This Instructable takes Da Vinci's cryptex to a miniature level.

The basic premise of the cryptex is that it allows the creator to hide a secret within the capsule and lock it using a simple slotted key mechanism. A password aligned perfectly with the arrow is the only way to unlock the cryptex. Or you could smash it to pieces. The password is entered using a series of dials that spin around the canister and allow the key to be released.

The fundamental components of a cryptex are its key, dials and canister. You could make one from scratch and there are instructions to do so, but if you want to fit this thing in your pocket, I have just the solution: a lip balm tube; specifically Nivea.

Step 1: Materials

List of Materials:

> Foam board 5mm [20x20cm board is sufficient]
> Thin cardboard
> Pencil
> Ruler
> Xacto knife
> Glue gun
> Cutting board

> Nivea lip care

Step 2: The Canister

The key must slide through a slot in the canister; the slot should be 5 mm wide and span the entire tube. Use the cap of the lip balm as the canister and use either a sharp knife or exacto-blade to cut the slot.

Try to keep the slot as straight as possible in order for the key to slide smoothly through it. The genius of this particular cryptex is that the fundamentals of the device is already done since we have sliding tube system in tact at this stage.

Step 3: The Key Prep

Assuming you already had the Nivea Lip Care before you decided to convert it to an ancient secret holding device, the next step would be to clean out all of the lip balm from the tube.

If you bought a new one specifically for this purpose, like myself, simply cut out the lip balm stick and wash out the insides of the tube.

Step 4: The Layout

For this step, you will need the sheet of foam board to make the rings for the dials and spacers. You will need to make 3 dials and 4 spacers. Essentially, we are going to cut foam strips and score one side of them to allow wrapping around the canister. Then, using cardboard, we will cut similar strips and glue them around the foam to create the writing surface for the letters.

Dial: Make 3 strips, 1.0cm wide using foam board. Score the foam along the horizontal lines and curve. Cut 3 strips, 1.0cm wide using cardboard. Score lightly along the horizontal lines and curve.

Spacers: Same as above, but make 4 spacers, each 0.5cm wide.

Step 5: Form the Dials

The method to create freely turning dials is to wedge them between the spacers. The spacers will be glued to the canister and the dials will be free to turn.

The foam rings were dimensioned so that they would not fully surround the canister. The idea here is to keep the slot in the canister free for the key to slide through. To do this, glue the foam spacer strip around the canister, leaving the slot uncovered. Trim the foam ring to fit. [Picture 1]

Next, glue the cardboard strip around the foam ring. This will hide the gap in the foam ring and will completely surround the canister. [Picture 2]

Now create the same ring using a strip for the dial. This time do NOT glue this to the canister, but have it free-turning. It should just slide onto the canister. [Picture 3 & 4]

Repeat the above steps by alternating spacer and dial until you have covered the whole tube. Keep in mind that the cardboard around the dials are used to write the password letters on. Make sure the gap in the foam ring is lined up with a cardboard surfaces. These particular surfaces are the key code when lined up so make a small mark on them so you remember which ones they are.

Step 6: The Key

The cryptex is locked when the keys are stuck between the dials when the wrong password is entered. In this stage, the key knobs are sitting in the gaps in the spacers. Therefore, the first step is to mark down where the spacers are on the key.

To make the key shaft similar to the canister, I added a foam ring to the handle in the same way as we make the dials. [Picture 2]

1> Line up the key and the canister and mark down where the first 3 spacers are. [Picture 1]
2> Cut-out 3 small square pieces of foam board, about 0.4 cm across.
3> Glue these 3 pieces on the key shaft in a straight LINE. This is very important. {Picture 3]
4> Key complete

Step 7: Stylize

Once your key and canister are completed, line up your marked dials and insert the key. It should slide in with no obstructions. Try turning the dials to make sure there is no interference with the key. [Picture 2]

Now it's time to think of a code word. It could be arbitrary or the answer to some riddle or a logical puzzle in itself. This cryptex uses the word 'SKY' for its unlocking. There are not enough spaces to write the whole alphabet on the dials, so randomize the characters around the ring. [Picture 1]

Cut a circle out of cardboard to cap off the end of the cryptex. This will hide the last spacer. [Picture 3]

Make a small arrow > to mark off where the codeword has to line up. This arrow must be exactly in like with the slot in the canister. Add some decals or whatever you like to fancy up your cryptex. [Picture 4]

Step 8: The Secret

Your cryptex is not complete until it serves its purpose to enclose a secret or gift only those worthy enough to solve the riddle can have access to.

Whether it be a message, some tic tacs, or even a pack of matches, it's entirely up to you. The neat thing about using a lip balm tube is that when you turn the bottom knob, the contents will pop out.

Et voila... with a bit of glue, some foam and a bit of da vinci genius, I bring you the Pocketex: the miniscule cryptex.

Here's a much larger one made using cardboard tubes, foam board and 4 dials. [Picture 2]

Enjoy!