Enigma Variations |

Introduction |

A lot has been said and written about the Enigma. However, when we speak about the Enigma, we have to realise that there are in fact many different flavours of Enigmae. First of all there was the commercial Enigma, available before the war, followed by the Army Service Enigma, the Naval Enigma, etc. Some variants of the Enigma are so different, that they are not 'compatible' with the other models. Furthermore, the wiring of the wheels may be different for certain models, despite the fact that the wheels have the same numbers. The section below, gives a brief description of the various models and shows a small image of each of them. All known Enigma models are available on the Enigma Simulator for RISC OS.

Commercial Enigma |

|  | The first Enigma to be available was the Commercial Enigma as it was originally introduced by its inventor Arthur Scherbius. It had three wheels and a settable UKW, hence the reason for having four letter windows. The first one became available in 1920 and it was withdrawn from the market in 1932, after the German army took it over. Many different versions of the Commercial Enigma have been produced, such as the C, D and K models.

Heeres Enigma |

|  | After adoption of the Enigma by the German Army (Heer), some modifications were made. The wiring of the wheels was changed and new wheels were added. At the same time, a Steckerbrett (plugboard) was added, which added greatly to the complexity of the machine. This machine had numbers (1-26) on the wheels rather than letters (A-Z) and was used by the Luftwaffe and Wehrmacht. Initially it was issued with 5 wheels, any 3 of which could be used in any particular order. It also had a set of two UKWs, one of which could be used in combination with the other wheels.

M3 Naval Enigma |

|  | The German Navy used a slightly different variant of the Heeres Enigma. First of all, it had letters on the rotors rather than numbers and later in the war, three more wheels were added. The wiring of the wheels was the same as for the Heeres Enigma. The Naval Enigma was difficult to break, especially because of the very complex setup procedures employed by the German Navy.

M4 Naval Enigma |

|  | The M4 Enigma was probably the most difficult one of them all. It caused the codebreakers at Bletchley Park great problems, especially during the first part of the war. The M4 was used by the U-boat section of the German Navy and had an extra wheel. It is often referred to as a 4-wheel Enigma. Basically, the machine is a modified M3 Enigma and the space for the extra wheel was taken from the UKW. The M4 therefore has a 'thin' UKW and a 'thin' 4th wheel, which is not interchangable with the other wheels. Two sets of UKW (B and C) and 4th wheel (Beta and Gamma) were available. The 4th wheel is often referred to as the Greek Wheel.

Abwehr Enigma |

|  | This is probably the most rare Enigma in existence today. It was designed for the Abwehr (the German Intelligence Service) and its mechanical 'heart' is completely different from the other Enigmae. It has no Steckerbrett, and it has only 3 wheels that could be placed in any particular order. The difficulty is however, that the wheels have more than one notch, therefore causing the wheel next to it to step more frequently. The wheels had 11, 15 and 17 notches respectively and it has a movable UKW, which means that the UKW is also rotated frequently during the encyphering. The machine is also called Enigma G or the 11-15-17 machine. One of the few remaining specimen was stolen from the Bletchley Park Museum in 2000 but was recovered some time later.

Tirpitz, Japanese Enigma |

|  | The Japanese used different coding machines, such as Red and Purple, but at some point in the war, they ordered Enigma machines from the Germans. A special model was made for the Japanese: without a Steckerbrett and 3 wheels, from a set of 5. Is was based on the commercial Enigma, but had different wiring. The Tirpiz machines were captured by the allies during a raid on the French coast, where they were discovered in a warehouse waiting to be despatched to Japan. It is assumed that these machines were never used to encode messages.

Railway Enigma |

|  | This is a rather strange variant of the Enigma as it has never been seen by anyone outside Germany and no machines have been recovered after the war. The machine was used by the German Reichsbahn (railway) and messages were first intercepted in 1940. Despite the fact that this machine was clearly based on a commercial Enigma, it was sometimes very diffucult to break.

Swiss-K Enigma |

|  | This machine was based on a Commercial Enigma K and was used by various parts of the Swiss Army. It has 3 wheels (from a set of 3) and a single notch on each wheel. As the Swiss didn't want their messages to be compromised, they frequently changed the wiring of the wheels. Some Swiss-K models have an external lamp panel, that could be used by a second clerk. Some of these specimen are in remarkable good condition and can be seen in various museums around the world.

Norway Enigma |

|  | In the years following WWII, many Enigme were used by Intelligence Agencies and Armies all over Europe. The machine shown here was used by the Norwegian Police Special Brance for many years. It is based on the Heeres Enigma (standard Service model), but the wheels are wired differently. The name 'Norway Enigma' is just used to indicate the difference from a Heeres Enigma.

Polish Replica |

|  | This machine was designed and built by Polish cryptographers just before the war, after they first broke the Enigma ciphers. The replica was used to decode messages once the key was broken. The Poles give away some of these replicas to the French and British Intelligence Services just before Germany invaded Poland in 1939. Note that the Steckerbrett is above the wheels rather than on the front of the machine.

Enigma-E |

|  | Although this is not a wartime device, it still is a real Enigma. In fact, it's an electronic variant of the Enigma, based on modern electronic components, which is now available as a DIY building kit. The Enigma-E, as it's called, can be setup to simulate an M3 and M4 Enigma and is therefore also compatible with the Heeres Enigma. More about the Enigma-E More information on the Enigma-E website

Enigma Simulator for RISC OS |

The Enigma Simulator for RISC OS is capable of simulating all of the above devices. It contains the wheel wiring for all known wheels and it has a fully featured Steckerbrett. Messages encoded on a real Enigma, can be decoded on the RISC OS version and vice versa. Furthermore, the serial port of the computer can be used to link Enigma Simulators together, which might prove useful for educational purposes. Additionaly, the Enigma-E building kit also has an RS232 serial port, which makes it possible to connect it to the RISC OS version.

© Copyright Paul Reuvers. Last changed: Fri,17 Oct 2003.12:47:18