Lockpicking: Types of Locks and Why They Can All Be Picked
Lockpicking isn’t just a criminal act in pursuit of someone else’s valuables—it’s also a popular hobby among information security specialists. Knowledge in this area can help you choose a lock or come in handy if you ever lose your keys. In this article, you’ll learn about the different types of locks, their weak points, and how to distinguish a more secure lock from a less secure one.
A Brief History of Locks
The need to protect property and control access to spaces has existed since ancient times. The first locks were invented in Ancient Egypt. Back then, they were more like modified bolts with special holes for pins. Using a “key,” you had to lift the pins up, after which you could pull the key and remove the locking part.
The real evolution of locks began in the 18th century. In 1784, Joseph Bramah displayed his uniquely designed lock in a shop window, offering a reward of 200 guineas (about $200,000 in today’s money) to anyone who could pick it. Despite the generous reward, it took 67 years before Charles Hobbs finally picked it at the Great Exhibition in 1851, spending 51 hours on the task.
Another notable inventor was Jeremiah Chubb, who in 1818 invented the lever lock, now known as the Chubb lock. This lock required two keys: the first for regular use, and the second to reset the lock if someone tried to pick it, putting it into a “protected” mode. This not only made picking harder but also alerted the owner to a failed break-in attempt. However, even this lock was eventually picked—by the same person and at the same exhibition as Bramah’s lock.
Today, things have become even more interesting. Let’s look at the most popular types of locks, starting with the most common: the pin tumbler lock.
Warning
The author and editors are not responsible for any harm caused by the use of information from this article. By applying this knowledge, you act at your own risk and are aware of the consequences. Breaking and entering, theft, or property damage are punishable by law. Use this knowledge only when it will not harm anyone!
Pin Tumbler (English) Lock
This lock consists of several parts: the lock body, a rotating cylinder where the key is inserted, holes for pins, and the pins themselves (upper and lower) with springs pressing on them. In conversation, these pins are often called “pins.”
On the right side of the diagram, you can see the position of the pins when no key or the wrong key is inserted. The upper pins are between the lock body and the cylinder, preventing the cylinder from turning. When the correct key is inserted, the pins align and allow the cylinder to rotate.
Vulnerability of the Mechanism
Why can this type of lock be picked? Many cybersecurity specialists love randomness, but in lockpicking, it’s all about tolerances, which play a key role here. If you look at the lock from above, in theory, all the pins should be on the same axis. In practice, this is nearly impossible, and the pins are on slightly different axes.
Looking from the front, if you start to gently turn the cylinder, it will catch on the pins—importantly, not all at once, but just one, usually the leftmost. By lifting it, you allow the cylinder to turn slightly and catch on the next pin, and so on.
Lockpicking Tools
The classic tools for picking these locks are a hook pick and a tension wrench. The hook is a metal plate, somewhat like half a tweezer with bent ends. The tension wrench is also a plate, but bent into an L-shape. First, you insert the tension wrench into the cylinder from the side opposite the pins and start to gently turn the cylinder. Then, you insert the hook about the length of a key to reach the farthest pin and begin lifting and lowering the pins one by one from back to front. Some upper pins will drop back down, meaning the cylinder isn’t catching on them at that moment. When an upper pin stays in the lock body, it means the cylinder was catching on it and you’ve set the pin correctly.
There are other tools for working with pins. For example, the “snake rake” allows you to quickly rake the pins without having to lower the tool after each attempt, which can speed up the process if there are no additional security features.
Another technique, called “bumping,” uses a specially prepared key with its cuts filed down and a couple of rubber rings. You insert the key, tap it with a rubber mallet, causing the pins to jump, and while the upper pins are in the air, you try to turn the cylinder. There are also semi-automatic and automatic bumping tools that use spring mechanisms or vibration motors to do the work for you.
Additional Security Features
Security can be improved by changing the shape of the upper pins. There are several types of security pins with special shapes. For example, mushroom-shaped pins can create a false set, making the picker think the pin is set when it’s not. Spool and serrated pins can also make picking more difficult by catching and binding in the lock, giving false feedback to the picker.
Disc Detainer Lock
Another notable type is the disc detainer lock. Instead of pins, these use discs, a lock body, and a locking element. When the lock is closed, the lock body and moving part are held by a pin. To open the lock, you must rotate it to a specific angle so the pin falls into a slot, allowing the lock to open.
To pick this lock, you use special tools to individually rotate the discs until all the slots align. However, this is more difficult than with pin tumbler locks, as the simpler construction allows for tighter manufacturing tolerances. Some disc detainer locks also have false gates to mislead pickers.
Cross (Cruciform) Lock
The cross or cruciform lock is a variation of the pin tumbler lock, but with pins arranged on four axes instead of one. It is picked with a similar tool, but designed to reach all four sets of pins.
Lever Lock
The lever lock is also very common. Its mechanism includes a bolt and a protrusion on the bolt that fits into holes in the levers. The key has a prominent “flag” that pushes the bolt, while the other cuts on the key lift each lever to a specific height. Only when all levers are lifted to the correct height can the bolt move and the lock open.
Picking these locks also relies on manufacturing tolerances. Using a filed-down key and an L-shaped wire, you can lift the levers one by one. Specialized tools called self-impressioning keys can also be used. These have movable cylinders instead of cuts, which adjust themselves as you turn the key, eventually matching the original key’s pattern. This allows you to open the lock multiple times or even make a copy of the key if needed.
Some lever locks have additional security mechanisms that prevent the bolt from moving if a lever is lifted incorrectly, making picking more difficult.
Bonus: The Reality of Modern Locks
Unfortunately, there’s bad news for owners of standard pin tumbler locks. Anyone—from a child to a senior—can find detailed videos on YouTube showing how to pick many common locks. For almost all cheap locks, there are guides on how to make a simple pick from a paperclip. This applies to most apartment locks, padlocks, mailbox locks, and so on.
When people want to improve security, they often buy a new lock with a dimple key. However, if it has a thumbturn on the inside, it can still be opened with a bent paperclip or a special tool known as a “quick turner.” This method works on almost all Chinese locks and even some domestic brands like Paladium and Apex.
Remember, locks can become less secure over time. Today you might install an expensive door with high-quality locks, but tomorrow someone may find a way to pick it and post the method online or start selling ready-made tools. Even high-end brands like Mottura, Abus, Tesa, Kaba, and Mul-T-Lock have been compromised. For the Mul-T-Lock 7×7, for example, there are several affordable picks available for $25–$50. If you take lock security seriously, you’ll need to regularly check if your lock has become vulnerable.
How to Live With This?
First, consider whether extra security is worth it. If breaking in would cost $100, but you’re only protecting $10 worth of goods, it may not be worth the effort—no one will bother unless they’re very foolish. If you’re protecting something truly valuable, someone will eventually find a way in—it’s just a matter of time. So, focus on the motives and goals of potential attackers and the existing security measures.
For low-budget solutions, it’s best to use a steel door and two locks. You can also install a fake security camera, though this can be a double-edged sword: it might deter some, but attract others. Another trick is to put up a sticker like “protected by security.” If it looks official, it might scare off intruders.
And finally, get rid of Chinese-made locks entirely. This is important because they’re not only easy to pick, but can also break at the worst possible moment, locking you out. In that case, your lockpicking skills might come in handy!