Sections 18.1-18.2, due November 26

1. I'm having a hard time understanding error correcting codes. One of the aspects I don't get is how we get d(C) using the Hamming distance. How do we pick u,v?
On a later note, what does the code rate mean? I don't understand the definition in the book.

2. I really like the idea of parity checks and other codes to figure out if the message was sent with an error. It seems like it would be hard to get a perfect message sent every time, so they seem very useful. I've done homework exercises with ISBN codes in other classes, and it's interesting to learn that such a common number that everyone sees uses a parity bit.

Section 2.12, due on November 25

1. In theory I understand the Enigma, but when I looked at figure 2.2, I realized that I don't understand it at all. I don't understand the different roles of the rotors, reversing drum, and the plugboard very well. The outcome of the Enigma makes sense, but how it gets there is a mystery.

2. I think it's really interesting how they attacked the Enigma by finding similar plaintexts to corresponding ciphertexts. I'm surprised that the original system of writing worked all the way until 1938, when a different method of transmitting keys was developed.

Section 19.3 and the blog, due November 22

1. I understand the basic idea of the Fourier transform, but I really don't understand Shor's algorithm. What is its goal? How does it work?

2. I really enjoyed reading the blog because it used fairly simple concepts. It helped me to understand that we can find the period for Shor's algorithm through his use of the clock analogy. However, I still don't really understand Shor's algorithm.

Section 19.1-19.2, due on November 20

1. How do Alice and Bob establish the bases they are working with? I didn't understand that from the reading.

2. I haven't taken a physics class is four years, so it was fun to revisit that area. I also knew what polarization looked like because 3D movie glasses are often polarized. When you put one of those lenses perpendicular to another lense, you can't see through them. I was really interested to find out that this concept can be used to establish a key.

Pre-Test Questions, due November 15

I think we have covered many aspects related to RSA, so I think really understanding how to encrypt, decrypt, and attack encrypted messages using RSA is an important topic. I also think that signatures are an important topic and are relevant in many different fields. They are used in a variety of situations, so knowing how to correctly use them and being aware of forged signatures is a useful skill.

I expect to see a lot of encrypting and decrypting questions, especially with RSA. I also expect to see a couple of signature questions, where we need to sign the message and verify the signature.

I need to study everything a lot. I've missed a week and a half of school for fly-out job interviews since the last exam, so I really need to spend the weekend studying everything we've learned, so that I'm prepared to take the exam on Monday.

Sections 8.1-8.2, due November 6

1. I don't really understand the third requirement of a cryptographic hash function. I realize the importance of it, but I don't get the difference between strongly collision free and weakly collision free and how they are related.

2. I'm excited to be learning about hash functions. I understand that the example in 8.2 is very simple, but I am glad to be getting into even more complex cryptosystems. I am interested to learn what makes hashes more secure beyond just rotating.