I've seen https://en.wikipedia.org/wiki/AAA_(computer_security) https://en.wikipedia.org/wiki/AAA_(computer_security) because authentication, authorization, and

I've seen https://en.wikipedia.org/wiki/AAA_(computer_security) https://en.wikipedia.org/wiki/AAA_(computer_security) because authentication, authorization, and accounting (audit trails) need to go together so often. You need to know who they really are and whether they're abusing the system.