Editing Enigma machine (section)

=== Military Enigma ===
The various services of the [[Wehrmacht]] used various Enigma versions, and replaced them frequently, sometimes with ones adapted from other services. Enigma seldom carried high-level strategic messages, which when not urgent went by courier, and when urgent went by other cryptographic systems including the [[Geheimschreiber]].

==== Funkschlüssel C ====
The Reichsmarine was the first military branch to adopt Enigma. This version, named ''Funkschlüssel C'' ("Radio cipher C"), had been put into production by 1925 and was introduced into service in 1926.{{sfn|Kahn|1991|pp=39–41, 299}}

The keyboard and lampboard contained 29 letters&nbsp;— A-Z, Ä, Ö and Ü&nbsp;— that were arranged alphabetically, as opposed to the QWERTZUI ordering.{{sfn|Ulbricht|2005|p=4}} The rotors had 28 contacts, with the letter ''X'' wired to bypass the rotors unencrypted.{{sfn|Stripp|1993}} Three rotors were chosen from a set of five{{sfn|Kahn|1991|pp=40, 299}} and the reflector could be inserted in one of four different positions, denoted α, β, γ and δ.{{sfn|Bauer|2000|p=108}} The machine was revised slightly in July 1933.{{sfn|Stripp|1993|loc=plate 3}}

==== Enigma G (1928–1930) ====
By 15 July 1928,{{sfn|Kahn|1991|pp=41, 299}} the German Army (''[[Reichswehr]]'') had introduced their own exclusive version of the Enigma machine, the ''Enigma G''.

The ''[[Abwehr]]'' used the ''Enigma G''. This Enigma variant was a four-wheel unsteckered machine with multiple notches on the rotors. This model was equipped with a counter that incremented upon each key press, and so is also known as the "counter machine" or the ''Zählwerk'' Enigma.

==== Wehrmacht Enigma I (1930–1938) ====
Enigma machine G was modified to the ''Enigma I'' by June 1930.{{sfn|Kruh|Deavours|2002|p=97}} Enigma I is also known as the ''Wehrmacht'', or "Services" Enigma, and was used extensively by German military services and other government organisations (such as the [[Deutsche Reichsbahn#Deutsche Reichsbahn-Gesellschaft (1924-1937)|railways]]{{sfn|Smith|2000|p= 73}}) before and during [[World War II]].

[[File:Bundesarchiv Bild 101I-769-0229-10A, Frankreich, Guderian, "Enigma" cropped.jpg|thumb|upright|[[Heinz Guderian]] in the [[Battle of France]], with an Enigma machine. Note one soldier is keying in text while another writes down the results.]]
The major difference between ''Enigma I'' (German Army version from 1930), and commercial Enigma models was the addition of a plugboard to swap pairs of letters, greatly increasing cryptographic strength.

Other differences included the use of a fixed reflector and the relocation of the stepping notches from the rotor body to the movable letter rings. The machine measured {{convert|28|x|34|x|15|cm|in|abbr=on}} and weighed around {{convert|12|kg|lb|abbr=on}}.{{sfn|Stripp|1993|p=83}}

In August 1935, the Air Force introduced the Wehrmacht Enigma for their communications.{{sfn|Kruh|Deavours|2002|p=97}}

==== M3 (1934) ====
By 1930, the Reichswehr had suggested that the Navy adopt their machine, citing the benefits of increased security (with the plugboard) and easier interservice communications.{{sfn|Kahn|1991|p=43}} The Reichsmarine eventually agreed and in 1934<ref>{{harvnb|Kahn|1991|p=43}} says August 1934. {{harvnb|Kruh|Deavours|2002|p=15}} say October 2004.</ref> brought into service the Navy version of the Army Enigma, designated ''Funkschlüssel'' ' or ''M3''. While the Army used only three rotors at that time, the Navy specified a choice of three from a possible five.{{sfn|Kruh|Deavours|2002|p=98}}
[[File:Bundesarchiv Bild 101I-241-2173-09, Russland, Verschlüsselungsgerät Enigma.jpg|thumb|left|Enigma in use on the Russian front]]

==== Two extra rotors (1938) ====
In December 1938, the Army issued two extra rotors so that the three rotors were chosen from a set of five.{{sfn|Kruh|Deavours|2002|p=97}} In 1938, the Navy added two more rotors, and then another in 1939 to allow a choice of three rotors from a set of eight.{{sfn|Kruh|Deavours|2002|p=98}}

==== M4 (1942) ====
{{See also|Cryptanalysis of the Enigma#M4 (German Navy 4-rotor Enigma)}}
A four-rotor Enigma was introduced by the Navy for U-boat traffic on 1 February 1942, called ''[[Cryptanalysis of the Enigma#M4 (German Navy 4-rotor Enigma)|M4]]'' (the network was known as ''Triton'', or ''Shark'' to the Allies). The extra rotor was fitted in the same space by splitting the reflector into a combination of a thin reflector and a thin fourth rotor.

<gallery mode="packed" heights="160">
File:Enigma-G.jpg|Enigma G, used by the ''[[Abwehr]]'', had four rotors, no plugboard, and multiple notches on the rotors.
File:Enigma-IMG 0484-black.jpg|The German-made Enigma-K used by the Swiss Army had three rotors and a reflector, but no plugboard. It had locally re-wired rotors and an additional lamp panel.
File:Four-rotor-enigma.jpg|An Enigma model T (Tirpitz), a modified commercial Enigma K manufactured for use by the Japanese
File:Enigma Decoder Machine.jpg|An Enigma machine in the UK's Imperial War Museum
File:Bundesarchiv Bild 101I-241-2173-06, Russland, Verschlüsselungsgerät Enigma.jpg|Enigma in use in Russia
File:Bundesarchiv Bild 146-2006-0188, Verschlüsselungsgerät "Enigma".jpg|Enigma in radio car of the 7th Panzer Div. staff, August 1941
</gallery>

[[File:CMoA Enigma Machine Exhibit in Georgia.JPG|thumb|A three-rotor Enigma machine on display at [[Mimms Museum of Technology and Art]] and its two additional rotors]]