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Military and intelligence history mostly dealing with World War II.

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    In my essays Compromise of OWI - Office of War Information communications and Allen Dulles and the compromise of OSS codes in WWII i’ve looked into the compromise of OSS and OWI communications in WWII. Unfortunately it is very difficult to find detailed information on the cryptosystems used by these organizations in WWII but a report found in SRH-145 ‘Collection of memoranda on operations of SIS intercept activities and dissemination 1942-45’, dated 16 October 1943 says that they used cipher machines and hand systems (M-138 strip cipher and double transposition).

    I’ve added this information in the aforementioned essays.

    Acknowledgements: I have to thank Rene Stein of the National Cryptologic Museum for sending me SRH-145.

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    If you like playing around with codes and ciphers the CryptoCrack program created by Phil Pilcrow might be worth checking out. It’s free and can be downloaded here.

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  • 10/07/14--08:42: Update
  • I’ve added information from a report titled ‘Penetration and compromise of OSS in Switzerland and Western Europe’ in Allen Dulles and the compromise of OSS codes in WWII.

    I’ve also located a very interesting report on tank warfare during the Korean War. There is information on the performance of the T-34 tank from US reports and N. Korean POW interrogations. It seems the T-34/85 had serious shortcomings in Korea…I’ll write more about this in the future.

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  • 10/11/14--10:22: Update
  • In my essay German intelligence on operation Overlord the paragraph

    Another German agent in Lisbon said in May 1944: ‘the plan of attack favored by the Allies was an assault on La Manche (Cherbourg) peninsula.’ [Source: ‘British intelligence in the Second world war’ vol3 part 2, p61]

    is replaced with:

    From Lisbon the agent Paul Fidrmuc sent a report correctly identifying the endangered area ‘the plan of attack favored by the Allies was an assault on La Manche (Cherbourg) peninsula’. According to his postwar interrogation he got this information from his agent ‘TOR’ in the UK.


    [Sources: ‘British intelligence in the Second world war’ vol3 part 2, p61 and KV 2/198‘Paul Georg FIDRMUC, alias FIDERMUTZ, RANTZAU, codename OSTRO’]

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    Intelligence services collect information from various sources such as magazines, journals, newspapers, government reports, secret agents etc. However the most accurate source has always been the decoded traffic of a foreign state’s diplomatic and military networks. For this reason there has always been a close relationship between a country’s human intelligence and signal intelligence agencies.  

    During WWII the British foreign intelligence service benefitted from the successes of Bletchley Park versus Axis military, diplomatic and agents codes. Similarly the German foreign intelligence services received summary reports from the Signal Intelligence Agency of the Supreme Command of the Armed Forces - OKW/Chi (Oberkommando der Wehrmacht/Chiffrier Abteilung).

    The Sicherheitsdienst was the security service of the SS and its foreign intelligence department Amt VI (headed by General Walter Schellenberg) had some notable successesduring the war. According to two SD officials their agency received daily reports from OKW/Chi, containing important diplomatic messages from Bern, Ankara, Algiers, Moscow and other areas.

    Since it seems that most of the OKW/Chi archives were destroyed or lost at the end of WWII these statements are important in evaluating the successes or failures of that organization.

    SS-Sturmbannführer Dr. Klaus Huegel was an important SD official with knowledge of German spy activities in Switzerland and Italy. In one of his postwar interrogations he mentioned that from April 1943 to March 1944 he had access to the daily reports sent from OKW/Chi to General Schellenberg. The reports often included US diplomatic messages from Bern, Switzerland, British messages from the Bern embassy, De Gaulle traffic from Algiers to Washington and messages from the Turkish ambassador in Moscow.

    Giselher Wirsing was an accomplished author and journalist, who in 1944 joined the SD foreign intelligence department as an evaluator. Wirsing had come to the attention of General Schellenberg due to his clear headed analysis of the global political situation and of Germany’s poor outlook for the future. Under Schellenberg’s protection he wrote a series of objective reports (called Egmont berichte) showing that Germany was losing the war and thus a political solution would have to be found to avoid total defeat. While writing his reports Wirsing had access to the OKW/Chi summaries sent to the SD leadership. According to him the messages ‘did not reveal any startling news‘ but were useful in assessing  information from other sources. He remembered messages from the US, Japanese, Turkish and Bulgarian ambassadors in Moscow,  State Department messages to Paris, traffic from the US mission in the Balkans and messages from the Polish mission in Jerusalem to their London based goverment in exile.
    Overall it is clear that OKW/Chi provided valuable information to the Sicherheitsdienst leadership, even though they served different masters (OKW/Chi was subordinated to the military while the Sicherheitsdienst came under the control of the Nazi party).

    Sources: CIA FOIA reports HUEGEL, KLAUS No 22 and WIRSING, GISELHER No 16.

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    Signals intelligence and codebreaking played an important role in WWII. British and American codebreakers solved many important Axis crypto systems, such as the German Enigma machine and the Japanese Navy’s code JN25. Similarly the codebreakers of the Axis nations also had their own victories versus Allied codes.

    One of the most important Allied cryptosystems compromised by the codebreakers of Germany, Finland and Japan was the State Department’s M-138-A strip cipher.  This cipher system was used for important messages by US embassies around the world and also by the Office of Strategic Services and the Office of War Information.

    Unfortunately accurate information on the compromise of this system is limited and the statements made in some of the available TICOM reports are often contradictory. Still it is clear that from 1941 till late 1944 the Axis codebreakers were able to read a lot of the traffic sent on the ‘circular’ and ‘special’ strips.

    In complicated cases like this one the only way to find more information is by checking all the available sources. During WWII there was an exchange of information between Germany, Finland and Japan on the State Department’s strip cipher. Some of these messages were intercepted and decoded by the Western Allies, so it is possible to track the progress of the Axis codebreakers through their decoded messages.

    For example a message sent from the Japanese military attaché in Helsinki, Finland to Tokyo, Japan in January 1943 lists the alphabet strip solved by the Finnish codebreakers in the previous year (1).

    Similar messages were decoded by the Allies in the period 1943-45, especially once they were able to solve the ‘Coral’ cipher machine. The ‘Coral’ was used by Japanese military attachés and the Allied codebreakers were finally able to figure out how it worked in March 1944 (2).

    From then on they could decode most of the traffic from Japan’s attaches in Europe and some of the most important messages were those dealing with the exchange of information on Allied codes and ciphers. It seems that in 1944 the German leadership decided to share more information with the Japanese representatives and the Signal Intelligence Agency of the Supreme Command of the Armed Forces - OKW/Chi (Oberkommando der Wehrmacht/Chiffrier Abteilung) gave them decoded Polish and US messages (3).

    It is possible that some of these US diplomatic messages were enciphered with the M-138-A strip cipher. A message from Tokyo said that ‘We conclude that the German Special Intelligence in your 190 comes from reading strips. If this is so, please send the strips concerned’.

    The codebreakers of Bletchley Park also thought that the No 190 telegram  should be brought to the attention of the Americans and their message stated ‘in view of more serious nature of leakage …. grateful if you would ensure that attention of G2 is drawn’. Surprisingly the response of the State Department was that this was simply the old Brown code, known to be insecure. It is not clear why the Germans would bother sending the Japanese messages encoded with ‘Brown’, since they had received a copy of that codebook from the Japanese in 1941…

    It is possible that this might not be the whole truth. In the US national archives there are several boxes containing decoded US diplomatic messages titled ‘German decrypts of US diplomatic messages 1944’ (4). In one of these boxes there is a report WDGSS-93 ‘Translations on American decodes’ with a detailed list of several US messages. Using that report I was able to track down the message from Bombay. It was No 451 of August 9, 1944.


