General der Nachrichtenaufklärung


The GdNA was the signals intelligence agency of the Heer, before and during World War II. It was the successor to the former cipher bureau known as Inspectorate 7/VI in operation between 1940 and 1942, when it was further reorganised into the Headquarters for Signal Intelligence between 1942 and 1944, until it was finally reorganised in October 1944 into the GdNA. The agency was also known at the OKH/Gend Na, GendNa or Inspectorate 7 or more commonly OKH/GdNA. Inspectorate 7/VI was also known as In 7 or In/7 or In 7/VI and also OKH/Chi.

Chi-Stelle

The letter "Chi" for the Chiffrierabteilung is, contrary to what one might expect, not the Greek letter Chi, nor anything to do with the chi test, a common cryptographic test used as part of deciphering of an enciphered message, and invented by Solomon Kullback, but only to the first three letters of the word Chiffrierabteilung. Chi-Stelle, which was also a short hand for Chi, translates to Cipher Department Location.

Background

Key personnel

Senior personnel

, was Director of the Code and Cipher section of the Defense Ministry from 1931 to 1932 and held the dual combined office of Chef HNW and Chief Signal Officer Armed Forces from 1939 until 20 July 1944. Fellgiebel was executed in July 1944 after an attempt on Hitler's life in the failed 20th July plot.
The unit was then subordinated to Generalleutnant Fritz Thiele, who was Director of Section III of the Armed Forces Signal Communication Group, Radio Defense Corps, or more accurately the AgWBNV, Radio Communication Group 3, were responsible for locating, eliminating, or neutralizing all enemy agents' radio activities.
Generalleutnant William Gimmler, was Chief Signals Officer subordinated to Commander in Chief OB West and Chief of the Armed Forces Signal Communications Office. Gimmler was responsible for coordinating all the cryptographic security studies undertaken by German Armed Forces and was notable for standardising wireless phraseology between different Army Groups. Gimmler succeeded Theile before being hanged by piano wire later.
Colonel Hugo Kettler was a career Signals officer, who volunteered at the start of World War I, entering the Telephone Replacement Department No. 6 and after undergoing continual promotion during World War I and the interwar period, was a senior signals officer at the start of World War II. Colonel Hugo Kettler was a Director of OKW/Chi since the summer of 1943.
Kettler was first director of HLS Ost and who would later become Chief of OKW/Chi in the summer of 1943. During the summer of 1942, Kettler was succeeded by Baron Colonel Rudolf Von Der Osten-Sacken, who remained its chief until July 1944, when he was implicated in the 20 July plot on Hitler's life and committed suicide before he was scheduled to be hanged.

Headquarters

Oberst Fritz Boetzel, was the officer who was responsible for the German Defense Ministry's signals intelligence agency, during the important interwar period, when the service was being enlarged and professionalised, In 1939, he was posted to Army Group Southeast to take up the office position of Chief of Intelligence Evaluation in Athens, Greece. In 1944, following the reorganisation of the Wehrmacht signals intelligence capability, Fritz Boetzel, now General Fritz Boetzel, who was promoted by Albert Praun, created 12 Communications Reconnaissance Battalions in eight regiments, with each regiment assigned to a particular Army Group. Fritz Boetzel was considered to be one of the sources for the Lucy spy ring. Boetzel knew Hans Oster and Wilhelm Canaris and had fit the anti-nazi personality of Rudolf Roessler contacts, the man who had run the spy ring.

Cryptanalysis unit command

The directors of the In 7/Vi cryptanalysis units from January 1941 to February 1945 were:
Oberstleutnant Mettig was a career signals officer who joined the military in 1933, and worked up to command the Germany Armies cryptologic centre, Inspectorate 7/VI from November 1941 to June 1943. After working in the Signals Battalion on the Eastern Front for several months, he was assigned second in command of OKW/Chi in December 1943, and subordinated to Hugo Kettler, and held the position until April 1945. After the war he was considered such a high-value target that he was moved to England to be interrogated by TICOM.

Communication office

The following German Army officers worked with the communication office and provided the main liaison function for conveying intelligence from the central office to the field.
Unit Commander Johannes Marquart and I/C Cryptanalysis Leutnant Schlemmer were Commander of KONA 5 and were communication intelligence liaison officers for several army groups on the southern part of the Western Front.
Unit Commander Major Lechner and I/C Cryptanalysis Leutnant Herbert von Denffer were Commander of KONA 6 and were communication intelligence liaison officers for several army groups for the northern part of the Western Front.
Colonel Walter Kopp, was a senior communication intelligence officer for OB West, i.e. for Sig. Int. West
Oberst Gotthard Heinrici was on the General Staff and Chief Signals officer for OB West.
Oberst Leo Hepp was a member of the General Staff and was Deputy Chief of Army Signal Communication. Hepp was later chief of staff for the Chief Signals Officer at the Oberkommando der Wehrmacht and directly subordinated to Fellgiebel and later General Albert Praun, when Fellgiebel was killed.
Colonel Muegge was a communication intelligence officer for an army group.
Colonel Kunibert Randewig was commander of intercept units with various army groups. Randewig was a career Signals officer, who joined the German Army in 1914. During the World War I and the interwar period, he became a veteran of monitoring Soviet wireless communications and a support of decentralisation of signal intelligence. He would eventually become Commander of all KONA Signal Intelligence regiments in the west. Randewig would later work on the rocket programme.

Cryptanalytic staff

. He was a mathematician, who was also a German Army hand cryptographic systems specialist. In a later role, he was the liaison officer between the clearing centre of communications intelligence, and the Western Intelligence Branch, Army General Staff.

History

1919–1933

Little was known about the Signals Intelligence of the German Army during this period. A Codes and Ciphers Section of the German Defence Ministry was subordinated to an Army Signal Officer, that had been maintained in skeleton form since the end of World War I. The following people were directors of the unit:
The directors of the ciphers section also controlled the Defense Ministry's intercept network, which was used to gather operational intelligence and was divided into two branches. The first branch was the fixed intercept network stations which were dated from 1923–1924 , and at least seven stations were operating before 1933 in military districts. The second intercept branch was the motorised Intercept Companies, created by Fellgiebel himself. Six of the stationary intercept stations were aligned specifically to the interception of foreign military traffic and the last one specifically designed for foreign diplomatic traffic. The military traffic stations were: Stuttgart, Munich, Münster, Königsberg, Leignitz and Breslau with the diplomatic traffic intercept station located at Treuenbrietzen. Each intercept station was assigned a series of intercept assignments, with the most important assignments monitored by two stations, e.g. the Soviet Union was monitored from Königsberg and Frankfurt, and so on. The assignments were established in the Assignment Plan H-Aufgabenplan. Each assignment was prioritised from first to fourth, sometimes absolute, sometimes relative, e.g. Poland was assigned first for Frankfurt/Oder stations and a first or second for Königsberg. Priority could change depending if a country went to war.

1933–1939

During the 1933–1934 period, the Defense Ministry created three more intercept stations: one Feste was at Hersbruck, with the other two located at Striegau and Chemnitz. Using the ten intercept stations to intercept foreign military and diplomatic communications, the Defense Ministry created its own military code and cipher section, called Intercept Control Station in 1933/34. To run the control station, the Ministry reassigned several trained cryptanalysts from the Ministry of the Reichswehr Codes and Cipher Section. All Army intercepts were forwarded to the HLS, but other intercept traffic types were forwarded to the Commander-In-Chief aligned agency, e.g. Foreign Air Force traffic was sent to chi-stelle, the Luftwaffe Cipher Bureau. Diplomatic intercepts were sent to both German War Ministry and to Foreign Office civilian cipher bureau AA/Pers Z S.

1939–1941

During the early years of World War II, substantial change occurred within the German Army signal intelligence service. The main developments were:

Western evaluation centre

During the middle of war, the small staff of the intercept and listening stations was found to be inadequate to cope with the large amount of traffic resulting from the pressures of the war. A central cryptanalytic agency was established in Berlin, around 1 February 1941, that was designated as Inspecktorate 7 or more simply In 7. It was also commanded by the Chief of the Army Equipment and Commander of the Replacement Army, specifically Obstlt. Hassel. The experience of 1940 illustrated the fact that huge expansion of the German Army cryptologic effort was desirable. A central evaluation agency was created at the Zeppelin bunker near Zossen, which was designated as Control Station for Signal Intelligence .
Gruppe VI of In 7 was organised by Major Mang, whose aim was to not only build staffing levels at the centre, but to provide reserves of staff that could be called upon when necessary. In order to provide sufficient staff, Mang subordinated the In 6/VI unit to Chief of the Army Equipment and Commander of the Replacement Army. In matters of policy, In 7/VI was subordinated to the Field Army only. Considered a curious form of organisation, it enabled the cryptanalytic service to recruit sufficient staff without operational interference, at the same time maintaining close support of field units. The cryptographic section would eventually become independent

Eastern evaluation centre

During the first months of the unit, Russian cryptanalysis was conducted as part of the operational schedule of In 7/VI, with Russian evaluation included as part of the cryptanalytic work done by unit LNA. Both of these units felt, incorrectly, that cryptanalysis and evaluation of Russian intercepts should be carried out close to the front lines of the field army in East Prussia. This resulted in significant numbers of personnel being detached from the LNA and In 7/VI in late 1941, made up of cryptanalysts and evaluators skilled in Russian traffic and sent to Loetzen to work. This group would eventually become the nucleus of the organisation: Intercept Control Station East for Russian evaluation and traffic analysis. From this point on until November 1944, signal intelligence was divided into Russian cryptanalysis carried out by HLS Ost, and non-Russian signal intelligence carried out by OKH/Chi and LNA.

Expansion

In 1942, the responsibility for security testing of existing German Army cryptographic systems had been transferred from In 7/IV to In 7/VI From that time, the Army Signal Security Agency, In 7/IV had been confined to the development of new systems for the Army and for the production, printing, and distribution of current keys and systems.
In the autumn of 1943, OKH/Chi had been transferred to the newly created Department of Signals of the General Army Office and renamed Signal Intelligence, Department of Signals, General Army Office, Army High Command . Minor changes in internal organisation were affected, but the function and operation of the agency was not changed.
Although there was no essential change in the organisation of the field units of Germany Army Sigint Service from 1941 to 1944, additional units were put in place in the field. In 1942, the eastern KONA units were supplemented by the addition of KONA 6, which was formed to cover the German campaign in the Caucasus. The KONA unit was not subordinated to any Army Group but was directly under HLS Ost. KONA 7 was established in February 1943 and was subordinated to the Commander-in-Chief South, Albert Kesselring, who controlled Army Group C, and the German forces in Italy.
The organisation of the German Army Sigint Service in 1944 consisted of the following:
In October 1944, the various organisations of the German Army signal intelligence service was completely changed again, through the amalgamation of the three central agencies. The In 7/VI, the LNA, and HLS Ost was combined into one central cryptanalytic and evaluation agency: OKH/GDNA. This combined unit was the logical result of the retreat of HLS Ost together with the German Army, from East Prussia to Zeppelin bunker near Zossen where In 7/VI and LNA were situated.
The KONA signal intelligence regiments were not greatly affected by the amalgamation of the central agencies into the GdNA, although the KONA units did come under closer centralised control in matters of administration and signal intelligence policy. The main change to the Armies field organisations in 1944 were brought on by the Allied invasion of France in June 1944. To cope with the situation, KONA 6 was moved from the eastern front to the western, and a Senior Commander of the Signal Intelligence was created to coordinate and control KONA 5 and KONA 6. In late 1944 and early 1945, two additional KONA regiments were created, KONA 8 and KONA Nord, but it is worth noting that these KONA regiments were largely borrowed from other eastern front regiments, and were not a mark of expansion, merely a redeployment to areas under stress.
Colonel Boetzel, chief of the OKH/GdNA stated that KONA 4 was transferred to the west at the end of the war. A captured document indicated that KONA 4 had been succeeded by a signal battalion, 16, in February 1945 but did not mention its transfer to the west. It is probable that the KONA disintegrated and that various parts were sent to the different fronts.
The organisation of the signal intelligence service at the end of World War II consisted of the following:

Intercept Control Station

Intercept station operations 1939–1944

Before the war, cryptography in the German Army was carried out by In 7 Listening Position . This organisation originated in the cipher section of the German War Ministry and grew up in parallel with the cipher section of OKW/Chi. Before the war, In 7 Horchleistelle was merely a small department. It had a number of fixed intercept stations called Festes, i.e. Fixed News Services . These were staffed by a skeleton organisation and were working to monitor the traffic of neighbouring states.

Inspectorate 7/VI organisation

In Autumn 1941, Inspectorate 7/VI was headed by Major Mang, and was divided into the following sections:
Between 1941 and 1943, the following changes in OKH/Chi took place:
In the spring of 1943, OKH/Chi organisation was as follows:
The sections of In 7/VI were housed during this period in buildings near the Bendlerstrasse in Berlin. The Headquarters Training Section and sections for USA, French and Agents traffic were located at Mattaekirchplatz 4; the British and Balkan sections were located at Schellingstrasse 9, with the Hollerith machinery located at Viktoriastrasse. Location of the Mathematical section was not known. In November 1943, the first large RAF raid on Berlin destroyed a large part of the offices of the Army High Command on Bendlerstrasse in Berlin, among which were those of OKH/Chi. In 7/VI was thereupon moved to Jüterbog in Oct 1943, where it was located until its amalgamation in November 1944 into GdNA. No estimate is given of the number of people employed in In 7/VI.

Organisation of AgN/NA

When In 7/VI was reorganised as the Signal Intelligence Section of the Department of signals of the General Army Office, of the Army High Command , the internal organisation was changed. The previously independent sections were organised into a main section for mathematics, and a main section for languages. The Hollerith section retained its autonomy.
The main section for languages, with the exception that one section was added for Swedish traffic, covered the same field as had been covered by the additional language sections of OKH/Chi. The organisation of AgN/NA is as follows:

Control Station For Intelligence LNA

The nature of this obscure unit was as an evaluation agency, which focused primarily on non Russian traffic. The unit which was called Control Station For Intelligence had sections for evaluating British, USA, Italian, Balkan, Greek, Turkish, Tunisian, Near Eastern, Portuguese and Spanish traffic. Evaluation was made both of traffic and post decoded intercepts, passed to the unit from OKH/Chi. This unit size of the LNA was small, and consisted of 75 military personnel.

HLS Ost

The Intercept Control Station East was the central cryptanalytic and evaluation centre for Russian traffic located at Loetzen, East Prussia from late 1941 to late 1944. The size of the unit was not known, but had the following organisation, as defined below:
In the winter of 1942–43, the Baudot Reception Station was moved from Minsk to Loetzen and subordinated to HLS Ost, Referat 4. The first director of HLS Ost was Colonel Hugo Kettler who would later become Chief of OKW/Chi in the summer of 1943. During the summer of 1942, Kettler was succeeded by Baron Colonel Rudolf Von Der Osten-Sacken who remained its chief until July 1944 when he was implicated in the 20 July plot on Hitler's life and committed suicide.

