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Military and intelligence history mostly dealing with World War II.

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    The NSA has declassified the TICOM report I-170 ‘Report on French and Greek Systems by Oberwachtmeister Dr. Otto Karl Winkler of OKH/FNAST 4’ (dated January 1946).

    I’ll probably write a more detailed essay on the compromise of Greek military, diplomatic and partisan codes in WWII.

    Some interesting excerpts from the report:

    My first employment was on the breaking and translating of Greek Air Force messages in Spring 1941. The unit was in BUCHAREST at that time and later it was at BANJA KOSTENIC in Bulgaria. C.O. was Hptm. SCHMIDT, head of the cryptography and translation department from then until Autumn 1944 was Prof. Alfred KNESCHKE, a Professor of Mathematics from Saxony.


    Greek Army and Navy messages were not broken until after the conquest of Greece, when captured ‘Codes’ were read during the attack on Crete.


    In May 1941 the unit moved to ATHENS. In the autumn of that year the De Gaulle troops in Syria began to send cipher messages. ………………………………………………… Practically the whole Syrian WT traffic was read and a complete picture obtained of the build-up, strength, composition and Organization of the French armed forces, of the political administration and the names of all important personalities, as well as all changes and troops movements. In charge of evaluation of French material at this time was Wm. KÜHNAPFEL (from KONIGSBERG).

    As the French used also to refer to British troop movements and officer personalities from time to time, such pointers were of considerable use to our English evaluation section, as the British ciphers could not as a rule be broken by German Sigint.


    The unit moved to BELGRADE in Autumn 1943, thence, in August 1944 to PERNITZ near WIENER NEUSTADT, However, I received a new task in Spring 1944 with the appearance of Greek messages sent by ELAS. In the course of our two year stay in Athens I had been able to learn modern Greek almost perfectly, on the basis of a knowledge of classical Greek and spurred on by love for and interest in Greece. In addition my duties had provided me with a certain experience of cryptography and a good translation technique. Thus I was put in charge of Greek cryptography and was assisted in the actual cryptographic work by Uffz. Diether STROBL from BERLIN, an English interpreter and technical student. I had held the rank of Wachtmeister since Christmas 1943.


    Double transpositions are regarded as a secure type of cipher and are therefore used by many British agents. To the best of my knowledge the unit never succeeded in breaking one and only occasional captured material has rendered it possible to read some traffic retrospectively. For the sake of security it is essential to avoid using complete or even square boxes, typical beginnings or endings of messages and constantly recurring addresses and signatures, to use each key as little as possible and as far as possible to have different keys for each box of the pairs The Greeks overlooked all these rules right up to the end, with the result that messages in the same setting and with the same number of groups (Elementeanzahl) cropped up.


    In any case we succeeded in breaking 50 – 60% of the traffic tackled and as important messages were always retransmitted on several links with different keys, we were able to build up an almost complete picture of the build-up, organization and composition of EAM and ELAS, to compile lists of their leading personalities and officers and to inform the competent German political and military authorities in good time about many planned military and political actions, acts of sabotage, ambushes, dynamitings, etc. I can only remember a few details and cannot reproduce examples systematically as the evaluation of the material wan not my job, which consisted only of deciphering, decoding and translating the available material.

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    A history lesson

    At the start of WWII the Kingdom of Greece, ruled by Ioannis Metaxas (head of the 4th of August Regime) followed a neutral foreign policy and tried to avoid taking part in the conflict. However constant Italian harassment and provocations (such as the sinking of the cruiser Elli) and the transfer of Italian army units to Albania made it clear that war could not be avoided for long.

    In October 1940 Italian forces invaded Greece, in the area of Epirus, and the Greek-Italian warstarted. The Greek forces were able to contain the assault and the Greek counterattack forced the Italians back into Albanian territory. After the defeat of a major Italian offensive in spring 1941 the front stabilized inside Albania.

    At the time Britain was overextended with obligations in Europe, Middle East and Asia. However the British armed forces made a small contribution with an RAF expeditionary corps. When more British forces started to arrive in March 1941, their involvement gave Germany an excuse to become involved in the conflict.

    German forces invaded Greece in April 1941 and made rapid progress due to the fact that almost the entire Greek Army was fighting in the Epirus area. The remaining units and the small British forces transferred to Greece in March-April 1941 were unable to stop them. Then in May 1941 the Germans were also able to defeat the Greek and British forces that had retreated to the strategic island of Crete.

    In the period 1941-44 Greece was split into three occupation zones, controlled by Italy, Germany and Bulgaria.  This measure fractured the Greek economy and together with hyperinflation and loss of value of the paper currency led to the collapse of the economy.

    Greece was a poor agricultural country prior to WWII. The war of 1940-41, the splitting of the country into three occupation zones and the confiscation of goods by the occupying powers led to the impoverishment of an already poor population.

    Greek resistance groups

    Under these circumstances several resistance groups were formed by Greek patriots in order to oppose the Axis powers.

    Small groups operated in urban centers but the bigger ones could only survive in the countryside where the presence of Axis troops was limited.

    The main ones were the military wing of the Greek Communist Party - ELAS (Greek People's Liberation Army) and the liberal EDES(National Republican Greek League).

    The resistance forces organized by the Communist Party were ostensibly created in order to oppose the Axis rule and liberate Greece but in reality their main goal was to eliminate their liberal rivals, unify all resistance groups under communist control and gain power in postwar Greece (1).

    During the period 1943-44 the Communist forces showed more interest in attacking and destroying other resistance groups than in attacking the occupiers. One of their most infamous acts was the destruction of the EKKA (National and Social Liberation) resistance group and the execution of its commander Dimitrios Psarros.

    The ΕΑΜELAS movement grew in power during the occupation for several reasons. Compared to the other resistance groups it had an advantage in that it was tightly controlled by the Communist Party, an organization that knew how to operate in adverse conditions. The main achievement of the communists was that they managed to get British backing for their operations. British liaison officers were transported to Greece and British money and arms supported the ΕΑΜ ELAS movement.

    In addition to British support, with the collapse of Italy in September 1943, several Italian military units in the Balkans surrendered to the partisans and the capture of their heavy weapons (mortars, artillery, machine guns) gave ΕΑΜ ELAS the ability to conduct regular military operations.

    Radio communications and ciphers of the ELAS movement

    According to German sources ELAS radio communications began to be intercepted by the units of KONA 4 (Kommandeur der Nachrichtenaufklärung - Signals Intelligence Regiment) in early 1944.

    KONA 4 was a German Army signal intelligence unit assigned to cover radio traffic from the Balkans and the Middle East. In the period 1943-44 the unit was able to decode a large volume of Yugoslav partisan traffic.

    The quarterly reports of the unit for 1944 (2) show that Greek communist radio traffic was worked on by NAZ G (Nachrichten Nahaufklärungszug - Close Range Signal Intelligence Platoon).

    The report Ez Bericht 1944/II says that in April 1944 radio traffic of the Greek communist groups from the areas Volos, Lamia and Olympus was intercepted. The messages were sent in 4-figure and 5-letter groups. The first procedure was a letter to figure Caesar cipher and it was discontinued by the end of April. The second procedure was double transposition with the same key used for both cages. Both were solved and 240 messages read.


    Mitte April wurde erstmalig ein griechischer kommunistischer Bandenfunkverkehr mit Funkstellen im Raum Volos - Lamia und im Olymp-Gebiet festgestellt. Seither sind hauptsächlich zwei Arten von Chisprüchen der Elas (Griechisches Volksbefreiungsheer)- Verkehre angefallen: 4Z- und 5B-Sprüche.

    a) 4Z-Sprüche.

    Statistische Untersuchungen des Spruchmaterials ergaben eindeutige Hinweise auf ein mehrfach belegtes 2Z-Cäsar-Verfahren, das in seinen verschiedenen Schlüsselformen durch 4Z-Kenngruppen bezeichnet wird. Es wurden schliesslich fünf derartige 2Z-Buchstaben-Silben-Cäsaren gelöst. Bereits Ende April wurde dieses Verfahren ausser Kraft gesetzt.

    b) 5B-Sprüche. 

    Die in grösserem Umfange zwischen dem Obkdo. der Elas und der Gruppe der Divisionen Makedoniens mit ihren unterstellten Einheiten abgesetzten 5B-Sprüche wurden als Klartext-Verwürfelungen erkannt. Untersuchungen auf einfache Verwürfelungen waren erfolglos. Erst als zwei nahezu textgleiche Sprüche mit gleicher 4Z-Kenngruppe auftraten, von denen der eine die mit einer Spalten-vertauschung versehene Wiederholung des anderen war, konnte die Losung erstellt und der Spruch als Doppelwürfelverschlüsselung gelöst werden. Die folgende Entschlüsselung aller mit dieser Losung verzifferten Sprüche ergab, dass der Verschlüssler beim Obkdo der Elas besonders für volle Würfel eine Vorliebe hat. Diese Annahme bestätigte sich, als festgestellt wurde, dass darüber hinaus sogar qruadratische Würfel vorlagen, für die eine einfache Lösungsmöglichkeit besteht. In arderen Fällen lagen der Verschlüsselung halbquadratische Würfel zugrunde. Solche können gleichfalls gelöst werden, da in zwei Halbzeilen des waagerecht eingetragenen Chitextes oft eine bekannte Unterschrift gefunden werden kann. Unter Ausnutzung dieser Verschlüsselungsschwächen des Gegners wurden bisher 20 Doppelwürfelosungen erstellt.
    In der Berichtszeit wurden insgesamt ca 240 Sprüche mitgelesen die wertvolle Aufschlüsse über den organisatorischen Aufbau, die militärische Gliederung und die militärischen Aktionen der kommunistischqp Banden im griechischen Raume gaben.

    ELAS radio-traffic

    Mid-April radio communications of a Greek Communist gang , with radio stations in the area of Volos - Lamia and Olympus, was detected for the first time. Since then, mainly two kinds of cipher messages in the ELAS traffic (Greek people's Liberation Army) have turned: 4-figure and 5-letter messages.

    a) 4-figure messages.

    Statistical investigations of the intercepted material gave clear indications of a multiply occupied 2-figure Caesar system, which in its various cipher forms is identified by 4-figure indicator. Finally five such 2-figure letter-syllable Caesars were solved. Already at the end of April this procedure was cancelled.

    b) 5-letter messages.

    The 5-letter messages, which in larger extent were sent between the ELAS headquarter and the group of divisions in Macedonia with its subordinate units, were recognized as plaintext transpositions. Studies based on simple transpositions were unsuccessful. It was not until two nearly textually equal messages with the same 4-figure indicator group occurred, of which one could be seen as a column swapped repetition of the other, that an answer was found and the message solved as a double transposition. The following decryption of all the enciphered messages with this solution revealed that the cipher clerk at ELAS headquarter had a special preference for complete transposition rectangles. This assumption was confirmed when it was found that it even square transposition templates was used, for which there exist a simple solution. In other cases, the enciphering was based on using half-square transposition templates. Those can equally be solved because in two half-lines of the vertically entered ciphertext one often will find a well-known signature. So far 20 double transposition solutions have been created using these encryption weaknesses of the enemy.
    During the period under review a total of about 240 messages were read which gave valuable insights into the organizational structure, the military plans and the military action of the Communist rings in the Greek area.

