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Die Handelsmaschine
Printing Enigma machine · 1923

Die Handelsmaschine (the commercial machine, or trade machine) was a printing cipher machine, developed in 1923 by Scherbius & Ritter
oHG
in Berlin-Wannsee (Germany), and manufactured at Gewerkschaft Securitas (later: Chiffriermaschinen AG) in Berlin. It was the first cipher machine to be sold under the Enigma brand. As far as we currently know, there are no surviving examples of this model. The machine was succeeded in 1926 by Die schreibende Enigma (printing Enigma).

The heavy and bulky Handelsmaschine printed its output directly onto paper, which is why it belongs to the class of the schreibende Enigma (printing Enigma). The description below was taken from an article in a technical magazine of November 1923 by inventor Arthur Scherbius [1].

The machine had four cipher wheels with 28 electrical contacts at either side, and a cog-wheel driven stepping mechanism. Each cog-wheel had a different number of teeth (using prime numbers and numbers without a common factor) in order to guarantee a long cipher period and irregular (i.e. less predictable) stepping [2].

The four cipher wheels were fitted permanently inside the machine. Their starting position could be set with four knobs at the right. By pulling out a knob, the position of the driving (notched) cog-wheel could also be altered. A fifth knob at the top was fitted to the main transport axle. By inserting a crank into this knob (as shown in the image on the right), the entire cipher mechanism could be moved forward and backward, allowing for simple typing errors to be corrected easily.

Above the cipher wheels was a 5-digit counter (German: Zählwerk) that counted the number of characters entered on the keyboard. The counter was reset with a handle sticking out at the left.
  

As the cipher operation was not reciprocal (i.e. reversible), a handle was present at the front of the machine to select between ciphering, deciphering and plain text. When switching between ciphering and deciphering, the electric current through the cipher wheels is reversed, which also reverses the algorithm. When set to plain text, the machine can be used as a common typewriter.

At the top of the machine, towards the rear, is the actual printer which resembles the printing part of a standard electrical typewriter of the era. It consists of a paper carriage and a wheel printer. When creating cipher text, the characters were printed in groups of 5 letters each, after which a space was inserted automatically. Ten such groups fitted on a single line (50 characters), and the user had to return the carriage manually before each new line. When deciphering, spaces would be inserted automatically where appropriate, so that the text was directly legible again.

The keyboard features letters, numbers and puctuation marks, and has a spacebar. A plain text message may consist of a mixture of these elements, whilst two Shift-keys are used to toggle between letters and figures. The output, i.e. the cipher text, only consisted of letters however, as the cipher wheels have just 28 contacts each. As an added advantage, letters are typically shorter in morse code than numbers, which resulted in shorter messages and cheaper telegrams [1].

The cipher wheels of 'Die Handelsmaschine'. Click to view at maximum resolution.

The machine featured a complex cog-wheel driven wheel turnover mechanism with irregular stepping. Each cipher wheel had a large cog-wheel attached to its right side, driven by a set of smaller cog-wheels (each with a different diameter) from which a number of teeth were missing.

According to Scherbius, it had a cipher period of approx. 1 million, which means that the cipher pattern repeats only after 1 million characters. About 20,000 of such periods were present. Part of the wheel turnover mechanism is described in German patent DE429122 of 26 March 1924 [2].

Click to download patent DE429122

So far, we have not found any better images of this Enigma variant. The pictures shown here were taken from a detailed technical description of the machine — by Arthur Scherbius himself — in Elektrotechnische Zeitschrift (Electro-technical Magazine) of 29 November 1923 [1]. In 2008 we found this magazine at an antiques shop in Germany. The full article can be downloaded below.

The complete 'Handelsmaschine' 'Handelsmaschine' with the cover removed Close-up of the cipher wheels
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The complete 'Handelsmaschine'
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'Handelsmaschine' with the cover removed
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Close-up of the cipher wheels

Improvements
Die Handelsmaschine – i.e. the first Enigma cipher machine – was developed and introduced in 1923. Due to reliability problems with the print wheel mechanism, development of a new model was started in 1924. The new model had type-bars (German: Typenhebel) – just like a regular typewriter – but due to mechanical and manufacturing problems, its introduction was delayed until 1926. The new machine became known as Die schreibende Enigma (the printing Enigma).

Due to recurring mechanical problems with Die schreibende Enigma, it was decided to develop yet another model that had push-bars — also known as shift-bars — instead of type-bars. It was introduced in 1929 and became known as Enigma Model H29, or simply Enigma H (internal designator Ch.14). In the German Reichswehr (later: Wehrmacht) it was known as Enigma II.

A year after the introduction of Die Handelsmaschine, the company also released the first portable Glühlampen-maschine (glowlamp machine), the Enigma A, which was much smaller, far less heavy and above all much cheaper. Although the lamp-based machine was technically far less advanced than the printing variants, it was far more successful and eventually evolved into the Enigma I that became the mainstream cipher machine of the German Army during WWII.

CONFUSION — Over the years, the general understanding of the model names and designators of the various Enigma machines, has changed several times. For a long time, it was assumed that the machine described on this page — i.e. Die Handelsmaschine — was known as the Enigma A, but from archived documents it has meanwhile become clear that Enigma A was the first lamp-based Enigma machine (Glühlampenmaschine) [3]. It seems likely that the first two printing Enigma machines did not have a single-letter model name.
Documentation
  1. Enigma Chiffriermaschinen, Handelsmaschine
    Description and operating instructions (German). 1
    Chiffriermaschinen AG, 6 August 1924. 16 pages.
  1. Document courtesy Anders Wik.

References
  1. Dr.-Ing. Arthur Scherbius. Enigma Chiffriermaschine
    Elektrotechnische Zeitschrift. 29 November 1923. Heft 47/48. p. 1035-1036.

  2. Paul Bernstein, German Patent DE429122
    Chiffriermaschinen Aktiengesellschaft. 26 March 1924.

  3. Frode Weierud, Personal correspondence
    January 2019.

  4. Anders Wik, Enigma documents courtesy Anders Wik
    Personal correspondence, January—February 2019.
Further information
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Crypto Museum. Created: Sunday 23 August 2009. Last changed: Tuesday, 05 February 2019 - 16:28 CET.
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