Signal Intelligence Agency

The three agencies, OKH/Chi, HLS Ost and LNA were amalgamated in November 1944, into the Signal Intelligence Agency of the Army High Command almost intact. OKH/Chi had some personnel reassigned, and became Group IV of GdNA, which was assigned responsibility for all cryptanalysis on foreign military traffic. LNA was transferred as a unit to Group II of GDNA, except for those referats which had been dealing with wireless and news agency traffic. These section were assigned to Group I and GDNA. The various sections of HLS Ost were absorbed into the appropriate sections of GDNA as follows:

Organisation of GDNA

This organisation of OKH/GdNA was in effect from November 1944 to the end of the war. Approximately 700 people were employed by the unit.

Intercept Control Station

HLS before World War II was principally engaged in intercepting traffic from France, Belgium, Netherlands, Poland, and Russia; Switzerland was only casually monitored. The main successes were gained at the expense of France, Netherlands and Russia.

Russia

HLS was able during the first Russo-Finnish War to break a number of Russian 2,3 and 4-figure codes. In addition, a copy of the Russian 5-digit code was obtained, which was handed over to the Finish General Staff. That particular code was used by the Russians in the first year of the war with Germany in 1939.

Netherlands

An exercise of the Dutch Army was covered in 1937. Very simple techniques, principally double transposition ciphers, were used and these could be read without much difficulty. As a result, it was possible to establish the Order of battle of the Dutch units participating in the exercise down to the battalion level.

France

Continuous and significant successes were obtained against the French before the war. Before 1939, HLS Ost covered the French static wireless net which radiated from Paris to the static formations in France. Cypher procedures were continuously read, and provided valuable information during the international crisis of 1937, Spring and Summer 1938 and 1939.

Britain

Very little success was obtained in the reading of British cyphers before the war, principally due to the low quality of the personnel involved.

Inspectorate 7/VI operations

Static period 1939 to 1940

The signal intelligence picture provided during the early period of the war was good. The complete picture of British, French and Dutch orders of battle was available. Changes in that order could always be followed. The French, Belgium and Dutch picture was partly obtained as a result of cryptanalysis achievements, the order of battle of the British Army could only be built up by the results of Direction-Finding information, and the evaluation of call-signs and other items of the wireless traffic procedure.
France
In 1939, OKH/Chi cryptanalysed the mobile cipher which had replaced the peacetime cipher of the static French wireless net with the outbreak of war. All messages of an administrative or supply nature, nevertheless, helped to fill in the tactical picture, e.g. the strength of units being created on the training ground at Camp de Châlons at Mourmelon-le-Grand, was estimated by statistics of water bottles and blankets. It was equally possible to deduce facts about the shortage of armour-piercing ammunition with the French infantry units. Similarly, the conversion of the 2nd and 3rd Cuirassier Regiment to armoured division status in the area northeast of Paris was ascertained in December 1939. Likewise, the order of battle of the French 6th Army on the French-Italian border was well known.
Poland
According to Lieutenant Colonel Metting, who was interrogated, that owing to the speedy development of the Polish campaign, very little cryptographic work was undertaken. The main signal intelligence information on the regrouping of the Polish forces was derived from the Polish relay wireless traffic which was believed to be carried out in Plaintext.

German offensive May–June 1940

France
With the opening of the offensive in May 1940, the French began to use ciphers in increasing quantities. Germany at this point suffered an acute shortage of forward cryptographers and was therefore unable to undertake much work on the French forward ciphers. As a result, the forward units concentrated on the two French cipher machines, the B-211, which was an elecromechanical cipher machine, designed and built by Boris Hagelin for use by the French Army and the C-36. Progress was slow, but as the result of the research on two captured C-36 machines, Army Group C was in a position, by July 1940 to undertake satisfactory reading of the traffic. Likewise, it was impossible to break the B-211 machine in time for that information to be of any value. Nevertheless, the research undertaken during this period was to justify the results later.
Great Britain
Although similar successes were achieved against the Dutch and Belgian ciphers, Germany still failed to break into any important British procedures. The English desk cryptanalysts, consisting of six personnel from the HLS, were put to work while located in Bad Godesberg, but in spite of a plentiful supply of intercepts, they failed to achieve any successes.
Supplies of cryptanalysts in the west 1939 to 1940
When the forward intercept units moved into the field in 1939, no cryptanalysts were available. Oberst Kunibert Randewig, the commander of all units in the west, was able to procure a number of cryptanalysts from intercept stations around Berlin and filled that number out by calling in a number of mathematicians and linguists including translators and language interpreters from the statistical offices of insurance companies. As a result, when the offensive started in April 1940, the intercept stations with the army groups, contrived to have a moderate supply of cryptanalyst personnel.

Reorganisation of Inspectorate 7

The experience of 1940 showed that considerable expansion in the German Army cryptographic service was desirable. This organisation was carried out by Major Mang. His aim was not only to increase the cryptanalysis staff at the centre, but also to provide reserves of cryptography to work in certain key areas. The cryptanalysis section thereupon became independent and was reorganised as Group VI of In 7. Henceforth it was subordinated to the reserve army for personnel and administrative matters, but remained subordinated to Chef HNW of Field Army, just as Horchleitstelle was converted to Group IV. Nevertheless, this curious form of organisation paid, and enabled the cryptographic service to recruit sufficient personnel without serious interference.
In general, the object of OKH/Chi was the organisation of cryptanalysis in the field and in the rear; training of cryptographers and the investigation of the security of German Ciphers
It was also felt that in certain critical regions, an extra cryptanalytic effort should be enforced, to help in the cryptanalysis of War Office cipher W, the British Armies universal high-grade codebook, which carried traffic between Whitehall, commands, armies, corps and later divisions. To this end, the Russian Referat of OKH/Chi was detached to the Horchleitstelle Lötzen, while special cryptanalysis sections for British traffic were detached to the Horch kp in the Middle East under the command of Lieutenant Seebaum and Commander of Signals Troops in Athens.
Reorganisation of Referat
In 1942, the Mathematical Referat had expanded to such an extent that three sections were created out of it. Sonderführer Steinberg and the mathematicians who had been working with him on the M-209 cipher machine and the strip cipher separated to form the American Referat while two separate sections were formed, one under Oberleutnant Lüders for the investigation of cipher security and security of own processes, and one under Wachtmeister Dr Döring for the investigation of secret teleprinters.
Work on Hollerith Referat
The Hollerith Referat was commanded by Baurat Schenke. The department was equipped with all kinds of German machines and also with all kinds of French Hollerith equipment. This department proved invaluable in the investigations of unclear or difficult cipher techniques. A lot of time and manpower was saved, particularly in the sorting of traffic and the ascertaining of parallelisms and in the calculation of recurring differences. Contrast this with the Cipher Department of the High Command of the Wehrmacht, the organisation that In 7/VI grew out of. The OKW/Chi cipher bureau did not have a Hollerith machinery department, hence custom mechanical aids had to be built, termed Rapid analytic machinery that were time-consuming to build and costly, and only worked in specifically defined areas, whereas Hollerith machines were generic in nature. The exploitation of Hollerith methods was particularly favoured by Baurat Schulze, who in civilian life was an employee of Hollerith company Deutsche Hollerith Maschinen Gesellschaft at Lankwitz in Berlin.
Work on Mathematical Referat
Baurat Dr Hans Pietsch collected together in this section the best available mathematicians. In this section all unbroken intercept traffic from the country desks was investigated for however long it to achieve initial cryptanalysis by purely analytical methods. As soon as a technique for breaking a particular cipher was evolved, they handed back for further work to the specific country desk concerned. In some cases mathematical specialists were attached to a specific desk to work on various procedures.
A further large field of work undertaken at the Mathematical Referat was the investigation of the security of the current German cipher procedures, i.e. security own processes, and in the assessment of discoveries that were always being brought forward. The compromise of the security of a cipher usually resulted from exceeding the days safety margin for transmission, thus creating Depth or by other breaches of standard operating instructions.
In order to provide some check on the use of German ciphers and to provide the Mathematical Referat with the necessary material, the News Reconnaissance Division/Chief of Army Equipment and Commander of the Replacement Army was created in Berlin during November 1941. Two companies of this unit were to act as normal holding companies for In 7/VI, while the third was an intercept company which worked within the field and for the Reserve Army for collecting material to use to build statistical models to determine the efficacy of German ciphers. However, at the end of February 1942, this unit was dissolved owing to personnel shortages. Thus the control of cipher security became once more the responsibility of the Field Army, a responsibility which was never fully undertaken.
As a result of the security investigation of German ciphers and the reporting of new discoveries, Pietsch's Referat naturally began to develop new cipher techniques of its own. In 1942, however, the development of these techniques was handed over to OKW/Chi. However, by the time the organisation had morphed into the OKH/GDNA, it had been specifically banned from intercepting and attacking German traffic as a security precaution.
The main investigation carried out by the Mathematical Referat was a continual enquiry into the security of the main German cipher machines: Enigma machine. The cause of this anxiety lay in the fact that it had been established before the war that Czechoslovakia in collaboration with France had been able to read traffic enciphered by the Enigma cipher machine. This was named as an old model, without plugboard and socket connections, possibly describing a commercial Enigma K. Evidence on this subject was captured during the occupation of Czechoslovakia during 1938. Moreover, in Poland in 1939, the plaintext version of a wireless transmission message was found; this message has been transmitted from a German cruiser in Spanish waters during the Spanish Civil War, and had been transmitted using Officers Keys. An exact proof as to whether these successes were due to compromise, or to cryptanalysis, despite detailed investigation, is not known. As this instance of compromise affected the Stecker Enigma, investigations were carried out thoroughly. The Biuro Szyfrów located in the right wing of the Saxon Palace in Warsaw was searched in 1939. In subsequent years, in 1943, and 1944, General Erich Fellgiebel ordered the re-interrogation of two captured Polish cryptanalysts to check this point. This was the so-called Der Fall Wicher. In 1943–44, the two Polish officers, who were being held in a PW camp in Hamburg volunteered the information to Pietsch, that the Enigma was being read several years before the war, considering the fact that after so long a period, the information was no longer valuable.
Nevertheless, these investigations revealed that the safety margin of the Enigma cipher machine had to be reduced from 50,000 to 20,000 letters on a day's cipher. As the final result of the investigations described above, the value of carrying out investigations into machine ciphers of enemy nations was recognised and the process undertaken.
Russian Referat
This department had a curious history in that it was detached to Chef NNW Horchleitstelle at Lötzen before the outbreak of hostilities with Russia. Under the leadership of War Administration Inspector Dettman, and for a time under Professor Peter Novopashenny, this unit achieved considerable initial success until spring 1942. The 5-figure code was acquired by the Germans during the Winter War of 1939–1940, and was still used by the Russians, two years later. An additional copy of this procedure was also captured by Germany. Through the allocation of call signs and of indicator groups, it was possible to establish the entire Russian order of battle and the location of strategic reserves. This was additional to intelligence gained by reading the content of traffic. On 1 April 1942, the Russians introduced a new 5-figure code. The migration from the old to the new cipher was so faulty that within the first week it was possible to establish 2000 groups of the new code. Indeed, it was possible at that time to leave the decoding to the front line NAZ unit cryptanalysts, instead of at the rear at the large centralised Signal Intelligence Evaluation Centre unit. The Russians gradually improved their security, and by spring 1943, altered the indicator group system and split up the code, making it specific to various front sectors. As a result, it was necessary to collect all the 5-figure traffic at Lötzen and to call in the assistance of the Hollerith Referat of OKH/Chi. Only by this method was the necessary depth on a days traffic, achieved. The quantity of traffic read decreased considerably. 2,3 and 4-digit traffic was continuously decoded.
Cryptanalysis work on partisan traffic was carried out by the forward Long Range Signal Intelligence Platoons in the area. Particular successes were achieved in the Smolensk area with the arrival of specialist cryptanalysts and translators.
It was in the summer of 1943 when KONA 6 with Oberleutnant Schubert in charge, was committed to anti-partisan work, that the traffic between Moscow and the partisans was successfully read.
British Referat
This referat commanded by Oberinspektor Zillman was assisted in its early days by the successes of its forward cryptographic teams. These successes, however, were restricted purely to forward techniques.
In spite of continual efforts, Oberinspektor Zillman was unable to break into the British Typex cipher machine. Several British cipher machines were captured during the summer campaign of 1940, but for each of them, the wheels were missing.
The general successes of the British Referat ceased therefore, in the summer of 1942, after an intercept company, commanded by Oberleutnant Seebaum was captured in North Africa. Despite the report to the cryptanalysis section, by a NCO who had escaped, that all cipher material had been destroyed, it had obviously proved possible for Britain to recognise, from other evidence, which British procedures had been read and which had not. In consequence the department was reinforced in order to win back the lost ground, which it was unable to do.
From summer 1942, Germany concentrated on watching military exercise traffic in Great Britain from KONA 5 in Saint-Germain-en-Laye and the Stationary Intercept Company in Bergen. The Feste also watched Swedish traffic, but apart from unimportant police wireless there was very little army traffic to provide enough depth to break the British encryption.
As a result of watching traffic in Great Britain, it was still not possible to gain any assistance in winning back the ground lost in the Mediterranean traffic. It was nevertheless possible to gain some information regarding the training and order of battle for the forthcoming invasion of the continent, although the extent of this information was not known by TICOM interrogators.

Intercept station operations

Soviet cryptanalysis

Organisation of cryptanalytic effort against Soviet Union

Review of Central Office organisation

Prior to 1939, the Intercept Control Station had a section for handling Russian traffic, but little was known of its operation or achievements. Early successes against Russian cryptography were evidenced by cryptanalysis of 2,3, and 4-figure codes with 5-figure codes broken at the start of the war using a Russian 5-figure code book obtained from Finland, that was used in the first year of the war. When HLS was replaced in 1941 with the new agencies: OKH/Chi and HLS , the Soviet evaluation section was moved to LNA and the cryptanalysis unit for the Soviet sector remained with Inspectorate 7/VI. In late 1941, on a recommendation by Kunibert Randewig, both cryptanalysis and evaluation sections were moved to Loetzen, East Prussia. This section formed the nucleus for the third central agency, the HLS Ost . From that time, until 1944, the German Army Signals Intelligence activities were sharply divided into non-Russian, which were undertaken at Inspectorate 7/VI and into Russian activities, performed by HLS Ost and the LNA.
In October 1944, the three agencies were amalgamated together into the GdNA, into a central agency.
For a breakdown of Russian signals intelligence activities, Group II under Captain Gorzolla and Group IV under Major Rudolf Hentze were the principal units with the GdNA which worked on Russian systems .

