2.1, 2.2, and 2.4, due September 7th

1. The most difficult part of the reading for me came in two parts: the first part was the "chosen plaintext" and "chosen ciphertext". I don't understand how you can choose the plaintext or the ciphertext. I thought that was already sent or received. The second part that was difficult for me was not understanding really. I realized how difficult even "simple" ciphertexts can be to break even if you know how to decrypt them.

2. I loved the explanation for how to decrypt affine ciphers.  Also, the substitution ciphers section was very interesting. I realized the ciphertext you gave us would have been much much harder without spaces and that we would have had to use frequency analysis, pretty much exclusively. Also, I love the writing style of the book and how easy it is to follow!