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Enigma Tree Rotor Enigma H → ← Die Handelsmaschine
Printing Enigma machine · 1924-1926
Die schreibende Enigma (English: the printing Enigma) was an electromechanical
cipher machine,
developed between 1924 and 1926 by Chiffriermaschinen AG (ChiMaAG)
in Berlin-Wannsee (DE), as the successor to the so-called
Handelsmaschine.
It was the second machine to be sold under
the Enigma brand and was succeeded in 1929 by the improved
Enigma H or Enigma Model H29.
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Unlike Die Handelsmaschine
– which featured a rotating print wheel
that was unreliable at high speeds – the Schreibende
Enigma is equipped with regular type-bars, which were already
used widely in the typewriters of the era. For this reason, the machine
is also known under the name Typenhebelmaschine (type bar machine).
The rare photograph shown on the right shows the first version of the
machine, which is based on a 'Cardinal' typewriter made by
Uhrenfabrik vorm. L. Furtwängler Söhne in Furtwangen (DE).
An additional mechanism is added at the right.
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Development of the machine was started in late 1923, with a projected
introduction sometime in 1924, but this appeared unrealistic due to
manufacturing problems and reliability issues with respect to the
printing mechanism. The nature of these problem is currently
unknown, but it prompted manufactuer – ChiMaAG –
to look for a different supplier of the printing mechanism.
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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 schreibende Enigma — was known as
Enigma B, but from surviving documents it has meanwhile become clear
that Enigma B was one of the first lamp-based Enigmas
(Glühlampenmaschine) [2].
It seems likely that the first two printing Enigma machines did not
have a single-letter type designator.
Around 1925, a new supplier of the printing mechanism was found
and development of the Schreibende Enigma continued.
The new version was released around 1926.
It is currently unknown who the new supplier was and how many machines
were eventually produced, but it seems likely that a small number
were manufactured in 1927, with another small batch in 1928.
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The two images on the right were found in 2009 in the archives of the
Swedish National Defence Radio Establishment (FRA) [1], and are believed
to show the improved version of the machine.
Keyboard, type-bars, ink ribbon and carriage of an existing
typewriter are used, whilst additional crypto-related parts
were added at the right and behind a panel in the space under the printer.
The keyboard consists of 60 keys, divided over 6 rows, plus a space
bar with a special SHIFT-key at either side. The SHIFT-key at the left
is used to switch to figures, whilst the one at the right returns to letters.
Pressing either SHIFT-key automatically inserts a space in the output.
As the cipher rotors had only 26 contacts, only the letters A-Z were included
in the ciphertext. This means that a special trick had to be used to SHIFT
between letters and figures, such as the one described in
German patent DE425566.
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In the patent, filed on 28 February 1924, inventor Paul Bernstein describes
a system to use the letters 'J' and 'Q' for switching to numbers and back
to letters. In the output, the real letter 'J' is replaced by an 'I' and the
letter 'Q' is replaced by a 'K', so that the text is still comprehensible.
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The image on the right shows the same version of the machine from the front
right, whith the cipher compartment under the type-bars visible.
When zooming in on this photograph it becomes clear
that there are two scramblers, one at the left and one at the right,
mounted on a common axle. Each of the scramblers consists of two cipher
rotors held between entry and exit discs.
The rest of the cipher mechanism is housed in the large blob at the right
side of the machine. It has several knobs for setting the initial position
of the rotors and a set of smaller wheels at the top right, of which the
current setting is visible through windows in the machine's metal cover.
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It is likely that these smaller wheels are used for setting the
message key – consisting of 4 letters and 5 digits – using the knobs
on the right. As an extra detail, this photograph shows
two symbols at the front edge of the machine
– under the keyboard – which might be the
company logo
of the new supplier of the printing mechanism.
In 1929, the Schreibende Enigma was succeeded by the
Enigma Model H29 (designator Ch.14) —
the last printing Enigma machine.
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In the meantime, a smaller and much more affordable machine had
been introduced in 1924. Known as the
Glühlampenmaschine (glowlamp
machine) it used light bulbs for its output and was easier to handle
as it was a reciprocal system. The first machine of this type was
the Enigma A,
soon followed by Enigma B
and Enigma C.
It was the beginning of a long line of cipher
machines that ended with the Enigma I
— M4, that were used by the German
Armed Forces during WWII.
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© Crypto Museum. Created: Sunday 13 September 2009. Last changed: Monday, 22 May 2023 - 14:52 CET.
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