Review of Field Office organisation

The KONA was the basic element of the field organisation of the German Army signal intelligence organisation during World War II. Owing to the chronic staff shortage in the German Army, personnel were culled from the fixed intercept stations and trained for field work. Five of the KONA units were sent into the field as complete low level intercept and evaluation units attached to Army Groups. Two went to the western front. KONA 1 KONA 2 and KONA 3 were assigned to the eastern front. These eastern KONA were supplemented by KONA 6, which was sent to cover the German campaign in the Caucasusus, and which was attached directly to HLS Ost. Low level cryptanalysis and evaluation of the decode traffic was also done by KONA 8 and KONA Nord, which were made up from other Eastern front signal intelligence regiments, and activated in late 1944 and early 1945.

Cryptanalytic effort against Soviet Union

Introduction

The Soviet Union state used various military cryptographic systems in order to secure its communication. Two organisations prepared and evaluated cipher procedures. This was the NKVD 5th Department and the Red Army's 8th Department of the main intelligence directorate GRU. The soviet military used 2,3,4, and 5-digit codes enciphered with substitution methods or with additive sequences used with the most important 4 and 5 figure codes. The NKVD relied on figure codes enciphered both with substitution and addition methods. Partisan groups also used figure codes enciphered with additive sequences or transposed based on a key word. The diplomatic service used 4-digit codebooks enciphered with One-time pads tables.

2-Digit codes

The Soviet Union 2-digit codes were used by the Russian Army, Air Force and NKVD. In the Army, they were used by Army Groups, Armies, Corps, Divisions, and Regiments; and by small independent special units such as Combat Engineer Brigades, Motor Regiments, and artillery. In the NKVD, they were used on regimental communication close to the front, and from divisional level downwards.
Cryptanalysis of 2-digit systems was done mostly in FAK units at the company level, but was also handled by NAA, the NAAS and at HQ level of the GDNA itself.
It was clear from interrogations that 2-digit codes were not always in use, but were being constantly read. POWS of NAA 11 stated that the last known table was PT-43, and it could not be constructed. For Lieutenant Alexis Dettman, who stated that solving PT codes was:
Dr. Wilhelm Gerlich of NAAS 1, stated that one or two men at NAAS 1 were able to cope with decipherment of 2-digit messages, especially as the greater part of them were being solved at company level. KONA 1 prisoners stated categorically that the Soviet Union has ceased using 2-digit codes after 1943, however other evidence would seem to have indicated that they were used up until the end of the war by the Red Army and NKVD, particularly by units in active combat, and were still being actively used, even if not appearing.

3-Digit codes

3-digit codes were used by the Red Army, the Air Force and the NKVD. They were first used in 1941–1942, initially mainly by the Air Force and later, more widely, by the Army. Traffic from Army Group down to Battalion had its own 3-digit code. The 3-digit codes were replaced by 3-digit Signal Codes in 1943, which were used by all units. For the NKVD, they were used by the Black Sea Fleet and from division downwards.
The solution of these codes was done mostly in FAK companies, but also handled by the NAA, NAAS and the HLS Ost.
They were first noticed in February, 1941, and used increasingly from May 1941 at the beginning of the Russian campaign. From then until late summer 1942, the Air Force made the most use of the code and each Air Division had its own cipher. In 1942, the 48th Army, the first Army to use it, started by using a 3-digit syballic code.

Interrogations of personnel from Feste 10 and KONA 1: By the time of Stalingrad practically every Army engaged in the battle had its own 3-digit cipher. Dettman and Samsonov do not discuss any 3-digit codes as such, so it must be assumed that they considered these types of codes similar to the 2-digit PT series, and did not warrant discussion as a special sub-type.
Technical description
The first 3-digit ciphers were very simple in form, consisting of several pages, ten at most, and contained alphabetically semi-hatted or completely hatted, the numbers 1 to 0 and punctuation marks. See Fig IV.
Soon afterwards the letters of the alphabet were put in their alphabetic position in the book. See Fig V.
Besides the above types of codes, syllabic codes contained few words but practically all the possible syllables which could be formed out of 2 or 3 letters. All codes of this kind which were broken were alphabetic. See Fig. VII
After some months, the strictly alphabetic nature of the books was given up and the alphabeticity only maintained within the area of a letter. The numbers were at the same time distributed at random over the page. See Fig VI. The book could have 1000 groups, but Oberleutnant Schubert stated that the average number of groups was 300–800, stating: in general small scope, but frequent change. If the codes were smaller than 1000 groups, alternatives were given either to pages or first figures of the lines. The substitutions could be constructed without any recognizable system or they could be made up from a Latin square, with the square usually lasting about one month, although with the Air Force, it sometimes lasted longer. Schubert stated that towards the end of the war, there appeared quite isolated 4 to 7-digit substitution, presumably private systems of the respective cypher departments, but appeared very seldom.
From the beginning of 1943, most 3-digit codes no longer contained single letters but used the initial letter of the words for this purpose. In order to indicate which meaning was to be used two groups were introduced:

The 3-digit groups were read in the order of page-line. The recipher of 3-digit ciphers was as varied as in the case of 2-figure ciphers. Each figure was re-enciphered separately. This is to say, for the page numbers, a hatted order of the figures 1 to 0 was substituted. Thus Page 1 became 4, 2 became 6 and so on. Fig. VIII.
3-digit code R3ZC which was mentioned by Corporal A. Faure of NAA 11 and was discovered as part of the Norway codes. It was a code with 10 pages of 100 positions each, 10 x 10 alphabetically arranged. One column of each page, the 8th was empty. Only the 100's and 10's figures of each group were reciphered.
The 3-figure code, it is clear from all interrogations, was mainly used by the Army, but also by the Air Forces. According to a report by Uffz. Karrenberg of Group VI, on regimental networks and for less important messages on the level of assault armies, mainly the 3-digit codes was used. KONA 1 personnel stated that every Army Group down to Battalion had its own 3-digit code.
It is curious to note that a good deal of plaintext was inserted into the 3-digit enciphered code as it was transmitted. Gerlich pointed out the advantages of plaintext insertion stating: They often gave words and names not contained in the code. 3-figure traffic was always solved when one encipherment was available 3-figure traffic was only slightly more secure that 2-digit code traffic and was 80% readable. It was known that Air Force codes were often current for much longer periods than those for the Army, and thus be able to find depth. Army 3-digit codes were changed after a big operation and were in use for one week to one month. However, all 3-digit codes were readable and Lt. Col. Mettig stated that from spring 1943 to 1945, 2-digit and 3-digit traffic was read regularly, providing a large amount of tactical intelligence.
The operational 3-digit codes were discontinued in 1943 and replaced by 3-digit Signal Codes, which were different only in that they contained no letters, only words and phrases of importance, and were not alphabetic but had meanings grouped under headings such as attack, defend, enemy movements. Each meaning had two or three, 3-figure groups allotted to it. As in the case of the former code, anything not in the codebook was sent in plaintext. It was assumed that these types of codes were also read as consistently and as fully as the 2-digit and 3-digit codes they superseded.

4-Digit codes

4-digit codes were used by the Army, Air Force and NKVD. There were used in the Army as General Army Codes, called General Commanders Codes, and on lower operational levels by mobile formations such as Tank and Mechanised Corps, Tank Armies, and Tank Administration and Supply Units. For the NKVD, they were used on Railway and Transport Nets.
Solutions to these codes were handled at FAK, NAA and GDNA level. At FAK level, the companies usually had a 4-figure unit, as well as a 2-digit unit and 3-digit units, in a cryptanalysis department.
Lt. Schubert of KONA 6 stated under interrogation that: The Soviet Army keys are 3 or 4-digit systems. The basis is the same. The construction of 4-digit codes was the same as 3-digit codes, except the book had a possible 10,000 groups instead of 1,000. with the book length being described as either six or seven pages each with a block of consecutive numbers, or with KONA 1 personnel stating that book length being of from 5 to 100 pages long. The latter value seemed more likely. The Air Force Codes usually had about 10,000 groups and the Army 5,000 groups, and each page could have a variant page designation.
Technical description
The actual construction of pages varied in 4-digit code books as much as it did in 3-digit books, in respect of alphabeticity and sequence of numbers. But the methods of enciphering the last two digits were still more varied than those used in 3-figure systems:substitutions by row, digraph substitution, combinations of these two, abbreviated figures in the substitution, and others. Uffz. Corporal Karrenberg, who was a GDNA cryptographer, and was a specialist on Russian Baudot stated, while under interrogation, in his discussion of the Russian Cryptanalysis course given for field training, that 3-digit or 4-digit could also be reciphered on an adder. For this purpose a text chosen at random is enciphered and the code text added to or subtracted from. There was no other indication in interrogations that this method was met in actual practice. The general method seem to have been variant page designations for the book and encipherment of the last 2-digits by various means, including 2-digit Latin square.
From May 1942, the Air Force began to use 4-digit codes in many different forms, but often of the simplest construction. In the middle of 1943, many mobile formations, Tank and Mechanised Corps, Tank Armies and Administration, and Supply units also started using these 4-digit codes. They were also used by the Railway and Transport Nets.
Dettmann and Samsonov described the first general army and air force code, which was a 4-figure with 4,600 groups, enciphered by digraphic substitution. The successor codes were the names OKK5 to OKK8 which were General Commanders Codes that rapidly replaced one another from 1939 to 1941. OKK 5 was captured in the Winter War, and OKK 6, 7, 8 later.
Dettmann and Samsonov stated:
Ltn. Harry Loeffler of Feste 10 stated that a:
There was no indication in interrogations that 4-digit codes were either less or more frequently employed. In 1944, 4-digit Signal Codes, of the same form as the 3-digit Signal Codes, appeared, and were used by army groups. and probably superseded in great part, if not wholly, the 4-digit codes discussed above.
Four-digit codes were changed less frequently than other codes but Dr Wilhelm Gerlich's of NAAS 1 of KONA 1 stated, the change in encipherment was not quick enough to make decipherment impossible . Certainly the 4-digit codes gave Germany cryptanalysts a certain amount of trouble, as a large amount of material was absolutely necessary and the majority of unsolved 4-digit codes and ciphers were abandoned because of an insufficient number of messages.
Captain Holetzlo, a member of LN Regiment 353, the Luftwaffe signals regiment intercepting Russian Air Force traffic, speaking mainly about 4/F air force codes stated that they were only 60% readable. Corporal Heudorf of NAA 8 of KONA 2 stated that later 4/F traffic provided some difficulty in cryptanalysis, but an Engineer unit's in March and April 1945 was being read concurrently.
In the interrogations of KONA 1 members, the following 4/F codes were listed as solved:
Lieutenant Horst Schubert of GDNA simply stated:

5-Digit codes

5-digit codes were used by the Army, Air Force and NKVD. In the Army, they were used by the People's Commissariat for Defence, Army Groups, Armies, Corps, Divisions and Brigades. In the Air Force, they were used by Air Armies, Air Corps, Air Divisions, Regional Air Bases, Anti-Aircraft Corps and Divisions and Anti-Aircraft units. They contained strategic, tactical, personnel and supply matters, and political reports and directives.
With the exception of a short period in 1943, when KONA 1 did independent 5-digit cryptanalysis, solution of 5-digit codes was handled exclusively by the GDNA.
In discussing the achievements of the OKH/Chi, Lt. Col. Mettig, stated glibly:
The Soviet 5-digit code was broken chiefly by War Administration Inspector Lieutenant Alexis Dettman. When rating the relative importance of cryptographic including cryptanalysis achievements contributing to total intelligence, Mettig was most impressed by the continuous breaking of the Russian 5-digit code despite the difficulties that were experienced after spring-summer 1943. However Mettig could have been stressing organisational changes carried out to facilitate the breaking of codes rather than actual cryptographic achievements. Dr Otto Buggisch, also of OKH/Chi stated that Mettig had few fundamental ideas of cryptanalysis.
Certainly other evidence exists that points conclusively and without doubt to an almost complete failure on the part of the German cryptanalysts to make any progress with the solution of the 5-digit code. Corporal A. Althans of the KONA 1 stated that cryptanalysis of 5-digit codes was only possible with the following conditions:
Dettmann and Samsonov stated that codes 011-A, 023-A, O45-A, 062-A and 091-A used successively from the beginning of World War II to the end, did prove difficult from a pure cryptanalytic solution. They stated:
In the reports of personnel from NAA 11, a Captain Schmidt stated that:
One Corporal Karrenberg, of GdNA,while under interrogation discussed 5-letter and 5-digit codes used for operational orders, stated:
Blocknots were random sequences of numbers contained in a book and organised by numbered rows and columns and were used as additives in recyphering and were considered as a type of One-time pad. The GdNA mathematician Johannes Marquart conducted research on Blocknots and was unable to determine how they were generated. Corporal Karrenberg stated flatly:
5-figure and 5-digit messages were not touched at all. In general very little work was done on decipherment of 5-group messages, although these contained the most important operation reports. They were only used to identify units and were only read if code books happened to have been captured.
In 1943, KONA 1, for a period, undertook 5-digit cryptanalysis independently of GdNA, but the general practice was for all units to forward 5-digit traffic directly to Berlin to GdNA for possible cryptanalysis and evaluation. Karrenberg stated:
Finally Lt. Schubert, when questioned on possible success on 5-digit codes replied:
Technical description
This small measure of success was obviously due to the fulfilment of the two conditions set forth by Corporal Althans for successful cryptanalysis.
Corporal Althans stated that successful cryptanalysis is possible only if:
Cryptanalysis starts from the mathematical rule that the difference between two code groups remains constant if both have the same additive row applied to them. For example:
The most important cryptanalytic aid was therefore the catalogue of differences, a numerically arranged table of the differences between the most frequently used code groups.
Directly the code, which changed approximately semiannually, was captured, about 1000 frequently used clear groups were written out by the Gen. d. N.A., arranged and serially numbered according to frequency, and then each subtracted from the other, non-carrying, by Hollerith machines and entries made on the catalogue as follows:
In 1943 KONA 1 for a period undertook 5-figure cryptanalysis independently of GdNA. For this purpose a difference catalogue of 200 clear groups was compiled by hand. A calculation aid, in the form of a wooden frame with five paper belted wheels I to V, where one wheel represented each digit of the 5-figure group, was used. The apparatus also served as an aid in actual decoding, when a great deal of non-carrying addition or subtraction had to be done. Note: little information is available from TICOM as to how this device functioned.
The Finnish predecessor to the Finnish Defence Intelligence Agency, during the early period of World War II had captured and turned over to the Germans, a Russian 5-figure book which was used continually until the Winter War. An additional copy had been captured by the Germans and though the Russians introduced a new 5-figure code on 1 April 1942, the changeover was faulty, and it was possible to establish 2000 groups of the new code within a week. Indeed, it was possible at this time to leave the decoding of this procedure to the forward KONA units. The Russians gradually improved their security, however, and in the spring of 1943, altered the indicator group system and split up the code into various front sectors. As it result it was necessary to collect all the 5-figure at Giżycko intercept station and to use the Hollerith department of the In 7/VI. Only thus could have the necessary depth on a day's traffic be achieved. But it was clear that after this time, there was practically no success in 5-figure code solutions, although the Germans were able to establish the nature of the book and the type of encipherment:
Alphabetic at first, the 5-digit codebooks later became partially alphabetic. They contained:
The encipherment was effected by applying additives taken from enciphering pads known as Blocknots, that were a variable of sheets on which 50–100 5-figure groups appeared. The second condition for successful cryptanalytic success established by Corporal Althans was fulfilled: Depth was established.