    The report Ez Bericht 1944/III says that double transposition continued to be used in ELAS radio communications. Due to poor cipher practices this system could be solved. In the reporting period about 120 keys were solved and 2.200 messages read.

    Elas bewegung

    Sämtliche Funkverkehre der Elas-Bewegung im griechischen Raume verwenden nach wie vor die Dopelwürfelverschlüsselung. Aus der bereits im letzten Bericht erwähnten Vorliebe der gegnerischen Schlüssler für volle Würfel hat sich ein gangbarer Weg zur Lösung dieser Doppelwürfel finden lassen. Unter Verwendung bereite bekannter Unterschriften wurden die Würfellosungen gefunden an quadratischen, doppelquadratischen, halb- und viertel-quadratischen Würfeln, ferner an längen- und lösungsgleichen Würfeln und Würfeln mit Spaltenvertauschung,Dass in einer Anzahl von bereits entzifferten Sprüchen auch Hinweise auf neue Losungen gegeben wurden, erleichterte die Entzifferungsarbeit beträchtlich.

    Mit ca. 120 Losungen konnten in der Berichtszeit nahezu 2.200 Sprüche mitgelesen werden,

    ELAS movement:

    All radio traffic of the ELAs movement in the Greek area still uses the double transposition system. From the preference of the enemy cipher clerks for complete transposition squares, as mentioned in the last report, a practical method of solving this double transposition has been found. By using well-known signatures solutions were found for square, double square, half - and quarter square transposition templates, as well as solutions to same length and solution-equal transposition templates and templates with column swapping.

    The decipherment work was eased considerably by the fact that a number of already decrypted messages also gave hints about new solutions. With about 120 solutions nearly 2,200 messages could be read during the reporting period.

    The last report Ez Bericht 1944/IV says that approximately 50% of the messages were read:

    Elas Bewegung

    Der griechische Bandenfunk wurde ausschliesslich von NNA Zg G bearbeitet, der sich in der Berichtszeit 2 Monate auf dem Rückzug befand. Im letzten Vierteljahr 1944 wurde als einziges Verfahren der Doppelwürfel verwendet . Ungefähr 50% der angefallenen Sprüche wurden mitgelesen. Für ca. 30 Kenngruppen wurden die Losungen  erstellt.

    ELAS movement

    The Greek agent radio traffic was processed exclusively by NNA Zg G who, during the reporting period, had already been on the retreat for 2 months. In the last quarter of 1944 the only method used was double transposition. Approximately 50% of the attacked messages were read. Solutions were found for about 30 characteristic groups (indicators).

    Dr. Otto Karl Winkler and TICOM report I-170

    Additional information on the exploitation of ELAS communications is available from the TICOM report I-170 ‘Report on French and Greek Systems by Oberwachtmeister Dr. Otto Karl Winkler of OKH/FNAST 4’ (dated January 1946).

    The report was written by Dr. Otto Karl Winkler, a member of KONA 4. Dr Winkler was in charge of decoding and translating the Greek messages and in pages 4-6 he stated about his work:

    The unit moved to BELGRADE in Autumn 1943, thence, in August 1944 to PERNITZ near WIENER NEUSTADT, However, I received a new task in Spring 1944 with the appearance of Greek messages sent by ELAS. In the course of our two year stay in Athens I had been able to learn modern Greek almost perfectly, on the basis of a knowledge of classical Greek and spurred on by love for and interest in Greece. In addition my duties had provided me with a certain experience of cryptography and a good translation technique. Thus I was put in charge of Greek cryptography and was assisted in the actual cryptographic work by Uffz. Diether STROBL from BERLIN, an English interpreter and technical student. I had held the rank of Wachtmeister since Christmas 1943.

    Regarding the cipher systems used he also mentions the 2-figure Caesar system and the double transposition cipher. Solution of the latter depended on the poor practices of the ELAS cipher clerks:

    Double transpositions are regarded as a secure type of cipher and are therefore used by many British agents. To the best of my knowledge the unit never succeeded in breaking one and only occasional captured material has rendered it possible to read some traffic retrospectively. For the sake of security it is essential to avoid using complete or even square boxes, typical beginnings or endings of messages and constantly recurring addresses and signatures, to use each key as little as possible and as far as possible to have different keys for each box of the pairs The Greeks overlooked all these rules right up to the end, with the result that messages in the same setting and with the same number of groups (Elementeanzahl) cropped up.

    The solution of these messages provided valuable information about the organization, personalities and operations of the ELAS partisan forces:

    In any case we succeeded in breaking 50 – 60% of the traffic tackled and as important messages were always retransmitted on several links with different keys, we were able to build up an almost complete picture of the build-up, organization and composition of EAM and ELAS, to compile lists of their leading personalities and officers and to inform the competent German political and military authorities in good time about many planned military and political actions, acts of sabotage, ambushes, dynamitings, etc. I can only remember a few details and cannot reproduce examples systematically as the evaluation of the material wan not my job, which consisted only of deciphering, decoding and translating the available material.

    Radio traffic of British liaison officers in Greece

    Apart from ELAS communications the Germans were also able to read some of the messages sent by British liaison officers assigned to the Greek partisans. The German Army’s codebreaking agency OKH/Inspectorate 7/VI was able to decode some of these messages in the period 1943-44 (3).

    The British authorities kept in contact with partisan groups in the Balkans through liaison officers sent by the intelligence services SIS and SOE. These small teams transmitted traffic by radio to their controlling stations in Cairo, Egypt and Bari, Italy. The cryptosystems used were double transposition and the War Office Cypher, enciphered with one time pads.

    Some of the encoded radio traffic of British officers in the Balkans was exploited by the Germans. They were able to read messages both through captured material and by cryptanalysis. 

    The reports of KONA 4 show that some cipher material was captured in the field and messages read. For example in 1943:

    Field units had to rely on captured material in order to read British agents transmissions but this was not necessarily true of the central department. The reports of Inspectorate 7/VI show that this traffic (special traffic to Cairo with indicator GESH) was first solved in June 1943 by Referats 6 and 12:

    Traffic continued to be read till November 1944 but it seems this was mostly from the team assigned to the headquarters of General Mihailović and from the liaison officers in Greece. 

    For example:

    September ’43:

    April ’44:

    July ’44:


    In the period 1941-44 the Greek population suffered under a triple occupation by Italian, German and Bulgarian forces. The collapse of the Greek State, of the economy and the falling living standards led many Greeks to take up arms against the occupiers.

    This situation gave the Greek Communist Party an opportunity to build up a large partisan movement in the countryside and use it to monopolize the anti Axis resistance in Greece. With support from the British and after capturing Italian heavy weapons in 1944 the Communists were one step away from gaining power in the country.

    During this period the German authorities were aware of the growing strength of the partisan movements in the Balkans but they did not have the military forces needed to permanently destroy them. Instead their forces garrisoned strategic areas and urban centers.

    Both in Yugoslavia and in Greece they were able to monitor the military operations and political maneuvers of the partisan movements through signals intelligence.

    In 1944 the German Army’s signal intelligence agency was able to solve a large part of the ELAS radio traffic. Their success was possible mainly due to the many mistakes made by the ELAS cipher clerks. This traffic provided valuable intelligence on the ELAS organization, personalities and planned military and political actions.


    (1). A good summary of the main issues surrounding the goals of the Communist party and EAM ELAS can be found in ‘Εμφύλιαπάθη: 23+2 νέεςερωτήσειςκαιαπαντήσειςγιατονΕμφύλιο’ - ΣτάθηςΝ. Καλύβας, ΝίκοςΜαραντζίδης (2016)

    (2). KONA 4 - Ez Bericht 1944/II, Ez Bericht 1944/III, Ez Bericht 1944/IV (NARA - RG 457 - Entry 9032 - box 22 - ‘German deciphering reports’)

    Additional information:

    1). In TICOM report I-170, p9 an example is given of the ELAS double transposition cipher. 

    The sample message reads:


    My translation: ‘For Macedonian group of divisions – Day – STOP we request that you report immediately if the five officers of the British mission have arrived STOP Stefanos Sarafis’.

    Stefanos Sarafis was the military commander of the ELAS forces.

    2). It seems that the Greek communist military forces continued to use insecure cipher systems even in the late 1940’s. An FBI report dated August 1950 (4) says the AFSA (Armed Forces Security Agency) was working on the following Greek communist crypto systems:

    These were monome-dinome substitution (enciphered with additive) and single and double transposition, similar in concept to the systems used in 1944.

    It is reasonable to assume that the use of insecure ciphers by the communists was exploited by the Greek Army and US agencies during the Greek Civil War.

    Acknowledgments: I have to thank Frode Weierud for translating the KONA 4 summaries and Randy Rezabekfor sharing his copies. 

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    In the construction and use of tactical cryptosystems there are two conflicting requirements. One is security and the other is ease of use. If a system is highly secure but hard and time consuming to use then important messages might be secure from cryptanalysis but they could arrive too late, with disastrous consequences. On the other hand if a system is extremely easy to use but insecure then the messages will get through on time but the enemy will also be able to read them.

    The Slidex code, used by the US and British armies in WWII was easy to use but it could be solved in a few hours by the German codebreakers.

    However the British Army’s double transposition cipher and the US Army’s M-209 cipher machine were basically secure systems, since they could only be solved through mistakes in encipherment. It seems that contrary to regulations the Allied troops did not always use these systems in the field since it took too long to encipher their messages.

    UK example

    Letter from the War Office to the Commanders in Chief 21st Army Group, Home Forces, Middle East, Persia-Iraq (dated February 1945):


    I am commanded by the Army Council to inform you that further consideration has been given to the suitability for operational purposes of the Low-Grade cipher "Double Transposition" which was introduced for use throughout the Army by War Office letter 32/Tels/943 dated 5th November, 1943.

    2. Experience shows that while this cipher affords adequate security, unit personnel find it difficult and slow to operate. There is, therefore, a tendency to avoid the use of cipher with a consequent possibility of overstrain of other safe means of communication or the use of wireless in clear to a dangerous extent.

    3. It has, therefore, been decided to adopt a new Low Grade cipher, called LINEX, details of which are given in appendices A to D, in place of Double Transposition.’

    US example

    Report of interview with S/Sgt, Communications Section 79 Inf Div, 7th Army. (dated March 1945):

    "The US Army code machine #209 was found to be something that hampered operations. It would take at least half hour to get a message through from the message center by use of this code machine and as a result the codes of particular importance or speed, for instance mortar messages, were sent in the clear."

    Sources: British national archives WO 193/211 ‘Wireless, cable and signal (including cipher) communications: policy and codes: action from report of Godwin-Austen Committee’, US national archives - collection RG457 - Entry 9032 - box 1.024 - US COMSEC reports.

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    During WWII the German Army made extensive use of signals intelligence and codebreaking in its operations against enemy forces. German commanders relied on signals intelligence in order to ascertain the enemy’s order of battle and track the movements of units.

