Which term describes the factor of security that is based on information that only the user knows?

The term that describes the factor of security based on information that only the user knows is called the knowledge factor. This concept is central to understanding authentication methods that rely on something the user has learned or memorized, such as passwords, PINs, or answers to security questions. The effectiveness of the knowledge factor lies in its exclusivity; it's presumed that only the authorized user has access to this specific information, thus enabling secure authentication.

In security frameworks, leveraging knowledge factors is integral for ensuring that users can be positively identified before granting access to sensitive information or resources. Although other factors, such as possession (something the user has) and inherence (something the user is, like biometric data), are also relevant in the broader scope of security authentication, they do not encapsulate the essence of knowledge-based security, which focuses specifically on identifiable information known only to the individual user.