CompTIA CASP+ Practice Test

Which scenario is the best example of single sign-on?

1. A user enters a password for multiple applications

2. A web access control infrastructure performs authentication and passes attributes in an HTTP header to multiple applications

3. A user authenticates with two-factor authentication for a single app

4. A unique username and password are created for each application

The correct answer is: A web access control infrastructure performs authentication and passes attributes in an HTTP header to multiple applications

Single sign-on (SSO) is a user authentication process that allows a user to access multiple applications with one set of credentials. In the scenario described, when a web access control infrastructure performs authentication and subsequently passes attributes in an HTTP header to multiple applications, it exemplifies how SSO streamlines the user experience. Once authenticated, the user does not need to log in again for each application accessed, as the authentication information is shared. In this context, the use of HTTP headers to communicate authentication details means that the user can seamlessly transition between applications without needing to remember and input different passwords for each one. This enhances security and usability, reducing the chance of password fatigue and related vulnerabilities. Other options do not embody the principles of single sign-on. For instance, entering a password for multiple applications implies that the user must still manage multiple credentials, which contradicts the purpose of SSO. Two-factor authentication for a single app demonstrates an additional layer of security for that specific application but does not allow access to multiple applications without re-authentication. Creating unique usernames and passwords for each application is the opposite of SSO, as it leads to multiple logins rather than a consolidated session. Thus, choice B accurately represents the concept of single sign-on.