    In another box at NARA there is a folder ‘M-138-A numerical keys/daily key table/alphabet strips’ (5) which contains State department alphabet strips and keylists both circular’ and ‘special’. A report in these files shows the alphabet strips and keylists used on specific messages. Originally I thought this report was connected with an investigation of the Finnish exploitation of the State Department’s strip cipher but it is possible that I was wrong and it concerns the German effort based on the decoded Japanese military attaché messages.

    The report shows that a message from Bombay, dated 9 August ’44 was enciphered on the keylist No13 and either the No 20-3 or 20-4 alphabet strips and also mentions a message from Calcutta of August 10, 1944. If these were the same messages as in the No 190 telegram then it means that the State Department was willing to cover up its own security failures by lying to the British…


    (1). British national archives HW 40/132

    (2). United States Cryptologic History, Special Series, Volume 6, ‘It Wasn’t All Magic: The Early Struggle to Automate Cryptanalysis, 1930s – 1960s’, p146-148

    (3). British national archives HW 40/132 and HW 40/221

    (4). NARA- RG 457 - Entry 9032 - Boxes 205-213

    (5). NARA - RG 457 - Entry 9032 - Box 214

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    Sometimes the answer to an interesting question is right in front of us but we can’t see it because we’re not paying attention…

    In my essay German intelligence on operation Overlord I said about the M-209 cipher machine:

    The M-209 cipher machine was used extensively by the US armed forces in the period 1943-45. Army units in England sent training messages on the M-209 which the Germans decoded.

    The USAAF used it in operational and administrative networks.

    M-209 traffic together with D/F may have allowed the Germans to discover the concentration of US forces in the South.

    After having a look at the report E-Bericht Nr. 3/44 der NAASt 5 (Berichtszeit 1.4-30.6.44) it is clear that the Germans were in fact able to get order of battle intelligence on the US forces in the UK. In pages 2-3 it says:



    Activity report before the invasion


    1). AM1:

    Focused on decoding the AM1. Ten absolute settings were recovered, which brought the deciphering of 1,119 messages. This cipher-material, mostly composed by the U.S American Expeditionary Corps, gave valuable insights into the location of enemy groups.

    AM1 (Amerikanische Maschine 1) was the German designation for the M-209.

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  • 11/02/14--00:43: Update
  • I added information from ‘Report on interrogation of Walter Schellenberg 27 June- 12 July 1945’ (which can be found in British national archives folder KV 2/95) in Intercepted conversations - Bell Labs A-3 Speech scrambler and German codebreakers, Reich security service and OKW/Chi reports and Allen Dulles and the compromise of OSS codes in WWII.

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  • 11/14/14--03:23: Update
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    In 1926, the British Government set up an Inter-Departmental Cypher Committee to investigate the possibility of replacing the book systems then used by the armed forces, the Foreign Office, the Colonial Office and the India Office with a cipher machine. It was understood that a cipher machine would be inherently more secure than the codebook system and much faster to use in encoding and decoding messages. Despite spending a considerable amount of money and evaluating various models by 1933 the committee had failed to find a suitable machine. Yet the need for such a device continued to exist and the Royal Air Force decided to independently fund such a project. The person in charge of their programme was Wing Commander Lywood, a member of their Signals Division. Lywood decided to focus on modifying an existing cipher machine and the one chosen was the commercially successful Enigma. Two more rotor positions were added in the scrambler unit and the machine was modified so that it could automatically print the enciphered text. This was done so these machines could be used in the DTN-Defence Teleprinter Network.

    The new machine was called Typex (originally RAF Enigma with TypeX attachments). The first experimental model was delivered to the Air Ministry in 1934 and after a period of testing 30 more Mark I Typex machines were produced in 1937. The new model Typex Mark II, demonstrated in 1938, was equipped with two printers for printing the plaintext and ciphertext version of each message. It was this model that was built in large numbers and the first contract for 350 machines was signed in 1938. Typex production was slow during the war with 500 machines built by June 1940, 2,300 by the end of 1942, 4,078 by December 1943 and 5,016 by May 1944. By the summer of 1945 about 11.000 (8.200 Mk II and 3.000 Mk VI) had been built (1).

    The following pics from Crypto museumshow the Mark II version on the left and the portable Mark VI version on the right:

    The Typex cipher machine was used by British civilian and military authorities during WWII and up to the early/mid 1950’s.

    Typex compared to Enigma

    The Typex was much more secure than the commercial Enigma device since it had 5 rotors in the scrambler unit compared to 3 in the Enigma D and K versions. The 2 rotors at the right end of the scrambler did not move but could be set by hand. The 3 rotors on the left moved according to the same principle as the other Enigma devices. The ‘fast’ rotor moved with each letter and also caused the other two rotors to move thanks to the notches in their ratchet wheels. Unlike other Enigma devices the Typex had multiple notches per rotor. The commercial Enigma and the improved version used by the German Army and Airforce had one notch per rotor, making wheel movement very predictable. The German Navy had three additional rotors, each with two notches.

    The Typex on the other hand had rotors with 3-9 notches. For example (2): 


    The use of multiple notches per rotor meant that the ‘fast’ rotor turned the other two movable rotors much more often than in the commercial Enigma or the German military’s version thus defeating certain types of cryptanalytic attacks. The Typex also had an advantage in terms of speed and ease of use since it automatically printed the cipher text. In the standard Enigma models the cipher clerk had to write down the cipher text after depressing each key.

    However compared to the German military’s Enigma I and its plugboard the Typex, despite its multistep rotors, was not superior cryptologically (3). According to ‘The Typex cryptograph’:

    The Enigma plugboard offers more security, in spite of its reciprocal nature, than the two stator setup in the Typex. While the Army Enigma and the Typex are roughly comparable in design and cryptographic strength, the German Naval Enigma probably possessed an edge over the Typex due to the introduction of the three "thin" reflector rotors which, in effect, made the machine a four rotor device (the reflector was a stator however).

    The same article admits that this comparison is only theoretical since the security of each device depended on the way it was used (indicator procedure, introduction of new rotors etc).

    The problems with Typex were:

    1). Due to the failure of the Inter-Departmental Cypher Committee to select a cipher machine for mass production and the solitary efforts of the RAF in the mid 1930’s there were only a small number of Typex machines available at the start of WWII. The first contract in 1938 was for 350 machines and it’s doubtful that all would have been delivered by September 1939. Note that at that time the Germans had about 10.000 Enigmas in use (4). 

    2). The ability to print the enciphered text came at a heavy (literally!) price. While the German Enigma machine was relatively small and compact, the Typex version built in large numbers Typex Mk II was bulky, weighed 54kg and required electrical supply. Thus it could only be used at prepared sites.

    3). For the same reason Typex was too complex to mass produce during the war. According to ‘The Development of Typex’:

    Some of the reasons for the low production rate are clear. Any rotor-based machine tends to be very complex mechanically. Figures 2 and 3 illustrate just how many different parts a Typex machine included. Typex Mk. VI contained about 700 parts, few of which were common to other models. Typex must have been a quartermaster's nightmare - much more so than Enigma, because of Typex's printer. Typex's relative complexity proved too much for the British machine tool industry. Overloaded as the industry was with the demands of the war economy generally, it took almost two years to obtain the machine tools required to manufacture Typex, despite the priority that would have been accorded to it. Only 2,300 Typex machines had been made by the end of 1942, 4,078 by December 1943 and 5,016 by May 1944.

    4). Because they were complex the machines often malfunctioned (5).

    The production problems meant that during the war the Brits did not have a cipher machine in widespread use like the Germans did. For comparison’s purposes at least 40.000 Enigma machines were built by the Germans (6).

