Which type of authentication uses only one of the available factors to verify identity?

The correct answer is Single-Factor Authentication. This type of authentication relies solely on one identification method to verify a user's identity. It often involves the use of something the user knows, such as a password or a personal identification number (PIN). The simplicity of Single-Factor Authentication can be advantageous for user convenience because it requires only one piece of information for access. However, it also presents security vulnerabilities, as it lacks the added protection provided by additional factors that are characteristic of more robust authentication methods.

In contrast, Multi-Factor Authentication combines two or more factors from different categories, enhancing security by requiring multiple forms of verification. Single-Sign-On Authentication allows users to log in just once to access multiple applications, but it does not strictly relate to the number of factors used. Two-Factor Authentication, as the name suggests, specifically employs two distinct factors, further bolstering security but still is not representative of the simplicity of Single-Factor Authentication. Thus, Single-Factor Authentication is accurately described as using only one method to verify identity.