5. Access Control, 20 points) Answer the following questions. a. Consider a computer system with three users: A. B. and C. A owns the file File A. C can read and write the file Files, which owns, but A can only write it. Only C can read and write the file Filec. which she owns. Assume that the owner of each of these files can execute it. Create the corresponding access control matrix. [5 points) b. Discretionary access control (DAC) restricts access based on resource owner's discretion. What is the inherent weakness of DAC? Discuss it with an example. [4 points] Discuss how mandatory access control (MAC) can address the issue. (4 points) c. Mandatory access control (MAC) is based on security levels, category, and labels. Fill out the following blanks. [7 points) | - | 1 = 1 1 x PCI 1) {confidential, secret) : {army, navy} PL 1) = {0, army}, {navy}, {army, navy}} 1 = {(confidential, {army}), (secret, {army}), .... (secret, )} 3