Three different protection mechanisms that we have discussed are capabilities, access control lists, and the UNIX rwx bits. For each of the following protection problems, tell which of these mechanisms can be used.

(a) Ken wants his files readable by everyone except his office mate.

(b) Mitch and Steve want to share some secret files.

(c) Linda wants some of her files to be public.

For UNIX, assume that groups are categories such as faculty, students, secretaries, etc.