Would you be able to explain how a paper enigma works? (Usually made with a Pringles can). I'm a little lost and not finding a lot of info on how to use it....
Yeah, I’ve never built one myself, but I have made simpler cipher devices. Here’s a picture from a site about them so others can see what we mean:
Basically it’s the guts of an Enigma machine, printed on paper and taped around a cylinder, a Pringles can as you mentioned. The bar to the far left and right are the reflector and the key/light board of the machine, and the three pieces in the middle with letters on them are the rotors. The gray bars to the left and right mark the starting position of the machine. So in this picture the Enigma message starting rotor positions are FHL. Now you just replicate the motions of an Enigma machine with your hands.
1. Turn the left most wheel one click towards you (the Enigma was an electromechanical machine, so pressing a key down made the rotors move, then when the key reached its lowest point a circuit was created that allowed electricity to pass through the machine’s parts and light up the enciphered result of that keypress. So you have to move the rotor before enciphering the first letter, or else the entire message will be one letter off each time.)
2. Let’s say the first letter of your message is W. Find W on the cylinder on the right side, which is your keyboard, and follow it over to the right most rotor. In this pic you can follow the nice red line there over to P, where the electricity would exit the right most rotor and enter the middle rotor. Following that line we see that the electricity exits the middle rotor at H, and exits the left most rotor at G. It then is bounced back by the reflector, the left most piece of paper, and although we can’t see the line in this picture, it just goes back the same way, following the line through each of the three rotors, until it arrives back at the keyboard.
3. When it arrives back at the keyboard, it will arrive at one of the 25 letters that isn’t W. Let’s say you are encrypting a message, and the lines lead back to Z. Plaintext W = Ciphertext Z, and if you were to follow the line back, you would of course get the reverse. The reflector and key/light board circuit make enciphering and deciphering the same process, just set the rotors to FHL and move the left rotor, then feed your ciphertext back into the machine and you get the plaintext message.
4. I assume a plugboard can be easily simulated. It is simply an alphabet of 26 characters, with zero to ten plugs connecting some of the letters, such that if W was plugged into A, then the W at the start of your message would first be turned into an A before entering the rotors, and the steps we did above would give a completely different result.
Doh… forgot to say, there are markings so you know at what point a rotation of the left most rotor causes the middle and right most rotors to rotate one position.