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Enigma
Enigma cipher machines

The Enigma cipher machine is arguably the most famous cipher machine in the world, not least because of the important role it played during World War II (WWII), while at the same time it was broken at an uprecedented scale. Based on the principle of the rotor machine, the text is scrambled by electrically wired rotors. This page provides an index to the various models, accessories, simulators, manufacturers, patents and related subjects.

Please note that there is no such thing as the Enigma. Enigma is the brand name of a series of cipher machines, developed before and during WWII, some of which are compatible with each other, and some of which are not. If your are interested in the history of Enigma, you might want to check the Enigma Family Tree, the Enigma Timeline, or the Enigma Glossary.

Before and during WWII, Enigma was the inspiration for many other designs of rotor cipher machines, such as the British Typex and the American SIGABA. And even after the war, some cipher machines were based on the same principle, such as the American KL-7, the Russian Fialka and the Swiss Nema.

We are always interested in acquiring new equipment, documents and other artefacts for the museum. If you have something to offer, please contact us.

 Enigma history
 Enigma family tree


  
Enigma machines
A series of early prototypes from 1918 onwards
'Die Handelsmaschine' (the trade machine), the first Printing Enigma (PE) of 1923
'Die Schreibende Enigma' (the Printing Enigma) of 1926
Enigma H29, the last printing Enigma (Schreibende Enigma) of 1929
Enigma A, the first lamp-based Enigma (Glühlampenmaschine) of 1924
Enigma B, the successor to the Enigma A (Glühlampenmaschine) - 1924/1925
Enigma C, lamp-based Enigma (Glühlampenmaschine) of 1925 (including Funkschlüssel C)
The main Commercial Enigma machine on which all later models were based - 1926
Enigma K, special versions of the Enigma D
Heeres Enigma (Wehrmacht and Luftwaffe)
Naval 3-wheel Enigma machines M1, M2 and M3
M3
Naval Enigma M4 (used by the U-Boats or the German Kriegsmarine)
M4
Zählwerk Enigma A28, the predecessor of the Enigma G
Zählwerk Enigma (Enigma G and Abwehr Enigma)
Enigma T (Tirpitz) used by the Japanese
Special version of Enigma K for the Swiss Army
Railway Enigma used by the German Reichsbahn
Enigma Z, the numbers-only Enigma
Polish Enigma double (replicates Enigma I)
Enigma accessories
Schreibmax printer attachement
External lamp panel for Naval Enigma
Enigma Uhr (also known as UhrBox)
Uhr
Power Supply Unit
PSU
Lückenfüllerwalze (configurable-notch wheel)
Lf
Umkehrwalze D
Flat-faced Enigma lamps
Empty message forms that were used for taking down Enigma messages
Cipher material, bigram tables, trigram tables, etc.
Related subjects
History
Working principle of the Enigma
Enigma wheel wiring
Enigma Steckerbrett (plugboard)
Enigma family tree
Enigma timeline
Enigma and Enigma-related patents
Real Enigma messages
Real wartime photographs of Enigma in action
Enigma logo in various formats
Enigma simulators and replicas
Reproduction parts, such as batteries and lamp films
Cyclometer (Cyklometr) a device for helping to break the enigma traffic, made by Rejewski
Bletchley Park, Britain's codebreaking centre during WWII
Breaking Enigma with the Polish BOMBA, the British BOMBE and the US BOMBE.
Various Enigma-related items
Recent changes
Similar machines
Enigma is arguably the most well-known implementation of the rotor-based cipher machine. As its patents were registered in various countries, many designs of similar machines were based on it. Many of the later machines, including the machines that were used by the Allied Forces during and after WWII, were largely based on the design of the Enigma. Here are some examples:

B-21, Hagelin's first cipher machine
ECM Mark II (SIGABA, CSP-888/889, CSP-2900, CSP-1600, CSP-1700)
British wheel-based cipher machine used extensively during WWII
Swiss NEMA (replacement for Enigma K)
TSEC/KL7 (Adonis, Pollux)
Fialka M-125 cipher machines
OMI-Nistri (Italia)
OMI
 Other rotor machines


Working Principle
Many attempts have been made to describe the working principle of the Enigma machine on the internet. Some of these are correct, and some are not. This is yet another attempt.

