What defines multifactor authentication?

Multifactor authentication (MFA) is defined by the requirement of two or more types of authenticators to verify a user's identity. This approach enhances security by combining different categories of authentication factors, which typically include something you know (like a password), something you have (like a smartphone or security token), and something you are (like biometric data such as fingerprints or facial recognition).

The use of multiple factors means that even if one factor is compromised (for example, if a password is stolen), an unauthorized user would still be unable to gain access without the other required factors. This layered approach significantly increases the overall security of the authentication process, making it much harder for attackers to successfully breach an account.

In contrast, using only passwords constitutes single-factor authentication, which relies solely on something the user knows. Relying solely on biometric verification is also not multifactor authentication, as it represents just one type of factor. Similarly, single-factor verification methods do not provide the enhanced security that multifactor authentication offers. Thus, the correct definition of multifactor authentication revolves around the use of two or more authentication methods to bolster security.