What is two-factor authentication?

Two-factor authentication (2FA) is a security method that requires two different factors for verification to access an account or system. This approach enhances security by combining two distinct components: something the user knows (like a password) and something the user has (such as a smartphone app that generates a time-sensitive code or a hardware token). By requiring two different types of verification, even if one factor (like the password) is compromised, the second factor helps to prevent unauthorized access.

This method significantly reduces the risk of unauthorized access, as it adds an additional layer of security beyond a simple username and password combination. In contrast to the first option, which incorrectly suggests that two passwords constitute two-factor authentication, the correct definition emphasizes the need for different methods of verification. The other choices, while related to technology and security, do not accurately define two-factor authentication, focusing instead on recovery software and employee monitoring, which do not pertain to the dual-method verification process.