What is two-factor authentication (2FA)?

Two-factor authentication (2FA) is defined as a process that requires two different forms of access to an account, enhancing security by adding an additional layer beyond just a username and password. This method typically combines something the user knows, like a password, with something the user possesses, such as a smartphone or a security token.

The significance of 2FA lies in its ability to greatly reduce the likelihood of unauthorized access since even if one form of identification is compromised, the adversary would still require the second form to gain access to the account. This dual-layered security mechanism is widely recognized as a best practice in cybersecurity, particularly for protecting sensitive information and critical systems.

In contrast, other options describe security measures that lack the necessary components of 2FA. For example, using just a single form of identification would not provide the enhanced protection that 2FA offers, while mentioning permanent access or encryption does not pertain to the definition or purpose of two-factor authentication.