A light blue marker with a two-pin header replacing the tip, being pressed against the back of the keypad baord that's removed from the safe

Anyone Can Be The Master Of This Master Lock Safe

June 5, 2022 by Arya Voronova 21 Comments

[Etienne Sellan] got one of these lovely $5 logic analyzers. As with any shiny new tool, he started looking for things to investigate with it, and his gaze fell on a Sentry Safe (produced by Master Lock). On the surface level, this keypad-equipped safe is designed decently when it comes to privilege separation. You can take the keypad board off and access its backside, but the keypad doesn’t make any decisions, it merely sends the digits to a different board embedded behind the safe’s door. The solenoid-connected board receives the PIN, verifies it, and then controls the solenoid that unlocks the safe.

[Etienne] hooked up a logic analyzer to the communication wire, which turned out to be a UART channel, and logged the keypad communication packets — both for password entry and for password change. Then, he wrote some Arduino code to send the same packets manually, which worked wonders. Bruteforcing wasn’t viable, however, due to rate limitation in the solenoid controller. Something drew his attention from there – if you want to change the password, the keypad requires you enter the factory code, unique to each safe and supplied in the instruction manual. That code entry is a separate kind of packet from the “change password” one.

More after the break…

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3D Printing A Combination Lock

March 21, 2019 by Lewin Day 2 Comments

Combination locks! They’re great if you’re skilled at remembering arbitrary strings of numbers, and have a dramatic flair that’s made them a famous part of many a heist movie. They come in a wide variety of styles, and are vulnerable to a different set of attacks than the more typical pin-tumbler locks used on a household basis. If you fancy tinkering with a combination lock, why not 3D print one yourself?

It goes without saying that any lock you 3D print is going to have issues with strength. Such a lock should not be used to protect anything of real value, but it could be handy to prevent the kids getting at the Halloween candy you’re saving for October.

Regardless, 3D printing and assembling your own combination lock is a great way to learn about how they work. It’s a fun project that is also much easier than sourcing and disassembling the real thing. For a greater understanding of the underlying mechanism, this video should make the basic operation clear.

That’s not all 3D printing can offer to the locksport community, of course. You can always print your own keys, too. Video after the break. Continue reading “3D Printing A Combination Lock” →

Giant 3D Printed Lock Helps Teach Picking

August 22, 2018 by Tom Nardi 12 Comments

Despite what the media might tell you, picking locks isn’t just for spies and guys wearing balaclavas. Those who pick as a hobby, or even competitively, think of locks as logic puzzles. Each lock is a unique challenge, and defeating it requires patience, dexterity, and perhaps most importantly the experience that comes from regular practice. But where does one start if they want to get into the world of recreational lock picking, also known as locksport?

Many people begin their journey on a practice lock, usually made of clear plastic so you can see its inner-workings. That’s fine for the individual, but what if you’re trying to demonstrate lock picking to a group? [John Biggs] may have the solution for you, assuming you’ve got the time and material. His huge 3D printed cutaway lock, and appropriately sized tools, allow even the folks in the back of the room to see how basic picking techniques work.

A print of this size is nothing to sneeze at; a quick peek on the reference printer here at the Hackaday Chamber of Secrets indicates you’re probably looking at the better part of 20 hours to print everything out. Once printed you’ll likely need to take a file and some sandpaper to all the surfaces to make sure things operate smoothly. It doesn’t appear to be a terribly challenging print all things considered, but we wouldn’t call it a beginner’s project either.

The only non-printed part in this design is the springs, which [John] mentions he hasn’t quite found the solution for yet. They need to be fairly weak or else the lock is too hard to pick, but springs large enough to work with the pins are usually pretty strong. This might be a perfect application for some custom wound springs.

After you’ve mastered the PLA lock, it might be time to make your own picks and see if anyone is giving free lock picking workshops in your area.

3D Printed Key Saves The Day

December 18, 2017 by Adam Fabio 53 Comments

When [Odin917’s] parents went away on vacation, they took the apartment mailbox key with them. With the mail quickly piling up in the mailbox, he needed to get in there. He could have had the building super replace the lock, for a fee of course. Instead he had his parents email a photo of the key, which he used to 3D print his own copy.

Using a photograph as a template for a 3D printed copy is nothing new. We’ve covered it in-depth right here. However, this is the first time we’ve seen the technique put to use for good – in this case avoiding a hefty lock replacement fee.

He did his modeling in Autodesk’s free Fusion 360 CAD software. He then printed it out, and the box didn’t open. It took three revisions before the perfect key popped out of the printer. This particular mailbox uses a 4 pin tumbler, which makes it a bit less forgiving than other mailbox locks we’ve seen.

Admittedly this isn’t [Odin917’s] first time working with locks. Back in 2013, he submitted a parametric bump key model to Thingiverse.

Picking locks isn’t just for getting the mail. Locksport is a popular pastime for hardware hackers.

Medeco High Security Lock Picking

July 29, 2008 by Eliot 11 Comments

Despite, Hack a Day seeming to be fairly lock heavy lately, we’ve yet to cover a major story from The Last HOPE. At the conference, [Jon King] talked about vulnerabilities in Medeco locks and presented his Medecoder tool. Medeco is really what makes this story interesting; unlike the EU, the US has very few high security lock manufacturers. You pretty much have to use Medeco and it’s found in many government agencies.

The Medeco locks have a vertical row of six pins arranged like most pin tumbler locks. Unlike your average lock, the rotation of the pins is important. When the key is placed in the lock, it not only moves the pins to the correct height, it also rotates them to the correct orientation. A sidebar blocks the cylinder unless the pins are rotated properly. Each pin has three possible orientations. They’re biaxial as well, which means the pin’s offset point allows for three more possible positions.

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