Due October 1st

I think that the most important things that we have studied so far are probably DES and AES since they are the more modern cryptosystems. Also the basic number theory sections are probably up there in importance because those topics will probably come up again in the systems that we learn about in the future.
Hopefully questions that are comparable to the homework (even though the first few on this last assignment were really hard).
DES, AES, the stuff about fields, and then I need to memorize the modes of operation. I feel like everything else I can just review very briefly and I should be fine, but these things need some work.

5.1-5.4 Due September 29

The reading today was pretty enjoyable and interesting. AES seems like a pretty cool and complicated system.
I did get a little bogged down in some of the details. But, I was glad that I had a good understanding of the G(2^8) stuff or that would have thrown me. I am starting to feel, as the systems become more complex, that I am losing the ability to see what makes one stronger than another one. Both AES and DES just had a lot of steps and I never really got the whole picture of why all of those steps were a good thing (like how they helped to strengthen the encryption).

Due on Sep 27

I don't know exactly how long I have spent on the homework, but I will say that at times it has definitely felt like too long. Especially the one time pad problem on the last assignment. That took me like 3 hours. That was lame. But I do feel like lecture has prepared me for the homework, even if some of the problems are more about playing around with the problems online than doing something ourselves...
Time in lecture has contributed to my learning the most. I think that you do a great job of unraveling complex subjects.
I don't know what would make the class better for me. It's pretty good right now.

3.11 Due on Sep 24

Well, not only was abstract algebra quite a challenge for me, it was also a few years ago. So most of this section was pretty far over my head.
The most interesting part for me was the rules for multiplication in the GF(2^8) field. I did not understand why things worked that way, but I thought it was interesting that they did...

4.5 to 4.8 due September 22

The most interesting part of today's reading for me was section 4.8 about password security. I do have one question though. If you have a true one way function, doesn't that just mean that the function isn't 1-1? Otherwise it would have an inverse, right? Anyway, if it isn't 1-1 won't there be multiple passwords that encode to the same value? And then wouldn't it be possible to break into someone's account just with any password that encodes to the same value?
The most difficult part of the reading for me was section 4.5. I don't even think that I comprehended enough of what was going on to have specific questions.

2.9-2.11 due Septamber 17th

Well, the idea of a code that is completely unbreakable is interesting, but I guess that I just don't see how it can be implemented securely. I mean if you make the random key when you encode the message, then you have to transmit the key so that the message can be decrypted right. So why can't Eve intercept the key right along with the cipher text? And if you have some other way of generating a random key (like it talked about with the satellites), even if you did implement it so that both parties generated the same key simultaneously (which seems very dicey to me), how can we guarantee that Eve didn't know our method for key generation and and thus get the key herself?
Also, I didn't get much of anything out of section 11. I couldn't even figure out what the point was.

3.8 and 2.5-2.8 due Semptember 15th

I really have enjoyed reading about all of the different kinds of cryptosystems. That has been super interesting. Reading about block ciphers was probably the most interesting part since it began to present solutions to many of the problems and questions that I encountered while trying to write my own cryptosystem.

The only part that was a little confusing for me was how exactly the attacks on the Hill cypher worked. But the problem might just be that my ability to think about linear algebra problems has greatly diminished over that last two years.

2.3 Due September 13

I thought that the Vigenere cipher was a very cool idea. Also, I thought it was interesting that it existed for so long without anyone figuring out how to break it. That is impressive.
The most difficult part of the reading for me was trying to understand why the method that we use to determine key length works. I read and reread that section and just didn't get it, so I am hoping that will make sense when we discuss it in class today.

Guest Lecture Due Septamber 10

I can't think of anything that was difficult to understand during the lecture yesterday since the material was primarily historical and not conceptual. But there certainly were some interesting things that she discussed. I really liked the "Mason" code. That was pretty cool. Also the substitution cipher that had the shifting key. That was also interesting.

3.2 and 3.3 due on September 3

The toughest part of the reading for me was probably just trying to wrap my head around fractions when we are working with mod. That is not something I have been exposed to before. Also, I have done the Euclidean Algorithm before, but it was unclear while I was reading it.
The most interesting part of the reading was probably also the fraction part. It was pretty fun to think about it and try to figure out how it worked.