    Use of Typex by British armed forces

    The Typex device was originally developed by the RAF but once full scale production started devices were also requested by the Army. Both the Army and the RAF used the Typex as a high level cryptosystem but due to the production problems they couldn’t replace their codebooks with it. Instead the available devices were used for securing the most important communications.

    The Royal Navy was also interested in acquiring a large number of Typex machines and equipping its shore stations and naval units with it (7). In fact the first Navy order in 1939 for 630 devices was three times that of the War Office. Unfortunately for the Royal Navy this plan could not be carried out due to the production difficulties. Instead the limited number of Typex devices were used by shore stations, fleet flagships and landing ships headquarters.

    During the war the device was upgraded significantly in terms of security. In that sense it’s possible to differentiate between the ‘simple’ Typex of the period 1939-42 and the ‘improved’ Typex of 1943-45.

    In the period 1939-42 it doesn’t seem like Typex was used in a completely secure manner and this was despite Bletchley Park’s centralization and intimate knowledge of Enigma theory.  

    Insecure procedures

    Up to February 1941 the RAF had two sets of rotors for its Typex machines, the Mk I for higher formations and the Mk II for all units but they both used the same settings. From February onwards different sets of settings were introduced for each set of rotors and during the war many additional ‘keys’ were issued for different geographical areas (Middle East, Med, Home, Empire, India, Australia, Canada etc). Regarding the indicator system (showing the starting positions of the 5 rotors) initially the indicators were not enciphered but then an indicator book was introduced with disguised-true indicators and finally the disguised indicators were further enciphered on Typex. (8)
    The Army also used an ‘open’ indicator system till May ’41 (for the UK) and November ’41 (for worldwide users), also at the start of the war there was only one set of 5 rotors available. Another weak spot for the Army was the use of stereotyped beginnings till January ’41, when codress burying was introduced (meaning that the address at the start of the message was moved to the middle before being enciphered) (9).
    The Royal Navy used the same settings for both Code and Cypher traffic till August ’40 when different settings were made effective. The settings changed weekly till September 1940 when daily change was introduced. Just like the Army the rotors available at the start of the war were only 5 but in June ’41 two more were introduced. Indicators were sent in the clear till November ’41, when the first edition of the Naval message settings book was introduced (10).


    Security over efficiency

    Although initially the Typex was not used in the most secure way possible during the war it was significantly upgraded through the use of a rewirable reflector, ‘split’ rotors and several sets of indicator books and ‘key’ settings. At the same time different sets of rotors were introduced for different areas and higher levels of command.  

    The rewirable reflector (called plugboard) was introduced in 1941 but it took time before all machines were equipped with it. For example the Navy did not introduce Naval plugboard settings keys till March 1942 and it wasn’t until May 1944 that the three services had enough plugboards to introduce an inter-service plugboard key (11).

    The ‘split’ rotors were Typex rotors with detachable rotor cores (called inserts). This way the cores could be switched between different rotors. Also the cores could be inserted in two different ways, effectively doubling their numbers. According to report HW 40/89 the first series of split rotors were introduced in November 1942 (12).

    The indicator procedure was further modified, first through the use of disguised-true indicator books and then in 1944 by further enciphering the indicator on the Typex to get the message ‘key’ (similar procedure used by the Germans). The new procedure was introduced in February 1944 and used two disguised indicators taken from the indicator book. The true setting of the first one was used to set the Typex rotors and the true setting of the second one was enciphered on it. The resulting 5 letters were the message ‘key’ (13). 
    Many different sets of machine ‘keys’ (meaning the 5 rotors valid for each day and the order they were inserted into the machine) were introduced for each geographical area and also for higher commands.  For example by the end of the war the RAF had ‘no less than 30 machine settings in use, excluding Chief Of Staff and Y settings’ (14).

    Finally the introduction of several sets of rotors with different wirings meant that even if one network was compromised in some way this would not affect the security of the other networks. At the start of the war the Army and the Navy had only 5 rotors for their machines but during the war they received several more sets. The Navy got 2 more rotors in June 1941 and in 1943 introduced two sets of 7 rotors each, one for Cypher and the other for Code traffic. The original 7 rotors were then used only for inter-service traffic. The RAF also had different sets for Cypher and Code traffic and it is possible that the Army followed this system too. According to ‘The Development of Typex’ the total number of rotors must have been somewhere between 120-252 (15).

    All these measures meant that the ‘improved’ Typex was much more secure than the German military Enigma but this came at a cost, as significant resources had to be allocated for the production of Typex rotors, cores, reflectors etc (including an entire RAF unit with 200 personnel tasked with wiring the rotors) (16).

    Also the new indicator procedures and the use of different ‘keys’, rotors and inserts meant that the work of the cipher clerks was negatively impacted. This is clearly admitted in reports ADM 1/27186 (17) and AIR 20/1531 (18), which state:

    ‘Moreover, Typex operation has been complicated in recent years by the progressive introduction of numerous and tiresome procedures and restrictions which the operator must bear constantly in mind in the interest of security. What the Navy requires, and must press for, is a machine which, whilst providing the highest possible security, is nevertheless reasonably simple to operate and maintain in good running order. The Typex Mark II machine is far from reaching this standard.’

    As with book cypher, the method of use of the machine became more complex. Indicators, instead of being self-evident, were first of all chosen from a disguised-true indicator book, and, later, indicators were recyphered in addition. A. plugboard scrambling device was fixed to all machines and the drums were provided with removable wirings, which were changed about 3 or 4 times a month. The effect on output in cypher offices was most marked, not only because encyphering and decyphering became slower, but because more messages became indecypherable, and more time had to be spent on correcting them. The rate at which cipher work could be done, even in large offices, fell to about a quarter of that at the beginning of the war.


    Research on Typex by German Army codebreakers

    The German codebreakers solved many British cryptosystems during WWII, both high and low level. The most important systems compromised were the Royal Navy’s Code and Cypher, the Army’s Cypher, the RAF Cypherand the Interdepartmental Cypher.

    Regarding Typex, several sources claim that the Germans tried to solve it but gave up shortly afterwards because they considered the task hopeless (19). These statements are correct for the codebreakers of the Navy, Airforce, OKW/Chi, Foreign ministry and Forschungsamt. However their Army counterparts did not give up so easily!

    In the period 1940-41 the cipher research department of the German Army’s signal intelligence agency Inspectorate 7/VI had several talented mathematicians (Pietsch, Steinberg, Marquart, Schulz, Rinow) tasked with examining difficult foreign cryptosystems. The war diary of Inspectorate 7/VI shows that these individuals investigated the Typex device and by May ’41 had ascertained that it was mainly used by the RAF and was issued with 10 rotors. Their research on its internal cipher operation however was slow and had not led to any breakthrough. Things changed in May when they visited the facilities of the Signal Intelligence Agency of the Supreme Command of the Armed Forces - OKW/Chi and were able to examine a Typex machine captured at Dunkirk. The device worked according to the Enigma principle with the two rotors on the left remaining stationary and the wiring of the entry and reflector wheels could be recovered.

    Progress report:

    The studies of the English cipher machine Type “X” were continued. A summary report of the present results was written by Dr. Pictsch (see Vol. 45); a more accurate report on the individual results with appendixes is still in process.

    The most important result was the information about a model of Type “X” at Chi/OKW. This resulted in the following fundamental characteristics: the machine works after the Enigma principle. The entry wheel and reflector wheel are known. The wiring of the five wheels, which are situated between the entry and reflector wheels and which are selected from a set of 10 wheels, is unfortunately unknown. Two of the five wheels, next to the entry wheel, are always at rest; they are not moved during operation, but can only be adjusted manually from message to message. The middle wheel moves at every step and for every complete rotation it moves several times the second wheel from the left, which in turn at every complete rotation moved several times the first wheel from left. The machine prints plaintext and ciphertext at the same time, it is driven by a motor, which results in very light typing. The ciphertext is written in groups of five, the plain text with word spaces. The wheels are equipped with double rings of contact pins and contact pads, which guarantees better electrical contacts than with the Enigma. Due to these facts, partly also due to suspected facts from the previous work that now has become a certainty, could the further studies be directed in a more definite direction. It was now pointless to search over a larger material of several months for parallel passages. These studies should now rather be limited to a single day’s material.

