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Enigma H
Model H29 - Enigma-II - wanted item

The Enigma H was the last model in the range Schreibende Enigma (printing Enigma) machines. It was developed/introduced in 1929 as the successor to the Enigma B of 1926 and was mainly used by the German Wehrmacht where the machine was known as Enigma II (pronounced: two). Some machines were sold to foreign customers such as Hungary, where it was used by the Army.
 
The official model number of the Enigma H was H29 and the internal designator used by the manufacturer was Ch. 14. The Reichswehr (later: Wehrmacht) referred to it as Enigma II (say: 2).

The machine had 8 cipher wheels, but only 4 of these were used for the actual coding of the electric signals. The other 4 wheels were used to control the wheel turnovers. Each wheel had 26 contact points (A-Z) and the machine was capable of encrypting both letters and numbers.

The Enigma H printed directly onto paper, using push-bars, but wasn't very reliable. In practice, there were many complaints about blocking machines, despite several improvements.
  

The price of an Enigma H was rather high: it was offered for RM 80001 to Mr. Walter Edström in September 1929 [11] and for no less than RM 12000 to the Spanish Government in 1931 [12].
Not many H29 machines were ever built and even fewer have survived. The only example that is currently known, is in the Military Museum in Budapest (Hungary). Unfortunately, that machine is in pretty bad condition and many keys and other parts are missing (more information below).
 
  1. RM = Reichsmark, the German currency in those days.
Opened Enigma H29 seen from the right [7] Opened Enigma H29 seen from the left [8] H-221 seen from the front H-221 seen from the rear View of the controls of the Enigma H29 with serial number H-221

 
Hungarian H-221
A number of H29 machines were sold to Hungary before the outbreak of WWII, probably around 1931. The Hungarians ordered an unknown number of H29 machines with a printer connection, and 24 Enigma G31 models with a socket for connection to the larger machines (Ch.15b) [7].
 
In 2005, whilst on holiday in Europe, American tourist Eric Tischer [1] accidentally photographed a machine in an unknown military museum in Budapest (Hungary). This cipher machine later turned out to be the extremely rare Enigma H29.

In August 2012, Crypto Museum rediscovered the machine in the vaults of the Hungarian Museum for Military History [10], with the help of some very good friends in Austria and Hungary. The machine wasn't on public display at the time, but museum historian Dr. István Ravasz was kind enough to lift the machine from the archives.
  
View of the controls of the Enigma H29 with serial number H-221

He granted us access to the machine and put his office at our disposal for an entire day. The machine has serial number H-221 and is in pretty bad condition. It was possibly used as a parts-donor when repairing other machines. Many keys are missing from the keyboard and the paper carriage at the rear is missing completely. Furthermore, some smaller parts, such as one of the wheel-windows, have been removed. More strikingly however, the Enigma logo has clearly been removed from the front panel. Nevertheless, we were very exited about this extremely rare find. All full-colour images on this page are from the H-221 and have been taken at the museum.


The image above gives an overview of the various controls of the machine. The machine itself looks like a rather bulky electric typewriter and measures approx. 65 x 45 x 38 cm. It weights nearly 60 kg and is mounted on a wooden panel that contains the wiring of the entire system. When not in use, a wooden hood would normally be fitted over the machine to protect it against dust. The machine could be carried by pulling out two metal grips at the front and rear.

The machine is powered by an (external) 80-90V DC power source that is connected at the rear. By using large power resistors, it was possible to connect it directly to the 110V or 220V DC mains (where available). For use on AC networks, an optional external rectifier was available.

Power was turned on an off with a standard electrical switch that was mounted on the wooden bottom panel at the right front. Is has been removed from the machine shown here. An indicator at the top left of the keyboard showed that power was turned on. It should be noted that the machine is not motor-driven, but that is is completely operated by means of electrical solenoids. As a result, the machine only makes noise when a key is pressed, and the key-presses are 'soft'.
 