Several years ago, when creating the Enigma-E, an electronic replica of the Enigma, we had trouble understanding the precise operating principle of the Enigma machine; something that is vital for a reliable simulation. At the time, most websites only gave a rough description of the machine and important details were omitted. We then created out own description and made it publicly available.

 More information
 Wheel wiring

If you are interested in building your own electronic Enigma machine, you might want to learn more about the Enigma-E self-build kit. It is compatible with a real Enigma machine.

  

Animation
A great animation on how the Enigma works is available below. It was created in December 2021 by Jared Owen, and features Enigma I — the most common Enigma model that was used by the German Army during WWII. For more great animations, visit Jared Owen's YouTube channel [3].


 Video: How did the Enigma Machine Work?


Enigma models on this website
Before and during WWII, many different Enigma machines were developed and built. Some of these machines are compatible with each other, but others are not. Below is a list of some of these machines that we've seen over the years. Please note that this list is by no means complete and will be subject to future changes, as and when we find 'new' machines. Each machine is described briefly below. Click the image for a full description with many photographs.

Die Handelsmaschine   1923
In 1923, the first machine under the Enigma brand appeared on the market. It was known as Die Handelsmaschine, and was large and bulky. The machine resembled an electric typewriter and printed its output directly on paper.

Although we've never actually seen the machine, and therefore have no good photographs of it, we did find an accurate description of the machine by inventor Arthur Scherbius himself.

 More information
  

Die schreibende Enigma   1926
Die schreibende Enigma was developed between 1924 and 1926, as the successor to the Handels­maschine. The rotating print head of the earlier machine was replaced by a series of type-bars, like the ones commonly found on typewriters.

The machine looks very similar to a standard typewriter and is very well finished. Nevertheless, there were many production problems and it appeared very difficult to operate it reliably at higher printing speeds.

Eventually, in 1929, it was replaced by the Enigma H (see below) which was far more bulky.

 More information
  

Enigma H (H29)   1929
The Enigma H was the last model in the range of Schreibende Enigma (printing Enigma) machines. It was developed and introduced in 1929, as the successor to the Die schreibende Enigma.

The official model number for this machines was H29 and the internal designator was Ch. 14, whilst it was called Enigma II by the Reichswehr (the predecessor of the Wehrmacht). This machine was sometimes used as a printer for a modified Enigma I or Enigma G.

 More information
  

Enigma A   1924
Enigma A was the first Enigma cipher machine that used light bulbs for its output. It is therefore also known as the Glühlampenchiffriermaschine (glow lamp cipher machine). It had a rather uncommon layout and required a special key to be pressed in order to set the rotors in motion.

The machine was introduced in 1924 was soon succeeded by its successor, Enigma B. As far as we know, there are no surviving examples of the Enigma A.

 More information

  

Enigma B   1924/25
The Enigma B was the second machine that used light bulbs (Glühlampen) for its output. It was introduced in 1924/1925 as the successor to the Enigma A. Different versions of the Enigma B have existed, including a Swedish one.

The letters on the keyboard and on the lamp panel are organised in the order of the alphabet. It is the first Enigma with removable wheels.

 More information

  

Enigma C   1925
Enigma C was the successor to the Enigma B. It is the first machine has a power switch at the top, plus two terminals for connecting an external power supply. It has an improved keyboard and contains two spare light bulbs.

A special variant of the Enigma C — known as Funkschlüssel C — was used by the German Reichsmarine from 1926 onwards. It has 28 contact points and 29 keys on its keyboard.