    Investigations continued, with visits to the cryptologic departments of the Airforce and the Foreign Ministry in order to share the available information but at the same time these organisations admitted that they were interested in receiving information but could not contribute much because their resources were already stretched too thin. In the period May ’41-November ’41 the Army codebreakers investigated the stepping motion of the Typex rotors, the indicator system, the first and last codegroups from past traffic and developed theories of solution based however on knowing the wirings of the Typex rotors.

    Report of June ’41:

    The studies of Type X made progress. Mainly it was the completion of a very extensive and detailed report on the present results. Besides the study into the explanation of the movement rules for the wheels, the transport notches and the wheel order, studies were started on the possibility of a deciphering under the condition that the wheel wirings are known.

    Report of July ’41:

    The studies of Type X made progress. The detailed Report 1 was completed, furthermore 2 memoranda of which one investigated the question what period lengths Type X will have considering three to four transport notches on the wheels or respectively how long stretches without stepping one can expect for special studies. The second memorandum dealt with the possible reconstruction of the machine settings with given cleartext and ciphertext (for further information see Volume 45).

    Furthermore, studies are underway to clarify the question if the last five-letter group of Type X messages always are filled with a certain number of letters and if so by which letters. The previous studies in this direction seem to show that the last group mostly is filled with the cleartext letter X.

    Report of August ’41:

    The studies of Type “X” were continued. In particular, extensive statistical studies of the last 5 letters and the first 5 letters of the cipher messages were carried out because, as expected from the nature of this cipher machine, particularly frequent cleartext letters will appear very seldom in the ciphertext in those positions. It showed indeed that the plaintext letter X has a clearly visible minima in the last four ciphertext positions, from which it can be inferred that the last five-letter group is filled with the cleartext letter X. Furthermore, the statistics of the first 4 letters revealed that the letter A is most common in the 1st position, the letter I in the 2nd, the letter R in the 3rd and the letter X in 4th place, which seems quite understandable, as the message material mainly comes from the Royal Air Force networks. Further studies are on-going, that as a precaution deal with the question of when and under what conditions material can be solved when knowing the wheel wirings or whether the wheel wirings can be determined under certain conditions.

    From the available reports it seems that without the wheel wirings they could not solve any traffic, as the report of November ’41 says:

    The studies of Type X were temporarily ended. Some further statistical studies were in addition put down in writing. So far the studies of this machine and the statements of the prisoners show it is pointless to process material enciphered with this machine when the wheel wirings are not known.

    The Typex compromise investigation

    During the fighting in N.Africaboth the Germanand Italian codebreakers were able to exploit many important Allied cryptosystems. Eventually the Allies secured these systems and from mid 1942 they were the ones solving enemy high level codes. At that time Typex was only available at Corps level and there were no indications that it had been compromised in any way. Yet in May 1943, when the fighting ended with the defeat of Axis troops in Tunisia, two German prisoners claimed that a mysterious officer named Wagner had a Typex machine and was using it to solve British army traffic. The two men were Lieutenant Hanswolf Haunhorst, the intelligence officer of the 334th ID, who befriended the personnel of the signal intelligence unit NFAK 621 (supplying radio intelligence to Rommel) and First lieutenant Werner Possel, head of the senior fixed army wireless station in Africa HeFu 7 (20).


    Under normal circumstances their statements would have been dismissed as lies but the fact that both had assignments dealing with radio intelligence and their accurate description of a Typex device (with 5 rotors and two sets of printers) meant that a thorough investigation had to be undertaken to check whether Typex had been compromised.

    The investigation focused on locating the intelligence officer ‘Wagner’ and on ascertaining whether a Typex device had been captured by the Germans at Tobruk in 1942. These investigations during WWII were inconclusive however at the end of the war they resumed, since many German cryptanalysts had fallen into Allied hands and could clear things up.

    The relevant reports show that Typex was investigated but could not be solved. The most important individuals making these claims were Erich Huettenhain (chief cryptanalyst of OKW/Chi), Walter Fricke (Army cryptanalyst responsible for evaluating cipher security, later transferred to OKW/Chi), Otto Buggisch (Army cryptanalyst) and Ferdinand Voegele (chief cryptanalyst of the Luftwaffe’s Chi Stelle). On the other hand colonel Mettig, head of the Army’s signal intelligence agency in the period 1941-43 stated that Typex had been solved in spring 1942 but later claimed that he had made a mistake and the machine had never been solved (21).

    The investigations seem to have concluded in 1947, when US intelligence located the archives of the German army’s signal intelligence agency in a camp in Glasenbach, Austria, where they had been hidden at the end of the war (22). As has been mentioned earlier the war diary of Inspectorate 7/VI shows that Typex was investigated in the period 1940-41 but research stopped in November 1941 due to the problem posed by the unknown rotor wirings.

    Bletchley Park and Typex (in)security

    One thing made clear by the Typex investigation is that Bletchley Park’s knowledge of Enigma theory had not been used to fortify the Typex machine, at least that was the case till late 1943. The famous codebreaker Gordon Welchman wrote in a report: ‘after all we ourselves have made no serious attempt to use the experience of the experts on breaking the German enigma to improve the security of our Type X’.


    Another report on the Typex case, dated 16 September 1943, says: ‘Colonel Tiltman said that it had been decided some weeks ago that the time was ripe for a large scale investigation of the security of typex as no comprehensive examination had ever been made, but only ad hoc investigations regarding various individual points as they arose’.

    The fact that Bletchley Park with its vast resources had neglected the security of Typex for so long shows that cryptologic centralization does not automatically lead to better outcomes. Moreover the emphasis on codebreaking at the expense of cipher security affected not only Typex but also other important cryptosystems such as the Navy’s Cypher No3. According to the article ‘Tunny Reveals B-Dienst Successes Against the ‘Convoy Code’: ‘GC&CS excelled at breaking the codes and ciphers of the Axis powers, and devoted huge resources to doing so. In March 1942, GC&CS employed about 1.600 people on codebreaking operations, but only Travis (in theory) and Dudley-Smith were then assigned to investigating cipher security, even though Comsec was one of GC&CS’s two main functions. It was clearly too few, especially since Travis had no time to devote to Comsec, and Dudley-Smith was not a cryptanalyst. Even in October 1943, when GC&CS’s staff had more than trebled to over 4.800, only Dudley-Smith (in a ‘part-time’ capacity!) and ‘two or three girls’ worked in the ‘Security of Allied Communications’ section, which investigated the security of the Army’s and Royal Air Force’s signals (and even those of some allies), in addition to the Royal Navy’s signals. Comsec is not as glamorous as codebreaking, but is probably more important.


    In the interwar period the British military and civilian authorities knew that they would eventually have to replace their dated codebook system with a cipher machine, as it could transmit more information than the codebooks, in less time and do so securely. However their Inter-Departmental Cypher Committee failed to find a suitable device and in the 1930’s the experimental RAF Enigma cipher machine with Type X attachments was the only available model for mass production. In this case it is ironic that the device they chose to produce was already available in the 1920’s in its commercial version. Thus the period 1926 (when the Committee started evaluating cipher machines) to 1938 (when the first contract for mass production was signed) was time lost for no gain.

    The Typex machine was similar to the commercial Enigma but with slight modifications that gave it adequate but not impenetrable security for that era. Had it been produced in large numbers and used by naval warships and military units then several WWII campaigns would have ended sooner and with fewer casualties for the Allies.