The beautiful city of Budapest The museum, currently undergoing restoration Museum entrance Cheers to the re-discovered Enigma H-221 in Dr. Ravasz' office Dr. Ravasz operating the Enigma-H H-221 seen from the front H-221 seen from the rear Photo by Eric Tischer in 2005. Reproduced here by kind permission [1]. Paul and Günter investigating the H-221
H-221 seen from the rear Font view of the H-221 View of the controls of the Enigma H29 with serial number H-221 Carrying grip extracted Power socket and serial number shield Power indicator at the top left of the keyboard Bottom view of the H-221 Close-up of the wiring at the bottom of the H-221
Power switch missing View of the left side of the keyboard Side panel missing Machine number two in the Hungarian Army inventory. The other number (2012.3.1) is the museum ID number. Top view of the machine Front view of the H-221 The lock of the wheel cover can be protected by a lead seal in order to prevent unauthorized opening Serial number engraved in the chassis

It is unknown at present how many H29 machines were bought by the Hungarians. According to Dr. Ravasz at the Museum, the Hungarian Army had three machines in their inventory at one time. Each machine was marked with a large number, with the H-221 carrying the number 2 on its rear panel. This has yet to be confirmed and no supporting documents have been found to date.
 
Restoration
A year after our re-discovery of the Enigma H-221, on 31 July 2013, we visited Budapest again to see what had become of this rare Enigma family member. The machine was now on public display at the Hungarian Spy Museum in the Royal Cellars in Budapest [13] and had been partly restored.
 
The missing keys have been added with the correct inlays in the formerly missing spots. Just above the keyboard, the second wheel window from the left has been reconstructed. And finally, the Enigma logo has been fitted to the front of the machine. As a result, the Enigma H-221 now stands out pretty well in an exhibition.

Despite the successful cosmetical restoration, the paper carriage is still missing and it is doubtful whether the machine will ever run again. Nevertheless it is a unique historical artifact that you must see on a trip to Budapest.
  
The partly restored H-221

The Hungarian Spy Museum is located in the Royal Cellars in Budapest, which are just a few hundred metres away from the Hungarian Military Museum. It is unclear at present whether the Spy Museum is still open, as the website [13] is unavailable at present (March 2014).
 
The partly restored H-221 The restored keyboard of the H-221 Our Hungarian friend Kálmán Tóth inspecting the H-221 The investigation team behind the H-221 (except for Paul Reuvers who made the photo) The restored wheel windows The wheel windows seen from the front Close-up of the type bars The new Enigma shield at the front

 
Operation
Setting the key of the H29 is rather straight forward. As all cipher wheels are permanently mounted on a single axis, they cannot be removed or swapped. When setting the key, the user first has to press a large knob (Lock) at the right side of the machine to disengage the wheels.
 
Now that the wheels can be moved freely, the user can then set all eight wheels to the desired Message Key (Spruchschlüssel) by moving the protruding thumbwheels up and down.

It is also possible to change the setting of the index rings (Ringstellung) on each of the wheels, by unlocking and raising the metal wheel cover. Altering this setting is called the Basic Setting (Grundstellung) and has no impact on the overall cipher security. It is merely a way of obscuring the key from the user. Once the Grunstelling has been altered, the top lid can be sealed.
  
8 cipher wheels

Once the cryptographic key is set, the locking knob at the right side has to be pulled out again in order to engage the wheels again. The machine is now ready for operation. The main mode of operation is selected by means of a large lever at the left side of the machine. This lever has three settings: Chiffrieren (Ciphering), Klarschrift (Plaintext) and Dechiffrieren (Deciphering). Ciphering has to be enabled first by setting a slide switch from Code aus (code off) to Code ein (code on).
 
8 cipher wheels with cover closed Top view of the 8 cipher wheels 8 cipher wheels Unlocking the metal wheel cover Front view of the H-221 with wheel cover raised MODE selector Close-up of the mode selector Unlocked mode selector (Code ein = Code ON)

 
Cipher wheels
The Enigma H29 features 8 cipher wheels that are mounted on a single axle. The middle 4 rotors are the actual electrical coding wheels, which are similar to the coding wheels of a lamp-based Enigma. Each rotor has 26 spring-loaded contacts on one side and 26 flat-faced contacts on the other side. The letters of the alphabet (A-Z) are engraved around each wheel (index ring).

Top view of the 8 cipher wheels

The outer 4 wheels (i.e. the leftmost two and the rightmost two) control the stepping of the electrical wheels. Each stepping wheel has a different number of steps (26, 27, 29 and 31) and controls one of the electrical wheels. As some wheels have more than 26 possible positions, they have numbers on the index ring in addition to the alphabet. All eight wheels are shown above.


