This video begins the discussion of the various access control models. We don't dig too deeply into these models in this section. That will be done in Part 04, however, we emphasize the importance and need for these controls. The concept of subject (user)/object (resource) is introduced. The basis of authorization is controlling what actions a subject is authorized to perform on an object with the appropriate rights. We point out that the principle of least privilege goes hand-in-hand with these concepts. The actions a subject can perform on an object are defined by the so-called CRUD operations: - Create - Read - Update - Destroy We next touch on the access control models: - DAC - discretionary access control - MAC - mandatory access control - RBAC - role-based access control - RuBAC - rules-based access control (firewalls or filtering using logic rules) We conclude this section by mentioning the important principle of accountability. This is concerned with tracing (associating) an action to a subject (identity) and falls under the auditing process. It's important to note that a multi-user environment were all users work on a shared account is not only ill-advisable on so many levels, but also prevents any kind of auditing and accountability. A key part of auditing is logging. Metrics and techniques typically maintained or used in audit logging are time stamps, source ID, and hashing to ensure the integrity of the logs. Policies such as how long to retain logs as well as the threshold for overwriting logs are also important considerations.