Mis 589

HOMEWORK WEEK # 5

CHAPT# 6

 R17. What is the difference between a permanent address and a care-of address? Who assigns a care-of address? A permanent address is the address the address that is assigned before the node leaves its network. A COA is assigned @ a foreign network (ie: Border router)

CHAPT#8

 R1. What are the differences between message confidentiality and message integrity? Can you have confidentiality without integrity? Can you have integrity without confidentiality? Justify your answer. Message confidentiality is when two or more hosts communicate securely using encryption, message integrity means that the message transported has not been tampered with. Yes, you can have one without the other. Just because the nodes communicate with encryption, doesn’t mean that the messages haven’t been tampered with. To verify integrity you can take a hash of the message on both sides to compare using md5 hash sums.

 R3. From a service perspective, what is an important difference between a symmetric-key system and a public-key system? One difference between symmetric and public key systems is that in symmetric key systems both the sender and receiver must know the same key. In public key systems, the encryption and decryption keys are different.

 R29. Stateful packet filters maintain two data structures. Name them and briefly describe what they do. The data structures are Filter table and connection table. Filter tables dictate whether the data gram should be given way in or dropped based on certain rules/protocols. The connection table keeps track of connections, allowing for a finer degree of packet filtering.