    The German Army’s signal intelligence agency operated a number of fixed intercept stations and also had mobile units assigned to Army Groups. These units were called KONA (Kommandeur der Nachrichtenaufklärung - Signals Intelligence Regiment) and each had an evaluation centre, a stationary intercept company, two long range signal intelligence companies and two close range signal intelligence companies.

    The KONA units did not have the ability to solve complicated Allied cryptosystems. Instead they focused on exploiting low/mid level ciphers and even in this capacity they were assisted by material sent to them by the central cryptanalytic department in Berlin. This was the German Army High Command’s Inspectorate 7/VI

    The War Diary of Inspectorate 7/VI

    Some files of the German army signal intelligence service survived WWII and were retrieved in 1947 from a camp in Glasenbach, Austria, where they had been buried at the end of the war.

    The War Diary of Inspectorate 7/VI for the years 1939-45 can be found in the US National Archives, in collection RG457 and in the TICOM collection of the German Foreign Ministry’s Political Archive.

    The reports of departments 1, 7, 13 and F occasionally have information on the Enigma cipher machine (both commercial and plugboard versions).

    Initially department 1 was responsible for general cryptanalytic research but in 1941 department 7 was created to look into the security of German cipher systems. For a time both 1 and 7 did general crypto research. In November 1942 department 13 was created and from then on department 7 dealt solely with German hand systems, while department 13 was responsible for German cipher machines. In 1943 department F (Forschung/Research) was created to do general cryptanalytic research.

    I’ve copied the relevant passages from the War Diary and used google translate. However many terms were not translated correctly so it was up to Frode Weierud, an expert on Enigma history, to correct these passages.

    Thus I present the War Diary entries dealing with the Enigma machine for the years 1941-45 (I’m afraid I don’t have the files of 1939-40):

    Jan-Mar 1941

    Referat 7

    Gleichzeitig wurden die Arbeiten der Abt. Auswertung 3 zur "Enigma" vom Dezember 39 und Januar 40 einer eingehenden Prüfung unterzogen. Wenn auch an einigen verhältnismäßig unwichtigen Stellen Korrekturen der damaligen Überlegungen vorgenommen werden mußten, so zeigte es sich doch, daß die erzielten Ergebnisse und die daraus gezogenen Folgerungen zu recht bestehen. Es gelang, einige wesentliche neue Erkenntnisse bei der ungesteckten Enigma, die im Attachéverkehr eine Rolle spielt, zu erhalten. Hauptergebnis ist, daß eine Bestimmung der Walzen- und Ringstellung bei Vorliegen eines Chitextes von mindestens 50 Buchstaben möglich ist unter der einzigen Voraussetzung, daß die Walzenschaltung bekannt ist. Das dieser Bestimmung zu Grunde liegende Prinzip ist ganz ähnlich dem bei der sogen. "Zwischen-K-Methode" bei der C 36 verwendeten: Es wird für die ungesteckte Enigma eine sogenannte "E-Leiste" hergestellt, d.h. es wird die Reihe der Chibuchstaben aufgestellt, die sich bei fortgesetztem Anschlag des Klarbuchstaben E ergibt. Der vorliegende Chitext wird dann auf dieser E-Leiste so lange entlang geschoben, bis sich eine Übereinstimmung von ca. 15 - 20 % des überdeckten E-Leisten-Stückes und des Chitextes ergibt. Diese Stelle gibt dann die Walzenstellung an. Über die praktische Anwendung dieser Methode sind die Überlegungen noch nicht abgeschlossen. Ebenso sind die Überlegungen über die Anwendbarkeit dieses Prinzips auf die gesteckte Enigma noch nicht beendet. Ferner wurde eine Reihe eingereichter Vorschläge für neue Chiverfahren geprüft und an Chi/OKW weitergegeben.

    At the same time, the work of Evaluation Dept. 3 (of Group In 7/IV ) on the "Enigma" of December 39 and January 40 was subjected to an in-depth examination. Even if some relatively unimportant points had to be corrected by the considerations made at that time, it turned out that the results obtained and the conclusions drawn from them were correct. It was possible to obtain some important new insights into the unsteckered Enigma that plays a role in attaché traffic. The main result is that a determination of the wheel and ring positions is possible when a ciphertext of at least 50 letters is available, provided that the wheel wirings are known. The principle underlying this determination is very similar to that of the so-called "Intermediate K-Method" used for the C 36: A so-called "E-strip" is produced for the unsteckered Enigma, that is, a row of cipher letters is produced by continuous typing of the cleartext letter E. The available ciphertext is then slid along this E-strip until it is obtained an agreement of approx. 15 - 20% between the overlapped E-strip piece and the ciphertext. This position then indicates the wheel position. The consideration concerning the practical use of this method has not yet been completed. Likewise, the considerations about the practicability of this method to the steckered Enigma have not yet been finished. In addition, a number of submitted proposals for new cipher systems were examined and passed on to Chi / OKW.

    April 1941

    Referat 7

    Der Bericht 11 zum Enigmaverfahren wurde fertiggestellt. Es handelt sich dabei um die Bestimmung von Walzenlage, Anfangsstellung der Walzen und Ringstellung bei bekannter Walzenschaltung und Steckung, wenn ein Chitext von etwa 60 Buchstaben vorliegt, mit der Methode der E-Leisten.

    Die Untersuchungen werden in der Richtung fortgesetzt, daß nunmehr Walzenlage, Walzenstellung und Ringstellung vorgegeben werden und die Steckung mit Hilfe der E-Leisten bestimmt wird. (Die Walzenschaltungen werden dabei wieder als bekannt vorausgesetzt.)

    The report no. 11 on the Enigma procedure has been finalized. This involves the determination of the wheel order, the initial setting of the wheels and the ring position in the case of known wheel wirings and plug connections, if a ciphertext of about 60 letters is available, by using the method of the E strips.

    The studies are continued in the direction that now the wheel order, the wheel position and the ring position are known, and the plug connections are determined by means of the E strips. (Again we presume the wheel wirings are known.)

    May 1941

    Referat 7

    Die Untersuchungen zum Enigmaverfahren wurden fortgesetzt. Bei der Bearbeitung der Aufgabe, das Enigmaverfahren ohne Ausnützung einer besonderen Schlüsseltechnik allein aus den Sprachhäufigkeiten (und der Maschinenkenntnis) heraus zu lösen, wurde eine weitere Teillösung gefunden: Bestimmung der Steckung bei bekannter Ring- und Walzenstellung aus einem Chitext von rd. 200 Buchstaben. Über die Methode wird ein Bericht ausgearbeitet.

    The studies of the Enigma system have been continued. In the course of dealing with the task of solving the Enigma system without using a special cipher technique but only from the language statistics (and the knowledge of the machine), a further partial solution was found: Determination of the plug connection at known ring and wheel positions from a ciphertext of approx. 200 characters. A report describing the method is being prepared.

    June 1941

    Referat 7

    Bezüglich der Enigma wurden die in Gang, befindlichen Untersuchungen — Bestimmung der Steckung bei Kenntnis der Grund- und Ringstellung und der Walzenlage aus einem Chitext von 200 Buchstaben mit Hilfe der "Buchstabenleisten"— weitergeführt und ein diesbezüglicher Bericht in Angriff genommen.

    With regard to the Enigma, the studies in progress – determination of the plug connections with the knowledge of the base and ring positions and the wheel order from a ciphertext of 200 letters with the use of the "letter strips"– were continued and a report about this was started.

    July 1941

    Referat 1/7

    Die Untersuchungen zur Enigma und zum Doppelkastenschlüssel laufen weiter. Bei der Enigma wurde die Untersuchung und ein zugehöriger Bericht über die Bestimmung der Steckung bei Kenntnis der Grund- und Ringstellung und der Walzenlage bei Vorliegen eines Chitextes von ca. 200 Buchstaben abgeschlossen. Eine weitere Untersuchung über die Bestimmung der Schaltung der Umkehrwalze bei bekannter Grund- und Ringstellung und Walzenlage und bei bekannter Walzenschaltung ist in Bearbeitung.

    The studies of the Enigma and the double Playfair cipher continue. Concerning the Enigma, the studies and an accompanying report on the determination of the plug connections with knowledge of the base and ring positions and the wheel order for a ciphertext of about 200 letters were concluded. A further study is carried out to determine the wiring of the reflector (UKW) in the case of known base and ring positions and wheel order and with known wheel wirings.

    August 1941

    Referat 1/7

    Die Untersuchungen zur Enigma und zum Doppelkastenschlüssel laufen weiter. Neu aufgenommen wurde eine Untersuchung der Schlüsseltaste.

    The studies of the Enigma and the double Playfair cipher continue. A new study was started on the Morse code cipher (Menzer Schlüsseltaste).

    September 1941

    Referat 1/7

    Die Untersuchungen zur Enigma, zum Doppelkastenschlüssel und zur Schlüsseltaste laufen weiter. Bei der Enigma wurde speziell das Problem untersucht: Ermittlung der Schaltunen der Umkehrwalze bei bekanntem Tagesschlüssel und genügendem Chimaterial. Letztere Untersuchungen wurden zu einem Abschluß geführt. Ein Bericht darüber soll noch angefertigt werden.

    The studies of the Enigma, the double Playfair cipher and the Morse cipher are still continuing. In the case of the Enigma, the problem of determining the wiring of the reflector when the daily key is known and when sufficient cipher material is available was specially studied. The latter studies were concluded. A report on this is still to be prepared.

    October 1941

    Referat 1/7

    Die Untersuchungen zur Enigma, zum Doppelkastenschlüssel und zur Schlüsseltaste laufen weiter, zeitweilig unterbrochen durch Urlaub und durch Einziehung zur Grundausbildung der betr. Bearbeiter. Berichte über die bisherigen Arbeitsergebnisse zu diesen einzelnen Verfahren sind in Angriff genommen.

    The studies of the Enigma, of the double Playfair cipher and to the Morse cipher are continuing, temporarily interrupted by leave and by call up to basic training of the concerned personnel. Reports on the results of the work to date on these individual systems have been launched.

    November 1941

    Referat 1/7

    Die Bearbeitung eines Berichts über ein spezielles Untersuchungsthema zur Enigma konnte nur langsam weitergeführt werden, da der Sachbearbeiter ( Fu. Dr. Luzius) einen erheblichen Teil seiner Zeit zur Überwachung des Gefangenen verwenden musste.

    The work on a report on a special Enigma research topic was only slowly continued, since the specialist (Private Dr. Luzius) had to use a considerable amount of his time to monitor the prisoner (English prisoner of war codenamed “Gottfried Müller“).

    December 1941

    Referat 1/7

    Desgleichen hatte Sdf. Dr. Pietsch Anfang Dezember eine Besprechung mit Sdf. Kühn über die Bearbeitung des Schweizer Enigma-Verfahrens. Ferner hatte Sdf. Dr. Pietsch eine Reihe von Besprechungen mit Hptm. Kempe und Major Bunge über Fragen der Sicherheit der bisher im Heer verwandten Rufzeichentabellen und über die Sicherheit des Enigmaverkehrs im Bereich der festen Funkstellen, da hier der Materialanfall eine kritische  Grenze zu erreichen droht und gegebenenfalls weitere Sicherungsmaßnahmen erforderlich macht.

