4.1, 4.2, and 4.4 due on September 20

1. (Difficult) Things were going relatively well (some things being review) until I got to section 4.4.1, DES Is Not a Group.  I don't have trouble believing that DES is not a group, the only trouble is I wouldn't know how to show that anything was a group or what a group is, for that matter.  I hope that anything we need to know from this section will be covered in class.  Again, more careful reading would probably help my understanding.
2. (Reflective) We studied DES some in CS 465, so some of the material was review.  I find the history of DES to be interesting.  There were mysterious parts, the justification of which weren't known for several years.  I don't recall any such mystery surrounding AES, but maybe we'll learn some in this class.
   My inclination is to want to implement DES, more than understand the math, but, I know both are valuable.