Week 5 Homework

Chapter 6

R17 What is the difference between a permanent address and a care-of address? Who assigns a care-of address?

A permanent address for a mobile node is its IP address when it is at its home network. A care-of-address is the one its gets when it is visiting a foreign network. The COA is assigned by the foreign agent (which can be the edge router in the foreign network or the mobile node itself)

Chapter 8—Questions

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 means that the message being sent is only known by the sender and the recipient. This differs from message integrity, which means that a message is not tampered with and that the sender and recipient are exactly who they say they are. I believe you can have integrity without confidentiality because your message to each other could be public and yet you could authenticate the sender and recipient.

R3, From a service perspective, what is an important difference between a symmetric-key system and a public-key system?

Symmetric key uses one key to encrypt and decrypt. So both parties need to know the key.

Public key systems use two keys: public and private. Anyone can encrypt with public key and send to a person and only they can decrypt with their private key.

Or in reverse they can encrypt with their private key and anyone can decrypt with their public key. Usually used to prove who the message came from. This is the basis of digital signatures.

R29 Stateful packet filters maintain two data structures. Name them and briefly describe what they do.

Stateful and Stateless IP

There are several advantages to using a static IP filter. It has a combination of low overhead and high throughput. Stateless IP filters are very inexpensive, and many are free. They are included with router configuration software or...