German enigma machine Patch#

Inserting a plug disconnected the upper jack (from the keyboard) and the lower jack (to the entry-rotor) of that letter. Each letter on the plugboard had two jacks.

However, normally only 10 pairs were used at any one time.Ĭurrent flowed from the keyboard through the plugboard, and proceeded to the entry-rotor or Eintrittswalze. Several such steckered pairs, up to 13, might be used at one time. For example, when an operator presses E, the signal was diverted to Q before entering the rotors. The effect was to swap those letters before and after the main rotor scrambling unit. Enigma without a plugboard (known as unsteckered Enigma) can be solved relatively straightforwardly using hand methods these techniques are generally defeated by the addition of a plugboard, and Allied cryptanalysts resorted to special machines to solve it.Ī cable placed onto the plugboard connected letters up in pairs for example, E and Q might be a steckered pair.

The plugboard contributed a great deal to the strength of the machine's encryption: more than an extra rotor would have done. It was introduced on German Army versions in 1930, and was soon adopted by the Navy as well. On 1 February 1942, the Enigma messages to and from Atlantic U-boats, which Bletchley Park called ''Shark,' became significantly different from the rest of the traffic, which they called 'Dolphin.

German enigma machine Patch#

The plugboard ( Steckerbrett in German) permitted variable wiring that could be reconfigured by the operator (visible on the front panel of Figure 1 some of the patch cords can be seen in the lid). The German Navy 4-rotor Enigma machine (M4) which was introduced for U-boat traffic on 1 February 1942.