Exercise 3: Permissions Matrices vs. ACLs Compare the size of data needed for a permission matrix versus an access control list.

Consider being able to cover 100 subjects, 10000 objects, 5 different actions, and 25 groups.

a) Describe the data structure representation for the specific permission matrix. (be specific about the representation for the subsets of permitted actions).

b) Determine the number of bits required for the representation of this data structure for the number of subjects, objects, and actions needed.

c) Describe the data structure representation for the specific access control lists. (be specific about the representation for the subsets of permitted actions, and be specific about the representation of group memberships, and association of objects to owners and to groups).

d) Determine the number of bits required for the representation of this data structure for the number of subjects, objects, actions, and groups needed.

e) Compare the number of bits needed for a permission matrix versus an access control list.

f) Determine the number of subjects, objects, actions, and groups where the permission matrix needs fewer bits (if possible).

g) Determine the number of subjects, objects, actions, and groups where the access control list needs fewer bits (if possible).