The cryptographic Enigma machine was a product of the early 1900s. It came out of a necessity that runs through history, that of protecting and securing essential information. The invention of the Enigma by Arthur Scherbius was a modern take on this ancient problem. It was primarily used for military purposes with certain exceptions where civilian use was permitted. The Enigma evolved through the years, providing further technological advancements in every part of its production. During that regarded era, it was considered as an impenetrable defence mechanism. This device proved to be a Trojan horse build by their very hands. In the end, it was used by the allied forces to infiltrate enemy lines and bring a decisive victory that ended one of the greatest wars in history.


This intriguing device known as the Enigma was invented by Arthur Scherbius a German Engineer. On the 23rd of February 1918, his company Scherbius & Ritter filled for a patent on a rotor cipher machine under the name Enigma (DE Patent 416219). Although it was one of the first and most comprehensive designs, it was not the only rotor cipher machine at that time. The rotor machine was initially invented in the Netherlands during the year 1915 by two naval officers, R.P.C. Sprengler and Theo Avon Hendel. However, it was not until a decade later in the year 1928, that the German Army authorised the machine for general use by its divisions. Scherbius never lived to see all this happen as he died shortly after a horse carriage accident in 1927. After this unfortunate incident, his colleague Will Korn took the reins of the Enigma project and developed it even further.

Even though the machine is known as the Enigma, it eventually became nothing more than a brand name which was carried out and used during that historical period. The original manufacturer to produce the Enigma was Chiffriermaschinen AG; based in Berlin. It was also manufactured by five more companies under license. Each company had an official manufacturer’s code. The codes assigned to each licensed company were: aye for Olympia, bac for Ertel-Werk, gvx for Konski & Krüger, jla for Heimsoeth und Rinke and jmz for Atlas-Werke AG. These codes were imprinted on the machines and can give us a clue as to where and when they were manufactured. Many batches of machines where produced by these companies, developing quite a few variants with different rotor wirings. Most of these machines were used by military and diplomatic services in different countries around the world such as Italy and Spain.

The time period that we observe ranges from the very conception of the Enigma in 1918 to right after the ending of the war in 1945. This is the broad area in which the Enigma story resides in. In a more specific manner, the Public Enigma Simulator focuses mainly to the period ranging from 1926 to 1944. This period represents the main development era of the machine, initiating from the commercial Enigma D to the many military variants such as the M3 and M4. Some focus is given to how the machine carried on being used after the war. An example of this was the Norwegian Police Security Service obtaining a few machines and rewiring them for further use.

The evolution of the Enigma was divided into two historical periods of development. This is based on their means of producing output. The first Enigma to be constructed implemented a printing function for presenting output. For this reason this branch is classified as Printing Enigma's. They were heavy, bulky machinery but introduced a very sophisticated for its time mechanism. It included a cog-wheel driven, wheel turnover mechanism with irregular stepping. The other alternative which was developed later on, introduced a panel fitted with special light bulbs that replaced the printing function. These machines are therefore categorised as Lamp Enigma's. These machines dominated the scene as they were light, compact and very efficient. They also were the main focus of development which led to the creation of various models. In this simulator, the printing Enigma's are left out, as focus is given around the other branch of the Enigma tree, the so called Lamp Enigma's.


The first Lamp Enigma was produced in 1924 and carried the code name C. Resources and details for this model appear to be limited. The wiring of the machine that is crucial to understanding it, also remains unknown to this date. Therefore, Enigma C is not included in the simulator. This is not to say that it is not an important machine. It was a significant milestone that altered the evolution of the Enigma and opened the way for the development of Enigma D.

The commercial Enigma D was released in 1926 and revealed new horizons for the machine. It is clear that this model was the first widely available machine, besides the fact that it was only released for a year. Most qualities represented by an Enigma machine can be observed and understood just by inspecting this model. The blueprints of this machine would later become the basis of all further development. The design ethos of the Enigma D can be seen on all machines manufactured after it, until the end of the war.

At this point, the evolution of the Enigma began splitting into distinctive variants, that incorporated many machines and became a category of their own. Based on a reliable model such as the Enigma D, development was very rapid and we can see multiple variants manufactured in a short period of time. Three variants came to leave a mark on the Enigma production line. They were developed to a high degree and became examples of their own, gaining infamous recognition due to their status.

In 1927, Enigma K was released which apart from some minor manufacturing alterations was identical to Enigma D. Another variant that sprung from this machine was the Enigma I during the year of 1932. It was one in a series of models to be produced for military use only. This machine also led to the development of the famous Enigma M3 and M4. A more sophisticated version came in 1928, based on the body of the Enigma D. This version was branded as the Zählwerk Enigma. It featured a complex cog-wheel driven mechanism as well as irregular stepping, similar to the early Printing Enigma's. A few models were developed based on this concept until production was eventually halted due to high manufacturing costs.

All the variants have been meticulously indexed and documented by: Hamer, Sullivan and Weierud (1993).


There is wide a variety of Enigma machines, having alternate ways of operation and construction. Even though most Enigma's seem incompatible to each other, some compatibility and interoperability appears to exist between them. For example, the Enigma M3 and M4 can create a communication channel if the machines are set up in a certain way. The M4 was manufactured in such a way as to allow that. Both machines have a choice of multiple reflectors. Enigma M3 has UKW-B which is equal to M4's thin UKW-B and the Greek rotor Beta in position A. Likewise M3s UKW-C reflector is the same as combining M4s thin UKW-C with the Greek rotor Gamma in position A. Having been set up in this way, the machines produce identical results.

This can also be regarded as feasible between other variants. The wiring of the service Enigma I, is identical to the first five rotors of the M3 and M4. Here we have yet another communication channel between three variants. In addition, the Enigma D is wired in the exact same way as the commercial K and therefore the machines can communicate. The Zählwerk Enigma A28 was found with an identical wiring to the commercial Enigma D and K. This also justifies the A28s relation to the Enigma D. However, this is not enough to ensure interoperability, as it had an irregular stepping mechanism. It operates under different principles that are incompatible with the traditional one. Since most machines received modifications to the rotor wirings, it is somewhat difficult to ensure that communication between machines is possible.