More about untrustworthy padlocks

Last weekend I put up a post titled ‘It seems most locks aren’t as secure as I thought‘.  One of the links it contained was to an article describing how Master Lock combination padlocks could be ‘decoded’ in a very short time, using a very simple method.

The author has now developed an automated machine to apply his technique.  It can undo any Master Lock combination padlock in a couple of seconds.  Here’s the machine in operation.

Let’s hope no burglars ever manage to develop a portable version of that thing . . .



  1. It already exists. Pretty cheap too.

    Fact is, this is a high tech answer to a very low tech problem… there's not that many instances where it isn't easier, faster, and cheaper to cut the lock, grab what you need, then (if you feel the need to re-lock it to allay suspicion) just reattach a new combo lock. The owner likely won't realize you cleaned out the shed until you're long gone and he decides to get in there.

    There's no such thing as a completely secure lock. You're just trying to make ripping you off more work and trouble than doing it to somebody else or not doing it at all.

  2. Let's hope no burglars ever manage to develop a portable version of that thing…

    I think it's a portable version now.

  3. On the other hand, the way my back door's frame splintered when they kicked it in last night, showed me that a padlock just would not have helped. Nobody was home so nobody got hurt. Insurance will cover the few things they stole, but not my peace of mind. It won't assuage my anger either. I just keep reminding myself that at least nobody got hurt.

  4. Read up on Richard Feynman's experiences with safe cracking during the Manhattan Project days sometime. He could get into pretty much every single safe at Los Alamos.

  5. Already portable, and no inverter required: the nicely-assembled model shown at the beginning of the video includes a lithium-polymer cell (of the sort used for RC models) as a power source – no inverter needed! (The cell voltage is a decent match for stepper motors, model-airplane servos, and older MCUs.)
    The one thing lacking is the ability to use it on a lock that's actually in use, which would be a non-trivial (but eminently possible) mechanical challenge.
    Er. I have a vision for a truly pocket-sized version that could be used on a lock that's on a door. More expensive and less versatile than The Raving Prophet's access code, but easier to conceal on one's person, and perhaps quieter in operation.
    If I can think of it, so can someone else; expect a pocket-sized automatic picker to be on the market, openly or otherwise, before the year is out.

  6. Isn't it Army doctrine that an obstacle not covered by fire is not an obstacle? Antibubba is right.

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