Which security approach requires both a username and a password?

The correct answer focuses on single-factor authentication, which necessitates only one form of verification for access—typically a username and password combination. In this scenario, when a user inputs their username and matching password, they are granted access, which is a straightforward and commonly used method for securing systems. This traditional approach relies solely on something the user knows, which is the password, paired with the username to identify the account.

Multi-factor authentication, on the other hand, requires two or more verification factors, which can include something the user knows (like a password), something the user has (like a smartphone for receiving a code), or something the user is (biometric data). Two-step verification is similar; it adds an extra layer of security by requiring a second factor after the initial password. Password-less security eliminates passwords entirely, using other methods like biometric authentication or one-time codes sent to devices.

Therefore, the essence of single-factor authentication lies in its simplicity, relying on just a username and password combination without additional factors or layers of security required.