    Funker Dr. Luzius beendete seinen Bericht über eine Untersuchung zur Enigma.

    Likewise, Special Leader Dr. Pietsch had a meeting with Special Leader Kühn at the beginning of December to discuss the Swiss Enigma system. Furthermore, Special Leader Pietsch had a series of discussions with Captain Kempe and Major Bunge on questions of the security of the call sign tables so far used in the army and about the security of the Enigma traffic in the area of the fixed radio stations, since the traffic volume threatens to reach a critical limit and, if necessary, requires further security measures.

    Private Dr. Luzius ended his report on a study of Enigma.

    January 1942

    Referat 1/7

    Die Untersuchungen zu den eigenen Verfahren, insbesondere Truppenschlüssel und Enigma, wurden fortgesetzt. Insbesondere gelang der Nachweis, daß erbeutetes, vom russ. H-Dienst aufgenommenes Material vom Truppenschlüssel innerhalb der kurzen Zeit von nur 4 stunden entziffert werden konnte.

    Ein Bericht hierüber wurde angefertigt.

    Verschiedene Besprechungen mit Gruppe IV hinsichtlich der Fragen des Enigma—Verkehrs der Festen Funkstellen sowie der Frage über die Sicherheit des Rufzeichenwesens hatte der Referatsleiter Dr. Pietsch geführt.

    The studies of our own procedures, especially troop cipher and Enigma, were continued. In particular, it was possible to prove, through captured material, that troop cipher material intercepted by the Russian signal intelligence service could be deciphered in the short time of only 4 hours.

    A report was made of this.

    Section Leader Dr. Pietsch had various talks with Group IV concerning the questions of the Enigma traffic of the fixed radio stations as well as the question about the security of the call sign system.

    February 1942

    Referat 1/7

    Investigations continued.

    March 1942

    Referat 1/7


    April 1942

    Referat 7

    May 1942

    Referat 7


    June 1942

    Referat 7

    4. Enigma als Spaltencäsar. Es wurde zunächst die Vorfrage in Angriff genommen, mit welcher Wahrscheinlichkeit die vorgegebenen Spalten bei einer vorgegebenen Buchstabenanzahl zu erwarten sind und hierfür eine Abschätzung aufgestellt. Die arbeiten worden fortgesetzt. Bearbeiter: Wtm v. Denffer.

    Enigma as a periodic substitution cipher. At first, the question was raised of the probability with which the given alphabets can be expected for a given number of letters and an estimate was made for this. The work is being continued. Specialist: Sergeant v. Denffer.

    5. Enigma als Maschine i.e.5. Die Erkanntnis über die Maschine wurde durch Bearbeitung 2er Teilprobleme (für die ungesteckte Maschine) weiter gefordert. Bearbeiter: Uffz-Döring.

    Enigma as a machine. The knowledge of the machine demanded further work on two sub-problems (for the unsteckered machine). Specialist: Corporal Döring.

    July 1942

    Referat 7


    August 1942

    Referat 7

    7. Enigma

    Bei der Enigma wurde der Problem der Vergatterung von Sprüchen und Lösung als Spaltencäsar erneut aufgegriffen. Die Arbeiten mussten jedoch wegen der anderen vordringlicheren Aufgaben Mitte des Monats zunächst bis auf weiteres unterbrochen werden.

    Concerning Enigma the problem of depths of messages and a solution as a periodic substitution cipher was again taken up. However, due to the other more urgent tasks in the middle of the month, the work had to be interrupted until later.

    September 1942

    Referat 7


    October 1942

    Referat 7


    November 1942

    Referat 7


    December 1942

    Referat 7

    6. Enigma

    Die vom Referat 4 zur Prüfung übersandten Italienischen 5B-Spruchen konnten mit Sicherheit als mit Enigma verschlüsselt erkannt werden. (s.Schreiben vom 7.12.42)

    The Italian 5-letter messages, which were sent for review by Section 4, could definitively be identified as being encrypted with Enigma. (See memo of 7 December 1942)

    January 1943

    Referat 13


    February 1943

    Referat 13


    March 1943

    Referat 13

    5. Schlüsselüberwachung

    Auf Grund der veröffentlichten Funksprüche aus Stalingrad wurde In 7/VI um ein allgemeines Gutachten gebeten, das die Stellungnahme vom Standpunkt der Entzifferung enthält.

    Based on the published radio messages from Stalingrad In 7/VI was asked for a general expert opinion as seen from the standpoint of deciphering.

    April 1943

    Referat 13


    May 1943

    Referat F

    1). Maschine Enigma.

    Uber die Enigma (Heeresenigma sowie handelsüblicher Typ) sind bereits umfangreiche Arbeiten durch verschiedene Bearbeiter in verschiedenen Richtungen durchgeführt worden. Es besitzt jedoch zur Zeit kein einzelner Bearbeiter eine vollständige Kenntnis alles auf diesem Gebiet Geleisteten, und es ist diese Kenntnis aus den bisher niedergelegten Berichten infolge ihrer Unübersichtlichkeit nur mit großer Mühe zu gewinnen. Es wurde daher folgende Aufgabe in Angriff genommen: 1. Durcharbeitung aller bisherigen Arbeiten und Zusammenstellung der Ergebnisse in einem übersichtlichen Bericht. 2. Klärung, inwieweit bestimmte, gegenwärtig besonders interessierende Fragen aus der bereits geleisteten Arbeit heraus beantwortet werden können und gegebenenfalls Versuch, die Lösung in dieser Richtung weiter zu treiben.

    Die Bearbeitung dieser umfangreichen Aufgabe wird voraussichtlich einige Monate in Anspruch nehmen.

    1). Enigma machine.

    Concerning the Enigma (Army Enigma as well as commercial type) different co-workers have already carried out extensive works in different directions. However, at this time no single person possesses a comprehensive knowledge of everything being done in this area, and this knowledge could be gained from the currently established reports only with a high effort, because of their complexity. Thus the following tasks have been initiated:
    1. Examination of all previous works and compilation of the results in a clearly structured report.
    2. Clarification on to which extent certain currently particularly interesting questions can be answered through the work already done, and if applicable, attempt to carry on the solution in that direction.

    The processing of this extensive task is expected to take several months.


    Bei Spaltenverfahren ist es oft Voraussetzung für die weitere Bearbeitung, daß es gelingt, ein gegebenes Spruchmaterial ohne Kenntnis der Spruchschlüssel zu vergattern, d.h. die gegenwärtige Lage der Anfangsstellungen zu erkennen. Bei ausreichender Tiefe der Vergatterung, d.h. wenn es gelingt, ausreichend viele sich gegenseitig überdeckende Sprüche zusammenzustellen, ist sogar jedes Spaltenverfahren elementar lösbar. Bei der ein Spaltenverfahren darstellenden Maschine Enigma sind insbesondere folgende, bisher nicht gelöste Teilfragen von Bedeutung.

    1. Welche Tiefe ist erforderlich, um eine elementare Lösung der Maschine zu ermöglichen?

    2. Mit welcher Wahrscheinlichkeit tritt eine bestimmte Tiefe bei gegebenen Spruchumfang auf?

    3. Lassen sich bei theoretisch bestimmter Tiefe die Sprüche in der verlangten Weise anordnen, mit welchen Mitteln und mit welchen Zeit- und Arbeitsaufwand?

    Die Bearbeitung der 1. Frage ist begonnen worden. Die Lösung der 2. Frage wurde in der Berichtszeit im wesentlichen erreicht. Es kann danach das Auftreten von Fällen, in denen eine elementare Lösung der Enigma möglich wird, mit einer Wahrscheinlichkeit von weniger als 1 % veranschlagt werden, wenn schlüsselgleiches Spruchmaterial von mehr als 100.000 Buchstaben nicht auftritt. Zur vollständigen Behandlung der 3. Frage fehlen noch einige statistische Unterlagen. Es zeigt sich jedoch bereits jetzt, daß der Zeit- und Arbeitsaufwand bei der Vergatterung so außerordentlich groß wird, daß er weder mit den bereits vorhandenen Maschinen (Hollerith) noch mit den bei OKH in Entwicklung befindlichen (Phasensuchgerät) zu einer lohnenden Entzifferung führen würde. Wie weit diese Auffassung zu ändern ist, wenn man dem Gegner einen wesentlichen Vorsprung in der Entwicklung von Entzifferungsmaschinen zugestehen will, wird noch geprüft.

    Messages in depth questions.

    For periodic substitution ciphers it is often a presupposition for a further processing that one succeeds in adjusting the depths for a given batch of ciphertexts without the knowledge of the message keys, meaning to identify the current settings of the initial positions. With a sufficient length of the depths, that is if one succeeds in compiling a sufficiently high number of different messages that overlap each other, actually every substitution cipher can be elementarily solved. For the Enigma machine, which represents a periodic substitution cipher, especially the following currently unsolved sub-questions are of importance.

    1. Which depth is needed in order to allow an elementary solution of the machine?

    2. What is the probability for the occurrence of a certain depth for a given amount of messages?

    3. With a theoretically given depth, is it then possible to adjust the messages in the needed manner, with which aids and with which effort concerning time and amount of work?

    The work on the first question has started. The solution of the second question has been essentially accomplished within the period of this report. Accordingly the occurrence of cases that allow an elementary solution of the Enigma can be estimated to be less than 1 %, given that messages in depth with more than 100,000 letters do not occur. For a comprehensive examination of the third question still some statistical data are missing. However already now it can be seen that the effort concerning time and amount of work for adjusting the depths becomes so extraordinarily high that it would not lead to a worthwhile decryption neither with the already available machines (Hollerith) nor with the ones currently being developed at OKH (phase searching device). On how far this assessment has to be changed, when conceding the opponent a significant advantage concerning the development of decryption machines, is still being investigated.

    Referat 13

    5. Enigma

    Am 21.5. fanden bei Gruppe IV und am 31.5. beim GBN Besprechungen über den Bau einer Einheitsenigma statt, die im wesentlichen technische Einzelheiten zum Gegenstand hatten. Von chitechnischer Bedeutung war dabei lediglich die Einführung einer vierten Chiffrierwalze. Die Entscheidung darüber, ob Walzen mit Lückenfüllern eingeführt werden sollen, wurde aufgeschoben, bis Erprobungsergebnisse vorliegen.

    On 21.5. discussions were held in Group IV and on 31.5. at the GBN about the construction of a unity Enigma, which essentially concerned technical details. Only the introduction of a fourth cipher wheel was of cryptological importance. The decision as to whether wheels with gap fillers (variable notch wheels) are to be introduced has been postponed until test results are available.

    June 1943

    Referat F

    5. Die im Vormonat begonnenen Arbeiten wurden fortgeführt, insbesondere die Arbeiten zur Maschine Enigma, die Untersuchungen über eine allgemeine Lösungsmethode für Versatzverfahren und gewisse Untersuchungen zum amerikanischen Streifenverfahren.

    5. The work begun in the previous month has been continued, in particular the work on the Enigma machine, the studies of a general solution method for transposition ciphers and certain studies on the American strip method.