 More information

  

Enigma D (A26)   1926
The Enigma D was developed in 1926 as the successor to the Enigma C. It is often referred to as the Commercial Enigma. The official model number was A26 and it was given the internal designator Ch. 8.

The image on the right shows a rare sample of the Commercial Enigma that was found in 2011.

 More information
  

Enigma K (A27)   1927
The Enigma K can be regarded as a series of 'special' machines based on the design of the Enigma D. The official model number is A27 and the first internal designator for this machine is Ch. 11b. The machine was introduced in 1927, but it wasn't before 1936 that the letter K was used in the serial number.

Other machines, such as the Tirpitz (T), the KD and the Swiss K, belong to this family.

 More information
  

Zählwerk Enigma (A28)   1928
At some point in the Enigma family tree, a machine was developed with an improved wheel-turnover mechanism and a counter. It was called the Zählwerk Enigma and was used by various intarnational commercial and military customers.

The later Enigma G (model G31) was based on this Enigma model.

 More information
  

Enigma I   1930
The Enigma I is the most well-known Enigma. It was developed especially for the German Reichs­wehr (later: Wehrmacht). All military Enigma machines are based on this model. Is has three cipher rotors, a fixed reflector (Umkehrwalze, UKW) and a plug board (Steckerbrett).

The initial Naval Enigma (M1, M2 and M3) is functionally identical to this machine, but has letters on the rotors rather than numbers.

 More information
  

Enigma Z (Z30)   1930
The Enigma Z is a rather strange variant of the light bulb machine (Glühlampenmaschine) as it only has 10 keys and 10 lamps, containing the numbers 0 thru 9.

Not much is known about this machine, although it is likely that there were two different versions of it; one based on the Enigma D and the other based on the Zählwerk Enigma (G).

 More information

  

Enigma G (G31)   1931
The Enigma G (model G31) was a slighly smaller variant of Zählwerk Enigma A28 (see above). The machine was sold to various international customers and was also used during WWII by the German intelligence service, the Abwehr.

Because the Abwehr was the biggest customer of the machine, it is often referred to as the Abwehr Enigma, but this is a misnomer. It was not the only cipher system used by the Abwehr, and the Abwehr was not the only user of the machine.

 More information

  

Swiss Enigma K (A27)   1939
The most famous version of the Enigma-K is the one that was supplied to the Swiss Army on the eve of WWII. For this reason it is often called the Swiss Enigma K or just Swiss K. It was modified by the Swiss Army and was supplied with an external lamp panel and a power supply.

As the Swiss knew that the Germans were capable of breaking Swiss Enigma traffic, they developed NEMA as a replacement.

 More information
  

Railway Enigma   1940
During WWII, the Germans used a special Enigma machine for the German Railway (Reichsbahn). It was basically a standard Enigma K with rewired wheels and a rewired UKW.

Enigma traffic from the German Reichsbahn was first encountered by the codebreakers at BP in July 1940 and later in February 1941.

 More information
  

Enigma M4   1942
Enigma T (Tirpitz)   1943
The Enigma T, codenamed Tirpitz, was developed during WWII by the Germans especially for use by the Japanese Army. It was based on the commercial Enigma K, but had differently wired wheels and multiple turnovers on each wheel. Furthermore, it had an Eintrittswalze (ETW) that was wired differently than all other Enigma machines.

 More information
  

On 2 February 1942, the Kriegsmarine (German Navy) suddenly introduced this new version of the Enigma machine. The M4 had 4 rotors rather than the usual 3, and was initially unbreakable by the Allied codebreakers. It is backwards compati­ble with the M3

The exta 4th rotor was used exclusively by the U-boat division of the German Navy. The rest of the Navy kept used it in M3-compati­ble mode.

 More information
  

Enigma KD (A27)   1944
The Enigma KD was a rare variant of the Enigma K, that was used by Mil Amt, the successor of the Abwehr. It is based on the Enigma K but has wheels with 9 notches each, plus a rewirable reflector (UKW-D).