Based on the brochure, the patent description and on observations of the machine, the drawing above should illustrate the basic operation of the machine. The outer 4 wheels are the stepping wheels (red). The rightmost stepping wheels of each set are driven by a common axle. Apart from driving the corresponding coding wheel, they also control the stepping of the adjacent stepping wheel by means of a cog-wheel that has 5 gaps (i.e. 5 teeth missing). The total period is then:

5 x 5 x 26 x 27 x 29 x 31 = 15,777,450

The brochure [2] confirms that the cipher period is indeed 15770450 and claims that the machine is capable of generating 17,576 different alphabets (26 x 26 x 26). This gives a total number of 277,304,461,200 unique keys that can be entered by the user. As the 4 coding wheels each have 26 contacts, the number of substitution alphabets is calculated as 264 = 456,976.

The wheels are all mounted on the same axle and can not be removed. The position of the wheels can be controlled with two knobs (one at either side of the machine) and manually by moving the outer thumb-wheel. In addition, the index ring of all 8 wheels can be altered (Ringstellung) as part of the machine's basic key (Grundstellung). This has no effect on the cryptographic strength.

Above the rightmost three wheels is a 5-digit odometer that counts the number of characters entered on the keyboard. The counter can be zeroized my means of a knob at the right. When the wheel cover is closed, the counter can be read through a small window at the top right.
 
8 cipher wheels with cover closed Top view of the 8 cipher wheels Stepping wheel 1 with 26 steps Stepping wheel 2 with 27 steps Stepping wheel 3 with 29 steps Stepping wheel 4 with 31 steps Changing the 'Ringstellung' Character counter

 
Russian copy?
The mechanism of the Enigma H29 shows great resemblance to the later Russian M-130 (Koralle) that was instroduced in 1965. The machine features the same principle of separate stepping wheels and coding wheels, although some improvements have been made in the M-130.
 
The image on the right shows the cipher unit of the Russian M-130. At the center are 5 electrical coding wheels (as opposed to 4 in the Enigma H29) and 2 stepping wheels at either side. Even the counter is mounted in the same position.

Another improvement over the H29 is the addition of a plugboard (Steckerbrett) to the left of the cipher unit. A similar Steckerbrett was available on the Enigma-I as well.

 More about the M-130
  
Russian M-130 cipher machine. Click for more information.

 
Keyboard
The keyboard of the H29 consists of 26 ordinary keys, plus 3 special keys at the bottom row. Two of the special keys are extra wide and are engraved with the text Ziffern u. Zeichen Zwischenraum (Numbers and Punctuation marks / Space) and Buchstaben Zwischenraum (Letters / Space). At the far left is a green key that can be pulled-out. It allowed switching to upper case characters.
 
The wider keys have a double function. They act as a 'shift' from letters to numbers and vice versa, but also insert a SPACE in the text when they are pressed. When in letter-mode, the leftmost space bar should be pressed in order to enter number-mode. Whilst in number mode, spaces are inserted with this key as well.

In order to go back to letter-mode, the rightmost space bar should be used. Whilst in letter-mode, this key can be used to insert spaces in the text. The WT-key, in between both space bars, was used to move the carriage (Wagen Transport).
  
Close-up of the keyboard

Some old black-and-white photographs of an Enigma H29 show a keyboard with bakelite keys. The Hungarian H-221 however, has metal keys with a glass window. It is unclear which keys are the older ones, but it is likely that bakelite keys were used later as a cost-saving measure.

The keyboard of the H-221 is incomplete and many of its key-tops are missing. This is another indication that the machine might have been used for spare parts. Fortunately though, the key tops are screwed onto a threaded shaft, making it relatively easy to restore this machine.
 
Close-up of the keyboard Rightmost space bar Angled view of the keyboard of the H-221 Top view of the keyboard of the H-221 Removing a key-cap A removed key-top Empty key post The restored keyboard of the H-221

Although the exact layout of the keyboard was initially unknown, the drawing below shows the position of the missing letters. By investiging the three characters on each of the type bars, it was possible to reconstruct the full keyboard layout and add the punctuation marks to the key tops.

