Section 2.5 - 2.8

The modular arithmetic involved in inverting the matrices for the hill cipher was sort of hard to follow. After reading the appropriate section in chapter 3 it became much clearer. I would still like to go through the example step by step using a computer to check the matrix operations in order to make sure its correct.
The Sherlock Holmes story was entertaining but it felt a bit too contrived. I under the authors desire to emphasize the importance of frequency analysis and mastery of the language but that example even though entertaining felt out of place.
The ease in breaking the playfair cipher was interesting I wonder how larger values of n would effect things.