 More information
  

Polish Enigma double   1933
The Polish Enigma double is a cipher machine, developed in 1932/33 by Marian Rejewski at the Polish Cipher Bureau, that replicates the German military Enigma I. It design is based on the comercial Enigma with a Steckerbrett added at the back.

The machines were built by the AVA Radio Company in Warsaw, and later also in France.

 More information

  




Accessories
Umkehrwalze D
During WWII, several attempts were made to improve the security of the Enigma. In January 1944, the Luftwaffe (Air Force) introduced a field-rewirable reflector, called UKW-D.

It is little known that there was a separate version of UKW-D for the Kriegsmarine (Navy). The UKW-D shown here is such a rare naval variant.

 More information
  

Enigma Uhr
In another attempt to improve the security of the Enigma, the Luftwaffe introduced the Enigma Uhr in July 1944; a small wooden box that could be connected to the machine's Steckerbrett by means of 20 cables.

On top of the Uhr is a large wooden knob that allows the operator to select any of 40 alternative wirings, preferably one for each new message on a given day.

 More information

  

Lückenfüllerwalze   wanted item
Another measure to make the Enigma safer, was the so-called Lückenfüllerwalze (gap-fill wheel) that featured 26 user-configurable notches. This way, the number and position of the notches of each wheel could be changed frequently.

The Lückenfüllerwalze was planned to be used in combination with UKW-D, but like UKW-D and the Uhr it came too late.

 More information
  

Power Supply Unit
In Switzerland, each Enigma machine that was used by the Army and the Foreign Office — commonly known as a Swiss-K — was supplied with a mains power supply unit (PSU). It allows the Enigma to be powered from any mains voltage, in addition to the internal battery.

Up to four Enigma machines can be connected simultaneously to a single PSU.

 More information

  

Schreibmax printer
For convenience a small printer was developed for Naval Enigma machines. They could be fitted on top of an M3 or M4, and had an external power supply unit. When typing, the enciphered text was printed on a 9mm paper strip.

It is likely that this printer was only used in the shore stations, as it has to be powered from the 75-220V AC mains.

 More information

  


Related subjects
Enigma Patents
In 1918, the first Enigma-related patent was registered by Arthur Scherbius in Germany. Since then, numerous other inventions have been patented by Scherbius and his collegues, in Germany as well as in many other countries.

We've collected the most important Enigma-related patents on a single page, which are also available for download.

 More information
  

Steckbrett
Of all the different Enigma models, only the military machines – used by the German Army before and during WWII – have a Steckerbrett (plugboard) at the front of the machine.

This plugboard is suitable for double-ended 2-pin plugs, each with a thick and in thin pin. It was not the first design of a Steckbrett however.

 More information

  

Messages
In recent years, some real Enigma messages have been recovered from the archives and from sunken U-boats and attempts have been undertaken to break these messages again.

This section of the website deals with some real Enigma messages, complete with the required settings of the machine, so that they can be decoded on a simulator.

 More information
  

Enigma lightbulbs
An Enigma machine uses small - rather unusual - lamps for its output. These lamps have a common E10 fitting, but have a somewhat flattened glass bulb. It is important to find these lamps, as ordinary bulbs are too high and will penetrate the celluloid lamp film. There are two variants: clear and half-opaque.

 More information
  

Reproduction parts
Many Enigma machines found today, are not in very good condition and may require some work in order to get them going again.

In the past few years, various people have made an effort to produce good and accurate reproduction parts in order to restore Enigma machines. Some of these parts are available through the Crypto Museum.

 More information
  

Family tree
Based on many years of research by Frode Weierud, we've been able to put together the most accurate family tree of Enigma machines to date. It shows the relationship between the various models and variants, and provides a lot of additional information.

Please note that the tree is based on ongoing research and is therefore subject to changes in the future.

