[DO NOT MERGE] fix bug 1075700 - add crypto pass-through crash store

r? @lars - @peterbe and @lonnen should look too if you have time.

Putting up for review/discussion, but please don't merge yet pending some further investigation of the ```simple-crypt``` package being used here.
I haven't :) My testing so far has consisted of running the unit test under Python 2.7 on my Mac. This is actually one of the issues I had in mind wrt to ```simple-crypt``` when I put in [DO NOT MERGE] (besides sec reviewing it)