7.3-7.5, due on November 2

1. I didn't understand the part about the machines that do Diffie-Hellman problems/ElGamal decryption.

2. It's nice to see that the things we've learned in the past couple of classes lead up to something.

7.2, due on October 30

1. I don't understand the part in the Pohlig-Hellman Algorithm where you break x into x0 + x1q1 . . . and why it works. I also didn't really understand the Computing Discrete Logs Mod 4.

2. I had the thought as I was reading that cryptography is just a lot of number theory. I also had the thought, "this is much funner than just plain number theory." It's because this points to something and has cool applications. It's not just proofs! :)

6.5-6.7 and 7.1, due on September 28

1. I was somewhat confused by the discrete logarithms section. I don't really understand how they work.

2. I think the thing with decrypting your message with your key and then encrypting it with their key, so that they decrypt with their key and then encrypt with your key to get the message is really clever.

6.4.1-6.4.2, due on October 26

1. I didn't understand the part about putting the prime factor powers in a matrix and finding linear dependencies (I don't fully remember this), and how the numbers that they got were 0 (mod 2).

2. I found the quadratic sieve method of factoring interesting. I'm impressed someone came up with that.

6.4, due on October 23

1. I didn't really understand how The p-1 Factoring Algorithm works or how it gives us a factor of n.

2. This is just a fun fact: I'm giving a presentation on Fermat tomorrow in my History of Math class, and it's just kind of cool to see his influence in so many different places, specifically here in number theory that relates to Cryptography.

6.3, due on October 21

1. I didn't understand the part about how to pick a prime number.

2. Is this used to make sure we pick good p's and q's?

3.10, due on October 19

1. I had a hard time understanding 4 and 5 of the Jacobi Proposition. How can n be congruent to anything other than 0 (mod n) (in 4.)?

2. I know I've learned the Jacobian before . . . I don't remember how to do it, so is this the same thing, by the same guy, or completely different altogether?

3.9, due on October 16

1. This section made little sense to me. It seemed like they were pulling random numbers out of a hat and putting them together. I didn't understand the Proposition at the beginning, which probably contributing to not understanding the rest of the section.

2. I'm interested to see how this is used in terms of RSA. I figure it breaks down somewhere, or RSA wouldn't be secure. Or I didn't understand the section and that's not even applicable.

6.2, due on October 14

1. I have no idea how the Timing Attacks works.

2. It's nice to know all these rules, but I still don't feel very confident in being able to pick p,q,e that work well.

3.12, due on October 12

1. I didn't understand the theorem or how it applied. The rest of the material was kind of overall confusing too.

2. I'm interested to see how this applies to cryptography. It seems very random.

6.1, Due on October 9

1. I was slightly confused by the claims, especially the second one. They seem like they contradict the fact that RSA is secure, but maybe I'm not reading them correctly. Either way, I had difficulty understanding this part.

2. This made me really excited because I think it's a really cool idea. It also makes me want to discover a way to quickly factor super large primes, even though I know it won't happen. It does make me wonder if someone will in the future . . .

3.6-3.7, due on October 7

1. I didn't understand Euler's phi-function at all. That made the rest of the reading somewhat confusing.

2. The discussion in 3.6.1 was nice to see how this stuff is applicable to cryptography. It made me more motivated to understand it.

3.4-3.5, due on October 5

1. I had some difficulty understanding the General Form of the Chinese Remainder Theorem. I just got a little lost in the different variables.

2. Modular Exponentiation reminded me of the Egyptian method of doubling (to find products and quotients) that I learned about in MTHED 300. It's a similar idea of doubling and then adding the ones that you want. This was a cool connection to make. :)

Study Prep, due on October 2

1. Which topics and ideas do you think are the most important out of 

those we have studied?

I think the more modern ciphers are important as well as the ideas of the other ciphers we've learned.

2. What kinds of questions do you expect to see on the exam?

I expect to see similar problems to the ones on the homework (processes relating to different cipher systems), possibly with the addition of some definition/term type questions.

3. What do you need to work on understanding better before the exam?

I had a hard time with the DES homework, so I need to work on understanding that better. I also need to just solidify my understanding of each of the other topics before the exam.