    Referat 13

    6. Enigma

    Es wurden die deutschen Maschinenschlüssel Fe Fu M1 und 2 geprüft; dabei stellte sich heraus, daß bei der Herstellung dieser Schlüssel nicht alle vorhandenen Variationsmöglichkeiten genügend ausgenutzt werden.

    Bei einem kroatischen 5B-Verkehr wurde festgestellt, daß er mit einer handelsüblichen Enigma Modell K verschlüsselt ist. Ein Versuch mit den von der Chiffriermaschinengesellschaft Heimsoeth & Rinke an Kroatien gelieferten Walzen ergab, daß tatsächlich die betreffenden Walzenschaltungen benutzt wurden. Unter Ausnutzung teilweise bekannter Schlüsselunterlagen gelang ein Einbruch und damit die Deutung der Schlüsseltechnik. Nach früher hier entwickelten Methoden wird eine laufende Entzifferung möglich sein.

    In einer Besprechung am 8.6.43 wurden einige Entzifferungsergebnisse über die handelsübliche Enigma mit dem Forschungsamt ausgetauscht. (Wm. Döring, Uffz. Rinow.)

    The German machine keys Fe Fu M1 and 2 (Fixed radio station keys) were tested; it turned out that in the production of these keys, not all available variations were sufficiently utilized.

    In Croatian 5-letter traffic, it was found that it is encrypted with a commercially available Enigma Model K. An attempt with the wheels supplied to Croatia by the cipher machine company Heimsoeth & Rinke showed that the respective wheel wirings were actually being used. By exploiting some partly known key documents, a break was successful and as a result the interpretation of the cipher. According to methods developed earlier, a deciphering process will be possible.

    In a meeting on 8/6/43 some deciphering results were exchanged with the Forschungsamt about the commercial Enigma. (Sergent Döring, Colonel Rinow.)

    July 1943

    Referat F

    4. Im übrigen wurden die Arbeiten des Vormonats, insbesondere die zur Maschine Enigma weitergeführt.

    The work of the previous month, in particular on the Enigma machine, has been continued.

    Referat 13

    Bei den kroatischen 5B-Sprüchen, die als Enigma-Sprüche (Modell K) erkannt wurden, konnten die häufigste nutzten Kenngruppen erstellt werden, sodaß fast der gesamte Verkehr mitgelesen werden kann.

    Am 27.7. fand bei ,Chi/OKW eine Besprechung über, die Untersuchung an der Enigma statt. Das von Chi dargestellte Verfahren zur Lösung der Steckerbrettenigma ist zwar theoretisch möglich wird aber praktisch kaum durchführbar sein.

    For the Croatian 5-letter messages, which were identified as Enigma messages (model K), the most frequent identification groups could be constructed so that almost all traffic can be read.

    On 27.7. a meeting took place at OKW / Chi about the studies of the Enigma. The method described by Chi for the solution of the plug board Enigma is theoretically possible, but it can hardly be carried out in practice.

    August 1943

    Referat F

    4. Vergatterungsfragen.

    Es handelt sich um die Weiterführung von Arbeiten aus dem Vormonat, die insbesondere für die Maschine Enigma interessieren. Die arbeiten werden demnächst vorläufig abgeschlossen.

    4. Messages in depth questions.

    It concerns the continuation of work from the previous month, which is particularly interesting for the Enigma machine. The work will be concluded for the time being.

    Referat 13

    5. Enigma:

    Die Erstellung der kroatischen Enigmaschlüssel wurde fortgesetzt.

    Die Bearbeitung italienischer 5B-Sprüche, die schon früher als Enigmasprüche gedeutet wurden, konnten noch nicht voll aufgenommen werden, da die Nachforschung nach dem verwendeten Modell noch nicht abgeschlossen ist.

    The preparation of the Croatian Engima keys was continued.

    The processing of Italian 5-letter messages, which already earlier were indicated as Enigma messages, could not yet be completely started since the investigation of which model is being used has not yet finished.

    September 1943

    Referat F

    5. Durch die Abgabe des 5-Z-Materials war es möglich, frühere Arbeiten über die Enigma, die Versatzverfahren und die Statistischen Prühverfahren wider aufzunehmen.

    It was possible by the handing over of the 5-figure material to yet again start with earlier work on the Enigma, the transposition systems and the statistical test systems.

    Referat 13

    5.) Enigma.

    Nachdem die Kroaten von Vierteljährlichem Schlüsselwechsel (100 Schlüssel) zu täglichen Schlüsselwechsel (10 Schlüssel) übergangen sind, erfordert die laufende Erstellung der Schlüssel mehr Arbeit als bisher.

    Durch die Erbeutung italienischer Schlüsselunterlagen für die dort verwendete Heeresenigma konnte ein Teil der 5 B Sprüche entschlüsselt werden. Ref. 4 wurde in die Arbeiten eingewiesen.

    5.) Enigma.

    After the Croatians have passed from quarterly key change (100 keys) to daily key changes (10 keys), the ongoing creation of the keys requires more work than before.

    Through the capture of Italian key documents for the Heeres Enigma used there, a part of the 5-letter messages could be deciphered. Section 4 was instructed in the works.

    October 1943

    Referat F

    5.  Fragen von allgemeinem Interesse.

    a) Der systematische zusammenfassende Bericht über Maschinen von Enigma-Typus ist fortgesetzt worden.

    b) Es sind verschiedene theoretische statistische Untersuchungen durchgeführt worden, die durch Fragestellungen der praktischen Ez, u. a. durch das sog. Vergatterungsproblem, veranlaßt sind. Über die Ergebnisse sind Berichte in Ausarbeitung.

    5. Issues of general interest.

    a) The systematic summary report on Enigma type machines is being continued.

    b) Various theoretical statistical studies have been carried out, which are motivated by practical deciphering questions, among other things the so-called depth problem. Reports are being prepared for the results.

    Referat 13

    3.) Enigma.

    Da die Schlüsselunterlagen zur kroatischen Enigma anderweitig besorgt werden, konnte sie laufende Erstellung der Schlüssel Mitte des Monats eingestellt werden.

    Die Untersuchungen über die Heeres-Enigma (Steckerenigma) wurden neu aufgenommen. Gleichzeitig wurde an der Lösung der K-Maschine weiter gearbeitet.

    Since the key documents for the Croatian Enigma are otherwise provided, the current construction of the keys could be discontinued by the middle of the month.

    The studies of the Army Enigma (plug board Enigma) were taken up again. At the same time, work continued on the solution of the K-machine.

    November 1943

    Referat F

    5. Enigma Bericht.

    Ein systematischer zusammenfassender Bericht ist in Vorbereitung.

    A systematic summary report is being prepared.

    Referat 13

    3.) Enigma.

    Es wurden theoretische und empirische Untersuchungen zum Bigrammverfahren durchgeführt (Aktennotiz). Außerdem wurde an dem Problem gearbeitet, mit Hilfe eines Kompromißtextes, die inneren Schaltungen der Walzen zu bestimmen.

    Theoretical and empirical studies on the bigram procedure have been carried out (Memo). In addition, the problem to determine the internal wirings of the wheels was worked on with the help of a compromised text (known plaintext).

    December 1943

    Referat b1

    Ein systematischer zusammenfassender Bericht über die handelsübliche Enigma steht kurz vor der Vollendung. Ebenso stehen ein Bericht über ein allgemeines statistisches Prüfverfahren sowie ein weiterer Bericht über Vergatterungsfragen bei der Enigma (vgl. Vormonat) vor der Fertigstellung.

    A systematic summary report on the commercial Enigma is about to be completed. There is also a report on a general statistical test procedure and a further report on the question of messages in depth for the Enigma (cf. previous month) ready for completion.

    Referat b2

    3. Enigma.

    Die Erstellung der kroatischen Schlüssel wurde wieder aufgenommen, da die Beschaffung auf dem früheren Weg in der neuen Schlüsselperiode noch nicht möglich war.

    The creation of the Croatian keys was resumed, as procurement via the previous method was not yet possible for the new key period.

    February 1944

    Referat b2

    3. Enigma: Die Spruchschlüssel zur kroatischen  Enigma wurden weiterhin erstellt.

    3. Enigma: The message keys for the Croatian Enigma were still created.

    March 1944

    Referat b2

    2. Heeres Enigma: Es wurden Untersuchungen angestellt, in wieweit die Heeres-Enigma durch Verrat bloßgestellt werden kann. Bei Aufrechterhaltung  der heutigen Schlüsseltechnik genügen 5 nach bestimmten Vereinbarungen gewählte Spruchschlüssel, um den Tagesschlüssel zu verraten, ohne dass eine deutsche Funküberwachung bei genauer Überprüfung den Verrat erkennen kann.

    2. Heeres Enigma: Studies were made to what extent the Army Enigma can be compromised by betrayal. If the current key procedure is maintained, then 5 message keys, selected according to certain rules, are sufficient to reveal the daily key without, on closer examination, a German radio monitoring service being able to detect the betrayal.

    April 1944

    Referat b2

    2. Heeres Enigma: Zur Klärung der Gegebenheiten für eine Abstellung der im Vormonatsbericht erwähnten  Verratsmöglichkeiten bei der heutigen Enigma-Schlüsseltechnik wurde Wm. Buggisch am 1.4. zu HNV IV und am 4.4. zur Fe.Fu.- Stelle Nedlitz kommandiert. Es ergaben sich zweckgeeignete Lösungen des Problems, die HNV IV zur Herbeiführung einer Entscheidung unterbreitet wurden.

    In order to clarify the circumstances for the elimination of the betrayal potentials in Enigma’s current key procedure as mentioned in the previous month's report, Sergent Buggisch was ordered on the 1.4. to HNV IV and on the 4.4. to Fe.Fu.- station (Fixed radio station) Nedlitz. It resulted in suitable solutions to the problem, which were submitted to HNV IV for the purpose of making a decision.

    May 1944

    Referat b1

    3. Enigma: Fertigstellung eines zusammenfassenden Berichtes über den gegenwärtigen Stand der hiesigen Erkenntnisse zur Enigma ohne Stecker. Aufnahme der Vorarbeiten für einen entsprechenden Bericht zur Enigma mit Stecker.

    3. Enigma: Completion of a summary report on the current status of the Enigma without plugs. Starting the preliminary work for a corresponding report on the Enigma with plugs.

    Referat b2

    2. Enigma:

    a). Marine Verfahren: Genauere Untersuchung der Schlüsseltechnik der Marine (Verfahren M allgemein) ergab, dass der Notschlüssel sicherheitsmässig völlig unzureichend ist. Auch der planmäßige Schlüssel M allgemein“ ist durch Kopplung mit Rufzeichensystem wahrscheinlich lösbar. Hierbei ergab sich noch eine allgemeine Lösungsmöglichkeit für das Kompromissproblem bei der Stecker-Enigma mittels einer umfangreichen Ez-Hilfsmaschine.

    Marine procedures: A closer study of the key procedure of the Navy (System M General) revealed that the security of the emergency key is completely unsatisfactory. The normal key for “M general” can also probably be solved through a coupling with the call sign system. From this followed a general solution for the compromise problem with the pluggable Enigma by means of a large auxiliary deciphering machine.

    b). Heeres-Enigma: Verfolgung der alten Untersuchungen nach der quantitativen Seite hin ergab Rekonstruktionsmöglichkeit des Tagesschlüssels aus 4 phasengleichen Chitexten von je etwa 250 Buchstaben mittels eines umfangreichen Systems von Ez-Hilfsmaschinen. In besonders günstigen Fällen dürfte diese Rekonstruktion auch schon bei einem einzelnen langen Spruch möglich sein, allerdings mit außerordentlich großem Arbeitsaufwand.

