CS591 ST 008

Lab 0 (due 2/4/09)

Alright, after re-reading the instructions provided by Jed, I realized that I need to write something about my experience with this CITI course.

Ok, first of all, I finished this drudgery course. I cannot for the life of me understand how learning about co-authoring applies to the Security and Privacy course. The videos provided were comical and almost worthless, but the text explanations were very well written. It did seem like they would reiterate the same thing more than needed.

Also, Peer Review and Mentoring? Really? It was good reading, since it had close ties to work I do professionally...but not sure this has much use for our class.

Some of the questions in the quizzes just seemed "off".

I think there should be a more appropriate training available.


Lab 1 (due 2/25/09) 1st week

I have taken time to study the DES structure and in detail how the F function works.
I have looked over the 8 bit DES program given to us by our instructor trying to understand exactly how it works.
I have built this program and generated my own cipher text using the plain text pdf file.
I'm really starting to appreciate the DES Feistel structure. It reminds me of the guys on the street that move the 3 cards around and ask you to pick the Ace. There is a lot of bit "shuffling", duplication and remapping.
The area I'm confused with is how do we determine a "good" choice for K3? When do you know you have a good selection? I know Jed mentioned that when we use this key with the Q value and somehow we get a 50+% parity bit of 0, then it is good? Not too sure. I'll need to come in to Jed's office hours and just do an example by hand.
NOTE: Looking at linear.cpp I realized that it wants you to run the pc.cpp file as input to it...not using a file (unless you want to "linear.out < pc_outfile.txt").
Here is the result from running the linear program using the example key of 22B8FA:
Likely candidates for subkey K3:

Subkey Deviation
-----------------
da 346
fa 346
92 258
b2 258
ea 228

NICE! FA was my key3 and it has it listed at the top.