    Unfortunately the decision to add a printer (two for the Mk II version) meant that it was needlessly complex and thus difficult to produce in mass. The numbers built were enough to equip the higher echelons of command but field units and warships were forced to rely on enciphered codebooks that were read by the Germans. Especially in the Battle of the Atlantic the compromise of the enciphered codebooks gave the Germans valuable intelligence on the routes of the Allied convoys that they wouldn’t have been able to get from other sources.

    As for its security, in the period 1943-45 the Typex was used with a rewirable reflector and several sets of ‘split’ rotors, indicator books and machine settings. In order to seriously compromise such a device the enemy would have needed to invest huge resources and build their own version of Bletchley Park, so in that sense the device was secure enough.

    Yet Typex security in the period 1939-42 was surprisingly weak and this was despite Bletchley Park’s knowledge of Enigma theory and their work on the German version. TICOM report D-83 (24) admits this failure and points out that one of the reasons that the device was not compromised was ‘sheer good fortune’:

    ‘However, by about May, 1941, OKH were in full possession of all the theory necessary for solving the problem and there can be little doubt that, had they been lucky enough to capture a set of drums at Dunkirk as well as the three machines the bulk of the Typex traffic up to July 1940 would have been read…..The immunity which Typex enjoyed in the first two years of the war was due partly to the care with which the drums were safeguarded, partly to German inability to grasp the potentialities of the problem, but mostly to sheer good fortune’.

    The fact that a global power like Britain took more than a decade in order to select a suitable cipher machine, then made it too complex for mass production and finally had to rely on ‘sheer good fortune’ to keep it secure from enemy codebreakers must be rated as a significant failure in the field of communications security.

    Sources: Cryptologia article: ‘The Typex cryptograph’,Enigma Bulletin article: ‘The Development of Typex’, ‘Intelligence and Strategy: Selected Essays’, Journal of Intelligence History article: ‘The Admiralty And Cipher Machines During The Second World War: Not So Stupid After All’, AIR 20/1531 ’R.A.F. signal communications: security’, ADM 1/27186 ‘Review of security of naval codes and cyphers 1939-1945’, FO 850/132‘Security of cyphers at posts abroad’, HW 40/88 and HW 40/89‘Investigation into POW reports that German Sigint authorities (NFAK 621) were exploiting TYPEX (British cypher machine) in North Africa’, War diary of Inspectorate 7/VI, Crypto museum


    (1). Enigma Bulletin article: ‘The Development of Typex’ and Journal of Intelligence History article: ‘The Admiralty And Cipher Machines During The Second World War: Not So Stupid After All’

    (2). Enigma rotor pic from Wikipedia user Matt Crypto, Typex rotor pic from Ralph Erskine

    (3). Cryptologia article: ‘The Typex cryptograph’:

    (5). ADM 1/27186 ‘Review of security of naval codes and cyphers 1939-1945’, p 105-6

    (6). Journal of Intelligence History article: ‘The Admiralty And Cipher Machines During The Second World War: Not So Stupid After All’, p3

    (7). Journal of Intelligence History article: ‘The Admiralty And Cipher Machines During The Second World War: Not So Stupid After All’

    (8). British national archives AIR 20/1531

    (9). British national archives HW 40/89: ‘Typex questionnaire’

    (10). British national archives ADM 1/27186, p30-36

    (11). British national archives ADM 1/27186, p35

    (12). British national archives HW 40/89: ‘Typex questionnaire’

    (13). British national archives FO 850/132 ‘Security of cyphers at posts abroad

    (14). British national archives AIR 20/1531

    (15). Enigma Bulletin article: ‘The Development of Typex’

    (16). Journal of Intelligence History article: ‘The Admiralty And Cipher Machines During The Second World War: Not So Stupid After All’, p3

    (17). British national archives ADM 1/27186, p106

    (18). British national archives AIR 20/1531

    (19). ‘British intelligence in the second world war - vol2’, p639: ‘Like the Typex, the CCM proved to be totally secure; indeed the Germans made no serious attempt to solve either system’.

    ‘Delusions of Intelligence: Enigma, Ultra, and the End of Secure Ciphers’, p202: ‘No section made an all-out attempt to solve Typex’.

    Intelligence and Strategy: Selected Essays’, p165: ‘In early 1940 German army cryptanalysts did basic research on Typex, which led nowhere’.

    (20). HW 40/88: ‘First interrogation report on two German Army officers captured in Tunisia’, ‘Answers to GCCS questionnaire’, The Typex Investigation – A WWII mystery

    (21). Various TICOM reports including I-66, I-112, I-16

    (23). British national archives HW 40/88

    (24). British national archives HW 40/169

    Additional information:

    The files of Inspectorate 7/VI, recovered in 1947 by the US authorities from a camp in Glasenbach, Austria include the following reports on Typex:

    Acknowledgments: I have to thank Ralph Erskine for sharing lots of information on the Typex machine, Frode Weierud for translating the relevant passages from the War Diary of Inspectorate 7/VI and Randy Rezabek for TICOM report IF-272, listing the Typex reports of In 7/VI.

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  • 12/09/14--01:31: Update
  • I added SRH-349 ‘The Achievements of the Signal Security Agency (SSA) in World War II’ in the notes of French Hagelin cipher machines and information from SRH-361 ‘History of the Signal Security Agency volume two - The general cryptanalytic problems’ in The French War Ministry’s FLD code.

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  • 12/14/14--06:03: Update
  • Added the following pics in French Hagelin cipher machines.

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  • 12/22/14--00:38: Overview of 2014
  • As the year comes to a close it’s time to look back at some of the top essays that I wrote in 2014, plus the ones that I extensively rewrote using new information.


    Compromise of Soviet codes in WWII

    British cryptologic security failures in WWII

    Decoded US diplomatic messages from 1944

    Compromise of US M-209 cipher machine prior to the invasion of Normandy

    Naval Enigma compromise and the spy in the United States Department of the Navy

    The US AN/GSQ-1 (SIGJIP) speech scrambler

    Professor Wolfgang Franz and OKW/Chi’s mathematical research department

    German special intelligence, the M-138 strip cipher and unrest in India

    Typex cipher machines for the Polish Foreign Ministry

    The German intercept stations in Spain

    The codebreakers of the Japanese Foreign Ministry and the compromise of US codes prior to Pearl Harbor

    The US TELWA code(added new information)

    The British War Office Cypher(added new information)

    The Soviet K-37 ‘Crystal’ cipher machine (added new information)

    Soviet partisan codes and KONA 6 (added new information)

    French Hagelin cipher machines(added new information)

    The RAF Cypher(added new information)

    The British Interdepartmental Cypher (added new information)

    The American M-209 cipher machine (added new information)

    US Military Strip Ciphers(added new information)

    The British railways code(added new information)

    Swedish Army codes and Aussenstelle Halden (added new information)

    The secret messages of Marshall Tito and General Mihailović (added new information)

    T-34 tank


    Abwehr agent Marina Lee and the Norway campaign

    Book reviews

    New books on Soviet cryptology in WWII

    Australian codebreakers of WWII

    I was able to find lots of new information in the government archives of the USA, UK, Germany and Finland and I got lucky with some of my freedom of information act requests to the NSA. Again I have to thank the people who helped me by giving me files and information and/or collaborating with me in locating interesting reports. I wouldn’t have been able to find so much without your help! As we say in Greece ‘ηισχύςεντηενώσει’.

    Is there anything left to cover in 2015? Actually there is. I’m waiting for several TICOM reports to be declassified by the NSA and there also some files from NARA and the UK national archives that I need to locate/copy. Regarding historical cases I need to cover:

    1). Τhe compromise of the codes of the Resistance movements in occupied Europe by the Agents section of Inspectorate 7/VI (German Army signals intelligence).

