DES is just used once during authentication and is not performance
sensitive so we save some space by generating and/or removing some
lookup tables. Also, shorten some very frequently used variables.
Shaves off about 100 lines.
The decrypt functionality is never used so remove it. Also, we can
assume that we are always DES encrypting 16 characters which allows
several things to be simplified in DES.
Overall this removes about 80 lines of code.