Modify Locks to Baffle Burglars

While it’s often thought of as a criminal activity, there’s actually a vibrant hobby community surrounding the art of lock picking. In the same way that white hat hackers try to break into information systems to learn the ways that they can be made stronger, so do those in the locksport arena try to assess the weaknesses of various locks. For the amateur, it can be exciting (and a little unnerving) to experience the ease at which a deadbolt can be picked, and if your concern is great enough, you can go a little farther and modify your locks to make them harder to defeat.

The lock in question was sent to [bosnianbill] by [Rallock67] with a device that [Rallock67] had installed using common tools. Known as a Murphy Ball, a larger-than-normal spring was inserted into one of the pins and held in place by a ball bearing. This makes the lock almost completely immune to bumping, and also made it much more difficult for [bosnianbill], an accomplished and skilled locksmith, to pick the lock due to the amount of force the spring exerted on the cylinder. The surprising thing here was that this modification seems to be relatively easy to do by tapping out some threads and inserting a set screw to hold in the spring.

Locksport and lockpicking are a great hobby to get into. Most people start out picking small padlocks due to their simplicity and ease. It’s even possible to pick some locks with a set of bobby pins. And, if you really want to see how easy it is to defeat some locks and/or how much good the TSA does for your overall security, you’ll want to take a look at this, too.

Thanks to [TheFinn] for the tip!

59 thoughts on “Modify Locks to Baffle Burglars

  1. I once had an issue with loosing keys so I would have to break into the house and then go buy a blank key to cut to fit the lock.

    Eventually I got sick of that so I cut the lock to fit the key and that meant I just had to go and buy a blank key and not need to break in. It amused people to see a blank key on your keyring.

  2. wait, why dont all americans buy some else lock, such as assa/abloy is making? why they still use rhis same style lock? i dont get it.

    and can the pickers pick anything else than this classic bump-pckable style lock?

    1. They’re more expensive, and there’s the sheer inertia behind the kind of locks we use. They can in fact pick locks without bump keys, that’s just the single easiest way to break into a house because you’re not fumbling around for a minute or so actually picking it.

        1. If the lock is secure enough, determined thieves will just break down the door. If the door is secure enough, determined thieves will just cut through a wall.

          A door lock is just going to prevent crimes of opportunity. It doesn’t need to be a technical wonder to do that job.

          1. A piece of plastic (with the right rigidity/flexibility) will get you though most locked front doors faster than the owner can get the key in the lock.

            Someone mentioned a “20 year old lock”. The older a lock is the easier it is to get around it. A piece chewing gum in the door jam wold probably be better than a 20 year old lock.

          2. I have always said that things such as locks, security, laws, are just there to keep the honest people honest. Criminals don’t care about such things, or they wouldn’t be criminals in most cases.

        2. People do what’s convenient. The big box stores only stock the likes of Kwikset, Schlage,and Yale.
          People move around a more frequently in the US and it’s currently in vogue to flip houses, so they may be buying locks more frequently, not that that makes it terribly more expensive.

          Abloy and high security lock makers do a bad job of marketing to homeowners. Unless you know a locksmith, work in security, or follow locksport, most people probably haven’t heard of these high security locks.

        3. ALSO, sheer inertia. Everything in stores is set up to support this flavor of lock. Most of the locksmiths here only really know how to deal with this flavor of lock. They can be trivially modified to be next to impossible to bump and vastly harder to pick, as seen in video.

      1. From my experience, people don’t bother with picking locks or using bump keys — they just kick in the door, most wooden door frames even with a deadbolt will yield to a swift kick. If that doesn’t work, a rock through a window probably does. So yes, typical household locks don’t provide much security — but they aren’t the weakest link, so people don’t want to spend more upgrading them.

        1. I’ve got a window on each side of my front door, probably for fire safety as well as for mid-70s design styles. They’re far enough away that would be slightly inconvenient for somebody to break the window, reach in, and unlock the door, but it wouldn’t be THAT hard. So when the door lock wore out, I thought about buying a lock that at least *I* couldn’t pick, but decided that it made more sense to go for a cheapskate lock with an ergonomic handle that I could open with my hands full.

    2. because a lock is for show. if i want into a house, i don’t even need to know how many you have. a good kick or two usually separates door from jam. yes, even steel doors and jams
      why spend hundreds on a technology that doesn’t actually protect anything?
      buy a cheap lock.

  3. Locks are like having a 1 bit encryption key. Better to have more than one lock, but use the same key, except some must be in a different state to the others for the entire device to open.

      1. Yes something like that, it would be more civilised than having a huge axe swinging down from the roof if you get the combination wrong. ;-)

        But triggering a silent alarm and or time-out mechanism would be useful too.

        The key point being that if you add a few layers of logic crude mechanical lock overriding tricks become useless.

