is prompted to supply information they know, such as a password, personal identification number (PIN), security key, or the answer to a security question.
Possession: This factor verifies the user’s identity using something they possess. For example, by sending a code to a mobile phone.
Inherence: This factor verifies the person by some unique personal attribute, such as biometric authentication or voice recognition.