This exercise asks you to consider the consequences of not applying the principle of attenuation of privilege to a computer system.
a. What are the consequences of not applying the principle at all? In particular, what is the maximal set of rights that subjects within the system can acquire (possibly with the cooperation of other subjects)?
b. Suppose attenuation of privilege applied only to access rights such as read and write, but not to rights such as own and grant_rights. Would this ameliorate the situation discussed in part (a)? Why or why not?
c. Consider a restricted form of attenuation, which works as follows. A subject q is attenuated by the maximal set of rights that q, or any of its ancestors, has. So, for example, if any ancestor of q has r permission over a file f, q can also r f. How does this affect the spread of rights throughout the access control matrix of the system? Develop an example matrix that includes the ancestor right, and illustrate your answer.