    1. Wrong! For example this lock in the video has around 6^5=7776 different combinations. 5 pins with around 6 different heights. If you are to compare this with digital encryption, it would be like decrypting a 13bit key by picking each bit in the key, hearing the algorithm working and checking the plain-text at each time.

      1. Except most lock’s combinations are very similar (like the top of a bell curve) with a small dip in a few spots. So that narrows down this range from like 7776 to somewhere like 42343. I don’t mean number of combinations, but if you plot pin heights on a visual scale and take about an average you get a narrow range somewhat in the middle. (Somebody draw this, I’m on my tablet.)

          1. That would be graphical now that I have had a few days to think about it. Imagine a graph of the pin heights, left to right, 1-6 on the y and 1-5 actual pins on the x, quadrant 1 only on a cartesian plane. Most keys fit somewhere in the middle by profile, not extreme to extreme.

      2. That key has 10 depths, but the geometry (called MACS, maximum adjacent cut specification) whittles down your total possible combinations because the cuts would overlap, on this brand it is 7. You are still looking at close to 15,000 possible combinations if I recall correctly. Yes, I am a locksmith by trade.

          1. They also have a constraint of cut depth going along the key from grip to tip because the closer to the grip that you have a deep cut – the more leverage the lock friction has to break the grip from the rest of the key. ie Uf you have a maximum depth cut closest the grip then metal fatigue will cause the grip to break off after a relatively short usage time with a stiff lock.

      3. You know a little smart can actually add up to a lot of stupid, or in your comment’s case, irrelevance. I was not talking about the sub parts of the lock, I am talking about locks and how you can arrange them in a way that prevents methods that nullify the combinatoric aspects of the pins within single locks. Talking about pin combinations is irrelevant as they are irrelevant too, otherwise you could never open even a single lock. The exploits that are applicable to locks do in fact render them as effective as a 1 bit encryption key.

  4. Unless you’re a bank, jewelry store, etc., a better lock isn’t really the answer. If a thief wants to get into your house, he’ll do it regardless. Drill out the bolt, break some glass, find the key hidden under the fake rock… The lock just has to be good enough to keep someone from casually strolling in. The building where my father worked, which had alarms on the doors, good locks, etc., was robbed by someone easily hammering though the cinder block wall. That said, lock picking is super fun and occasionally useful!

  5. Dear HaD, please stop snooping on my YouTube subscriptions. [eevblog] [bigclivedotcom] [AvE] [bosnianbill] what next? a post featuring [Drauga1] ? Maybe I should go add some weird subscriptions [mikediva] so we end up with things like “I’m on crack” in the news feed.

    1. Did you even read the rest of the comments? I’m not sure whether we just have a different style of criminal, or vastly different styles of homes. Very few criminals here bother with picking locks, they kick in the door or go through a window, when that fails the knock a hole in the wall or get you to answer the door.

  6. So far no body has mentioned drilling out the tumbler and/or the screws/bolts that hold the lock together.
    This is destructive and probably would not be a technique employed by a locksmith, but the criminals would have no problems with doing it and would probably be far easier than what Rallock67 is talking about (extra tensioning force).

      1. I don’t think it being noisy is really an issue…..the criminals could claim to be contractors (complete with a fake truck/uniforms) that are doing work on the house — most people wouldn’t think twice seeing a handmay truck and hearing noise.

        1. Beside, at our house my Dad is constantly working in the garage using all kings of noisy equipment with music blasting in the background……so no one would suspect anything if they heard a drill going.

  7. I may sell my simple interior device to STOP door locks from turning open.

    Imagine waking up to someone IN YOUR HOUSE!

    I’ve STOPPED that!

    (Also my door frame is super reinforced, and without windows)

    (I may also patent a door break-through alternative for police)

  8. Bosnianbill is actually an EOD technician, and funny bugger to boot. He has some mad skills, for sure!

    If we are talking about good security setups, I prefer a combination of things. Currently I have a double-bar in a steel frame with a pair of multilocks on my door (one for the bar, the other for a dead-bolt.) both are in steel with anti-drill spinners and pins. This keeps the kickers, and the pickers out. So does the security guard, concierge, lack of opening exterior windows (I live several stories up) and nosy neighbors in my building. I don’t count my big hound dog because he is lazy, never barks, generally cowardly, and far too friendly. This, all combined with living in Canada makes me relatively burglar proof. The real kicker is that those locks are actually worth more than anything someone might steal from inside my home.

    My last place came with a GREAT Fox Police Lock, camming model. That thing would stop a truck and used standard euro-profile cylinders so I threw a steel Kaba in there. The frame was thick oak, as was the door, so having the Fox was perfect because it mounted into the concrete floor.

    And yes, I have been a security consultant for 15+ years.

    btw @ Rallock67: I LOVE your work! Creative stuff!

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