[erock]

check out picked locks under an electron microscope.

http://pumpingstationone.org/2013/12/lock-picking-and-sem/

you can actually tell which ones were picked.

[emhart]

<3 PS1. In Ollie's seminal "Impressioning" he also used SEM to look at keys as they were impressioning locks.

[erock]

oohh i'm going to have to dig to find the one on impressioning

[gknoy]

I'm not sure if this is what he was talking about, but it seems like this is related:

DEFCON 19: "Key Impressioning" http://www.youtube.com/watch?v=e8QnG5RHyq8

[emhart]

Definitely related, and datagram & I covered the basics the year prior as well: http://www.youtube.com/watch?v=_-PqzkoQQ7s