Possible layout of the Enigma-H keyboard

As each coding wheel has 26 contacts, only 26 letters can be encoded. Normally this would be the full Latin alphabet (A-Z), but as we need two characters for letter-shift and number-shift, two letters had to be given up. According to patent DE425566 of 28 February 1924, this might have been done by sacrificing the letters 'j' and 'q'. Typing the 'j' on the keyboard would produce an 'i' and typing a 'q' would produce a 'k' so that the text would still be comprehensible.

The restored keyboard of the H-221

 
Writing to paper
Although electrical typewriters were not commonly used in 1929, they were available from some manufacturers both in Germany and abroad. Converting an electric typewriter for use as a cipher machine however, must have been a real challenge for the designers at Chiffriermaschinen AG.
 
The first Printing Enigma (Model A) featured a rotating letter-wheel, but this imposed so many problems that it was replaced in the Enigma B by standard type-bars (Typenhebel). In the Enigma H29 however, they moved away from type-bars and used push-bars (Stoßhebel) instead.

Unfortunately, the carriage of the Enigma H-221 is missing completely. The image on the right shows a rear view of the machine at the position where the carriage once was. It now gives us a clear view of the carriage transport mechanism, the ink ribbon and the typing mechanism.
  
Rear view of the H-221. The carriage is missing.

The printer features a rather high ink ribbon (26cm) that was not uncommon in those days. Below the ink ribbon spool is a bell that was probably used to indicate the end of a line when entering text. Each push-bar contains 3 characters: a lower-case letter, an upper-case and a number or punctuation mark. When typing, the letter bars would move forward and push the ribbon against the paper on the carriage, thereby printing the selected letter onto the paper.
 
Rear view of the H-221. The carriage is missing. Another view from the rear Close-up of the right ink ribbon spool Close-up of the left ink ribbon spool Part of the carriage transport mechanism Ink ribbon spool seen from the side Close-up of the shift-bars (Stoßhebel) Close-up of an ink ribbon spool and the bell

 
Using the H29 as a printer
Some Enigma H29 models were equipped with a special connector to allow the large machine to be used as an external printer to a (smaller) lamp-based Enigma machine, such as the Enigma-G (Model G31) and the Enigma-I. The lamp-based machine had to be modified for this as well. Please note that the Enigma H29 is not compatible with any of the (small) lamp-based Enigma machines. When connected to a small machine, it is just used as an external printing device.
 
The image on the right shows the special socket with 28 electrical contacts that is present on the left side of the H221. When unused, the socket is normally covered by a circular panel.

A lever at the front side of the machine allowed selection between Große Maschine (big machine) and Kleine Maschine (small machine). When the H29 was used as a stand-alone cipher machine, the big machine had to be selected (leftmost position). This was default operation. When the machine was used as a printer for a lamp-based Enigma, the lever was set to small machine.
  
Connection for 'small machine' at the left rear

Selecting the small machine would disengage the cipher mechanism of the H29 and bypass the coding wheels. In this position, the machine was used as an ordinary electric typewriter. Please note that the expansion connector shown here was not present on all Enigma H29 models. Although it is visible on the H29 brochure that was supplied to the Spanish Embassy in 1931 [2], it was missing from the photograph on an earlier leaflet [3] published in Cryptologia in 2002 [4].
 
Circular panel covering the expansion socket Connection for 'small machine' at the left rear View of the contacts of the expansion socket Close-up of the contacts Font view of the H-221 Close-up of the large/small selector Kleine Maschine (small machine) selected Selecting Große Maschine (large machine), i.e. native use

The use of the H29 as a printing device for a lamp-based Enigma is described in German patents DE536556 and DE595075. The image below was taken from one of these patents. At the right is the H29 with the lever clearly visible on the front panel (14). More related patents below.


At the left is a modified lamp-based Enigma; in this case a Zählwerk Enigma with a special socket (12) at the right instead of the battery compartment. Whether any lamp-based Enigma was ever modified in this way remains to be seen. The connector was more likely located at the left side.
 
In 2009, a special version of the Enigma Model G31 appeared at an auction house in Germany [9]. It appeared to be an Enigma-G (sometimes called: the Abwehr Enigma) with serial number G-111. It turned out that this machine was an extended version of the standard Enigma-G (Ch.15a) that featured a printer socket, just like the H-221 shown above. It is known as Ch.15b.

The image on the right shows the printer socket on the G-111, which is located at the left side of the machine, towards the rear. A circular cut-out in the wooden case gives access to the socket.
  