 More information
  

Breaking Enigma
It is sometimes thought that the Enigma was broken by Colossus, the first electronic digital computer. This was not the case, however.

The Enigma was broken manually (using hand methods) and with help of an electro-mechanical device, called the Bomba (Polish), and Bombe (British). The latter has been rebuilt and is now on public display at Bletchley Park (UK).

 More information
  




Enigma Manufacturers
Initially, all Enigma machines were manufactured by the original company Chiffriermaschinen AG – commonly abbreviated ChiMaAG – in Berlin (Germany). After the Germans acquired the Enigma patents, ChiMaAG was taken over in 1935 by Heimsoeth und Rinke. During World War II (WWII), additional companies were appointed to manufacture Enigma machines under license. Below is the list of all Enigma manufacturers and their manufacturer's code (when applicable) [1].

 
Initial production
Manufacturer Address From To
Chiffriermaschinen AG (ChiMaAG)
Steglitzerstraße 2
Berlin W 35
1923 1934
Chiffriermaschinengesellschaft
Heimsoeth und Rinke
Uhlandstr. 136
Berlin-Wilmersdorf
1935 1945
 
WWII production
Manufacturer Address Code Issued
Olympia
Büromaschinenwerke AG
Mainzerhofplatz
Erfurt
aye Oct 1940
Ertel-Werk
für Feinmechanik
Westendstr. 160
München
bac Feb 1941
Konski & Krüger
Fabrik elektr. u. mechanischer Apparate
Chausseestr. 117
Berlin N 4
gvx Jul 1941
Chiffriermaschinengesellschaft
Heimsoeth und Rinke
Uhlandstr. 136
Berlin-Wilmersdorf
jla Sep 1941
Atlas-Werke AG
Maschinenfabrik
Steinhöft 11
Bremen
jmz Sep 1941




Enigma logo
Below are digital copies of the original Enigma logo. This logo has been recreated from scratch and is presented here as a PDF file, in order to preserve the resolution. The copyright of this logo belongs to us. You may download and use these logo's for personal non-commercial use. For commercial use of the logo, please ask permission first.
    Enigma logo (fully shaded) (3KB PDF file)
    This file contains the Enigma logo at twice the normal size, with full shading so that it can be used directly on websites and printed material. Fully scalable.
    Enigma logo (black & white) (3KB PDF file)
    This file contains the Enigma shield that was present inside the top lid of the wooden case, in partular with commercial machines that were produced before WWII. The distance between the two mounting holes should be 65 mm.
    Enigma stamp (2KB PDF file)
    This file contains the stamp with the Enigma logo as it was sometimes present inside the hinged flag (Klappe) at the front of the wooden case. It is fully scalable, but is currently not scaled to the actual size.


Enigma Replicas
Every once in a while, someone decides to built a replica of an Enigma. Although the basic operating principle of the machine is pretty straightforward, making a reproduction is not simple at all. Bear in mind that a single coding wheel consists of over 300 individual parts. Below are some links to people who have successfully built a replica or a machine with similar functionality.




Enigma simulators
Enigma Simulator for Windows
Version 7.0.1 - 7 December 2011

In 2004, Dirk Rijmenants in Belgium released the first version of his graphical Enigma simulator for Windows. With this program he won the Superior Coding Award in the 2004 Planet Source Code Contest (PSC). Since then, the program has been enhanced several times and is considered one of the best Enigma Simulators for Windows.

The program simulates all known Enigma variants in great detail, including appropriate skins and sound. Operation of the simulator is very intuitive and online help is available at a click of the mouse. The image on the right shows a screen-shot of the M3 simulator.

 Download simulator (off-site)

  

Enigma Simulator for RISC OS
Version 1.70 - 3 November 2016

In 2001, Paul Reuvers developed a fully featured Enigma Simulator for RISC OS, the first operating system to run natively on ARM-based hardware. The software is maintained to the present day, and runs on modern hardware, including iMX6, Beagle Board, Raspberry Pi and Virtual Acorn.