Address codes

Soviet Address Codes were used by the Army for Army Groups, Armies and Independent Corps. They were used more widely by the Air Force and the Anti-Aircraft Defense.
Solution of address codes was considered somewhat special to judge the statements in KONA 1 interrogations describing cryptanalytic operations of the various units:
Although mention was in the KONA 1 interrogations of 2-digit address material, nothing was recorded in the interrogations on this subject except one statement in the final interrogation of NAA 11 personnel:
There was no record of extent or success of solution with regard to 2-F address codes. Likewise, there was no description of 4-F address codes nor any statement regarding the extent or success of solution.
Oberleutnant Schubert of KONA 6, stated that towards the close of hostilities, the Soviets were using 3-F codes for addresses. He stated:
The only description of 3-F address codes was given in the KONA 1 reports.
Technical description
3-Figure Address codes were used in conjunction with 5-Digit messages to enable wireless stations to ensure that messages arrived at their proper destination. Their construction was similar to that of the PT-39 or PT-42 codes, described above, but they contained only figures, unit designations, authorities, words such as for or from. See Fig X.
Example of an address:
A code of this type was first used at the beginning of 1944 on the 1st and 2nd Ukrainian and the 1st White Russian Fronts for communications between their Army Groups and their respective Armies and independent Corps. In the summer of 1944 armies began to use similar codes with their subordinates units and latterly the use of such codes increased still further.
The solution to these codes, given a fair amount of material, was generally easy. They were often simpler than the example given in Fig. X and sometimes appeared in the form of straightforward lists with each meaning numbered consecutively of 100 pages instead of 10. See Fig XI.
The same variations in construction occur as with three-figure.
Codes had anything from 5 to 100 pages. The Air Force Codes usually had about 10,000 groups and the Army 5000 or fewer. According to members of KONA 1, the solution of these codes given a fair amount of material, was generally easy. Members of the NAA 11 stated the following:

Miscellaneous codes

Most of the statements given here are taken from the interrogations of members of KONA 1. It is not the complete story, as the POW's themselves were aware:
4-letter codes
Two forms of four-letter codes first appeared in practice traffic between Army Groups and Armies and Independent Corps of the 1st Ukrainian Front in November 1944:
The contents of messages sent in both the above types of cipher were usually about technical signal matters though in later stages units and positions were named.
Word-Code
From the middle of 1944, a word code was used in the area of the 2nd Ukrainian Front. The book consisted of two halves, each designated by a word such as SEVER ZAPAD literally meaning North West. Clear groups such as numbers, units, offices, designations such as Tank, Guards, Mechanised, were grouped in two columns. Each half of the code identified was only used by the Army and contained strategic and tactical reports and the names of the units. They were small in size and contained only essential groups.
The first half of the code is used with column 1 and the second half with column 2. The order of the halves can be changed and indicated by the indicating word.
If the cleargroup consists of more than one word such as In the former sector = Dolvnost and the wanted word is former, this can be indicated by saying the second word of DOLVNOST. See Fig XVII.
Example:
The codes identified were only used by the Army and contained strategic and tactical reports and the names of units. They were small in size and contained only essential groups. Anything that could not be enciphered was sent in plaintext or in the clear. Coordinates also appeared in messages.
Periodic and Columnar Substitutions
Corporal Karrenberg stated in discussing the German Army Cryptography Course stated: "These rarely appear in Russian cipher systems... Periodic and columnar substitutions concluded the sections on substitutions systems in the course. Not so much time was spent on them as they are rarely encountered in practice."
Coordinate systems
These were very varied. Armies made up their own systems and arbitrary reference points and grids were used.
Machine Ciphers
The handling of Teleprinter traffic was processed exclusively at GdNA. Lt. Schubert, whose position at the GdNA chi-stelle was Director of Main unit East,, stated that teleprinter traffic was worked on in the machine section, specifically Group IV, whose director was Rudolf Hentze. Lt. Schubert thought that messages in Depth had been read, but was uncertain whether the machine had been recovered. Schubert himself never worked on cipher machines, but knew that the Soviet had a machine, already in use at the beginning of the war, but not on military traffic.
Corporal Karrenberg spoke of the Bandwurm, the so-called Russian FISH, who defined it as Russian Baudot letter strip, that should not be confused with Soviet 5-F traffic also carried on Baudot lines. Karrenberg believed the first traffic was intercepted in 1940 in Warsaw, and as far as he believed there was no interest taken in it. The first actual knowledge of the traffic, with the same external features,e.g. chat, indicators, was in summer 1943, when the first real interest was taken in it. Dr Pietsch and Döring conducted the initial research. The German intelligence agencies did not capture any of the apparatus used, but felt that it consisted of two parts:
Depths were frequent, but the Germans did not seem to make any attempt to reconstruct the wheel patterns. The system was used by the Red Army and the Air Force and to a lesser extent the NKVD.
Dr Otto Buggisch of the In 7/VI later GdNA and the OKW/Chi went into somewhat more historical detail and stated that:
Buggisch stressed one fact which had surprised him, that they never had information about either of these machines, from POW's or agent sources. He assumed that the one that the FA broke was not the same because of the difference of cycles.
The number of links, according to Corporal Karrenberg, varied according to the number of armies, with the maximum of eight. One end of the link was Moscow, the other mobile. After 1944, no work was done on the traffic except on the spot. No vital clues to the system were given away by the Soviets, though their security precautions were not considered effective.
NKVD codes
NKVD Codes were simple mono-alphabetic Substitution cipher 2-figure, 3-figure, 4-figure, 5-figure and 5-letter types. They were used without any apparent reason on two large networks:
4-figure and 5-figure codes were used on the front line: there was a 4-figure code, e.g. used by the military police, and a general 4-figure code used on Staff-Regiment-Battalion links.
Solution of NKVD codes was handled by the NAAS and the GdNA. In interrogation:
The German Army cryptanalysts reflected this Russian distinction in their own attacks on NKVD systems, allocating the work, again in their own attacks on NKVD systems, to levels of operation determined by difficulty of solution. Lt Ed. Wöllner of KONA 1, stated that:
On the same subject Lt. Löffler of Feste 10 stated that
But in neither case was there specified what type of NKVD traffic was worked on, and what type was passed to higher echelons. Apparently the distinction corresponded to that observed in the case of actual army traffic. All lower-level operational codes, up to 4-figure codes, could be handled by the NAAS. The 5-figure codes were not dealt with by the KONA, but handled by 40 to 50 men in the LNA, at Zeppelin bunker at Zossen. Löffler thought that a good deal of success was obtained in the case of Far Eastern Traffic. An additive was used for the recipher. Dettman and Samsonov substantiated this point, in their discussion of the German army cryptanalytic effort:
They also gave full descriptions of NKVD systems. There was no discrepancy between the facts in their report and the facts given by Lt. Löffler. The details of description were scattered throughout the report according to types of encipherment. They mentioned the following:
NKVD traffic was always covered, but only by Long Range Signals companies, with evaluation and cryptanalysis done by the NAAS units.
When W/T traffic was restricted during radio silences, NKVD traffic was often the most important source for Radio Intelligence. At such times, it was more completely covered. When the Army W/T was in full swing, coverage of NKVD was correspondingly reduced. On an average day, 6–12 receivers were employed exclusively on NKVD cover.
In general the following nets were covered:
Traffic of rear NKVD troops and of the Signals Regiment were of no interest, and were not covered by KONA 1.
A constant watch was kept on the 1st network, Central Authority of the Security Troops. It consisted of the communications between the Central NKVD Authority in Moscow and the commanders of those troops in Army Groups, directing staffs North and South, the less interesting GHQ Signals Regiments. These messages were not readable.
Apart from the characteristics already noted they were also to be recognised by their use of Call-signs which were made up from a square. The Russian wireless station numbers were:
The method of working was controlled circle working. The Kreise were known by the number of the controlling station. They were:
Call signs were mostly pronounceable. The Front Staff networks usually changed their call-signs daily, the Regiment networks at regular intervals of several days, in many cases of weeks. Frequencies used lay mainly between 2400 & 3600 kcs. It should be mentioned that 5-figure NKVD messages had been picked up in nets identified as belonging to the Army or the Air Force, such messages contained SMERSH in the
preamble. Such messages were originated by units of the Red Army counter-intelligence units.
Lt. Schubert spoke of two 5-figure codes, the SMERSH organisation code, used with an individual subtractor, and the Railways Troop codes, that was a 4-figure code, enciphered with substitutions tables, the 5th digit representing the quadrant on the page in which the group appeared. Schubert was more familiar with the 4-figure NKVD codes, which were apparently more exploitable than the 5-F codes.
The Security Troops Codes were of two types. One was used forward of regiment, when a regiment was used in approximately an Army Group Sector, i.e., it is a cipher, therefore, used forward of Army Group. This particular code ran for comparatively long periods, at least 1.5 years. The code, a Substitution cipher, was alphabetical and contained 100 pages, with 25 or 50 groups per page, and enciphered by means of an enciphered indicator, which provided for page and position substitution, the result of which was again enciphered by a substitution table. These substitution tables were also valid for a longer time and varied with the network. The additives on the page did not change, only the substitution table.
The second type, a code used rearwards of regiment, was enciphered by a figure subtractor originally from tables. The same tables could appear on different networks, and since the subtractor was used very frequently, it was not uncommon for 20 messages to have the same subtractor In October 1945, 2 subtractors were used, taken from different tables, and the indicators for the 2nd subtractor were enciphered with the first one. In spite of the potential difficulties involved in this method on encipherment, the system was solved by 15 February 1945, though mainly because of bad Russian usage of the system.
The Frontier Troops Code was exactly like the Security Code rearwards of regiment, with a different basic book, at least in traffic out of Saint Petersburg Lt Schubert made a statement on the Railways and Convoy Troops code quotes above.
The 4-F NKVD codes exploited by KONA 1 were used by front line units, i.e. regiments and battalions, mainly employed by the Soviet Military Police. From the period of 1933 to 1942, code R4ZC4 Russian 4-Figure, Code 4/ was in use. It consisted of a 100-page alphabetic book each with a hundred lines. It was broken by Germany in 1940. Only one code book, known to Germany as R4ZC 1800 and to the Russians as KODOWA TABLICA ZERNO was used by the NKVD from October 1943 until the end of 1944.
NKVD R4 Z C 1800 Code
The R4 Z C 1800 code, had since October 1943 had 50 pages, each consisting of 50 lines and totalling 2,500 clear groups, alphabetically arranged. Each page is shifted by means of Cipher antenna and the bigrams are then replaced by others according to a substitution table.
The recipher consists of two elements:
Shifting by means of Chiffranten enciphering: Any figure, chosen from Row A, will indicate on any page, in Row B below, the figure must be added to that standing beside the clear group. The chiffrant consisted of the figures 0 to 9 in random order printed at the top of the page, a different order being used for each page. The third figure of the 4-figure indicator group gave the number of the chiffrant to be used, i.e., if 5 was the 3rd figure of the indicator group, the fifth figure of the chiffrant reading from left to right would be the one used for each page. This number was then added to the numbers of the lines on the page before they were reciphered by means of the bigram table, i.e. if the number was 6 then line 00 would become 06 and line 24 would become line 05.
Substitution of bigrams: For the first and second halves of the 4-figure group there are substitution tables, each of which contains 100 bigrams. There are 10 such tables. Two different bigram substitution tables were used for recyphering the big ram representing the page and that representing the line. 10 such tables were in use concurrently for the recipher of both page and line. Each table was 10 x 10 so that each bigram could be reciphered in two different ways and each table was designated by one of the figures from 0 to 9. The figure designating the table used for the line was put in the second place of the indicator group and that designating the table used for the page in the fourth place. The first place was a dummy. A series of substitution tables was current for a period of from 2 to 6 months.
The reciphering is indicated by a 4-figure group which appears at a definite position in the message and contains;
Element ab yields 20 according to the pagination table. The clear-group therefore is on page 20. Element cd yields 02 according to the clear-group table. From this the chiffrant is subtracted, in this case 1. Thus the clear group 2001, which represents Komandirowatj is derived.
The indicator group was inserted en clair in one of the first ten groups of the message according to instructions. The penultimate group consisted of the date and length of the message and the last group the Chi number.
R4ZC4 was used from 1933, solved in 1940 and in use until 1942. There were 100 pages each with 100 clear groups arranged alphabetically. Recipherment was by means of 31 substitution tables.
NKVD Other codes
Though the emphasis by the POW's being interrogated by TICOM was on 4-figure NKVD codes, it should be pointed out that a great variety of encipherments were worked on, though not all of them read. Corporal Karrenberg, gave the following breakdown of nets and types of codes used:
Corporal Exeter of NAA 11 stated that he worked on 2-figure NKVD codes. Traffic of an NKVD net on the White Sea Front, controlled from the NKVD HQ at Archangel was worked on with some success.
NKVD Conclusions
In general, certain elements seemed to be constant in all NKVD codes:
Agents' Codes included codes used by agents, guerillas and scouts All systems were used from substitutions, double transpositions, grilles and subtractors to one-time pads. Solving agents' traffic was always done centrally in Berlin.
The solving of agent, guerilla and scout traffic was the responsibility of Referat IIIc of Group IV. Solving the cipher depended mainly on captured material and there was generally enough material to accomplish solutions. Some agent traffic was one-time tape and therefore unbreakable. By and large the group did not place much value on agent traffic and neglected it.
It should be pointed out that Russian agent systems were not handled exclusively by OKH/GdNA/IV/3c, but were also handled by:
There was, consequently, a certain duplication of effort and a certain amount of confusion as a result of this arrangement. There were also conflicting opinions of the opinions of the successes achieved. Schubert reported that Russian agents' systems were tried by Dr Vauck, who stated they could not be solved. Later, he said that they were digit substitutions and P/L enciphered with a one-time running key derived from a book. Schubert thought that in the middle of 1944, e.g. the Soviets had about 3000 agents in the field, and it was impossible to pick out one system and say that it was used in one area. Moreover, Schubert pointed out that he himself had worked on only Partisan and Kundschafter traffic and knew of other systems only indirectly.
Agent codes Technical description
For the W/T traffic of the Soviet Partisans and the spies there were used:
The subtractor systems consist of 3 Cipher elements:
The Basic Cypher


Special points of this substitution system are as follows;
The tens figures are taken from empty squares.
The following is an example, with an Indicator of 37245


The Composition of the Subtractor
The figure subtractors used are of three different kinds:
Indicators
Indicators for the subtractor, based on the roll, were always inserted plain. In the other systems there were several ways of putting in the indicator. Apart from a few exceptions, there were always two indicators. Possibilities regarding recyphering of these indicators were as follows:
In general both indicators are recyphered on the same process, where one indicator is included at the beginning and one at the end of the message. The groups used for enciphering are also taken one each from the beginning and the end of the message.