    2). The compromise of the DFC - Division Field Code of the US 29th Infantry Division, prior to the Normandy invasion in summer ’44.

    3). Find more information on the Polish diplomatic and military attaché codes of WWII (indicator MILITPOLΟGNE)

    4). Continue to investigate the compromise of the State Departments strip cipher.

    5). The compromise of the communications of General Barnwell R. Legge, US military attaché in Switzerland during WWII.

    6). Add new information regarding the compromise of the Bell Labs A-3 speech privacy system.

    7). Find more information on Goering’s Forschungsamt.

    With a bit of luck I should be able to uncover a great deal of interesting information.

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    Back in 2013 I wrote down several cases of WWII cryptologic history that require more research. Since then I’ve spent a lot of time and money trying to find new information. Has the effort paid off? Let’s have a look at each case:

    1). US State Department strip cipher

    I wrote: How bad was the compromise of the State Department’s high level system? That question is hard to answer because there is limited information available and it doesn’t seem like the Americans were really interested in learning the full extent of the compromise. Some documents that would shed more light on this affair are proving very hard to find…

    It is clear that Germans, Japanese and Finns were able to solve many alphabet strips both circular and special and thus read State Department messages from embassies in Europe and Asia. The most important intercepted messages seem to have been those from Bern, Switzerland and Chungking, China.

    Unfortunately several important reports are still classified by the NSA and we have to wait for the declassification procedure. At the same time I haven’t been able to track down the Carlson-Goldsberry report, detailing the Finnish solution of the State Department strip cipher. This report was written in late 1944 by two US cryptanalysts after interviewing Finnish codebreakers in Sweden. 

    Another aspect of this case concerns the messages from the OSS - Office of Strategic Servicesand OWI - Office of War Informationstations in Bern that were also sent via diplomatic channels. It’s not clear why these messages were sent using State department codes and not through their own systems. In this area information is lacking, since the OSS organization doesn’t seem to have officially acknowledged the compromise of their communications during the war.

    2). NKVD 5th Department codebreakers

    During WWII the Soviet Union invested significant resources in the interception and exploitation of enemy radio traffic. The internal security service NKVD and the Army’s general staff had codebreaking departments with the former recruiting many talented mathematicians. According to author Matthew Aid  By the end of World War II, the 5th Directorate controlled the single largest concentration of mathematicians and linguists in the Soviet Union.’

    So far very limited information is available regarding their war time efforts versus foreign codes (not only Axis but also US, UK and those of neutral countries).

     3). Referat Vauck success

    In the period 1942-44 the German Army’s signal intelligence agency Inspectorate 7/VI had a separate deparment (Referat 12) assigned with the solution of the encoded messages of Allied spy groups operating in occupied Europe. Head of the department was dr Wilhelm Vauck, so his unit was also called Referat Vauck. In 1944 they were transferred to the OKW radio defense department so their reports can no longer be found in the files of Inspectorate 7/VI.

    I had written about this case: How successful were they during the war? Unfortunately we do not know. The relevant file in the British national archives HW 40/76 ‘Enemy exploitation of SIS and SOE codes and cyphers’ says that postwar files have been retained and my request for the release of the interrogations of dr Vauck has been rejected by the archives staff

    Thankfully I‘ve been able to track down the monthly reports of Referat 12 for the period April ’42-February ’44 and I will be writing an essay on them.

    An interesting discovery, made while I was trying to find information on Referat Vauck, was that OKW/Chi was also solving Allied agents codes during the war (with significant success it seems). Not much is known about this aspect of OKW/Chi operations…

    4). Forschungsamt information

    Goering’s Forschungsamt was one of the main German codebreaking/intelligence agencies of the period 1939-45, yet a detailed history of that organization still eludes us. This is another case where it’s up to the NSA to declassify the relevant documents, written by Forschungsamt personnel in the 1950’s.

    5). German Enigma investigations

    Several authors claim that the Germans never suspected that their Enigma cipher machine was solved by the Allies and that they considered it to be unbreakable.

    I had written: The Germans constantly evaluated the security of their Enigma cipher machine. There were many studies on whether the daily key or parts of it could be retrieved through cryptanalysis. Those studies are the TICOM DF-190 to DF-190AN files…..More research is needed to evaluate the German methods and the way they influenced their security measures.

    Since then I’ve posted information on case ‘Wicher’ (Polish solution of the Enigma) showing that the Germans knew the device had been compromised in the prewar period and in 1943 they got information from the US regarding the solution of their naval version.  So far it’s clear that the German Navy’s codebreakers found a solution for their 4-rotor machine in late ’44 but we don’t know much about the similar work of the Army cryptanalysts. More research is needed in this case.

    6). Japanese Purple and Coral cipher machines

    Were the Germans able to solve the cipher machines used by the Japanese foreign ministry and by Japanese military attaches?

    I wrote: PURPLE was solved by American and Soviet codebreakers. Did the Germans have any success with it? Until recently the answer was no. 

    However it seems there is more to this story.

    The Coral machine was used by military attaches and the Anglo-Americans solved it in 1944. In the same year dr Steinberg of the German Army’s signal intelligence agency was transferred to OKW/Chi where he worked on a cipher machine used by the Japanese attaché. Did he manage to solve it? 

    TICOM report I-64 ‘Answers by Wm. Buggisch of OKH/Chi to Questions sent by TICOM’ says ‘B. thinks Steinberg (of 209 fame) solved some Jap machine traffic which was difficult but not so hard as Enigma. B. thinks it was traffic of the Jap Military Attache.

    There is scattered information that points towards the solution of an important Japanese code or cipher machine in the period 1943/44 but no conclusive evidence. Maybe more information will become available in the future.

    7). Soviet diplomatic code

    I wrote: The Soviet Union used a code enciphered with one time pads as its main diplomatic system during WWII. This system if used correctly is unbreakable. 

    Were the Germans able to read parts of this traffic? There are some strange statements in Allied and German reports…

    The recently declassified TICOM report DF-111 ‘Comments on various cryptologic matters’ by Adolf Paschke (head of the linguistic cryptanalysis group in the German foreign ministry’s decryption department) says that in the years 1927-30 parts of the Soviet diplomatic traffic could be read since the additive pads were sometimes used twice if the message was long enough. Paschke had also identified the use of the same additive tables more than once in some links. Regarding wartime traffic he says that they couldn’t solve any since there were no repetitions but in the report he also added cryptically that Russian material of the Forschungsamt and the High Command’s deciphering department OKW/Chi were destroyed in 1943 during a bombing attack on Berlin.

    Although the Germans might have not solved any Soviet diplomatic traffic they did succeed in solving Cominterncommunications.

    8). M-209 decoding device

    I wrote: I’m surprised that no one has figured out how this machine worked!

    I have to say I’m still surprised that this device has not received any attention from historians and/or the media!

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    It’s not often that movies on WWII cryptology and signals intelligence appear on the big screen, probably because the subject matter is too complex for the general audience. A new movie, called ‘The imitation game’ has been released and it has received a lot of favorable reviews in the media. The movie focuses on the legendary mathematician Alan Turing and his efforts to solve the German Enigma cipher machine.

    First let’s have a look at the trailer

    Hmmm the movie certainly looks good (sets, costumes etc) and the main actors are all well known (Cumberbatch, Knightley, Strong) but the problems start to add up…
    1). At 0:21: ‘It’s the greatest encryption device in history and the Germans use it for all communications’.

