CS209-01 Homework Assignment 7

Cryptosystems

Read "Designing an Authentication System: a Dialogue in Four Scenes" at http://web.mit.edu/kerberos/www/dialogue.html and in your words
1. in detail describe the new system Athena wants to implement.
   What are the similarities with the system in our lab?
   What related services and corresponding daemons and files did we cover and did not cover?
   What are the problems to be fixed?
2. What is it Charon?
   How does a client authenticates itself to a server?
   What are the problems found by Euripides in the original protocol?
   How were they fixed?
   What are the main issues to fix still? What is the problem?
3. Why do we need a ticket-granting service? How does it work?
   Why can we avoid sending a clear text of a password over the network?
   Why do we need expiration related information in a ticket?
4. What is the major problem with the system designed in Scenes 1, 2, and 3?
   What is a "session key"? How and when is it created? How is it used?
   Why do we need mutual authentication?
   Why is the name changed to Kerberos?
   

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