On 1 July 2009, Crypto Museum was invited to visit the auction house in Munich, and Paul Reuvers and Marc Simons were given the opportunity to take a closer look at the machine [5]. Our findings have been published in the report Enigma G111: A rare Zählwerk Enigma variant [6]. The exploded view below should clarify things somewhat. Please note that during our investigation, we were unable to dismount the switch assembly and are therefore uncertain about the shape of the centre part and the cylindrical contacts. We had to make a few 'educated guesses', based on our knowledge of the German manufacturing skills. The same is true for the shape of the plug.

Exploded view of the complex printer connector/switch inside the G-111. Copyright 2009, Paul Reuvers.

The socket on the side of the H-221 appears to be similar to the one on the G-111, but not identical. The flat-faced contacts on the pertinax panel are spaced differently. The G-111 socket features 28 contacts arranged in a zig-zag pattern, whereas the socket on the H-221 has 26 contacts in a zig-zag pattern and the remaining two contacts (33 and 34) in the inner circle. This means that the cable between the two machines had two different plugs. In order to prevent the cable from being inserted the wrong way around, the index key at the center of the plug at the Enigma-H side, has longer teeth. It would not fit the socket on the G-111.

Mounting connector and socket. Copyright 2009, Paul Reuvers.

The image above shows an educated guess of what the plug might have looked like. It shows a cross-section of the socket with a rotary switch on the right, and the actual plug on the left. The rotary switch was used on the G-111 to switch between the 26 lamps and the (external) printer. On the Enigma-H (H-221) such a switch is not available. Instead, the lever at the front is used to switch between normal operation (Große Maschine) and printer-use (Kleine Maschine).

Lamp-based Enigma (top) connected to H29 (bottom). Copyright 2009, Paul Reuvers.

The simplified circuit diagram above shows how the electric current would flow between the two machines. In this diagram, the H29 machine is represented by the yellow rectangle at the bottom, marked as 'Printing Device'. The upper part shows the lamp-based Enigma with disabled lamps.
 
Related patents
At the rear of the H29 machine is a metal plate with a long list of international patent numbers. This is a rather unique feature that we previously also found on the Enigma G-111. These plates were probably attached to both Enigma models, because the machines were also sold abroad.
 
The image on the right shows a close-up of the patent plate. The first two columns show the German Patents, or Deutches Reichs Patent (DRP), whilst the other columns list the patents in the USA, Great Britain (England), France (Frankreich) and The Netherlands (Holland).

The list also indicates that it has Patents Pending (ang. = angemeldet) in Germany and in the USA. The line at the bottom reads: Weitere Patente in allen Kulturstaaten (More patents in all civilized countries). For a full overview of Enigma-related patents, please refer to the Enigma Patents page.
  
Patent number shield at the rear of the machine

Although the patent plate is similar to the plate that was mounted to the rear of the G-111, and both machines were developed around the same time, it shows a number of different patents. They are listed below. A star (*) indicates that this patent was also listed on the Enigma G-111.
 
German Patents
  • DE383594 / 12 February 1922
    Patent for a ciphering machine with electrical coding wheels, filed by Securitas Amsterdam (Netherlands). This patent was also filed in other countries, e.g. United Kingdom (GB193035), USA (US1657411), and France (FR561910).

  • DE409301 / 20 September 1921
    Patent for a ciphering machine with a reduced number of contacts (by introducing multiple shift keys), electrical coding wheels, and a printer with a rotating drum. Filed by Securitas Berlin (Germany). This patent is similar to US1584660.

  • DE411126* / 18 Aug 1923
    Patent for the use of index rings (letter rings) on the cipher wheels and on other parts of the turnover system, in order to set the message key. Filed by Securitas Amsterdam (Netherlands).

  • DE412582* / 25 March 1924
    System for blocking the various cipher components after each key-press. This should avoid a cipher wheel from making more than one step on a single key-press.

  • DE416219* / 23 February 1918
    This is the first Enigma-related patent, filed by Arthur Scherbius, issued 23 February 1918. It was released on 8 July 1925.

  • DE425147* / 26 Sep 1920
    Patent for a cipher machine in which each key-press causes an irregular movement of multiple cipher discs. The drawings clearly show an early concepts of an electrical cipher machine with drums for ciphering and deciphering.