    Ehm, I don’t know what greatest encryption device means but the military Enigma was not revolutionary in any sense. It was simply a clever modification of the commercial version, sold to companies and countries around the world. In fact the Brits had their own Enigma version called Typex. As for the second part the Germans use it for all communications it’s also wrong. The Germans used hand ciphers for low level messages, the Enigma at regiment/division level and also by naval units and airbases and cipher teleprinters for communications between higher commands. So the Enigma did not cover allGerman communications.  
    2). At 0:25 ‘everyone thinks Enigma is unbreakable

    3).  At 1:15 ‘I’m designing a machine that will allow us to break every message, every day, instantly’.

    Bullshit. Sorry but there’s no other way to put it…I understand that some parts of Enigma theory need to be ‘dumbed’ down so that the general audience will enjoy the movie but come on! The bombe devices couldn’t break every message, every day and they certainly couldn’t do it instantly. Running ‘cribs’ took time and under the best conditions solutions could be achieved in several hours. Under the worst it could take days, weeks or possibly never…
    Even when the Enigma settings were retrieved it wasn’t possible to read the message instantly. Someone had to type the message on the specially modified Typex devices and write down the deciphered text. Without good ‘cribs’ the bombes didn’t work. Simple as that.

    3).  At 1:20: ‘They had to create the world’s first computer
    ……….The bombes were not general purpose computing devices. Apparently the producers of the film were thinking of the ‘Collosus’ but this was a different device, built by different people, for the solution of a different cipher machine, NOT the Enigma.

    4). At 1:29: Fake rivalry between Turing and Denniston.
    Historically inaccurate but I guess they had to insert some kind of conflict in the story for the general audience.

    5). At 1:50: ‘The Navy thinks that one of us is a Soviet spy’.
    Again historically inaccurate. There was a Soviet spy at Bletchley Park, John Cairncross but he was not a cryptanalyst and he didn’t work with Turing.

    So in only 2 and a half minutes we’ve seen some serious mistakes. On the other hand maybe I’m nitpicking here.  So how does the actual movie hold up? We’ll get to that in the next post.

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    Alan Turing was a legendary mathematician and a pioneer in the field of computer science. During WWII he worked for the Government Code and Cypher School, analyzing and solving Axis codes. His main achievement at GCCS was the solution of the plugboard Enigma, used widely by the German armed forces. Turing was undeniably a genius and after the war he continued his research into computers but in 1952 he got in trouble with the authorities after a police investigation into the break-in of his apartment revealed that the culprit knew Turing and had a homosexual relationship with him. Since homosexuality was a crime both men were convicted of ‘gross indecency’ and Turing had to undergo hormonal treatment. His conviction affected not only his personal life but also his professional opportunities. In 1954 Turing was found dead in his apartment, apparently the victim of cyanide poisoning. There is speculation on whether this was an accident or a suicide.

    From the information presented so far it is clear that Turing was a fascinating individual and a movie about him was long overdue but is ‘The imitation game’ up to the challenge?


    What I expected to see

    Since I’ve read quite a lot on WWII cryptology and signals intelligence there are some events that I expected to see in the movie, not only because they would add realism to the film but also because they prove that truth is stranger than fiction. What are they?

    Polish codebreakers: In the 1930’s the British and French codebreakers, despite their best efforts, were unable to solve the plugboard Enigma. If countries with great resources and a long tradition in cryptanalysis could not solve this device one would expect that no one else could have succeeded, especially a smaller country with limited resources. Yet contrary to all expectations the Polish codebreakers had not only managed to figure out the operating principle of the Enigma but had succeeded in retrieving the rotor wrings and then solved the internal settings of several networks. They managed to keep this a secret not only from the Germans but also from their close allies! They only revealed their success to the French and British representatives in July 1939 and thus helped them immensely in their codebreaking work.

    Gordon Welchman and the diagonal board: Welchman was a talented mathematician who worked on the Enigma with success, eventually running Hut 6, responsible for German Army and Airforce Enigma trafffic. Welchman’s great contribution was coming up with the idea of the diagonal board. Turing’s bombes were modified to add the diagonal board which made them much more efficient in their operation. As Gordon puts it in ‘The Hut Six story’, p304: ‘Turing, though initially incredulous, was quick to appreciate the importance of this new twist in Enigma theory, which greatly reduced the number of bombe runs that would be needed to ensure success in breaking an Enigma key by means of a crib

    Naval Enigma – Lofoten raid: By 1940 the British codebreakers were routinely solving current Enigma traffic, mainly from Luftwaffe networks. Against the naval Enigma however they had made little progress because the device was used in a more secure manner (additional rotors and use of enciphered message indicators). By March ’41 their only operational success had been the solution of the Enigma ‘key’ for 5 days of 1938 and 6 days in April 1940. In order to force this deadlock the Brits decided to put statistics on the side and use brute force instead! In March 1941 a commando raid was mounted against the German forces in the Norwegian Lofoten islands with the goal of capturing Enigma cipher material (monthly keylists and indicator tables). This operation was a success with material retrieved from the German armed trawler Krebs. This material allowed Hut 8 to decrypt the February traffic during March. Then thanks to the intelligence gained from this ‘break’ they were able to solve the April and May traffic cryptanalytically.

    4-rotor naval Enigma/4-rotor US bombe: In February 1942 the U-boat command stopped using the 3-rotor Enigma and instead introduced a modified 4-rotor version. This was much more secure than the 3-rotor version and immediately put an end to the British success. British and American efforts to solve it failed again and again. By December 1942 only 3 days traffic had been broken. This failure had strained relations between British codebreakers and the US navy’s OP-20-G. It was obvious that new 4-rotor ‘bombes’ were needed but the British reassurance that these would be soon introduced failed to materialize. The Americans then decided to build their own ‘bombes’ at the National Cash Register Corporation under engineer Joseph Desch. It was a good thing they did because the British 4-rotor ‘bombe’ design turned out to be problematic.

    Are these events mentioned in the actual movie? Let’s see.

    ‘The imitation game’

    The movie starts with the police investigation in 1952 and then takes us back to 1939 when Turing first visited GCCS. There he had to solve the Enigma while facing the hostility of Commander Denniston and the other cryptanalysts. Everyone thinks that Turing is a failure but eventually his ‘wacky’ idea to build a machine in order to decode a machine finally works and immediately the British know of the location of every German U-boat in the Atlantic. However they decide not to sink them all because that would alert the Germans. In fact Turing stops them from notifying an Allied convoy of an impending attack even though the brother of one of his fellow cryptanalysts is on board. Turing with the help of Stewart Menzies keeps his success with the Enigma a secret from the military authorities and also from Commander Denniston because he fears that they will misuse it. Instead he decides to use statistical theory in order to find where the Enigma intelligence should be used to have the best effect on the war effort. Having won the war on his own Turing then goes back to teaching and the movie shows how much he suffered from the police investigation and the hormonal therapy, leading to his accident/suicide.

    The movie is definitely entertaining with great actors, great sets, great cinematography etc. However the storyline isn’t just exaggerated in parts or simplified for the general audience. We’re talking about huge errors and strange conspiracy theories being shown to viewers who probably don’t know any better.  
    Am I exaggerating? Someone can counter that it’s not a documentary, it’s a movie. Let’s have look at the failures of the film in more detail. Grab a beer, coffee, tea, whatever works for you because you’ll need it…

    Alan Turing = part nutty professor part rain man

    Turing definitely wasn’t an average person and obviously had his idiosyncrasies, however the film makes him look completely helpless in his interactions with other people. Maybe the producers thought that the average viewer would only appreciate how smart Turing was by making him autistic.

    Bletchley Park = Four guys and a pub

    I thought that Bletchley Park was a huge organization with thousands of people working on Axis codes. Apparently I was wrong. According to the movie Bletchley Park consisted of four cryptanalysts (Turing included) and a rather homely pub. Oh, there’s also a storehouse where they keep the bombe ehh i mean ‘Christopher’.

