1, users and groups
2, file access/management authority disaggregation (Anything is file)
3, person have component right of a file
4, so many users and so many files make up the security system of
The key word is own, that means, somebody have own some authority of
Anther key word is disaggregation, a person only have one or some meta
authority of something.
It's completely the same as authority of the real world: somebody own
something or just a part of something.
On the other hand, Windows have a so complex security system which i can't
understand, but now I know the AD and other authority policy is just some
wrapper of the File Auhority system, the philosophy of windows is the far away
from K.I.S.S. , the better.
Be note that, the most important thing for an security system is the security sturcture and policy, the are include computer, principle, law,etc. Which OS you chose is not important, no matter you use windows or Linux, or anything else. If an OS have a back door, it's just a hole in your boat, you can stopple it by some material, but if you don't know how boating and how to make it safe, that's the real bad thing.
So, when somebody agument for which system is more safty, just ignore that.
Unix is OK, windows is OK, Mac OS is OK too, what you need to do is be more familar with it, they are just tools for computing usage.