128-bit AES electronic codebook

Rijndael (the core of AES) is an algorithm that might actually be shorter and simpler in C, but I was curious to see how natural I could make it look in Haskell. Thanks to Jeff Moser and Sam Trenholme for their clear elucidations.

Note that this code only does ECB mode; it computes rather than hard-codes the S-box; and it could be vulnerable to side-channel attacks. So enjoy reading it, but don't try to make a serious encryption app out of it. That kind of thing is best left to the professionals :)