    Turing = MacGyver

    Some books claim that the bombe was built by Harold Keen, the chief engineer of the British Tabulating Machine Company based on Turing’s designs. These books are wrong (according to the movie). The bombe was built by Turing himself with no assistance from anyone else.

    Where are the Poles?

    I’ve said earlier that the first to succeed with the military Enigma were the Polish codebreakers. For some reason the movie doesn’t acknowledge their success. When at the beginning of the movie Turing meets Commander Denniston he is told that everyone considers the Enigma unbreakable. This is after September 1939 because in the first scenes we hear the declaration of war between Germany and UK. Yet in July 1939 the Polish had revealed their success to the Brits and French.

    Later in the movie when MacGyver Turing is building his bombe he says that his machine was inspired by an old Polish machine but is infinitely more advanced. This is not explained further nor is any reference made to the Polish solution. In fact the Turing bombe was not necessarily infinitely more advanced from the Polish device, it basically worked on a different principle.

    Where’s Gordon?

    Apparently Gordon Welchman never existed. However the diagonal board is mentioned once without explaining how it works. In the movie it is discovered by Hugh Alexander.

    Turing industries: Build first - figure out how it works later

    In real life Turing came up with the idea of exploiting a ‘crib’ (suspected plaintext in the ciphertext) in the Enigma traffic and built a device around that idea. In the movie Turing starts building the bombe as soon as he arrives at Bletchley Park. Yet he only figures out cribbing much later thanks to Joan Clarke!!! What was he building all that time?

    Where are the Americans?

    The movie doesn’t make any reference to the new 4-rotor Enigma introduced in 1942 in the U-boat command. No mention is made of the technologically advanced US 4-rotor bombes.

    The Enigma panopticon

    According to the movie once they finally solved the settings for a day they easily found the locations of all the enemy submarines in the Atlantic. No mention is made of difficulties in interpreting messages, delays in decoding, lack of traffic or failure to decode. Yet decoding naval messages didn’t mean that someone could get their coordinates since they were enciphered with a manual system before being enciphered once more on the Enigma. As I’ve written in B-Dienst vs Bletchley Park - The invasion of Norway and the Battle of the AtlanticCoordinates were taken from a grid table. From June ’41 coordinates were further disguised by using fixed reference points on the grid table. From November ’41 an Adressbuch was used to encipher the grid references’. The coordinates problem was only mastered by the Allies in June 1944 when they captured an Adressbuch from U-boat U-505.

    Conspiracy theories

    The biggest problem I have with the movie is that it repeats some strange theories that probably belong in a conspiracy forum rather than a serious film.

    The first one is that the Allies only used Ultra intelligence when their statistical theory??? showed that it would have a big impact on the war situation. In the film they show a whole convoy being abandoned to the U-boats because had they changed its course the Germans would have found out about Bletchley Park. In real life Ultra intelligence was used on ALL fronts. Every measure was taken to ensure secrecy and only the top commanders were fully indoctrinated into the secret but the intelligence WAS used. For example what did the Brits do when (thanks to captured keylists) in summer 1941 they started solving U-boats messages with little time lag? They rerouted all their convoys around U-boat concentrations. Only 5 of 26 SC convoys, 2 of 31 HX convoys and 3 of 49 ON convoys were attacked…
    The other weird theory promoted by the movie is that the Soviet spy John Cairncross was known all along to the British security services. In fact Menzies tells Turing that it was him that allowed Cairncross to come to Bletchley Park so that he could send valuable intelligence to their ally Stalin. I guess no one can touch those British superspies. They can never lose. Even if you manage to get a spy into their organizations it’s only because they know about it and they allow it….

    More mistakes
    From the first scenes it’s clear that Commander Denniston doesn’t like Turing. He really, reallydoesn’t like him. Perhaps Turing fought for the Starks…

    When the Enigma device is first shown Denniston says that Polish intelligence smuggled one out of Berlin. Nope. The first Enigma was captured in February 1940 from U-boat U-33.
    The movie shows Enigma being used by U-boats, which is correct but it also shows Luftwaffe bombers sending messages which is not correct. Aircraft used hand ciphers for sending messages.

    A U-boat is shown attacking warships while underwater. Not accurate. U-boats usually approached on the surface and their main goal was to sink merchant ships not warships.
    The movie says in the beginning that thanks to the U-boats Britain was starving. Bullshit.

    When Turing decides not to use the Enigma intelligence in fear of alerting the Germans Keira Knightley says: ‘they’ll have changed the design of Enigma by the weekend’. In fact the Germans were planning to replace the Enigma with a new device during the war but they never managed it due to production problems.

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    During WWII the military forces of the Allies and the Axis battled in Europe and Asia but behind the scenes there were efforts to negotiate some sort of compromise peace. These efforts however never amounted to much since both sides distrusted each other and the military situation made it clear that the Allies could win the war through military force alone.  

    Since the 1930’s a segment of German society that opposed the National-Socialist regime had tried to establish contact with foreign countries in order to topple Hitler. During the war the same groups contacted US and British officials in neutral countries and tried to gain their support in order to remove the NS regime from power. The Western Allies were aware of these efforts but they did not offer material support to the members of the German resistance.

    At the same time elements of the NS regime came to realize that the war was lost and thus made cautious attempts to contact Allied officials that could promote some sort of compromise peace. Heinrich Himmler was leader of the SS security service and thus one of the most powerful men in Nazi Germany. Yet by 1943 he was beginning to realize that hopes for a successful conclusion of the war were slim. His subordinate General Walter Schellenberg, head of the foreign intelligence department of the Sicherheitsdienst, had many talks with Himmler on the need for a compromise peace and in 1943 he was able to make the first attempts at contacting Allied officials.
    The Germans knew that Allen Dulles was in charge of the OSS-Office of Strategic Services station in Bern, Switzerland and they chose to contact him through people associated with the German resistance.

    In early 1943 Prince Max Hohenlohe (working on behalf of the Sicherheitsdienst) was given permission to travel to Switzerland and meet Dulles. Unfortunately it doesn’t seem like their meeting remained a secret for long. In the Finnish national archives one can find the decoded version of message No 2.181 of April 7, 1943, giving an overview of their discussion.

    The original is available from the US National Archives and Records Administration - collection RG 59.

    Both the German resistance (through Admiral Canaris) and the Sicherheitsdienst (through Schellenberg) had warned Dulles that his communications were compromised but it doesn’t seem like he acted on this information. These efforts for a compromise peace were probably doomed from the start (especially since the Germans seemed to have overestimated the influence of Dulles) but even so without secure communications the talks could not have remained secret for long.

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  • 01/15/15--03:03: Update
  • I’ve added telegram No 2.181 in Allen Dulles and the compromise of OSS codes in WWII.

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  • 01/20/15--09:37: Update
  • I added the paragraph ‘Fuel tanks in the fighting compartment’ in WWII Myths - T-34 Best Tank of the war.

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  • 01/26/15--05:49: To err is human vol2
  • In ‘German special intelligence, the M-138 strip cipher and unrest in India’ I had said that the Western Allies were able to monitor the exchange of information on Allied codes and ciphers between Germany, Finland and Japan thanks to their solution of the Japanese Coral cipher machine. This was not correct.

    Ralph Erskine pointed out to me that the Coral was mainly used by Japanese naval attaches and that the relevant histories of this system do not mention it being used for transmitting Allied cipher material. Further research at the US National Archives and Records Administration revealed that the code used for transmitting solved Allied cipher material was JAT, a letter code used together with a Gronsfeld square and a book containing random 4-figure groups.  
    I’ve corrected the relevant passage in my essay and added scans from the document ‘JAT write up - selections from JMA traffic'.

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