3. The aphorism "security through obscurity" suggests that hiding information provides some level of security. Give an example of a situation in which hiding information does not add appreciably to the security of a system. Then give an example of a situation in which it does. 4. Give an example of a situation in which a compromise of confidentiality leads to a compromise in integrity. 5. Show that the three security services—confidentiality, integrity, and availability—are sufficient to deal with the threats of disclosure, disruption, deception, and usurpation. 6. ,policiescan be implicit (not stated). Why might this be done? Might it occur with informally stated policies? What problems can this cause? 7. For each of the following statements, give an example of a situation in which the statement is true. a. Prevention is more important than detection and recovery. b. Detection is more important than prevention and recovery. c. Recovery is more important than prevention and detection. 8. Is it possible to design and implement a system in which no assumptions about trust are made? Why or why not? 9. Policy restricts the use of electronic mail on a particular system to faculty and staff. Students cannot send or receive electronic mail on that host. Classify the following mechanisms as secure, precise, or broad.