Using two or more forms of identification to authenticate a user. The common single-factor authentication employs one password. For more security, multi-factor authentication (MFA) adds at least one more form such as a text message with a one-time number, a physical token or some form of biometrics.
Multi-Factor Fatigue
MFA is widely used, and it no doubt prevents a lot of fraud. However, people are getting tired of having to have their phone by their computer for a second-factor text message or to go to email and locate their verification key. Hopefully, passwordless authentication will be the norm in the future (see
FIDO). See
two-factor authentication,
authentication token and
biometrics.