Enigma

« Today, I’m going to talk about one of the most famous encryption devices in history: the Enigma machine that we studied last year. It was used by Nazi Germany during World War II to encode secret military messages, and for a time, it was believed to be unbreakable due to the enormous number of possible configurations. How did Enigma work? The Enigma machine worked using a system of rotors, plugs, and electrical circuits.  First, the operator typed a message on the keyboard.  The machine then substituted each letter through a complex path of wiring inside rotating wheels called rotors. The enigma’s strength was its rotors which always changed the electrical path and therefore the letter substitution Each time a key was pressed, the first rotor would rotate slightly, and it’s only when it made a complete turn that the second rotor would rotate of 1 notch and same thing for the third rotor.

Thanks to this, it wasn’t a simple shift : every time you typed the same letter, it could become a different letter (depending on the rotor positions.)  Finally, the encoded letter would light up on the lampboard, and the operator would write it down. Another key part was the plugboard.

This allowed operators to swap pairs of letters before and after the signal went through the rotors.

For example, you could plug A to G, so every A would be treated as G.

This added another layer of complexity to the system.

Even if someone understood how the rotors worked, they still had to figure out the plugboard settings. But why was it so hard to break? Let’s talk numbers.

The Enigma machine was considered unbreakable at the time because of its number of possible settings. First, choosing 3 rotors out of 5 gives 60 combinations Then Each rotor could be in 26 positions,.... »