Miscellaneous cryptanalysis

Period from 1939 to 1941

German Army Cryptanalytic Effort 1939-1941

In the early years of the war, the cryptanalytic staff of the Horchleitstelle was unable to cope with the added burden of the wartime traffic. The British section of the HLS was unable to solve British systems.
The failure of the British section of the Horchleitstelle to achieve any success with British ciphers and codes continued. In 1940, the six people comprising the section were moved to Bad Godesberg where no successes were achieved despite an abundance of material with which to work. Dr Otto Buggisch who in 1942 looked over the files of the British section regarding work on the British high grade machine, Typex, characterised the work of Inspector Breede who worked in the winter of 1939–1940 on the British big machine as complete nonsense. Buggisch stated that Breede described an imaginary machine which had nothing whatever to do with Typex. No cryptanalytic success was recorded in this period. In April 1940, however, the British section received a copy of the British War Office Code captured in Bergen, Norway. A second copy was obtained in Dunkirk. Successes with this system were therefore possible, since the British continued to use this system until 1943.
The failure of the cryptanalysts of the Horchleitstelle to solve independently the French Army succeeding the F110 was another indication of their inadequacy. In early autumn 1939, the French replaced the peacetime ciphers, the F90 and F110 cipher with a new wartime cipher whose names was not known to TICOM sources. The French section was forced to call upon the services of the OKW/Chi to aid in the solution of French Army systems. Dr Erich Hüttenhain was sent to the Army Intercept Station in Frankfurt to aid in the solution. Among his papers were two memoranda, where Hüttenhain reported that the task was accomplished with his own colleagues at OKW/Chi by October 1939. Among those who worked with Hüttenhain, when on 2 September 1939, the old French Army F110 code was changed was Professor Ludwig Föppl of HLS with Trappe and Schmidt of OKW/Chi. There were not enough cryptanalysts on HLS to furnish the forward units with adequate staffs. The system worked so successfully that all the September material could be read retrospectively. The system continued to be worked on successfully through to November. Hüttenhain returned to his own agency with the system solved. It may be noted that the head of the Army station requested of Hüttenhain to convey the thanks of the army to OKW/Chi for the assistance given to HLS's section and remarked that in his opinion such a large cryptographic task could not be done by the Army Command either then or in the near future.
The system was solved until the German offensive in the spring of 1940. At this time, the French began to use systems in forward echelons which Horchleitstelle was unable to solve. Mettig remarked that the Army cryptanalysts both of the forward units and the HLS finally concentrated on two machine systems, the C-36 cipher machine and the B-211. Neither was solved however, until after the Armistice of 22 June 1940 and a considerable quantity of captured documents. According to Mettig, the final solution of these two machines rated lower than that of the preceding system since it was not timely and was done only with the aid of captured material.
In the winter of 1939, the dearth of field cryptanalysts became apparent to the German Army. When the KONA regiments were preparing to move into the field, the army found that there were no trained cryptanalyst personnel to send with them. Colonel Kunibert Randewig, the commander of all intercept units in the west, was able to procure cryptographers for intercept units around Berlin and filled out that number with mathematicians and linguists.
Summary
HLS achievements during this period were minor, their success in intercepting traffic and solving known systems was a great aid to the German Army. Mettig stated that all messages which succeeded the F110 cipher were read from late 1939 and these messages, despite their administrative nature helped to reveal the tactical layout of the French. For example, the strength of units on the training ground at Mourmelon was estimated by statistics of water bottles and blankets. It was possible to deduce facts about the shortage of armour piercing ammunition with the French infantry units. Similarly, the conversion of the Second and Third French Cavalry Divisions into Armoured Divisions in the area north-east of Paris was ascertained in December 1939. By the end of 1939, the complete Order of Battle of the French Army was known to Germany. The capture of a copy of the British War Office Code in Norway in 1940 and a copy in Dunkirk in June of that year, afforded the British section its first successes and furnished a constant and important source of information from that time until 1943, when the British discontinued use of the code.
In this period, the Germans realised the inadequacy of their personnel effort, and set about correcting them.

Period from 1941 to 1945

German Army Cryptanalytic effort 1941-1945

Western and Southwestern Cryptanalysis 1941-1944

Western and southwestern cryptanalysis was handled at In 7/VI by British section with outposts in North Africa, Athens, Paris and Bergen, Norway. The American and the French section with subsections for the Swiss, Spanish, Portuguese and Brazilian traffic. The Italian section was within this group. The field units which handled western and southwestern traffic were the western field units, KONA 5 and KONA 7. The Swedish Army traffic was handled by a special unit of Feste 9 in Norway.

Work on British traffic 1941-1944

War Office Code
During the years 1941–1943, the main success of the British section was the reading of the British War Office Code, two copies which had been captured in early 1940, from Dunkirk and in Bergen, Norway. The code was numerical 4-Figure groups, enciphered by means of a subtractor. After the capture of these documents, the British section under Inspektor Liedtke was successful in reading messages from North Africa during the spring of 1941, encoded with WOC and superenciphered with additives. British traffic encoded with WOC was read constantly throughout 1941. In March of that year, a considerable volume of messages was read during the British Cyrenaic Offensive Operation Compass of the British 8th Army under General Archibald Wavell. The organisation of the base services and the Order of Battle of the Army were recognised. During the late summer of 1941, General Erwin Rommel's counter-attack took place leading to the Siege of Tobruk. The besieged fortress was solely dependent on radio for its signal communications to the 8th Army and Cairo, and as it used the WOC with an enciphering table almost exclusively, its traffic was read by OKH/Chi. The British section followed accurately the British 8th Army's relief attempts in November 1941, which led to the cutting off of Rommel between Tobruk, Sidi Omar and Sallum, eventually leading to Rommel's break-out to the west as Sidi Rezegh.
As the result of the success with the WOC in Berlin, a special detachment of eight cryptanalysts was sent to the evaluation centre of KONA 4 at Athens to solve traffic at that point and thereby reduce the time wasted in sending the traffic back to Berlin. Unfortunately for OKH/Chi about the time the party started in December 1941, certain difficulties were encountered in the solution of the War Office Code which prevented the solution of the WOC for the following eight or nine months. During this time period the British section suffered a further blow through the capture in July 1942 of the greater part of FAK 621, which had been in operation in North Africa under the aristocraric Seebohm. Although the remnants of the unit continued to operate under a Captain Habel, information gained from the captured part of the unit provided evidence to the British that their code was being read and from that time, the British section had no success with the code. Heinz Wolfgang Herzfeld stated in interrogation, that after his return to Berlin in October 1942, there was a little WOC traffic but that its volume was too small for successful exploitation. From December 1942 to March 1943, the British used enciphered indicators, and in March and April 1943 changed to a form of One-time pads for enciphering tables. The British section had no success with these innovations although Liedtke worked for a year attempting to break into the new system.
Slidex
From 1942 to end of the war, the only success attained was with the British low-level traffic, particularly Slidex. Slidex was designated by Germany as English Code , followed by a number to denote the variations of the basic system. Slidex was used by the British and later by the American and Canadian Army in front line units and in air support networks. The variations of the EC system mentioned in TICOM sources are:
After D-day, Slidex was also used by the American Army. When Germany found that the American MP units were using Slidex to report all Army units which passed their control points, the deciphering of Slidex was given high priority. Slidex messages were also particularly valuable for identifying bombing and artillery objects. The time estimate for the solution of Slidex was one to three hours if the basic cards were at hand, five or six hours if they were not. 65% of the work is said to have been done with the cards available.
Low grade codes and cyphers
Not much material concerning other British low-grade systems solved was found by TICOM. Hentze of KONA 5 stated that Maplay code was worked on throughout 1944, but this code was harder to break than Slidex, and were successful only with a great deal of traffic. Codex was solved by OKH/Chi largely with the help of a captured specimen which had been in the possession of Germany since the days of the Leros Invasion. It was read by Feste 9 in 1944–1945, when that unit was in Italy.
A Tiger-code, so called from its use during Exercise Tiger, was solved by OKH/Chi after six month's work. Solution was made possible by a long report in a British paper giving the names of the units, officers, etc. Another British system, the 999 code which was used during the pre-invasion period, was solved by In 7/VI, but was never used operationally. KONA 5 is said to have had considerable success with the Tiger-code and to have achieved a solution on the 4th or 5th day after its regular monthly changes. Matin, another British Army system, was never solved. Rudolf Hentze stated that Germany arrived at the decision that Matin was a small machine, but he does not say whether research on this system was carried out at OKH/Chi or in KONA 5.
Failures
The outstanding failure of the British section of OKH/Chi and of OKH/Chi in general, was the failure to solve the British big machine, Typex. Mettig states that had OKH/Chi been able to solve this system, it would have been their outstanding achievement. Mettig stated that Typex was read in 1942 from which time OKH/Chi had no more success. Ultra sources state that FAK 621 in North Africa had been reading Typex at the time of its capture in North Africa in July and November 1942, brought about a thorough investigation of this subject by TICOM interrogators. The story in brief was that in June 1943 one of the prisoners claimed that he had worked on British machine methods from 1937 to 1940 and that messages which could not be decoded by FAK 621, were sent to In 7/VI in Berlin. Two prisoners from FAK 621, Haunhorst and Possel, stated that all high grade traffic was handled by a Warrant Officer named Wagner. Wagner had one or two Typex machines at his disposal which had been captured in Tobruk. The evidence given by Wagner was later contradicted by Dr Erich Hüttenhain, Dr Walter Fricke of the OKW/Chi and Colonel Mettig emphatically denied having solved or heard of a solution to Typex. They had never seen a Typex machine with rotors although all admitted that a Typex machine without rotors had been captured at Dunkirk. The TICOM interrogators of Hüttenhain and Fricke reported:
Mettig, moreover, stated categorically that a success of this nature would have been mentioned in the list of German cryptographic success which was drawn up for him, prior to his visit to Supreme Headquarters Allied Expeditionary Force. Mettig's statement about Typex may have been misstatement for Slidex. At least, the interrogators assumed Hüttenhain, Fricke and Mettig were speaking the truth.
Although it is almost certain that OKH/Chi never solved Typex, a great deal of effort was expended on the project from 1940 to 1943. In January 1942, the files relating to the work on Typex were handed over to Otto Buggisch, who found work dating back to 1940, when Inspector Breede of the British section had attempted to solve the system. Breede recognised the traffic as machine traffic but described a purely imaginary machine, which Buggisch says bore no relation to the actual Typex, and as complete nonsense. In 1941, some mathematical studies were made on Typex, and in January 1942, Buggisch made a study of the system, from which he made the following conclusions:
There was no evidence that Buggisch proceeded further than this in his investigation. There seem to be no knowledge of how many rotors the Typex had. Buggisch estimated up to 25. No one at OKH/Chi knew the inner wiring of the wheels, nor how many wheels there were, so the question of cryptanalysis was of no practical interest. The whole matter was evidently permanently abandoned sometime in 1943.

Work on USA Traffic 1941-1944

The USA section of In 7/VI was created with the entry of the United States into the war in early December 1941. The section, made up of personnel who had been drafted from the mathematical section of OKH/Chi, was placed under the leadership of Friedrich Steinberg, a leading mathematician. Initial attempts at breaking USA traffic was fraught with difficulties. Due to the size of the USA wireless network and the use of alternative frequencies by USA operators, considerable trouble was experienced in identifying the various links and sorting the different systems. After a few weeks however, order was established through the reading of Call signs and the sorting of discriminants.
The first major success of the USA section was in the summer of 1942 when the M-94 device was solved. In 7 designated the M-94 unit, either URSAL, CDAF, strip and ACr2. URSAL was given to the system from the fact that traffic from the USA weather stations in Greenland which used URSAL as an indicator provided the first breaks into the system. CDAF was found in the traffic emanating from the Caribbean Defense Area. Strip and ACr2 stem from the fact that this system was long thought to be a strip system. The solution of the M-94 was achieved by Friedrich Steinberg and Hans-Peter Luzius, mathematicians of the USA section, who are said to have written a 25-page report on their work. After the cryptanalytic solution was achieved, a USA manual with a complete description of the M-94 was found in a Berlin library
Current solution of the M-94 from 1942 to 1943 was done both at OKH/Chi and at KONA 5 at St. Germanin. The work consisted of finding the daily key. A set of 25 charts of synpotic tables, corresponding to the 25 discs of the machine was constructed, apparently similar to the synoptic tables used by American cryptanalysts. The daily key was found by assuming a beginning, and using the charts to discover possible disc arrangements. Later, IBM machinery was used to eliminate impossible charts. Graupe of NAAS 5 stated that it usually took two days to recover the order of the discs and that only fifty groups were required for the system to be broken. Estimates on the amount of material solved range from 70% to 90%.
The M-94 was succeeded in 1943 by the M-209, which was first solved by the Germans in the autumn of 1943, and continued to be solved with some success throughout the remaining years of the war. The breaking of M-209 was achieved in OKH/Chi by Steinberg and Luzius, who were aided by the knowledge that the US government had brought the Hagelin machine which had once been offered to the German government. At first only relative settings could be recovered, but later the section refined its technique of recovering absolute settings so that not only paired messages but in a large number of cases, a whole day's traffic could be read. The technique of achieving true settings was passed on by OKH/Chi to the Kriegsmarine and the Luftwaffe.
Work on an operational level was carried out jointly by the USA section of OKH/Chi and NAAS 5 at St. Germain. Early in 1944, NAAS 4 had been supplied with a group of cryptanalysts skilled in work on the M-209, and this small group competed with the section at In 7/VI in the quick solution of M-209 traffic. It estimated that 10%-20% of all M-209 messages intercepted were read by establishing the true settings of the wheels, and that about half of these settings were established at OKH/Chi, half at NAAS 5. To insure speedy solution all subordinated to KONA 5 were ordered to teleprint to NAAS 5 all messages on the same settings or with Indicators differing only in the first two letters. Under the most favourable circumstances two days were needed to solve a depth, and two more days to reconstruct the absolute settings. There were times, however, when captured lists of keys or settings made possible a quick solution of the traffic. During the Allied invasion of Sicily and the Allied invasion of Italy, messages of great tactical value were decoded using captured booklets containing M-209 settings. At the time of the Normandy landings, the M-209 keys of the 82nd Airborne Division and 101st Airborne Division which covered the critical days of 6–11 June were captured and all traffic on those days was read.
In 7/VI knew of the existence of a big American machine which was designated the AM1, but it was clear that OKH/Chi never solved this machine and had no idea about its construction. Hentze stated that his unit never succeeded in getting a model of the machine. Other statements by OKH/ChiI that the machine was tackled in Berlin was considered utter nonsense
OKH/Chi were successful with American codes. The Army Administrative Code, designated by In 7/VI as AC 1 had been captured before 1939, and photostatic copies of the code had been distributed to all field cryptanalytic units. The code was a 5-letter code with 60,000 groups, each page containing 90 groups. Feste 9, intercepted and read traffic from this code from the summer of 1942 to the autumn of 1943, while stationed in Bergen, Norway. Although no traffic of strategic value was passed, the intelligence was valuable enough so that when AC 1 was succeeded by a simplified version designated as TELWA, Feste 9 reconstructed the code.
Feste 9, aided by the USA section of OKH/Chi, also broke the simple codes used by the US Army units stationed in Iceland and the Caribbean. These were designated as Divisional Field Code followed by a number indicating the variation of the system. The variations described in TICOM sources were: DFC 15, 16, 17, 21, 25, 28, 29.
Mention should also be made of the success of the USA section of OKH/Chi with the Air Transport Code used for air cargo and passenger transport circuits to Africa and South America. This code, consisting of two-figure elements from 00–99, was successfully decoded by In 7/VI from May 1942 until early 1943, when it was given to the German Air Force, the Luftwaffe.
Summary
The work on OKH/Chi, USA section, appears to have been successful in low-grade ciphers and in some medium grade ciphers such as M-94 and M-209. Mettig rated the solution of the M-209 as the outstanding achievement of this section and one of the best of In 7/VI. It is clear also from references concerning the work on this system made by members of other agencies such as Wilhelm Tranow and Ferdinand Voegele, that the USA section of OKH/Chi evolved the best technique of solving the M-208 and led the other German Signals Agencies in the work on this system.