    Army Enigma: Reviewing the old studies on the quantitative side revealed a reconstruction possibility for the daily key from 4 phase-equivalent (in depth) ciphertexts of about 250 letters each using a substantial system of auxiliary deciphering machines. In particularly favorable cases, this reconstruction may be possible even with a single long message, but with an exceedingly great expenditure of labor.

    c). Schlüsseluhr: Aufnahme der Untersuchung dieses Zusatzgerätes. Überprüfung einer HNV/IV vorgeschlagenen Schaltungsänderung und Erörterung verschiedener Möglichkeiten der Schlüsseltechnik.

    Cipher Clock (Enigma Uhr): Start of the study of this accessory. Examination of an HNV / IV proposed circuit change and discussion of various possibilities for this cipher system.

    June 1944

    Referat b1

    4. Sonstige Arbeiten: Weiterführung der Arbeiten zum Kompromissproblem der Heeres-Enigma.

    4. Other Work: Continuation of the work on the compromise problem of the Army Enigma.

    July 1944

    Referat b1

    3. Enigma: Bearbeitung des Kompromissproblem der Heeres Enigma.

    3. Enigma: Work on the compromise problem of the Army Enigma.

    August 1944

    Referat b1

    2. Enigma: Fortsetzung der Arbeiten des Vormonats.

    2. Enigma: Continuation of the work from the previous month.

    September 1944

    Referat b1

    Einstellung der Bearbeitung eigener Verfahren mit Monatsende und Übernahme derselben von OKW/WNV/Chi.

    Suspension of work on own systems at the end of the month and taking over of the same by OKW / WNV / Chi.

    2. Enigma: Abschluss der Arbeiten über das Kompromissproblem der gesteckten Enigma.

    2. Enigma: Conclusion of the work on the compromise problem of the pluggable Enigma.

    It is interesting to note that an OKW/Chi report on the security of the different Enigma models (dated 25 August 1944) says:

    3. Für die Heeres-Enigma (Steckerbrett, 3 Walzen mit je 1 Lücke) werden theoretische Lösungen gesehen, deren praktische Durchrführung bei erheblichem maschinellen Aufwand im Bereich des Möglichen liegt. Bei der Marine-Enigma (Steckerbrett, 4 Walzen mit je 2 Lücken) erscheint der Aufwand an Hilfsgeräten und Zeit  zu gross als dass Geheimtexte in tragbarer Zeit entziffert werden könnten.

    3. For the Army Enigma (plugboard, 3 wheels with one notch each), theoretical solutions are considered, of which the practical implementation is within the bounds of possibility with a considerable machine effort. In the case of the Naval Enigma (plugboard, 4 wheels with 2 notches each), the effort required for auxiliary equipment and time is too great for the cipher text to be deciphered in a reasonable time.

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    On June 22 1941 the military forces of Nazi Germany attacked the Soviet Union, thus starting the largest land campaign in history.

    Codebreaking and signals intelligence played a major role in the German war effort. Army and Luftwaffe units relied on signals intelligence in order to monitor enemy units and anticipate major actions.

    For a summary of German signal intelligence operations read Compromise of Soviet codes in WWII.

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    In April I said that I’ve been trying to locate the two missing reports of NAASt 5, which was the cryptanalytic centre of KONA 5 (Kommandeur der Nachrichtenaufklärung - Signals Intelligence Regiment).

    KONA 5 covered Western Europe and the cryptanalysts of NAASt 5 were able to solve the US M-209 cipher machine in 1944.

    According to the TICOM report IF-272 - TAB ‘D’ the following NAAS 5 reports survived the war:

    E-Bericht Nr. 1/44 der NAAst 5 dated 10.1.44

    E-Bericht Nr. 2/44 der NAAst 5

    E-Bericht Nr. 3/44 der NAAst 5 (Berichtszeit 1.4-30.6.44)

    E-Bericht 4/44 der NAAst 5 (Berichtszeit 1.7-30.9.44) dated 10.10.44 

    E-Bericht der NAAst 5 (Berichtszeit 1.10.44-30.12.44) dated 14.1.45

    The first three can be found in the US national archives, collection RG 457 - Entry 9032 - box 22, titled ‘German deciphering reports’.

    Unfortunately the last two (covering the second half of 1944) are not there.

    Initially the NSA FOIA office told me that the NAASt 5 reports had been transferred to the US National archives as part of transfer group TR-0457-2016-0014. However when the NARA FOIA office checked these files they were unable to locate any report titled E-Bericht NAAs 5.

    I then asked the NSA FOIA office again about these files, since it seems they made a mistake and I was told to check transfer group TR-0457-2017-0010.

    Now the response from the NARA research office regarding this transfer group has been the following:

    ‘We have received the records of which you speak and they must first of all undergo formal accessioning and any necessary preservation. Then they will need to be archivally described and professionally arranged before they will be available for research.   ALL of those steps will depend on how many previous accessions are in line to be processed.

    Although you have the most up-to-date information on these record transfers, our archival processing steps must be done prior to making the records available for public use.’

    So it seems that I’ll have to wait for NARA to process the transfer group TR-0457-2017-0010 and then they can search it for the NAASt 5 reports (assuming they are there).

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  • 07/09/17--06:27: Update
  • 1). I’ve made some corrections and also changed the title in The Japanese FUJI diplomatic cipher 1941-43 (for example instead of saying the Germans or OKW/Chi solved the code I mention the specific department etc)

    2). I uploaded the file containing the Japanese decodes of US diplomatic traffic from Diplomatic records Office, Tokyo, ‘U.S.-Japan Relations, Miscellaneous Diplomatic Correspondence-Special Information File’ (A-1-3-1, 1-3-2). Link here.

    Also fixed the broken links in Japanese codebreakers of WWII.

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    A new book on the NSA has been published recently. The book in question is ‘Working on the Dark Side of the Moon: Life Inside the National Security Agency’ by Thomas Reed Willemain.

    Maitland, FL (May 19, 2017) –Working on the Dark Side of the Moon provides the first, ground-level look inside the super-secret National Security Agency (NSA) and a shadowy think tank affiliated with it. The author, a software entrepreneur and statistics professor, volunteered for a year-long sabbatical tour of duty in the NSA. He ended up spending several years moving between the business and academic worlds and the secret world. This book records his impressions of people and places never before described in such intimate detail.

    A deeply personal account of the years spent within the most secretive organization in the world, Working on the Dark Side of the Moon explores the range of emotions an outsider experiences while crossing over to the “inside.” It also shows the positive side of an Agency whose secrecy hides dedicated men and women devoted to protecting the country while honoring the Constitution.

    Willemain writes, "The very secrecy that enables NSA to be effective also cripples its ability to explain its positive contributions. Into this void are projected grossly distorted views of what NSA does and what NSA people are like. This book puts a human face on the people who work in this secret world: their character, motivations, frustrations, sense of humor. Readers can develop a more balanced and nuanced view of NSA and its people."

    About the Author

    Dr. Thomas Reed Willemain served as an Expert Statistical Consultant to the National Security Agency (NSA) at Ft. Meade, MD and as a member of the Adjunct Research Staff at an affiliated think-tank, the Institute for Defense Analyses Center for Computing Sciences (IDA/CCS). He is Professor Emeritus of Industrial and Systems Engineering at Rensselaer Polytechnic Institute, having previously held faculty positions at Harvard’s Kennedy School of Government and Massachusetts Institute of Technology. He is also co-founder and Senior Vice President/Research at Smart Software, Inc. He is a member of the Association of Former Intelligence Officers, the Military Operations Research Society, the American Statistical Association, and several other professional organizations. Willemain received the BSE degree (summa cum laude, Phi Beta Kappa) from Princeton University and the MS and PhD degrees from Massachusetts Institute of Technology.

    His other books include: Statistical Methods for Planners, Emergency Medical Systems Analysis (with R. C. Larson), and 80 articles in peer-reviewed journals on topics in statistics, operations research, health care and other topics.

    Q&A with Thomas Reed Willemain

    The author was kind enough to answer some of my questions.

    1). Can you give an overview of your career prior to working for the NSA?

    I’ve had overlapping careers:  About 40 years as an academic, and about 30 years as a software entrepreneur. I have been a professor at Massachusetts Institute of Technology, Harvard Kennedy School of Government, and Rensselaer Polytechnic Institute. I am now Professor Emeritus of Industrial and Systems Engineering at RPI. I am also co-founder and Senior Vice President/Research at Smart Software, Inc. in Boston. A common thread has been the study of statistics, forecasting -- anything involving randomness.

    2). How/why did you consider working for the NSA?

    I was looking for a challenging and useful sabbatical leave. I’d previously spent a sabbatical leave at the Federal Aviation Administration and made some contributions there, even though I’d not had any formal background in aviation. I was wary of applying to NSA, since I was not in synch with the Bush administration. But I wanted another period of public service. I also knew that there would be no more intriguing place for a statistician to work. And I suspected, correctly, that when I came back to RPI I would have more to contribute to my students. That turned out to be correct, in that my courses were richer (and more computational) afterwards.

    3). What did you expect working at the NSA would be like and were your expectations accurate or not?

    I was very wrong about some things. One was politics, or the lack thereof. I mentioned my misgivings about President Bush. The woman who handled the sabbatical program was very diplomatic and not put off by my questions. When I finally met her in person, it turned out that she was a lesbian with an “Anybody but Bush” bumper sticker on her car – not at all fitting my stereotype of an NSA person. During the McCain-Obama election campaign, the bumper stickers in the vast parking lots were about 50:50, and there was no whiff of politics inside the wire. The only person who talked (incessantly) about the election was somebody from another country embedded with us. I did expect a high level of expertise, and that was definitely true.

    Something I should have expected but did not was how radically different the culture was from my university life. I was going back and forth between “inside” and “outside”. The academic culture encourages the question “Hey, what are you working on?” I had to learn to not ask that question on the inside unless it was behind a locked door, and not always then.

    Now, the NSA is a big place. And one of the people described in my book pointed out that I was in the Research Directorate, which is more like a playground for uber-geeks than most of the rest of the Agency, where a mix of civilians and service members grind out massive amounts of work every day. So my book must present a partial picture of “Life inside the National Security Agency”. I may have been the proverbial blind man feeling the best part of the proverbial elephant.

    4). Why did you decide to write a book about your experiences working for the NSA and was it difficult to gain approval from the agency?

    I’ll be 70 years old soon, and I found myself slowing down on the math side of things, so I looked for another way to contribute. I had a plan to begin substituting my words for my equations, and writing the book would be a good way to test the feasibility of that plan. But I was also motivated by a desire to continue serving as best I could. Most every depiction of NSA in the media has been negative, and distorted stereotypes about the people and the Agency are rampant. I wanted to offset that with an insider’s look at the reality. The Snowden affair in particular prompted me to try to offset that. It turned out that, without knowing what I was contributing to, some of my technical work helped the Agency offset some of the damage Snowden did. The book let me do more on that front.

