Editing Enigma machine (section)

=== Commercial Enigma ===
[[File:Scherbius-1928-patent.png|thumb|right|upright=1.45|Scherbius Enigma patent, {{US patent|1657411}}, granted in 1928]]
On 23 February 1918,<ref>{{cite web| url = https://www.cdvandt.org/Enigma%20DE416219C1.pdf| title = German patent No. 416219 from 23 February 1918}}</ref> [[Arthur Scherbius]] applied for a [[patent]] for a ciphering machine that used [[rotor machine|rotors]].<ref>{{cite patent |inventor-last=Scherbius |inventor-first=Arthur |title=Ciphering Machine |country-code=US |patent-number=1657411 |gdate=24 January 1928 |pridate=11 February 1922 |fdate=6 February 1923 |assign1=Chiffriermaschinen AG}}</ref> Scherbius and [[E. Richard Ritter]] founded the firm of Scherbius & Ritter. They approached the [[Reichsmarine|German Navy]] and Foreign Office with their design, but neither agency was interested. Scherbius & Ritter then assigned the patent rights to Gewerkschaft Securitas, who founded the ''Chiffriermaschinen Aktien-Gesellschaft'' (Cipher Machines Stock Corporation) on 9 July 1923; Scherbius and Ritter were on the board of directors.

==== Enigma Handelsmaschine (1923) ====
Chiffriermaschinen AG began advertising a rotor machine, ''Enigma Handelsmaschine'', which was exhibited at the Congress of the [[Universal Postal Union|International Postal Union]] in 1924. The machine was heavy and bulky, incorporating a [[typewriter]]. It measured 65×45×38&nbsp;cm and weighed about {{convert|50|kg|lb}}.

==== Schreibende Enigma (1924) ====
This was also a model with a type writer. There were a number of problems associated with the printer and the construction was not stable until 1926. Both early versions of Enigma lacked the reflector and had to be switched between enciphering and deciphering.

==== Glühlampenmaschine, Enigma A (1924) ====
The reflector, suggested by Scherbius' colleague Willi Korn,<ref name="Korn">{{cite book |last1=De Leeuw |first1=Karl Maria Michael |last2=Bergstra |first2=J A |title=The history of information security : a comprehensive handbook |date=2007 |publisher=Elsevier |location=Amsterdam |isbn=9780080550589 |page=393}}</ref> was introduced with the glow lamp version.

The machine was also known as the military Enigma. It had two rotors and a manually rotatable reflector. The typewriter was omitted and glow lamps were used for output. The operation was somewhat different from later models. Before the next key pressure, the operator had to press a button to advance the right rotor one step.

==== Enigma B (1924) ====
[[File:Enigma-Glühlämpchen.jpg|thumb|upright|Typical glowlamps (with flat tops), as used for Enigma]]
Enigma ''model B'' was introduced late in 1924, and was of a similar construction.<ref>{{cite web|url=http://www.armyradio.com/publish/Articles/The_Enigma_Code_Breach/Pictures/enigma_type_b.jpg|title=image of Enigma Type B|url-status=dead|archive-url=https://web.archive.org/web/20051021083422/http://www.armyradio.com/publish/Articles/The_Enigma_Code_Breach/Pictures/enigma_type_b.jpg|archive-date=21 October 2005}}</ref> While bearing the Enigma name, both models ''A'' and ''B'' were quite unlike later versions: They differed in physical size and shape, but also cryptographically, in that they lacked the reflector. This model of Enigma machine was referred to as the Glowlamp Enigma or ''Glühlampenmaschine'' since it produced its output on a lamp panel rather than paper. This method of output was much more reliable and cost effective. Hence this machine was 1/8th the price of its predecessor.<ref name="Enigma History"/>

==== Enigma C (1926) ====
''Model C'' was the third model of the so-called ″glowlamp Enigmas″ (after A and B) and it again lacked a typewriter.<ref name="Enigma History"/>

==== Enigma D (1927) ====
The ''Enigma C'' quickly gave way to ''Enigma D'' (1927). This version was widely used, with shipments to Sweden, the Netherlands, United Kingdom, Japan, Italy, Spain, United States and Poland. In 1927 [[Hugh Foss]] at the British [[Government Communications Headquarters|Government Code and Cypher School]] was able to show that commercial Enigma machines could be broken, provided suitable cribs were available.<ref>Bletchley Park Trust Museum display</ref> Soon, the Enigma D would pioneer the use of a standard keyboard layout to be used in German computing.  This "QWERTZ" layout is very similar to the American [[QWERTY]] keyboard format used in many languages.

===== "Navy Cipher D" =====
Other countries used Enigma machines. The [[Italian Navy]] adopted the commercial Enigma as "Navy Cipher D". The Spanish also used commercial Enigma machines during their [[Spanish Civil War|Civil War]]. British codebreakers succeeded in breaking these machines, which lacked a plugboard.{{sfn|Smith|2006|p=23}} Enigma machines were also used by diplomatic services.

==== Enigma H (1929) ====
[[File:Enigma-8-rotor.jpg|right|thumb|upright|A rare 8-rotor printing Enigma model H (1929)]]
There was also a large, eight-rotor printing model, the ''Enigma H'', called ''Enigma II'' by the ''[[Reichswehr]]''. In 1933 the Polish Cipher Bureau detected that it was in use for high-level military communication, but it was soon withdrawn, as it was unreliable and jammed frequently.{{sfn|Kozaczuk|1984|p=28}}

==== Enigma K ====
The Swiss used a version of Enigma called ''Model K'' or ''Swiss K'' for military and diplomatic use, which was very similar to commercial [[#Enigma D (1927)|Enigma D]]. The machine's code was cracked by Poland, France, the United Kingdom and the United States; the latter code-named it INDIGO. An ''Enigma T'' model, code-named ''Tirpitz'', was used by Japan.