Work on French traffic 1941-1944

French traffic from 1941-1944 was of two main types, Vichy France and Free France. Vichy French traffic which was under the direct control of the French Armistice Commission at Wiesbaden was monitored by the French section of In 7/VI. By agreement with the vichy government, the French were to inform Germany of their code and cipher procedures, but wary watch was kept on their traffic. The work on Free French traffic which emanated during this period from Free French troops in Syria and in North, West and Equatorial Africa was carried out by OKH/Chi and the Sig. Int. Evaluation centres of KONA 4 in Athens where the traffic was easily intercepted.
In a list compiled by the director of the French section, of the Free French systems worked on by In 7/VI and NAAS 4, the following systems were mentioned as being used in Syria:
From other sources may be added the de Gaullist's systems, two of which are named: Control Beduoin and Service Politique. These were initially read from traffic intercept at the French garrison at Bir Hakeim, but had proved impossible until the same cypher was used in Syria by the de Gaulle party. The work on French systems of KONA 4 was summarised by two members of KONA 4 who stated:
Among the Free French systems from North Africa which were solved and read by the units were listed by Kühn:
A 5-Figure de Gaulle code was used in North, West, and Equatorial Africa, and later in France, which had not been solved by the end of the year despite efforts made by In 7/VI from 1941 to 1942. In 1041 Otto Buggisch stated that he worked on this code for Werner Kunze, a Pers Z S cryptanalyst. However, no success was obtained, until compromise revealed that the code was transposed with daily changing keys. No further headway was made with this system.
The French section had solved the C-36 and the B-211, the machine cipher similar to the Soviet K-37 cipher machine system, after the French campaign in 1940. When the de Gaullist troops in North Africa and Corsica began to use the C-36 machine for their traffic, the French section already had a solution and it was easily solved during 1943. When a new indicator system based on numbers was introduced in early 1944, a high percentage of the traffic continued to be solved through the use of cribs and statistics. The indicator system itself was broken in the autumn of 1944.
At the end of the TICOM homework written by Kühn, on the French systems treated by the French section of In 7/VI and KONA 4, Kühn stated that the French section was greatly aided by certain fundamental weaknesses in French cryptography, which lead to easy solutions of most of their systems. These weaknesses were described by Kühn, stated thus:
With these weaknesses, it was possible for the French section to read all or most of Free French traffic during the years 1941–1944. Their previous experience with the C-36 and B-211, provided In 7/VI with solutions to the cipher traffic as it was being used by the Charles de Gaulle party. No high grade traffic appears to have been passed by the French during this period.

Work on Swiss, Spanish and Portuguese and Brazilian traffic

From the 1941–1944, the French section of OKH/Chi had subsections for Swiss, Spanish, Portuguese and Brazilian traffic. As Kühn stated, the volume of traffic was small and unimportant. Otto Buggisch worked with Kunze of Pers Z S on the solution of the Swiss Enigma K. Although they worked on a theoretical solution of the machine, and applied the solution to trial enciphered text, created by Buggisch himself, the theory was never applied at In 7/VI to Swiss traffic, as the volume of traffic did not warrant the effort. Moreover, easy solution of the traffic was precluded by the fact that the Swiss did their own wiring of the Enigma wheels and changed these frequently.
Monitoring of Spanish, Portuguese and Brazilian traffic was coordinated by the French section of the unit, and was carried out by various KONA field units. From 1939–1942, Signal Intelligence Regiment #Feste 3, from 1942 to 1943, it was FAK 624 and from 1944, by FAK 624 and Feste 12. The amount of traffic read in these units was evidently small enough to be handled by the personnel stationed there. A Spanish military transposition code and a Spanish digit with variant codes were read. Of seven Brazilians systems known, five were read.

Work on Italian traffic 1941-1944

From the beginning of the war, the security of the Italian systems was a matter of constant concern to Germany. An Italian section under Captain Dr. Fiala was established in the unit to check the security of Italian traffic, particularly on the route from Italy to North Africa. Germany feared that Afrika Korps troop movements in North Africa, were being betrayed by the insecurity of the Italian codes and ciphers.
As early as 1941, Dr. Fiala paid a visit to Rome to notify the Italians of the weaknesses of their systems and to request greater security. The visit made little impression on the Italians who remained confident of their own systems. An attempt to improve Italian security as well as to demonstrate the use of IBM Hollerith machinery section of In 7/VI. Captain Bigi, who was a cryptanalyst of the Servizio Informazioni Militare, the cipher bureau of the Italian Army was sent, but his report did not result in any changes in Italian cryptography. Captain Bigi's next visit to Berlin met only with coldness on the part of OKH/Chi staff. By late 1942, the general impression among the Germans was that the Italians were incapable of improving their own systems, even with Inspectorate 7 monitoring them. The Italian section of the unit was disbanded in 1942 when a leader order was issued by Hitler.
In June 1943, with the Armistice of Cassibile to the Allies, the work on the Italian Referat was restarted at OKH/Chi. The section consisted of small cadre, with Manaigo as section head. Heinz Wolfgang Herzfeld gave an account of this section's work to TICOM. Herzfeld worked on 400 messages that had been intercepted in May, to July 1943. Herzfeld worked on the material which consisted of 5-Figure messages. In the beginning of September 1943, an Italian recyphering table and some messages had been taken from the office of the Italian Commanantura in Athens, arrived in the section. When Benito Mussolini had been arrested, and the armistice had been signed, some German officers of KONA 4, stationed at the Neo Phaliron Velodrome, drove to the Commanantura on Amerikis Street in Athens, walked into the cipher office and started collecting material lying on the tables in the office, and packing it into a case, in front of Italian staff. When Italian officers came in, began shouting, and a scuffle started, the Germans left with the case. The recyphering table was used in the Ellade code and the Piave code.
In November 1943, the section was again dissolved, this time by Major Lechner. The decision to disband the section the second time, was justified such that after the fall of Leros, no more Italian wireless traffic was intercepted.
The two codes worked on by the section, in the later period was the Ellade and Piave codes. The enciphering tables captured in Italy enabled the Piave code to be reconstructed and enabled many messages to be captured from Northern Italy. The Ellade code was partly reconstructed when the section was dissolved from lack of current traffic.
At the end of the war, KONA 7 was ordered to cover the traffic of Italian bands in Northern Italy.

Work on Swedish traffic 1941-1944

Work on Swedish Army traffic from 1941 to 1944 was handled by a special detachment of Feste 9 called Out Station Halden, named from the fact that it was located in Halden. For administrative purposes the station was attached to the Halden Police. According to Bartel, a German cryptanalyst who worked on these systems, the following Swedish Army systems were worked on:
The first Swedish cipher machine was worked on in Norway in 1944 and was identified as similar to a small Hagelin cipher machine like the M-209. Messages were read at Halden with cribs, by errors in the cryptography, or by having two messages in the same key. The second machine was thought to be a large Hagelin machine. Two copies of the traffic on this machine were made, one for In 7/VI, and one for the station at Halden. A member of the station at Halden, thought during TICOM interrogation that SM 2 traffic was read. The intelligence gained from breaking of traffic of SM 1 and the simple field codes allowed Germany, during the spring manoeuvres of Feb-March 1945, to build up a complete tactical picture of the Swedish Army in two months. However, neither the high grade grille, nor the large Swedish machine was solved.

Work on Balkan (Southeastern) traffic 1941-1944

Southeastern cryptanalysis was handled at the unit by the Balkan section under the leadership of Rudolf Bailovic and in the field, by KONA. Kona had been stationed in the Balkans area during the entire period of the war, and in addition to its regular task of intercepting the traffic emanating from Syria and North Africa, it had been given the task of monitoring the traffic of the occupied countries in the Balkan area. The Balkan countries whose systems were worked on by the OKH/Chi unit and KONA 4 were: Greece, Hungary, Romania, Yugoslavia, Albania, Turkey and Bulgaria. The work done on the traffic of each of these countries is given below.

Work on Greek traffic 1941-1944

Dr Otto Karl Winkler provided the most information to TICOM regarding Greek ciphers and codes, from a single TICOM home work. Winkler was a translator and cryptanalyst with KONA 4 from the spring of 1941 to May 1945.
According to Winkler, work on Greek systems started in 1941 when KONA 4 was stationed in Bucharest. The first system was a Greek Air Force system which consisted of a single transposition send in 3-letter groups. Winkler stated that nearly all messages were read by the use of stereo-typed beginnings. Although the messages were of insignificant value, a continuous check on officer personalities, deliveries of stores and information concerning airfields contributed to tactical knowledge of the Greek forces.
KONA 4 worked at this time also on Greek Army and Navy messages, but without success until the conquest of Greece. At that time, Winkler stated Codes were captured which were used by Greeks during the attack on Crete.
The only other Greek system mentioned as having been attacked in 1941 was a 5-letter code with a cyclic recipherment which Buggisch says he worked on in the unit. Plaintext traffic was becoming rapid when the Greek campaign ended.
After KONA 4 moved its evaluation centre to Athens in May 1941, no more work was undertaken on these systems until NAAS 4 withdrew from Athens in autumn 1943. At the time, Greek Partisan traffic began to be intercepted. In the spring of 1944, KONA 4 gave Winkler the task of forming a small Greek unit to handle traffic of the traffic of the Greek People's Liberation Army. The unit consisted of six people, chief among whom were called Strobl, a cryptanalyst who solved a double transposition system of ELAS while Winkler concentrated on translating the traffic already readable. The work became more important and the unit, now increased to 16 people, was attached to a Close Range Signal Intelligence Platoons NAZ G
Winkler stated that in the beginning the Greeks sent their traffic in two figure substitution with alternative groups. As few messages were sent on the same substitution, it took several days to break and read these codes. ELAS soon went over exclusively to letter traffic based on double transposition, which was successfully solved largely through the aid given by the carelessness of the Greek cryptographers.
Winkler estimated that 50-60% of the traffic tackled by NAZ G was solved. From these messages, the unit was able to build up an almost complete picture of the organisation and composition of the Greek People's Liberation Army and the National Liberation Front. The unit also compiled lists of leading Greek personalities and officers and informed the competent German political and military authorities about many planned military and political actions, acts of sabotage, ambushes, dynamiting and so on. In addition, the messages provided the exact location of Allied airfields in the Greek mountains, regarding the position, strength and activity of the Allied military missions and various British Commandos, about Greek internal and inter-allied crises and struggles, about the British tactics for the occupation of Greece.
Work on Greek systems ceased on 15 October 1944 when Naz G was transferred to Sarajevo.

Work on Hungarian traffic 1941-1944

The Hungarians used the commercial model of the Enigma cipher machine, and had the rotors for the machine made by the German firm of Konski and Krüger. This firm usually turned over the records of the rotor wirings to the Armed Forces Radio Communications Branch which in turn gave them to OKH/Chi. However, Hungarians connected with the firm took the rotors at night and changed the wirings enough to make the firm's records incorrect. No effort appears to have been made on the part of OKH/Chi to recover the wirings or to prevent the sabotage. It is difficult to suppose that the unit could have been so easily duped had they wished to press the matter. Evidently, they did not consider the traffic worth causing embarrassment to the Hungarians.
With the onset of the war, however, OKH/Chi grew more cautious, particularly with the movement of German soldiers through Hungary. During the spring and summer of 1941, the radio traffic of the Hungarian State Railways was monitored from a Feste in Tulin. The code being used at that time by the railways was a turning grille with permanent squares which could be turned in four different positions, and reversed to give four additional positions. The code was solved by Dr S. Döring of the mathematical section of In 7/VI. After the check of the railway authorities had proved that they were dependable, interception was stopped.
Watch on Hungarian traffic was dropped from 1941 to 1943 due to the high priority given to Russian traffic. In 1943, however, interest again developed and a detail was sent from Feste 6, the former Army Fixed Intercept Station at Tulln, to Slovakia, near Bratislava to monitor Hungarian traffic. Some tenseness in the relations of Germany and Hungary may be reflected by the fact that all members of the detail wore civilian clothing. Also at that time, OKH/Chi began to resume its work on Hungarian traffic. Count Esterhazy of the Balkan section began work on a Hungarian code and turning grille. Messages enciphered with a 2-figure substitution key were also worked on.
Work on Hungarian traffic was done by the Balkan section of OKH/Chi only when the Army thought it necessary to check up on the Hungarian allies, but the attempts that were made were apparently successful. The solution in 1941 by Dr. Döring of the Hungarian grille, while not of great strategic or tactical importance, was characterised by Otto Buggisch as brilliant.

