2FA
From CryptoWiki
Two Factor Authentication, also known as 2FA, two step verification or TFA (as an acronym), is an extra layer of security that is known as "multi factor authentication" that requires not only a password and username but also something that only, and only, that user has on them, i.e. a piece of information only they should know or have immediately to hand - such as a physical token.
https://www.securenvoy.com/two-factor-authentication/what-is-2fa.shtm
