INFS 766 Spring 2004

Prof. Ravi Sandhu

Take-home Examination 2


Due in class on 6/15/04


This is an examination.  You must write the answer yourself  without ANY discussion with anyone else.  Your answers should be based on the material specified in the exam.  You are free to consult additional literature on the topic.


Provide a signed statement with your submission stating, I have not given help or taken help from anyone on this examination.


All questions have equal weight.  Please answer each question in less than 200 words.  Your solution should be prepared in soft copy, although diagrams may be hand-drawn.  Please submit hard copy on the due date in class.  If you cannot make it to class on the due date submit via email to or fax to 253 563 3509 before the class.  (For email submission a simple statement of the honor code is sufficient, physical signature is not required.)


The questions pertain to the following material.



The questions have roughly equal weightage.  Please answer each question in less than 200 words (this is an upper bound, not a suggested length).


1.      What is the security objective of DomainKeys, as best as you can state?  How does it relate to the classic security triad of Confidentiality, Integrity and Availability?  How about the fourth security objective of Usage?


2.      In section 6.4 the IETF draft discusses the problem of roving users and suggests several solutions in the third paragraph.  (Ignore the per-user DomainKeys solution since this is not yet published.)   Do you think this is a show-stopper?


3.      Discuss the DNS security and performance issues covered in sections 7.1.1 and 7.1.2 of the IETF draft.


4.      Why doesn’t this approach need Certificate Revocation Lists?  Discuss.


5.      Do you think objectives close to DomainKeys could be achieved by means of symmetric key technology?  Discuss.