PVC Cryptex Keeps Your Stuff Safe


Apparently we’ve never shared a Cryptex before! Made popular (and coined) by the Da Vinci Code, a Cryptex is a combination style lock originally used to store secret messages. You can make your very own using a few pieces of PVC pipe, some epoxy, and nuts and bolts!

Cryptexes have a clever design that cannot really be lock picked, without simply breaking it. In [Dan Brown's] novel, it was said that some Cryptexes stored a fragile vial of vinegar with the message written on papyrus — that way, if it was forcibly opened the vile would break, dissolving the thin papyrus note.

They work similar to a bicycle’s combination lock, where if the correct password is guessed, the tumblers inside align, allowing the two halves of the cylinder to come apart. It’s actually a very simple design on the inside, and the whole mechanism can easily be made by yourself with minimal tools.

Using PVC it’s a relatively easy project, although you could also make a much more impressive one out of metal instead, like this amazing one made from a copper pipe.


  1. asdf the third says:

    And now someone will be making a Cryptex bruteforce cracking tool.

    Actually, that’d be really cool. I’d imagine that it would have bands that wrap around the individual rings connectd to servos or so.

  2. I’m more into this:

    But sadly to little information on the entire worklog.

  3. Andrew says:

    That’s vile.

  4. voxnulla says:

    I thought everybody already forgot about this poor-mans Umberto Eco trash.

  5. Arguably a more impressive version here….


    (Steampunk is always more impressive)

  6. yetihehe says:

    Is it susceptible to the same attacks as bike combination locks, where if you pull cord and then turn rings starting from the most tough to turn, you can crack it in seconds? My friends were really surprised when I opened unknown locks in seconds :D

  7. RexJaguarius says:

    Awesome. More like this.

  8. smee says:

    “Cryptexes have a clever design that cannot really be lock picked, without simply breaking it. ”

    Yeah it can. Same as a bike lock. Pull and start turning one ring (usually the closest). When there is pressure on all rings equally, they will turn with the same resistance. When one has gotten to the unlocked position, that load will be distributed to the next highest binding ring and, if it is of high quality, all the other rings. Repeat until one ring is left. Give it a spin and it is open.

    The alternate with-tools method is to use a feeler gauge between the rings, attempting to probe for its ‘flat’, or the area on the ring that determines the unlocked position. Align them all, spin them together (as the index might not actually be the mechanical retention point) and it pops open.

    Same sort of thing can be applied to most any multi-ring lock, like briefcases and such. Sesamee style combination locks have a depress-able shackle and a locking plate to prevent this type of manipulation. Though they introduced an even easier bypass with that design…

    • Whatnot says:

      I’m sure you could think of some custom tricks to prevent that kind of manipulation though. Don’t you think?

      • Cryptexmaker says:

        I’ve been making Cryptex(R) Security Boxes (www.cryptex.org) for 10 years now. I have a series of false tumblers in the rings so when you try this lock picking trick, you will feel a slight click… but there are 8 clicks on each ring and you don’t know which one is correct. You can narrow it down to 32,726 possible combinations still, but that is a lot to try one at a time until you get the correct one.

    • Brian Neeley says:

      It should be simple enough to make a shallow notch at each “digit” on the cryptex. Each notch would be slightly larger than the slack of any one tumbler, so just pulling on the thing gains you nothing (well, one combination that probably doesn’t work… you are back to brute force).

    • Iskaral Pust says:

      Some links with more detailed explanations would be great. :)

  9. CJ says:

    I wonder if you could stagger the slots in the rings or maybe various height bolts and tiered rings, where you had to say, find one code, slide it out halfway, then have to guess a second code to pull it out further?

  10. Brett_cgb says:

    The original video posted with the project has nothing to do with the project.

  11. voxnulla says:

    Also, just smash it with a big hammer.. Vinegar will not dissolve ink, parchment, velum nor paper.

  12. Dax says:

    One possible way to stop it from being picked open is to add slight indentations to every key position in every ring so that pulling on the end with the wrong combination locks every ring in place. You can’t feel for the slot by rotating the rings because the rings won’t rotate.

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