Paper Enigma Machine

Secret codes and ciphers are so much fun to learn about and create! This particular secret code machine is a simpler model of the original that was so complex, it took a brilliant mathematician, Alan Turing, to devise the techniques which cracked the code.

In order to create this paper machine, you’ll need the templates which you can find here. Before you print and cut them out, watch the first part of the video, because chances are, you’re going to have to re-size it so it will fit your container.

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Materials:

• Pringles Chip can (empty)
• Tape
• Scissors
• Color printout of the templates

Here’s what you do to use this machine:

1. Line up the fray bars on the reflector and input/output (this is your start position)
2. Decide on a 3-letter key. You can use ABC, CAT, DOG… any three you want. Write these down now.
3. Turn the rotors so that the three letters of your KEY are lined up.
4. What is the message you want to encode? Choose a short message to start with.
5. For each letter of your message, turn JUST THE RIGHT ROTOR one step towards you (to the letter in line with the gray alignment bar goes to the next one in the alphabet).
6. Do NOT turn the reflector or the input/output cylinders!
7. You need to turn it ONCE BEFORE you start encoding.
8. Now find the letter from your message on the input/output cylinder and trace it through all three rotors, reflector, and back through all three rotors and back to the input/output cylinder. Write down your encoded first letter!
9. Continue to work your way through your message… read the next couple of points before finishing…

Rotor Turnover

You’ll notice that all three rotors have a shaded gray letter. This will help scramble up your message even more. Here’s how to handle it:

1. If the middle rotor is gray, TURN ALL THREE rotors one step toward you (this may be easier to do one at a time).
2. If the letter on just the right rotor is gray, turn the MIDDLE AND RIGHT rotors one step toward you.
3. If none are gray, just turn the right rotor one step toward you.
4. The gray on the LEFT rotor is not used. It’s there in case that rotor changes position to be a middle or right rotor in the future.
5. If you follow all the turnover rules, you might find that you have a gray shaded letter on the middle rotor that steps into position when turning over. If that happens, you need to DOUBLE STEP, meaning that ALL THREE ROTORS (not just the middle rotor) must step again when the next letter is processed.  Try this out to make sure you understand how to do it:

Use rotors I, II, & III and key A D S to decipher this message:

R Z F O G    F Y H P L

You should end up with two words you recognize and the rotors at positions B F C.

Enjoy your enigma machine!

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