“Bumping” lock-picking paper

Bruce Schneier links to a paper on refinements to bumping, a lockpicking technique for pin-and-tumbler locks where you insert a specially filed-down key and give it a quick whack to bounce the top pins out of the way. The principle is the same as a lockpick gun, though the authors claim it works better.

I haven’t played with lockpicks since my undergrad days, but I’ll probably play around with their method and see how well it works. The biggest question I have is how much wear and tear this method causes to the lock vs. other methods — the paper suggests some ways to limit damage to the lock but it still seems like it’d be worse than the lockpick gun since the driving force is side-long (into the lock) rather than straight up. Still, it’s got to be better than raking the lock. (I remember back when I was an undergrad at MIT there was one door in particular that needed its locks replaced every couple years due to the number of people raking it — most of the better pickers didn’t rake for just that reason.)