2.1-2.2 and 2.4, due September 10

1. (Difficult) There were a couple hard things with this reading.  One is easily following the modular arithmetic.  Rather than think every operation through carefully, I hope to gain practice, if necessary, on homework assignments.  Another difficult part was following the frequency analysis in 2.4.  Although the arguments made sense, it was tedious to follow all the logic, and I eventually just trusted they were correct.  I think the exercise is valuable, I just imagine that code-breaking is probably a tedious process.  I also think it would be difficult to think of all the frequency properties they mention without some more formal training.
2. (Reflective) This material is interesting to me as a researcher in Internet security because it helps me see the importance of stronger cryptography.  I can see why using simple ciphers is dangerous.
   I wonder, too, though if sometimes a simple cipher, like a substitution cipher would ward off most attacks, because while breaking them is possible, doing so appears to be non-trivial.  I also wonder how effective computers would be at breaking substitution ciphers.  I imagine they could do so very effectively, but writing the algorithm also doesn't seem trivial.