A security control in which a user must present several types of authentication evidence. For instance, a user might enter a password, then receive a mobile phone code, which must also be entered in order to access a website.
Multi-factor authentication is, by nature, much more secure than single-factor authentication (simply entering a passcode). It’s considered a better technology for confirming the identify of authorized users, and many security guidelines require multi-factor authentication.
As the most common multi-factor authentication mechanisms use two factors, this is sometimes called two-factor authentication.