Multi-factor authentication (MFA) is a security process that requires users to provide two or more independent forms of verification to prove their identity before gaining access to an account, application, or system. This approach significantly increases security by adding extra layers of defense beyond just a username and password, making it much harder for unauthorized users to access sensitive information—even if they have obtained your password.

The most common categories of authentication factors are:

  1. Something you know: Such as a password, PIN, or answer to a security question.
  2. Something you have: Such as a smartphone app that generates one-time codes, a hardware security key, or a smart card.
  3. Something you are: Biometric identifiers like fingerprints, facial recognition, or retinal scans.

To successfully log in with MFA enabled, a user must present at least two of these different types of evidence. For example, after entering a password (something you know), you might also need to enter a code sent to your phone (something you have) or use your fingerprint (something you are).

Synonyms:
multi factor authentication, MFA