Short Answers. Please answer briefly and completely, and cite all sources of information.

1. What is the principle of adequate protection? Do you agree with the principle? What difficulties are associated with implementing it?

2. What is the difference between a threat and a vulnerability? Define each, and then give at least one example of a threat and of a vulnerability.

3. Describe the fundamental principles in both the Bell-LaPadula and Biba security models. For each, explain what sort of security the model is intended to provide, the two key properties of the model, and then explain in your own words why each of the properties makes sense from a security standpoint.

4. Describe the similarities and differences between a virus, a Trojan horse, and a worm. Give examples of controls that could be implemented to mitigate the threat of each of these types of malicious code.

5. What is the difference between inference and aggregation? Give an example of each, and describe at least one way to mitigate each type of vulnerability.

6. Cite a risk in computing for which it is impossible or infeasible to develop a classical probability of occurrence. Why?