In a scenario where an organization requires multiple forms of login (username, PIN, password, and retina scan), how many distinct types of factors are being used?

In this scenario, the organization is utilizing multiple forms of login credentials that fall into specific categories of authentication factors. Authentication factors are classified into three distinct categories:

1. Something you know (knowledge factors) - This includes passwords, PINs, and answers to security questions. They require the user to have knowledge of a specific piece of information.

2. Something you have (possession factors) - This includes tokens, smart cards, or mobile devices that produce a one-time password. It necessitates physical possession of an item to authenticate.

3. Something you are (biometric factors) - This encompasses physical traits like fingerprints, retina scans, or facial recognition. These traits are intrinsic to the user and cannot be transferred.

In the given scenario, the organization mentions four forms of login: a username, a PIN, a password, and a retina scan.

The username is simply an identifier and does not count as an authentication factor. The PIN and password fall under the category of knowledge factors. The retina scan is a biometric factor, classified as something you are.

Consequently, the organization is employing two distinct types of factors: knowledge factors (PIN and password) and biometric factors (retina scan).