Enigma rotor details

During World War II the German Wehrmacht used to encrypt their secret communications of the rotor cipher machine ENIGMA. The heart of the machine represents a set of rollers of a roller entry (ETW), depending on model three or four rotating during the encryption process rollers ( rotors ) and a reverse roll (FM ) is. Rolls and reverse roll were usually selected by setting a (then) secret " key board " from a slightly larger range and inserted into the machine.

Decisive for the cryptographic security of the machine against unauthorized decipherment was the secrecy of the internal wiring of the rolls.

Rolling wiring

The following table lists the internal wiring of the rollers of different models of the cipher machine ENIGMA on (abbreviations: ETW = entry roll, FM = reverse roll ). ( " Hai " German ) indicated that the British code breakers gave the German encryption method in Bletchley Park: The model name of the code name like " Rocket" is additionally or "Shark" ( German after the steam locomotive " The Rocket ", " rocket" ).

Transfer scores

Depending on the position of the carry notch located in the various rolls at different points, the respective left adjacent the roller set roller iff one position continues to rotate ( roll forward), when a very specific letter appears in the rolling window of the right-hand corner of it roll. For the rolls I to V, the code breakers at Bletchley Park had the ( linguistically nonsensical ) mnemonic " Royal Flags Wave Kings Above" formed, which calls the respective letters in this order, which always appears in the window after a transfer to the next roll is made.