Work on Rumanian traffic 1941-1944

Very little is known of the work of the Balkan section on Rumanian traffic from 1941 to 1944. According to Mettig, the monitoring of Rumanian traffic ceased in 1941, due to the high priority given to Russian traffic and the chronic shortage of staff. However, in 1941, monitoring appears to have resumed. In 7/VI stated that Rumanian traffic was completely monitored at that time, and that the Balkan section was reading a Transposition cipher which was decoded with comparative ease. Other references to Rumanian systems were found in Herzfelds brief statement that the cryptanalysts of the Balkan section were working on Rumanian diplomatic code consisting of 5 or 6 figure groups. KONA 4 evaluation centre while stationed in Belgrade from September to December 1944 worked on Rumanian traffic.

Work on Yugoslav traffic 1941-1944

With the insistence of the German government that Yugoslavia align itself with Nazi party policy in the spring of 1941, and the consequent wave of Yugoslav national resistance, the Balkan section of the unit and KONA 4 undertook the heavy burden on monitoring the various types of Yugoslav traffic.
These types were:
When the German government established the puppet government of Croatia in 1941, the Croats were given the commercial model of the Enigma for use by the Army and Secret police The traffic of these units was read by the Balkan section currently without any delay. According to Buggisch, the solution of this traffic was not an outstanding cryptanalytic achievement for the following reasons:
Just to make sure, however, Buggisch added;
Although Buggisch did not recall the contents in details, he stated in interrogation that there were some interesting messages about actions against Tito. He also stated that Germany had intended equipping the Croats with the plugboard Enigma, but they had decided against this since they believed the corrupt Croats would continue to sell the keys to British agents. In that case, OKH/Chi would have to pay for the keys used by the Croats instead of solving them as they could with the commercial Enigma.
Rudolf Hentze of In 7/VI stated that the Balkan section was successful with the double transposition used by Croats but nothing is known of this system.
Herzfeld stated that the Dombrani and Ustaše used a 5-Figure code based on a former Yugoslav military code. Evidence is lacking about the actual results obtained but it is probable that the system was solved since the former code was known.
Solution of the systems of General Draža Mihailović and Marshall Josip Broz Tito was divided between a unit of KONA 4 in Belgrade and the Balkan section of OKH/Chi. The breaking of easy guerilla techniques, particularly the solution of daily recypherings, was carried on at Belgrade by a special detachment, NAZ W which had served in 1941 under Wollny as an evaluation centre for Section III Armed Forces Radio Communication Branch . With the assumption by the unit of work against the enemies Tito and Mihailović, the detachment came under Army control and was attached to KONA 4.
The solution of the more difficult systems was carried on at OKH/Chi by the Balkan section under the immediate supervision of Rudolf Bailovic, who was a specialist in Slavic traffic, and a specialist in the systems of Mihailović and Tito.
Herzfeld, a member of the Balkan section of OKH/Chi from 1941 to the capitulation, had written two reports, or homework for TICOM, specifically I-52 and I-69, that has a full discussion of the Yugoslav systems worked on by that section. The traffic of Mihailović was entirely double transposition with fixed key length and key word. They were regularly, if slowly, solved at In 7/VI with the aid of stereotyped phrases, frequency charts, and other well known cryptanalytic methods. Herzfeld stated that it took one to three days to break a single message.
The systems of Tito were far more varied, most of them of Russian origin. In I-69, Herefels lists among the Tito systems broken at In 7/VI as:
The system which succeeded the variable substitution key with short reciphering set was called Tito's Novo Sifra. It was used after June 1944 above division level and was not broken by In 7/VI. Herzfeld claims that it could have been broken with sufficient traffic and close scrutiny.
For a while the new system proved secure but regional commands obviously found it cumbersome and reverted to old insecure systems. Thus the Germans could read a lot of Partisan traffic even after mid-1944. Marshall Tito had close relations with the Soviet Union and during the war he was in constant contact with Moscow through a radio link. This traffic obviously became a target for the Germans and they investigated it in 1944 without finding a theoretical solution.
In the autumn of 1944, work on Tito traffic was increased. Besides the unit stationed in Belgrade under Wollny, the Evaluation Centre of KONA 4 was moved from Athens to Belgrade and began work on Tito ciphers. NAZ G, which had been working on Greek Partisan traffic was also moved from Thessaloniki to Sarajevo to cover Yugoslav traffic.
The only reference to the work of the Balkan section of OKH/Chi on Croatian resistance movement ciphers was that they were cryptanalysed by KONA 4 and rechecked by the OKH/Chi Balkan section.
In general, it may be said that the work on Yugoslav ciphers and codes was successful. The ciphers of Tito and Mihailović formed the most important part of the work of that section with Rudolf Bailovic performing the bulk of the work.

Work on Turkish traffic 1941-1944

Both the intercept and decoding of Turkish traffic was handled largely by signal units subordinate to KONA 4. NAZ T, which was stationed in Graz, worked only in Turkish traffic. At first it had intercepted Turkish Navy and Merchant Marine traffic as well as Turkish Land Forces and Police traffic, but certain disagreements arose with the Kriegsmarine over the interception of the Navy and the Marine traffic and this was abandoned.
The police traffic of Turkey is described as:
The Turkish Army codes were mainly transposition codes with a key word, sent in five letter groups preceded by a 4-figure number. All these systems were decoded by NAZ T and were set to OKH/Chi simply for the purpose of checking all work.
One special Turkish code is mentioned as having being read by either OKH/Chi or NAZ T, and that was the special code used by the President of Turkey İsmet İnönü, while sailing on the State Yacht, the Savarona. This code was used in 1943 for radio messages, while the President was on the yacht, and not used afterwards.
Sometime in 1942 to 1943, OKH/Chi received from the Research Office of the Reich Air Ministry, the mission of solving certain Turkish diplomatic traffic. This the Balkan section did under the supervision of Bailovic, with the decoded traffic being sent to the Forschungsamt. The traffic was used by the military attaches for their reports from Russia, Bulgaria and Italy, and that it was read continually by In 7/VI. TICOM knew from other sources that this traffic proved to be a very valuable source of information concerning Russia. Mettig remembered a number of reports from the winter of 1943–1944 on the Russian military situation and the preparations for an offensive. Despite many warnings from British sources that the traffic was being read, Turkey failed to change the system, and the reading of Turkish diplomatic traffic remained a constant source of information.

Work on Bulgarian traffic 1941–1944

There was very little work done on the traffic of Bulgaria during the war. The traffic on the Bulgarian military attaches was solved. Herzfeld stated that Thiele of the Balkan section worked on a Bulgarian cipher but no details are known.

Work on agents traffic 1941–1944

The Agents section of OKH/Chi was established in 1942. Before that time, the activities of this section which consisted of radio security inside Germany and monitoring of illegal transmissions had been carried out by Section III of the Armed Forces Signal Communication Group, Radio Communication Group 3 . The unit was subordinated to Generalleutnant Fritz Thiele. Thiele was succeeded by Wilhelm Gimmler when Thiele was hanged on piano wire on 4 September 1944 at Plötzensee prison in Berlin. Gimmler was also later hanged on piano wire for the same event.
In 1942, however, it seemed necessary to establish a deciphering section specialising in agents' ciphers. Fu III wanted to set the unit up within it own organisation but the Supreme Command of the Armed Forces and the Army High Command opposed the establishment of another cryptanalytic agency. As a result of their opposition, it was agreed to set up a section for agents' traffic with an existing cryptanalytic organisation. In 7/VI was chosen as OKW could not spare the personnel, in light of the fact that OKH/Chi had previously raided OKW/Chi for personnel to establish In 7. The agents section was thus attached to OKH/Chi although it appears to have maintained the close relation with Fu III, housing itself near FU III and moving with it, in November 1943 to Jüterbog.
The agents section was commonly called the Vauck section or Vauck Referat or Referat Vauck and named after its chief cryptanlayist Wilhelm Vauck. Mettig gave great credit to the work of Dr Vauck saying that this section achieved good results because of Vauck's leadership and his personnel cryptanalytic successes. The section was not large consisting of about 35 people in the main section, ten at outposts in Paris and Brussels, and other cities, with eight lent to the Polish section of OKW/Chi. Recognised traffic was decoded in the outstations, the rest was sent to Berlin. All traffic, moreover, was sent to Berlin in duplicate.
The cryptanalytic methods employed by the Vauck section differed from normal methods of solution because of the peculiar nature of the Agents' systems. When in spring 1942, when Referat Vauck started work on finding a solution to Allied agents' traffic, it was confronted with a completely new and difficult task. Success could not be achieved using the normal methods of cryptanalysis on Army or diplomatic ciphers. The peculiar construction of agents' ciphers and in particular the frequent changes of ciphers, demanded a new method of approach. Agent cryptographers has not only to be highly enthusiastic about their work and very flexible in their approach, but it was also desirable that a percentage, that was considerably higher that normal cryptography, had to be expert linguists.
The early research work of the Referat, carried out in close cooperation with the evaluation section of Fu III, was devoted to clarifying the use of Call signs, and to ascertaining systems of indicator groups and coding tables in different procedures. Material, in the shape of old messages which had been gathered in the past, was re-examined. Simultaneously a search began for possible source of compromise within the various ciphers under investigation.
To supplement this research work an arrangement was made with the appropriate agencies to allow representatives of Referat Vauck to take part in important arrests and in the interrogation of agents. Owing to a shortage of personnel in the Referat it was impossible to take full advantage of this concession. The concession was granted as it was recognised that when an agent was arrested and no cryptographer was present, cipher material, which was usually well camouflaged, was not recognised as such and therefore could not be properly utilised. Furthermore, the material was often not evaluated correctly and delays ensued in forwarding it. Sometimes ambitious amateurs wished to earn credit for themselves by exploiting cipher material. Another danger lay in the fact that when cipher experts were not present, agents might tend to give false or imaginary cipher information. In these cases the presence of an expert was of great value. Agents under interrogation who saw that their cipher methods had been compromised usually gave good signals information. Once the value of Dr Vauck's assistance was recognised, his section were frequently called in to assist the Abwehr and Gestapo in their work.
It became possible, with the advice of Referat Vauck, either to turn around more agents, or to play back the agent's wireless personality using German personnel. Errors occurred in this field when signals personnel were not present. Thus in the beginning of 1944, it was ascertained that two allied agents, who had been turned around by the Abwehr, were operating in a villa southeast of Bordeaux and were being handed clear messages for encipherment and transmission, without any supervision.

Work on Czech agents traffic

The Vauck section worked on Agents' traffic of the Czechoslovak Resistance movement. Mettig believed that the solving of the 1942-1943 of two links running to England made possible the arrest of British agents in Czechoslovakia, one of them a captain. The greatest success was achieved by intercepting the wireless communication of the Czechoslovak Resistance movement in London. This was the only case in which Mettig is certain that it was possible for the Vauck section to solve an agent network by purely cryptanalytic means, and this was largely through breaches of security on the part of the Czech chief. After the system had been solved, the book for enciphering was found and the key recovered. In September 1942, the Czechs were about to go over to a new system, but were foolish enough to name in the old system, the book to be used for enciphering in the new system. Contents of messages solved on this link were nearly always concerned with reports on the political situation and activities of the Czech Resistance Movement, and were so important that for a long time, the W/T traffic was allowed to continue unhindered.

Work on Yugoslav agents traffic

Work on Yugoslav Agents' traffic was carried on by a detachment in Belgrade under Lt. Wollny. This detachment had been under Group III of FU III but was attached in 1942 to KONA 4 because all fighting against hostile organisations such as Draža Mihailović and Josip Broz Tito was directed by the Army. Traffic which was not solved in this detachment was sent to the Balkan section of OKH/Chi for a solution.

Work on Southern France and Spain agents traffic

Agents' traffic in southern France and Spain emanated largely from the United States, Great Britain and Spanish Republican Army who were in radio contact with stations in Spain. To cope with this traffic, a camouflaged branch station was established in Madrid and the intercepted traffic passed to Referat Vauck for processing.

Work on Soviet Union Agents traffic

Mettig knew of three important Russian Agents' networks: The Red 3, the Schulze-Boysen case, named after its leader, Harro Schulze-Boysen and the two links running from Brussels. Mettig stated that these last named links were, as far as he knew, not solved. However it was known that this was the Red Orchestra #Trepper group named after Leopold Trepper who eventually became a double agent, working against the Soviet Union. Mettig perhaps was not privy to this knowledge.
In addition to Mettig's account of the Red 3, two memoranda were written by Wilhelm Fenner, the chief cryptanalyst of OKW/Chi. Fenner reported that on 23 February 1943, his agency was asked by Vauck section to collaborate in work on certain messages of Soviet agents on the Red 2 net. By the end of March, the Vauck section had furnished Fenner's cryptanalysts, Peter Novopashenny, Trappe and Schmidt, with all the traffic in that system since September 1941 so that a start was made on a solution. Fundamental findings were communicated to OKH/Chi which enabled that organisation to solve the system roughly at the time, as did Fenner's group. After the initial solution, it was agreed that OKH/Chi should continue to work on the system, and Mettig stated that from this help the Vauck section discovered that the system was based on a book text. In the autumn of 1944, Vauck was reported to have told Mettig that the exact sending position of this net had been determined to be in Switzerland. A raid was planned but had to be cancelled as Swiss authorities had forestalled the Germans. The station, according to Metting, was evacuated and destroyed before the Germans could take action.
The story of the second Soviet net, the Shulze-Boysen net operating from Berlin in 1942, is equally dramatic. This net received its name from First lieutenant Pyatidesyatnik) Harro Schulze-Boysen, whose house was the centre of a communist inspired espionage agency operating on a large scale. When the first inroad into this traffic was made by the Vauck section, Dr. Lenz, one of the members of Vauck's section, mentioned the name Schulze-Boysen to another member of the Vauck section named Haymann who frequented the Schulze-Boysen house. Haymann warned Mrs Schulze-Boysen. Subsequently, both Haymann and Dr. Lenz were arrested, and Haymann condemned to death. Lenz was released and transferred to an out-station in Paris. With the aid of knowledge obtained from decoded traffic, the Gestapo made arrests of from 79 to 80 people of whom 70 were condemned to death. The case was kept strictly secret because many of the accused were employed in various agencies and were betraying secrets to Russia.