  • DE425566 / 28 Feb 1924
    Patent for allowing two different alphabets (letters and numbers/punctuation marks) to be enciphered, using just the 26 letters of the telegraph alphabet. This was done by replacing 'j' by 'i' and 'q' by 'k', and using the contacts for 'j' and 'q' to select between letters and numbers.

  • DE429122* / 26 March 1924
    Patent for a cipher machine in which cog-wheels with a varying number of teeth (prime numbers and numbers without a common factor) are used to create a pseudo-random generator with a very long period. This patent is clearly related to the design of the very first Enigma model: Enigma A, introduced in 1923. It is also related to later machines.
    Click to view patent DE429122

  • DE454392 / 30 Jan 1924
    Patent for enhancing the irregular movement of the wheels during encipherment, in order to increase cipher security, by allowing a wheel to make multiple steps on a single key-press.

German Patents Pending
The following German patents are also related to the Enigma H29, but were pending at the time the H29 was released:
 
  • DE541702 / 30 January 1929
    Patent for the use of electromagnets in a typewriter or ciphering machine, in order to print a character on paper. Invented by Arthur Scherbius and Willi Korn.

  • DE524754 / 30 January 1929
    Patent that describes the construction of a cipher machine in which all keying elements are mounted on the same geometrical axis, making the setting of a message key much simpler as before. This includes both the electrical cipher discs and the gap-cog-wheels that drive the cipher discs. In previous systems a separate axle was used for each driving gap-cog-wheel. This patent clearly describes the Enigma H29.
    Click to view patent DE524754

  • DE550796 / 5 February 1929
    Patent for the addition of extra switching wheels, outside both fixed end-wheels, to allow easy selection between cipher, decipher and plain text, without the need for large - expensive - multi-pole switches.

  • DE536556 / 22 June 1929
    Patent for connecting a printing Enigma (Schreibende Enigma), such as the H29, to a lamp Enigma (Glühlampenmaschine) so that it can be used as a printing device. Invented by Willi Korn. The Enigma G111 is an example of a lamp-Enigma that was used this way.
    Click to view patent DE536556

  • DE595075 / 4 November 1930
    Supplement to patent DE536556. Patent for a switching connector inside the Enigma, allowing the lamps to be switched off when a printer is connected. Invented by Willi Korn and Karl Röpke. Enigma G111 is an example of a lamp-Enigma that was issued with this connector.
    Click to view patent DE595075

US Patents
  • US1533252* / 18 Sep 1920
    This is the US-version of the original Dutch Patent NL10700. It is filed by NV Securitas in Amsterdam (Netherlands) and lists Hugo Alexander Koch as the inventor.

  • US1584660 / 7 December 1922
    Patent for a ciphering machine with a reduced number of contacts (by introducing multiple shift keys), electrical coding wheels, and a printer with a rotating drum. Filed by Arthur Scherbius on behalf of Securitas Amsterdam (Netherlands).

  • US1657411 / 6 February 1923
    First US patent that clearly resembles an Enigma machine, filed in the US by Arthur Scherbius on behalf of Chiffriermaschinen AG (Germany). Note that this patent is identical to DE383594, filed by Securitas Amsterdam (Netherlands) and British patent GB193035, also filed by Securitas.

  • US1520089 / 15 Feb 1924
    Patent for an Electric Typewriting Machine and improvements of such machines, filed on behalf of Arthur Scherbius. This patent is used in the Enigma Model H29.

UK Patents
  • GB163357* / 10 November 1919
    Improvements in and relating to Ciphering and Deciphering Machine. This patent is basically the British version of Koch's original Dutch Patent NL10700.

  • GB193035 / 3 February 1923
    Patent for a chiphering machine, filed by NV Ingenieursburo Securitas of Amsterdam (Netherlands). This patent is identical to American patent US1657411, which was filed by Arthur Scherbius of Chiffriermaschinen AG.

  • GB213968 / 8 January 1923
    Ciphering Machine. Using multi-switches to select between subsitution alphabets. This patent is similar to German Patent DE385682 (19 May 1922) and was filed by NV Securitas in Amsterdam (Netherlands). It is clearly related to the printing Enigma machines.