    Getting the book cleared through NSA’s pre-publication review was a slow-motion crucifixion. It delayed the book by five months and blacked out about 15% of the book. There was some lying and bullying involved. Call it a character-building moment. I wrote about the process in the LawFare blog and discussed it with the House Permanent Select Committee on Intelligence, who were already reviewing the pre-pub process. The basic problem is that the process knows only one word: “No”. I tried to get the strategic communications people involved so there would be someone to say “Yes” to the idea of permitting a pro-Agency book to be published, but so far no luck. The Agency claimed, with perhaps dubious legality, that anybody described in my book, though anonymously, could require me to remove them from the book. If they had all done so, there would have been no book. But only one insisted that she be removed. She is now a large black rectangle.

    5). What new information is available from your book compared to previous studies of the NSA?

    I’m fairly certain that this is the only grunt-level memoir of service in the NSA. There are a few faux-memoirs that are works of fiction. Folks at the top levels have written books (e.g., Michael Hayden), but daily life below the top has been, well, rather like the dark side of the moon. There have been policy-oriented and history-oriented books about NSA, but not people-oriented books. So what it feels like to work there has been mysterious. Much of my book is centered on descriptions of about 40 people that I worked with, and the book is about their stories as much as mine. I also paid a lot of attention to comparing life inside against life outside, especially regarding the intellectual and administrative climates (including personnel evaluation systems). There are not many “insider/outsider” stories to tell, and mine is the only one in print.

    Actually, part way through my time inside, several of us academics were “traded” to NSA-affiliated think tanks. So my book is also the first to expose the inner workings of the Institute for Defense Analyses Center for Computing Sciences. That must be the world’s most comfortable SCIF, and it’s full of sharp, colorful characters. I think the director of IDA/CCS was even more opposed to publication of my book than the NSA itself, even though my book might be very helpful to recruiting people to take my place there.

    6). What is your opinion on the recent Snowden revelations regarding the NSA interception of US civilian communications?

    I have mixed feeling about Snowden, mostly negative. Perhaps some of his motivation was idealistic. But what he did was very damaging to the tracking of foreign targets, so he definitely belongs in jail. He also appears to be a narcissistic liar. He permitted a persona to be presented in the movie “Snowden” that was just not true. As I watched the movie, I kept thinking “That’s not true. And that’s not true. And that doesn’t really happen.” For instance, I write about my struggles to pass the repeated exams I had to take to certify that I knew about the practical implementation of the Fourth Amendment prohibitions as applied to foreign intelligence. The public should know how seriously the Agency regards those things. It is certain that something as powerful as the NSA bears constant watching, but facts ought to be the basis for judgment.

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  • 07/18/17--02:14: For the fans
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  • 07/30/17--05:50: Comrade detective
  • This is awesome!

    Comrades, it is your patriotic duty to report to the authorities anyone who doesn’t see this TV series. 

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  • 08/01/17--00:49: War By Numbers
  • Christopher A. Lawrence of the Dupuy Institute has published the book ‘War by Numbers Understanding Conventional Combat’.

    Available from Potomac books and Amazon.

    War by Numbers assesses the nature of conventional warfare through the analysis of historical combat. Christopher A. Lawrence (President and Executive Director of The Dupuy Institute) establishes what we know about conventional combat and why we know it. By demonstrating the impact a variety of factors have on combat he moves such analysis beyond the work of Carl von Clausewitz and into modern data and interpretation.

    Using vast data sets, Lawrence examines force ratios, the human factor in case studies from World War II and beyond, the combat value of superior situational awareness, and the effects of dispersion, among other elements. Lawrence challenges existing interpretations of conventional warfare and shows how such combat should be conducted in the future, simultaneously broadening our understanding of what it means to fight wars by the numbers.

    Table of contents

    Preface                                                                                          ix

    Acknowledgments                                                                         xi

    Abbreviations                                                                                xiii

    Understanding War                                                                        1

    Force Ratios                                                                                   8

    Attacker versus Defender                                                             14

    Human Factors                                                                             16

    Measuring Human Factors in Combat: Italy 1943-1944               19

    Measuring Human Factors in Combat: Ardennes and Kursk       32

    Measuring Human Factors in Combat: Modern Wars                  49

    Outcome of Battles                                                                       60

    Exchange Ratios                                                                          72

    The Combat Value of Superior Situational Awareness                79

    The Combat Value of Surprise                                                   121

    The Nature of Lower Levels of Combat                                      146

    The Effects of Dispersion on Combat                                         163

    Advance Rates                                                                            174

    Casualties                                                                                   181

    Urban Legends                                                                           206

    The Use of Case Studies                                                            265

    Modeling Warfare                                                                        285

    Validation of the TNDM                                                               299

    Conclusions                                                                                 325

    Appendix I: Dupuy’s Timeless Verities of Combat                       329

    Appendix II: Dupuy’s Combat Advance Rate Verities                  335

    Appendix III: Dupuy’s Combat Attrition Verities                            339

    Notes                                                                                            345

    Bibliography                                                                                  369

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  • 08/02/17--22:53: TICOM I-123
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    At the start of WWII the Kingdom of Greece, ruled by Ioannis Metaxas  (head of the 4th of August Regime) followed a neutral foreign policy and tried to avoid taking part in the conflict. However constant Italian harassment and provocations (such as the sinking of the cruiser Elli) and the transfer of Italian army units to Albania made it clear that war could not be avoided for long.

    In October 1940 Italian forces invaded Greece, in the area of Epirus, and the Greek-Italian war started. The Greek forces were able to contain the assault and the Greek counterattack forced the Italians back into Albanian territory. After the defeat of a major Italian offensive in spring 1941 the front stabilized inside Albania.

    At the time Britain was overextended with obligations in Europe, Middle East and Asia. However the British armed forces made a small contribution with an RAF expeditionary corps. When more British forces started to arrive in March 1941, their involvement gave Germany an excuse to become involved in the conflict.

    German forces invaded Greece in April 1941 and made rapid progress due to the fact that almost the entire Greek Army was fighting in the Epirus area. The remaining units and the small British forces transferred to Greece in March-April 1941 were unable to stop them. Then in May 1941 the Germans were also able to defeat the Greek and British forces that had retreated to the strategic island of Crete.

    Compromise of Greek military codes

    At this time there is very limited information available on the cryptosystems used by the Greek Armed Forces in WWII.

    According to TICOM report I-58 in early 1941 the codebreakers of the German Army’s signal intelligence agency investigated a Greek 5-figure code enciphered with a 35 figure repeating additive sequence (1). Progress was made in the solution of the cipher but the campaign ended just as the system was starting to be exploited operationally.

    c. Greek - In early 1941, B. solved a 5-letter code with a 7-cyclic recipherment (period of 35). Just getting to operational speed when the campaign ended.

    Information on Greek Airforce ciphers is available from TICOM report I-170 (2), written by Dr. Otto Karl Winkler, a member of NAASt 4, which was the cryptanalytic centre of KONA 4 (Kommandeur der Nachrichtenaufklärung - Signals Intelligence Regiment). KONA 4 was a German Army signal intelligence unit assigned to cover radio traffic from the Balkans and the Middle East.

    In the report dr Winkler said that in spring 1941 Greek AF single transposition messages were solved and translated.

    My first employment was on the breaking and translating of Greek Air Force messages in Spring 1941. The unit was in BUCHAREST at that time and later it was at BANJA KOSTENIC in Bulgaria. C.O. was Hptm. SCHMIDT, head of the cryptography and translation department from then until Autumn 1944 was Prof. Alfred KNESCHKE, a Professor of Mathematics from Saxony.

    The Greek Air Force messages were a matter of simple boxes, the text being sent in T/L groups. The indicator took the form of 3 letters which were always in a given position, the first three T/L groups and had to be knocked out before entering the cipher text in the clear box. This was broken by writing out the cipher text in vertical strips of varying depth and sliding them against each other until a few Greek syllables appeared above one another. After the initial break it became clear that a large part of the messages began with the words ‘parakalw', 'anaferw’ and ‘apesteilamen’ and that the width of the box was as a rule between 15 and 22 columns. On the basis of the above, initial words, all messages were tried out on the normal number of columns and nearly everything was read. I had less to do with the actual evaluation, firstly because the two departments were kept separate and secondly because we were kept fully occupied with our own job. In any case the content of the messages was usually of insignificant strategic value, although the continuous check on officer personalities, deliveries of stores and knowledge of airfields combined with D/F bearings indirectly contributed to considerable tactical results.

    According to dr Winkler Greek Army and Navy codes were not broken until after the conquest of Greece, when captured codes were read during the Battle of Crete. It would seem that Greek military codebooks were captured in mainland Greece and then used to solve Greek radio traffic during the Battle of Crete.

    Regarding Greek Navy ciphers there are translations of Greek naval radio messages in the Italian state archives (3). Thus it seems that some Greek Navy communications were read by the Italian codebreakers.

    The Greek Government in Exile

    After the occupation of Greece by the Axis powers the King and the politicians that had managed to leave the country constituted the Greek government-in-exile, based in Cairo, Egypt. During the period 1941-44 the Greek government and the military forces that it controlled supported the Allied cause. Greek forces fought in North Africa and in Italy, while the Greek Navy operated in the Mediterranean in support of British operations.

    In the diplomatic field the goal of the Greek government was to promote Greek interests in the Allied capitals and in the period 1943-44 to try and find an acceptable solution to the problem posed by the rise of the Communist controlled EAM-ELAS resistance movement in occupied Greece.

    Greek diplomatic codebooks

    The Greek foreign ministry used a series of codebooks in order to protect its sensitive communications from eavesdroppers. These were the cryptographic lexicons 1927, 1931, Η (ITA), Φ (PHI) and Ι (IOTA).

    Usually these codebooks were used without additional encipherment, however when messages of particular importance had to be transmitted then they were enciphered with bigram substitution tables.

    One interesting characteristic of Greek diplomatic codes is that they allowed for inflection. Greek is a highly inflected language and in order for the plaintext to be encoded correctly it was necessary to take this peculiarity of the Greek language into account. The way the system worked was that an extra letter (or number) was added to each codegroup in order to designate the grammatical form of the word in question.

    Examples of Greek diplomatic codebooks (4):

    Lexicon 1927

    Lexicon 1931

    Lexicon Η (ITA)

    Lexicon Φ (PHI)

    Lexicon Ι (IOTA)

    During WWII Greek diplomatic communications were read both by the Allies and the Axis powers.

    US effort

    According to the NSA report SRH-361 ‘History of the Signal Security Agency Volume Two The General Cryptanalytic Problems’ (5), Greek systems were worked on by a subsection of unit B-III-D of the Army Security Agency.

    This unit initially worked on the communications of Far Eastern countries, specifically Nationalist China and the Japanese controlled governments of occupied China, Thailand and the Philippines. In April 1944 the functions of the unit were extended to cover the traffic of Bulgaria, Croatia, Czechoslovakia, Greece, Poland, Slovakia and Yugoslavia.

