1. What are the three types of user authentication? Name three examples of each type of authentication.

2. List and define five desirable qualities in a process designed to evaluate the trustworthiness of an operating system.

3. It's been said that firewalls are dead. Some think that, because of the prevalence of application-layer attacks, packet filtering firewalls are of no real use in protecting networks. Name three advantages of using packet filtering firewalls in modern networks.

4. (TCO C) Respond to each part of this question:
a) Describe how a long number (encryption key) can be shared between sender and receiver without using any source that is obvious to outsiders and without directly sending the number from sender and receiver.

b) Describe how a long number (encryption key) can be shared between sender and receiver over an unsecured network without loss of confidentiality.