Password cracking challenges for students

First things first, all credit for this idea goes to Ming Chow at Tufts University (@0xmchow on Twitter).

Thanks, Ming!

Ming's archive of previous material on this work can be found at https://github.com/tuftsdev/DefenseAgainstTheDarkArts

I'm going to try this for students starting with the Fall 2018 semester, and see how it goes!