    Greek traffic was examined because the unit had a classical scholar who also knew modern Greek. According to the report this was dr Aubrey Diller, who was assisted by Mary Fennel, Lieutenant Praxythea M. Coroneos and Elaine Pulakos.

    In December 1944 the unit had about 50 workers, with 4 working on Greek ciphers. The Greek codebook GRB (lexicon IOTA) had been copied by the FBI in an undercover operation so messages on this system could be solved and translated without delay.

    Other systems examined by the unit were the highly enciphered code GRA and a new codebook GRE that was used during the San Francisco conference. The latter code was enciphered with digraphic substitution tables but some traffic was solved and several hundred codegroups recovered.

    A table dated September 1944, listing intercepts and decodes by country, shows that 1.333 Greek telegrams were received. Out of these 507 were original messages (the rest duplicates), of which 427 were deciphered and 417 translated or summarized.

    German effort

    Foreign diplomatic codes and ciphers were worked on by three different German agencies, the German High Command’s deciphering department – OKW/Chi, the Foreign Ministry’s deciphering department Pers Z and the Air Ministry’s Research Department - Reichsluftfahrtministerium Forschungsamt.

    OKW/Chi effort

    At the High Command’s deciphering department - OKW/Chi, Greek diplomatic systems were worked on by a subsection of main Department V. Depending on the source the unit was headed either by principal specialist Rudolf Seifert or by dr Poestgens (6).

    According to Wilhelm Fenner (head of the cryptanalysis department of OKW/Chi), three Greek codebooks were worked on (7).

    Pers Z effort

    At the Foreign Ministry’s deciphering department Pers Z Greek systems were worked on by the group ‘Italy, Greece, Vatican, USSR’, headed by senior specialist (Oberregierungsrat) dr Adolf Paschke.

    According to TICOM report I-22, paragraph 169 (8) three Greek codebooks were read by the unit:

    Greek: there were three systems, all of which were read:

    1) a clear 5 letter book, the fifth letter of which was dummy; this carried most of the traffic.

    2) a clear 4 letter book, used mainly for traffic with Berne.

    3) a four figure book used with bigram substitution of 30 tables of 100 bigrams each. It was used between London and Moscow, Washington, Cairo and Ankara. Traffic from London amounted to about 1 a day. The bigram tables changed according to the date.

    Forschungsamt effort

    At the Air Ministry’s Research Department Greek systems were worked on by Abteilung 9, Branch A, Section 2 (Czechoslovakia, Yugoslavia, Bulgaria, Greece, Albania) (9).

    According to dr Martin Paetzel (deputy director of Main Department IV - Decipherment) ‘just two plain codes were read’ (10).

    Examples of decoded Greek diplomatic messages

    Decodes of Greek telegrams can be found in the TICOM collection of the German Foreign Ministry’s Political archive (11):


    Translated telegrams


    In WWII Greek radio communications were read by the Axis powers to a considerable extent.

    During the Battle of Greece it seems that the solution of Greek military codes did not play a big role in the actual combat operations. However according to German sources Greek communications were read during the Battle of Crete. If this is true then the intelligence gained from reading Greek messages may have given the Germans a significant advantage during that costly operation.

    Greek diplomatic codes were insecure and were read not only by the Axis powers but also by the US and British codebreakers. Although Greece was a small country its politicians and diplomats had regular meetings with Allied officials and they were kept informed of important diplomatic and military initiatives. It is reasonable to assume that some of that information was transmitted in insecure Greek codes.

    From the German point of view it was a worthy investment to focus on the codes of small Allied countries since they did not have the expertise or the resources needed to secure their wireless communications.

    Wilhelm Flicke who was in charge of OKW/Chi’s Lauf intercept station wrote in his book ‘War Secrets in the Ether’ (12):

    Hitler's attacks on the small states of Europe from 1938 to 1941 had forced the governments of these countries to take refuge abroad in order to continue efforts for the recovery of national independence. Most of these governments in exile had gone to London. Here they maintained little ministries and kept in touch with their representatives in foreign countries, i.e. with their embassies, consulates, missions, delegations, and the like. They made extensive use of radio telegraphy and thus supplied raw material for the German intercept service. And this "raw material" was - first class!


    Everything that the "big fry’’ (i.o. the governments or Great Britain, U.S.A, Soviet Union. etc.) strove to keep secret, these "little fry" diligently tattled. It was fun to read their messages. Poland and some of the Balkan governments were the worst.


    (3). Archivio dell' Ufficio Storico della Marina Militare, Rome

    (4). US National archives - collection RG457 - Entry 9032 - NR 664, 665, 666 'Greek Cryptographic Lexicon I, O and I, NR 703, 704, 705, 706 'Greek Cryptographic Lexicon Φ, H, 1927, 1931, NR 2104 'Greek Cryptographic Lexicon'

    (9). TICOM report DF-241 ‘Part 1’, p10

    (11). German Foreign Ministry’s Political archive - TICOM collection - files Nr. 2.256    Griechenland ‘’GC B 4251-450’’ Diplom. Verkehr Vollst. Entschlüsselt and Nr. 781 Griechenland 1944 Entschl. Verkehr zw. zahlr. Griech. Konsulaten.

    (12). War Secrets In the Ether Part III by Wilhelm F. Flicke, p395-396

    Acknowledgments: I have to thank Enrico Cernuschi for sharing the messages from the Archivio dell' Ufficio Storico della Marina Militare.

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  • 08/05/17--05:17: Update
  • 1). In The secret messages of Marshall Tito and General Mihailović I added the Journal of Slavic Military Studies article: ‘The Key to the Balkans: The Battle for Serbia 1944’ in the sources.

    2). In Svetova Revoluce and the codes of the Czechoslovak resistance I added information from the report ‘Dopady lúštenia šifrovacieho systému čs. londýnskeho MNO z rokov 1940-1945 na domáci odboj’ and a short biography of Karol Cigan (from the essay 'STP cipher of the Czechoslovak in-exile Ministry of Defence in London during WWII’ by Štefan Porubský).

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  • 08/15/17--00:24: More TICOM reports
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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. These operations remained hidden from the public till the 1970’s, when several books finally acknowledged the Allied codebreaking successes.

    Since then countless books have been written about the Allied codebreakers, their successes and their contribution to the overall war effort.

    Information about the similar successes of the Axis codebreakers is much harder to find since the relevant material only started to be declassified in the 2000’s.

    The material that has been declassified reveals that at the end of the war in Europe the US and UK authorities were interested in finding out as much as possible about the operations and successes of the German codebreaking organizations. For this reason the TICOM (Target Intelligence Committee) project was created. The goal was to send small teams into Germany in order to capture the German codebreakers and their archives.

    A new book has been published that covers the operations and findings of the TICOM teams sent to Germany at the end of WWII. ‘TICOM: the Hunt for Hitler’s Codebreakers’ by Randy Rezabekis available in both paperback and e-book format.

    The book starts in 1944, when the Anglo-Americans expecting the war to end soon had started planning for the capture of enemy sigint personnel and archives.  The joint US-UK effort was codenamed TICOM and six teams were formed to go into Germany and search for the German signal intelligence personnel and archives.

    The operations of the individual TICOM teams are covered in the following chapters. Travelling through a war ravaged Germany they had to improvise and take risks in order to locate their targets. The teams managed to retrieve important enemy personnel and files, including the entire codebreaking unit of the German Foreign Ministry. Other great successes were the capture of a ‘Kurier’ burst-radio communications device in Northern Germany, multichannel radio-teletype demodulators found buried in a camp in Rosenheim and the retrieval of the OKW/Chi archive, found in metal boxes at the bottom of lake Schliersee in Bavaria.

    The author not only describes the operations of the TICOM teams but also explains the organization, personalities and achievements of the German codebreakers.

    The book contains maps and several rare photographs of personnel and material from that era. There is also an appendix with an overview of the different codes and ciphers used in WWII.

    Q&A with Randy Rezabek

    The author was kind enough to answer some of my questions.

    1). How did you become interested in WWII cryptologic history and why did you decide to write a book about the TICOM operation?

    Many years ago (35+) I was saving in the Navy and was stationed at a Naval Security Group intercept site running the local photo lab. I had a clearance and learned a bit through osmosis, but it wasn’t until I read Bamford’s book The Puzzle Palace that things became clear about what we were up to. I maintained an interest in things Sigint even though life moved on in different directions.

    About 2010 I was diagnosed with MS and that created physical limitations on many of my activities, so I focused on TICOM as a pastime that could focus on.

    I first learned about TICOM through another Bamford book Body of Secrets, also the account in The Ultra Americans by Parrish. I found the whole topic fascinating but little researched in the literature. Since then I have acquired a personal library of 150 or so volumes on Signit, intelligence and military communications.

    Since nobody else had written a book on TICOM I thought that was a worthwhile goal.

    2). How hard was it to find information about the TICOM teams and the information they gathered?

    About the time I got serious about this I started doing follow ups with NSA and NARA. It was around this time that TICOM documentation started being released. It was a very slow process, especially with the NSA FOIA requests, they often took years, and by the time they replied the requested documentation had been released to NARA anyway. The release of “European Axis Signal Intelligence…” was a great boon to researchers. In addition to the overview, I compiled a list of 150 or so TICOM reports that were cited in the footnotes, this gave me a guide on what to look for. I also hooked up with some other researchers in the field, such as Ralph Erskine, Frode Weierud and you. I made the acquaintance with David Kahn, who was a great inspiration, and met and corresponded with Stephen Budiansky, all have helped me find sources and sharpened my knowledge.

    Otherwise it was a matter of patience watching the slow drip, drip of releases over the years. NARA was a great help, when I started out there was no use of the Term TICOM in the descriptors. But by 2012 they had reorganize lot of the catalog and put the newer TICOM stuff into their own entries.

    3). You said in the book that the reasons why TICOM remained classified into the 21st century is perhaps its greatest secret. Do you think it was simple bureaucratic inertia or something else?

    At this point I think it was inertia. After the end of the cold war there was no real need to keep it secret from a security viewpoint. Human sources were long retired or dead, technologies and techniques were long superseded, and the use of captured German intelligence information against the Soviets would be obvious to even the most clueless observer.. But the law says a secret is a secret until properly declassified, even if everyone knows about it. And declassification is a laborious process with little priority: as I say in the book “nobody in the NSA ever got fired for not revealing a secret.”

    4). Are you going to write more books on the subject?

    At this point I think I have pretty well exhausted the topic. I tried to include as many details as possible in it to provide a guide to future researchers. If something comes out in future released that alter the story then I may do a follow up article or two. However, publishers don’t see enough profit in the story to bother, that why I had to publish it myself.

    0 0

    The TICOM report I-137 ‘Final report written by Wachtmeister Otto Buggisch of OKH/Chi and OKW/Chi’ that I recently uploaded was missing page 2.

    Thankfully the NSA FOIA office has sent me the page, thus I have re-uploaded the file.

    Missing page:

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  • 08/29/17--23:14: Info on Greek Army codes

  • A Greek file dated 1938 (1) mentions the following Army cryptosystems: small unit code 1937, large unit code 1937, small unit code 1938, mobilization code 1937, cryptographic lexicon 1935. 

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