Enigma-M

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With the serial number M 522 and dating from 1934, this exhibit is probably the oldest surviving marine Enigma.

The Enigma-M (also called: Enigma M , Key M or Marine-Enigma ) are models of the Enigma rotor key machine that were used by the German Navy before and during the Second World War to encrypt their communications. There were essentially four different marine enigmas, namely the M1, M2, M3 and finally M4 models, which were introduced one after the other over a period of eight years.

history

After the Enigma I was put into service by the Imperial Army of the Weimar Republic on June 1, 1930, the Imperial Navy of the German Empire followed in 1934 with the Enigma-M1 . A year later, on June 1, 1935, the German naval forces were renamed the Kriegsmarine . In 1938, the High Command of the Navy (OKM) introduced the Enigma-M2 and a year later the Enigma-M3 . Finally, in the middle of the war, on February 1, 1942, the M4 was put into service .

Enigma-M1

The roller set contains three interchangeable and rotating rollers, each of which can take up 26 rotational positions, which were marked A to Z on the Marine Enigmas (in contrast to 01 to 26 on the Enigma machines used by the Army and Air Force).
The roller marked by the Roman numeral VI was used exclusively by the Navy.

The Enigma M1 is almost identical to the most widely used Enigma machine, the Enigma I, which was used by tens of thousands of the army and air force of the German Reich before and during the Second World War . Both models (Enigma I and Enigma M1) contain three interchangeable rotating rollers and a non-rotating reverse roller (VHF). While there were initially only three rollers to choose from for the Enigma I (I to III) and from December 15, 1938, with the commissioning of rollers IV and V, then five rollers, the M1 had a range of six different rollers from the start (I to VI), three of which were inserted into the machine. So that the marine Enigma was cryptographically little stronger, because there was 6 x 5 x 4 = 120 possible roller positions, as opposed to only 5 x 4 x 3 = 60 layers of Enigma I .

An important difference between roller VI and the five other rollers are the two transfer notches in contrast to the only one transfer notch in each of rollers I to V. A minor distinguishing feature is the identification of the 26 roller positions and the connector on the connector board . While on the Enigma I the rollers are marked with numbers (01 to 26), the Navy preferred letters (A to Z). The opposite is true for the sockets. These are identified by letters on the Enigma I and numbers on the Enigma M, and occasionally ( redundantly ) by numbers and letters. As with the Enigma I, the sockets on the M1 were also labeled in the usual QWERTY order . There were also some minor design differences that did not affect the cryptographic compatibility of the models, provided that only reels I to V (and not reel VI) were used.

Enigma-M2

In addition to some design details, the main difference to the M1 is the seventh roller (VII) that is also available in the roller range. This increases the number of possible roller positions from 6 · 5 · 4 = 120 to 7 · 6 · 5 = 210. In contrast to the M1, the sockets were no longer labeled in the QWERTY order, but the usual alphabetical sorting was chosen. In addition, two more sockets were added that could be used to test the plug cables.

Enigma-M3

The connector board of this M3 is identified (redundantly) by letters and numbers (A1 to Z26).
The numerical identification (1 to 26) of the sockets on the connector board is easy to see on this marine Enigma.

The M3 also had an eighth roller (VIII), whereby the number of theoretically possible roller layers was increased again, now to 8 · 7 · 6 = 336. However, the rule was that at least one of the three exclusive marine reels (VI, VII or VIII) always had to be used. In contrast to the other rollers (I to V), these were characterized by two transfer notches and were therefore considered to be cryptographically particularly strong and indispensable. However, this measure did not exhaust the number of theoretically possible roller positions.

There were also some design and technical detail changes, such as a newly added 220 V connection, but cryptographically no changes to the M2. This only changed with the M4, which was cryptographically much stronger than all of its predecessors.

Enigma-M4

chronology

The following table lists the years of manufacture, serial numbers (Ser.No.), quantities and model names of the Marine Enigmas manufactured from 1934 to 1941. After 1941, thousands more M3 machines and, especially for the submarines, M4 machines were built.

year Ser.-No. number model
1934 M501-M901 401 M1
1935 M902-M961 60 M1a
1937 M962-M1111 150 M1a
1938 M1112-M1421 310 M2
1939 M1422-M2001 580 M2a, M3
1940 M2002-M2801 800 M3
1941 M2802-M3812 1011 M4

literature

Web links

Individual evidence

  1. ↑ The world's oldest naval ENIGMA . (English). Retrieved April 3, 2017.
  2. ↑ Louis Kruh, Cipher Deavours: The commercial Enigma - Beginnings of machine cryptography . Cryptologia, Rose-Hulman Institute of Technology, Taylor & Francis, Philadelphia PA 26.2002,1 (January), p. 11. ISSN  0161-1194 apprendre-en-ligne.net (PDF; 0.8 MB) accessed on April 3 2017.
  3. ↑ Michael Pröse: Encryption machines and deciphering devices in the Second World War - the history of technology and aspects of the history of IT . Dissertation at Chemnitz University of Technology, Leipzig 2004, p. 50
  4. ^ Hugh Sebag-Montefiore: Enigma - The battle for the code . Cassell Military Paperbacks, London 2004, p. 355. ISBN 0-304-36662-5 .
  5. ↑ Versions Enigma M1, M2 and M3 in the Crypto Museum ; Retrieved April 3, 2017.