My brain hurts. In Cryptology class today we learned about linear and differential cryptanalysis and about AES. I feel like I've been stuffed full of transformations and probability theory and S-boxes and XORs. Which perhaps makes it inappropriate for me to describe my mood as 'drained.' Too bad. Brains hurts too much to reconcile.

Thing is, the math isn't really all that advanced. Each individual transformation is something a fourth-grader could do. But there are so many transformations; the plaintext bits are mixed and shuffled and kneaded and stirred and spliced and shaken. So cryptologists need efficient ways to describe these transformations, and I think this notation is what's tripping me up. Our instructor's slides have all these diagrams that I can't quite understand because one introduces new variables without explaining them or another uses a box here to indicate a state but there to indicate a transformation. There's a lot that we're going to have to figure out for ourselves. (Our textbook is pretty terse.)

In general, I prefer diagrams to formulas when I'm learning, but both should be consistent and use a minimum of special notation and intermediate variables. Examples are good; I'm a little disappointed that we didn't get a fully worked-out AES encryption—we'll have to perform one in our homework assignment.