Unix® System Management Primer Plus

Authentication, Authorization, and Accounting

Before diving into the details of security, you first must understand the concept of authentication, authorization, and accounting—often referred to as AAA. The AAA concept is the basis for all Unix system access mechanisms, and access control plays a major part in system security. You will see the components of AAA reflected in many of the security tools and methodologies discussed throughout this chapter.

Authentication is the process of identifying yourself to a system. Most systems require an authenticator, which is usually a combination of an identifier and a secret code or component, the latter of which is known only to the owner of the account. The identifier and secret element usually take ...