Tuesday, 22nd August 2006

'Bump keying'

What would you say if I told you that your house was totally insecure and that anyone could enter and exit as they please, without you even knowing and without any sign of damage or breaking and entering?

Well, it looks like precisely this is now possible, due to a technique known as "bump keying". To find out more, visit YouTube and search for "bump key", or visit www.youtube.com/watch?v=7Uv45y6vkcQ.

Basically it consists of filing down the 'zig-zags' on a standard Yale type front door key so that all five (for five lever locks) positions are filed down to their minimum position - so that the key looks zig-zagged, then inserting it fully into the lock you wish to open. Now carefully pull it back one 'click' and put a slight rotational pressure on it (as if you're trying to open the door) with your finger. Now hit the key with the handle of a screwdriver or knife. You don't need to whack it hard, just a medium tap, and at the same time increase the rotational pressure to turn the key in the lock. Nine times out of ten, it will unlock the door.

How does it work?

It works in a similar way to hitting a row of billiard balls, lined up and touching each other, in that a sharp tap on one end will make the last ball move but all the previous balls stay standing still. The inside of the lock behaves a bit like the billiard balls and transfers the energy to the levers inside the lock, momentarily knocking them all away from the key, which you can quickly turn before they settle down again.

Apparently it also invalidates your house insurance too, because there is no damage and no sign of forced entry.

I'd encourage everyone to check their locks and be aware of this new trick. I'm guessing that a visit to your local locksmith or crime prevention officer might yield some advice on how to prevent this new craze.

I just discovered it's not that new after all. Bruce Schneier gave it a mention back in March.

Also, see www.hackaday.com/entry/1234000930055696/

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