  • GB231502* / 25 March 1925
    Patent for improving ciphering machines by using multiple ciphering discs and a complex irregular wheel turnover pattern by using special drive wheels. Filed by Chiffriermachinen AG of Berlin (Germany)

  • GB325020 ???
    This patent is mentioned on a plate that is mounted to the rear of the Enigma Model H29. However the patent is clearly not related to the Enigma in any way. It is possible that this was a so-called abandonned patent.

French Patents

Dutch Patents
  • NL10700* / 7 October 1919
    First Enigma-related patent registered in The Netherlands on 7 October 1919 by Hugo Alexander Koch. On 5 May 1922, the patent rights were transferred to Naamloze Vennootschap Securitas in Amsterdam, and on 28 January 1927 to Chiffriermaschinen Aktiegesellschaft in Germany (Scherbius).

  • NL12762 / 17 May 1922 (priority 23 May 1921)
    Patent for changing number-pairs into letter-pairs and vice versa, in order to avoid mistakes in sending (secret) telegrams. The patent was filed by NV Ingenieursbureau Securitas of Amsterdam on 17 May 1922, but claimed a priority of 23 May 1921 as a result of an earlier German registration. The patent is nearly identical to German Patent DE378238 which was filed by Arthur Scherbius a day later (24 May 1921). It was later transferred to Chiffriermaschinen AG in the same Act as the previous patent (see below).

Related Dutch documents
 
  • Act of Transfer 886 / 5 May 1922
    On 5 May 1922, the legal rights of Patent Application 13046 (the later Patent NL10700) were transferred from Hugo Alexander Koch to NV Ingenieursbureau Securitas in Amsterdam (Netherlands) for the amount of NLG 500 (approx. EUR 225).

  • Act of Transfer (10700 and 12762) / 28 January 1927
    On 28 Janury 1927, the legal rights of both patents above (NL10700 and NL12762) were transferred by Hugo Alexander Koch, acting on behalf of NV Securitas (Amsterdam), to Chiffriermaschinen Aktiengesellschaft in Germany (Scherbius) for NLG 600 each.

References
  1. Eric Tischer, Early full-colour photograph of Enigma H-221
    Personal correspondence. 11 January 2008.

  2. Chiffriermaschinen Aktiengesellschaft, Enigma H29 brochure
    Kurze Beschreibung der schreibenden ENIGMA-Chiffriermaschine.
    Date unknown, but probably from 1931. Crypto Museum #300302.1

  3. Chiffriermaschinen Aktiengesellschaft, Enigma H29 leaflet
    Date unknown, but probably from 1929. Also published in [4].

  4. Louis Kruh and Cipher Deavours, The commercial Enigma:
    Beginnings of Machine Cryptography.
    Cryptologia, January 2002, Volume XXVI, Number 1, pp. 1-16.

  5. Paul Reuvers and Marc Simons, Description of Enigma G-111
    Crypto Museum website, August 2009.

  6. Paul Reuvers and Marc Simons, G-111: A rare Zählwerk Enigma variant
    Detailed description of the re-discovered Enigma G-111. August 2009.

  7. Frode Weierud, Black-and-white photograph of Enigma H29
    Personal correspondence. Date unknown. Retrieved June 2009.

  8. Matt Crypto (pseudonym), The Eight-Rotor Printing Enigma
    Blog. 25 October 2005. Retrieved August 2012.

  9. Hermann Historica, International Auctions
    May 2009. Investigation 1 July 2009.

  10. Hadtörténeti Intézet és Múzeum (War History Institute and Museum)
    Budapest, 1 August 2012. With special thanks to Dr. Ravaz István.

  11. Chiffriermaschinen Aktiengesellschaft, Herrn Direktor Walter Edström
    Offering for Schreibende Enigma and Glühlampenmaschine mit Zählwerk (German).
    16 September 1929. Crypto Museum #300304.2

  12. Chiffriermaschinen Aktiengesellschaft, An die Spanische Botschaft
    Letter to the Spanish Ambassy, offering Enigma Z30, A27 and H29.
    Berlin, 19 November 1931. Crypto Museum #300300.1

  13. Hungarian Spy Museum
    Retrieved December 2013. (Website unavailable from January 2014 onwards.)

  1. Documents kindly supplied by Arturo Quirantes.
  2. Document kindly supplied by Frode Weierud [7].
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