[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