The program simulates all known variants of the glowlamp-based Enigma machine in great detail, including selectable skins and full sound effects. Setting up the machine is intuitive and online help is available at the click of a mouse.

Simulations are provided for the Enigma I, M3, M4, Abwehr G and variants of the commercial Enigma D and K. Also included are Enigma T (Tirpitz), the Polish Enigma Clone and Enigma E.

 More information

  

Other software
A number of Enigma computer simulations have been developed by various people, for a variety of platforms. Below is a list of popular Enigma simulations.

Hardware


In popular culture
Movies
An Enigma machine appears in the folloing movies:

  • 1981
    Movie
    Das Boot
  • 2000
    Movie
    U-571
  • 2001
    Movie
    Enigma
  • 2001
    Movie
    All the Queen's Men
  • 2014
    Movie
    The Imitation Game
  • 2018
    Netflix
    Das Boot (series 2018-2023)

Known Enigma models
 
Printing Enigma
Type Model Designator Year Description
- - - 1923 Die Handelsmaschine (print wheel)
- - - 1926 Die screibende Enigma (type bars)
H H29 Ch.14 1929 Enigma II (push bars)
 
Glowlamp Enigma
Type Model Designator Year Description
A - - 1924 First glowlamp machine
A' - - 1924 Kleine militärmaschine
B - - 1924 Removable rotors, Ringstellung
B' - - 1925 Swedish variant, fixed UKW, extra rotor
C - - 1925 Fixed UKW with 2 positions
C' - - 1926 Funkschlüssel C, UKW with 4 positions
D A26 Ch.8 1926 Settable UKW, notch attached to rotor body
K A27 Ch.11b 1927 Notch attached to letter ring
- A28 Ch.15 1928 Counter machine, cogwheel mechanism
Z Z30 Ch.16 1930 Mark 1: Numbers-only version
Z Z30 Ch.16 1930 Mark 2: Cogwheel mechanism
G G31 Ch.15a 1931 Counter machine, Abwehr Enigma
G G31 Ch.15b 1931 Connector for printing device
G G31 Ch.15c 1931 Version with plugboard
 
Specials
K A27 Ch.11b 1938 Swiss-K variant with external lamp panel
T A27 Ch.11b 1942 Tirpitz, version for Japan
KD A27 Ch.11b 1944 Enigma K with UKW-D
 
WWII military machines
D - Ch.11a 1927 Reichswehr, prototype Steckerbrett
I - Ch.11f 1929 Enigma I (Reichswehr, Wehrmacht)
M1 - Ch.11g 1934 Kriegsmarine version, 3 rotors
M2 - Ch.11g 1938 Similar to M1
M3 - Ch.11g 1940 Similar to M2
M4 - Ch.11g4 1941 Kriegsmarine version, 4 rotors

 Enigma family tree


Documentation
  1. Oberkommando der Kriegsmarine, Der Schlüssel M, Verfahren M Allgemein
    Operating procedure for Naval Enigma. Berlin 1940.
    Crypto Museum #300359. 1

  2. Doppelbuchstabentauschtafeln für Kenngruppen
    Bigram substitution table for Message Indicators. Crypto Museum #300356. 1
    1. Document kindly supplied by Arthur Bauer [2].

References
  1. Oberkommando des Heeres,
    Liste der Fertigungskennzeichen für Waffen, Munition und Gerät

    Reichsdrückerei Berlin 1944, reprinted by Pawlas, Nürnberg, 1977.
    ISBN 3-88088-214-2

  2. Arthur Bauer, Foundation for German Technology
    Historical Enigma documents kindly supplied for reproduction.

  3. Jared Owen Animations, How did the Enigma Machine work?
    YouTube channel Jared Owen, 11 December 2021
Further information
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© Crypto Museum. Created: Tuesday 07 July 2009. Last changed: Sunday, 02 June 2024 - 07:04 CET.
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