2FA or two-factor authentication is a specific type of multi-factor authentication. As the name suggests, 2FA requires two distinct forms of user verification factors to access a specific protected, registered user-only software system. In the past, software teams used only a one-factor authentication strategy with users' passwords, but nowadays, with growing security concerns and user authentication evolution, every digital product uses 2FA with password-based authentication, starting from simple SMS OTPs (One Time Tokens) to futuristic AI-powered adaptive 2FA methods and high-security hardware keys.
"By November 10, we're asking all accounts that use a security key as their two-factor authentication (2FA) method to re-enroll their key to continue accessing X. You can re-enroll your existing security key, or enroll a new one. After November 10, if you haven't re-enrolled a security key, your account will be locked until you: re-enroll; choose a different 2FA method; or elect not to use 2FA (but we always recommend you use 2FA to protect your account!)."