Dictionary · Cybersecurity Fundamentals

A login check that requires evidence from at least two different categories, such as a secret you know and a device you have.

A password plus another password is still one kind of evidence. A password plus a phone prompt, security key, or approved biometric is two kinds. It raises the cost of a stolen password.

Example: After the correct password, the account still requires a prompt on a registered phone. That second step is MFA.