Multi-factor authentication (MFA) is a technique for ensuring confidentiality of information by requiring a user to prove their identity with at least two of the following factors: - what you know (e.g., pin code) - what you have (e.g., credit card) - what you are (e.g., fingerprint) Simply asking for two things you know (e.g., pin and security question answer) is not MFA. A common form of MFA is two-factor identification (2FA).