How the Third Reich's main encryption machine, Enigma, was designed
During World War II, the German Armed Forces used a unique technology to create encrypted messages. Let's take a brief look at the design of the Third Reich's main encryption machine, the Enigma, which means "riddle" in German.
Externally, this equipment looked very simple, even primitive. It resembled a typewriter, with keys displaying the 26 letters of the Latin alphabet. It also had a panel with 26 lamps, next to which were also letters. Furthermore, there were rotating rotors—usually three of them.
When one of the keys was pressed, a light came on, but its letter designation was different. They pressed one key, and the light with a different letter came on.
The operator typed the text on the machine, writing it down on paper as he typed, using the letters that lit up as he typed. The result was complete gibberish. The recipient typed it on their own cipher machine in the same way, and the resulting text was normal.
The machine worked on the principle that it was a complex electrical circuit with tangled wires, which were used for encryption.
Current passes through three rotors, each numbered with 26 divisions corresponding to letters of the alphabet. Setting the rotors in a specific position allows the text to be "shuffled." When a key is pressed, electricity flows through the three rotors, reaches the reflector, and returns through the rotors a different route, changing the letter's value seven times along the way. Each press causes the rotor wheel to rotate, changing the combination again, and pressing the key again produces a new result. To further complicate the cipher, the letters on the keyboard could be swapped using jumpers on the front panel.
Before use, the machine's parameters were adjusted. These were written down on paper to prevent an adversary from deciphering the message, even if they possessed the Enigma but didn't know the settings.
Despite the machine's complexity, the Allies of the anti-Hitler coalition still managed to decrypt messages intercepted from the Nazis. As is well known, the British were the first to gain significant access to the Nazi encryption and decryption system, having discovered Enigma on board the "captured" U-110 submarine. Numerous encryption and decryption keys were also found there. However, there had been some successes before this, including by Rejewski's Polish group, which created a machine called "Antienigma" back in 1939.
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