Work on Polish resistance movement traffic

The most notable results in the Agents' section were achieved in the interception and solution of the systems used by the Polish Resistance Movement, particularly during the Polish uprising in Warsaw in 1944. From information passed on this system, the dispositions of the Polish liberation troops as well as friction between them and the Russians could be established. It was possible, moreover, to solve all wireless traffic which the Polish government in London carried on with its organisations in Poland. In order to preserve secrecy and to insure quicker delivery of the solved message traffic, eight members of the Vauck section were transferred in the autumn of 1943 to the Polish section of OKW/Chi for work there. The Plain text was published by the OKW/Chi as Reliable Reports, with an extremely restricted distribution. To ensure complete radio intercept coverage, OKW/Chi ordered its outstation at Lauf an der Pegnitz also to intercept the traffic. Schubert, a cryptanalyst at GdNA, wrote a brief account of the systems used by the Polish resistance movement in which he stated that systems 006, 117, 118 and 181 were broken and that others were worked on. Most of them were simple 2-figure substitutions used without an indicator, with some variations in development and the use of basic keys and key phrases.

Work on German traitors traffic

Mettig stated that he once saw a report concerning a German who transmitted, by wireless to England, details of a newly constructed signals shelter in Berlin urgently requesting that it be bombed. No details of these were known by TICOM.

Linguistic research 1941-1944

Linguistic research during the years 1941-1944 was carried on at the OKH/Chi, by the section designated as the Linguistic Research Department. Oberst Metting listed this section as one of the twelve sections of the original unit in 1942. Köhler was named by Mettig to manage this section in 1942 and Köhler remained head of the unit throughout the war, until November 1944, when the section was transferred from the GdNA to the OKW/Chi. Mettig claimed that it was contemplated that the members of the linguistic research section would advise the cryptanalysts on language problems and direct all matters of the Armed Forces concerning foreign languages. Although the plans were never realised, the nature of the work of the section can be inferred from these plans. It was known that the section would have had an exceedingly well stocked cryptographic library, including foreign maps in a large number of scales, journals, transport time tables, foreign reference works, extensive biographies of the enemy and other important categories of information related to cryptography in a wide variety of sources.

Mathematical research 1941-1944

According to Metting, Dr. Hans Pietsch was the Director of the Mathematical Research section. Pietsch had managed to collect the best available cryptanalysts, i.e. the best mathematical brains. The work of this section was twofold:
To achieve these purposes, three subsections were found necessary. Subsections F, 7 and 13 are described above in 5.6.1.
Cryptanalysis work on subsection ''F'' 1941-1944
Subsection F of the mathematical section appears to have done some excellent work in the solution of the more simple machine systems used by foreign countries. The following are examples of solutions:
Dr S. Döring's solution in 1941 of the Hungarian grille should be counted as one of the achievements of this section. As has been stated previously, this section had no success with the large cipher machines such as the British Typex, the USA SIGABA, or the large Swedish Hagelin machine. The outstanding men of this section were named by Buggisch as Fritz Hilburg, Willi Rinow and Wuenoche.

Use of IBM in cryptanalysis 1941-1944

The Hollerith section of OKH/Chi was derived from the IBM section established in 1939-1940 by the In 7/VI, at the suggestion of the mathematicians and former actuaries of this section, who knew Hollerith methods from civil life. It was natural that in 1942, when the study of the security of the German Army system was transferred from In 7/IV to In 7/VI, the use of Hollerith machinery for security studies was transferred to OKH/Chi and quickly adapted for cryptanalytic work on foreign systems. The machinery used by OKH/Chi was mostly of German make, although a number of captured French IBM machines were included in the unit. The Hollerith section grew considerably in the course of time, both in respect of the number of machines the unit had and of the personnel engaged. In 1943, there were perhaps 20-30 female punchers engaged and about 20-30 soldiers who were Hollerith mechanics and such like in civilian life. Baurat Schencke was in charge. Hentze stated that in 1944, there were 30 key punchers, and 2 tabulators.
Some of the bigger Hollerith machines were always being provided with special new wirings for special cryptanalytic purposes, e.g. for non-carrying addition and subtraction in codes work. Most of the tasks, however, consisted of the usual statistic, column statistics and of simple figure-calculations, e.g. in work on Hagelin machines. Buggisch stated that as a rule, no tasks were undertaken which could not have been carried out by hand by perhaps 100 people in a reasonable time.
New Hollerith section
The limited width of the Hollerith card was soon found to be inconvenient, particularly in counting out of repeats for the purpose of lining-up 2-cipher texts. The obvious solution appeared to be in this case to work with perforated strips and a 5-unit alphabet. Orders were given at the beginning of 1943 for the construction of such a machine. As Group VI only had a completely inadequate workshop at its disposal, and by that time it was already impossible to get any more tools, etc., an agreement was made with the Hollerith firm that a few more rooms, together with workshop machines and tools, in the factory buildings in Lichterfelde Ost be placed at the disposal of Section VI. An engineer from the Hollerith firm was placed in charge of this new section, but was found to be unsuitable. The repeat counting machine was ready in the autumn of 1943. It worked by the electromechanical principle, its speed was not considered very high, around 40 pairs of letters a second, and there was an idling period that was considered inconvenient. Buggisch stated that when the Hollerith section was completed, none of the specialist sections performing practical cryptanalysis had any use for it, so that the question was justifiably raised as to why such an apparatus had been built at all.
Mechanical aids
In late 1943 to early 1944, the workshop began to be engaged on the construction of various mechanical aids, that cannot be described as cryptanalytic machines. A machine was created that automatically punched on Hollerith Punched cards, the Soviet T/P traffic taken on perforated strips with a 5-unit alphabet. Plans were made in the spring of 1944 for machines which were to perform certain calculation tasks such as arose during work on Hagelin machines, that were considered special calculating machines. Buggisch stated that, in short, Ag N/NA had until June 1944, when Buggisch moved to OKW/Chi, no cryptanalytic machine which could be used for the practical solution of any codes or ciphers.
Summary
The major success obtained was the work on the Soviet 5-figure traffic. In the early stages of the Soviet campaign, it was comparatively simple to establish depths in these messages without the use of IBM, but by 1943 IBM machinery was indispensable for location depths. Buggisch stated that the lack of Hollerith machinery spurred the analysts of OKW/Chi to the development of new and better types of analytic devices while the OKH/Chi remained content with the inferior adaptations of IBM machinery. The German Army's general attitude concerning IBM machinery is hinted at in Buggisch's statement that the Enigma could probably be solved by a large enough array of Hollerith machinery, but it never occurred to him, evidently, that such would be contemplated by the enemy.
Towards the end of the war, the Hollerith machinery were outworn, outmoded and irreplaceable. The factories which had been producing parts were bombed out, and as the machines wore out, their work became inaccurate. In some instances, work by machine was abandoned. Mettig cited an example, in late 1944–1945, when In 7/VI, now reorganised as the GdNA, was to provide units below regimental level with signal tables. The values were to be set up by the Hollerith section, but the machine was no longer working correctly. As a result, the trigrams were not being reciprocally enciphered, so other methods of producing them had to be developed. In early 1945, the Hollerith section was offered to OKW/Chi, but Mettig stated that matter was never settled due to the confusion at the end of the war.

German Army cryptanalysis effort 1945

With the establishment of the GDNA in late 1944, all operational cryptanalysis was carried on by sections 2,3,4 of Group IV of the GdNA. There is no record of any new or difficult systems being solved after late 1944. The main effort of the GdNA was apparently directed to the deciphering of systems already solved and to the simple necessity of finding a place to operate. From February 1945 until the capitulation, Group V of the GdNA was constantly on the move seeking refuge in the south from the Allied advance.

German Army cryptographic systems

Training

Liaison

Liaison with the OKW/Chi

The relations of the GdNA and the OKW/Chi were conditioned by a number of important facts.
In 1942, OKW/Chi sent a special Soviet party to the HLS Ost to collaborate with cryptanalysts there in the solution of a Russian 5-figure code. Professor Dr. Peter Novopashenny who was Director of the party returned to Berlin in the autumn of 1943, but his cryptanalysts were absorbed into the unit at HLS Ost.
OKW/Chi also collaborated with the Agents section of OKH/Chi on the solution of Soviet agent traffic. The memoranda of Wilhelm Fenner, chief linguist at OKW/Chi, give a detailed picture of the nature of this collaboration.
On 23 February 1943, Fenner's department was asked by Section III of the AgWNV, i.e. Radio Communication Group 3 to collaborate with the Agents' section of OKH/Chi in work on certain Soviet agents' traffic. By the end of March In 7/VI had furnished Fenner's section with all traffic in that system interceped since September 1941, so that a start was made on solution. Fundamental findings were communicated to In 7/VI, which enabled its Agents' section to break into the system roughly at the same time as did Fenner's group. After the initial solution, however, it was agreed that OKH/Chi should continue the work on this system, while the OKW/Chi started work on another system. From then on, relations became somewhat strained because of the non-cooperative traffic to Fenner's section. The basic cooperation of the two departments, however, is noteworthy.
One of the most striking instances of cooperation between the OKW/Chi and the GdNA and OKH/Chi its predecessors is manifest in the work of the two agencies on Polish Resistance Movement Systems. During the years of 1943 and 1944, the Agents' section of AgN/NA was able to intercept and solve the systems used by the Poles in their traffic with the Polish government-in-exile in London. From this traffic the disposition of the Polish liberation troops as well as the friction between them and the Soviets could be established. The traffic was considered so important that the 8 members of the Agents' section were transferred in the autumn 1943 to the Polish section of OKW/Chi to work on solving the systems. The Plaintext was published by the In 7/VI in bulletins with extremely restricted distribution. The OKH/Chi also cooperated by intercepting this traffic at their own station at Lauf in order to be certain that it was completely covered. Speed in solving the traffic was obtained by having the messages sent to the IBM section of AgN/NA for sorting. The work on Polish traffic thus appears to have been as much a joint project as is possible for two separate agencies to attempt.
Long before the time of official Chi-conferences held by Generalleutnant Wilhelm Gimmler, chief of the Armed Forces Communications Branch , the Army and the Armed Forces, Signal Intelligence Services worked together on security studies of German cryptographic machines and issued joint resolutions concerning their investigations. Among the papers of Dr. Erich Hüttenhain of OKW/Chi are memoranda, describing this cooperation. As early as December 1942, OKH/Chi, OKW/Chi, and Wa Prüf 7 proposed issuing a statement concerning improvements for the teleprinter T-52c to be submitted to the big executive committee Although it is known specifically what is meant by the big executive committee, it is possible that it may have been composed of officials of these same organisations. Throughout 1943, Generalmajor Fritz Thiele, who held the position of Chief of the Army Communications Chief called conferences of representatives of the various services concerning matters of security. Otto Buggisch who worked in OKH/Chi early in the war, was one of the mathematicians of In 7/VI mentions conferences at which Dr. Karl Stein and Dr. Gisbert Hasenjaeger both of OKW/Chi were both stated to be present. The minutes of one of these conferences, dated 13 December 1943, have been published. It should be noted regarding these conferences, they were called by In 7/VI, and was held in the office of that unit at Mathaikirchlatz 4, Berlin. Those who took part were Major Kempe, Fricke, Kehren, mathematicians of OKH/Chi, Hans Pietsch, Döring of AgN/NA; representatives of Wa Prüf 7 and Hüttenhain, Stein and Hasenjaeger, mathematicians of OKW/Chi. From this evidence, it was clear that the later Chi-conferences called by Gimmler in 1944 were only a formal exteriorisation of an already existing relationship. This was the reason that Buggisch and Hüttenhain were able to minimise the efforts of Gimmler. Both observe that the conferences did not foster a closer relationship among the services. The cooperation of Army and Armed Forces had been one of the closest nature for many years, but the collaboration with other services was not improved.
At the formal Chi-conferences and at the official Army-Air-Naval conferences of 1944, the Armed forces could always depend upon the full cooperation of the Army. The completeness of this cooperation is illustrated by the fact that when OKW/Chi was ordered to take over the supervision of all duties of all security studies within the Armed Forces, on the order of Generaloberst Albert Praun, the Army compiled by transferring to OKW/Chi all personnel of In 7/VI and of the security sections of the Mathematical Section of AgN/NA.
In the field of machinery used for general cryptanalysis and security studies, the OKW/Chi and the In 7/VI appear to have informed each other fully concerning their respective developments although no exchange of machinery was made. As early as 1939 to 1940, the mathematicians and former actuaries who had been drawn into OKH/Chi suggested the use of Hollerith equipment for statistical studies. This led to an extensive use of the kit for these types of studies. When the studies were transferred from the In 7/IV to OKW/Chi in 1942, the Hollerith machine kit was developed by the unit for both security studies and cryptanalytic work. It is not known whether the OKW/Chi had its own Hollerith section separate from those of the Army or not.
Mettig and Buggisch both state that it had no Hollerith unit, but had a certain dependency on the In 7/IV unit. It was known later, that OKW/Chi had to build its own custom machinery, as it was unable to obtain sufficient Hollerith machinery. The In 7/IV unit Hollerith kit was used at the request of the OKW/Chi for instance, when for example, the preparation of 3-Letter codes for the use of Army, was performed at the Hollerith unit. In early 1945, the Hollerith unit was offered to OKW/Chi but was never carried out. It was known that the machinery was exceedingly out of calibration, and needing extensive repairs, that were never done due to severe lack of material and resources.
The relations of the OKW/Chi and GdNA could be summarised as complete cooperation. Although the problem domains of the two units were quite distinct, with OKW/Chi dealing specifically with diplomatic traffic, the GdNA with a variety of Army and Hand ciphers and codes, joint problems were dealt with by the two agencies, and in complete accord.
The general lack of collaboration between OKW/Chi and GdNA did not point to lack of coordination at senior administrative function, nor to professional jealously between the two agencies. Essentially the two agencies had two distinct operational foci. OKW/Chi was diplomatic and OKH/Chi was a military agency. Therefore, there was little need for detailed collaboration.

Liaison with the B-Dienst

The Signal Intelligence agency of the Kriegsmarine was B-Dienst of III of the Oberkommando der Marine or colloquially as B-Dienst, appeared to have little liaison with the GdNA and its predecessors. Wilhelm Tranow, the chief cryptanalyst of B-Dienst, stated that the Navy cooperated with the Army until early 1944, but that thereafter the attempt at cooperation was given up since no results of value were obtained.
The collaboration, where it existed, between the two agencies dealt principally with, M-209 and Hollerith procedures. In both instances, it so happened that the Navy received more from the Army than it gave.
As a matter of general policy, B-Dienst High Command disapproved of indiscriminate exchanges amongst the Military cipher bureaux. Lt Müntz stated that the Director of his section Franke, disapproved of contact with other agencies, and maintained contact with OKH/Chi regarding M-209 solution matters, due to it being seen as a security risk. Leutnant Schubert of GdNA stated that he personally could not bring about closer relations between the two agencies.
Wilhelm Tranow of the B-Dienst knew Dr Schauffler slightly and they had once collaborated over Japanese intercepts, but Tranow never had the time to address them.
Tranow later stated that, with the Army, the Navy had few occasions to work with them. Their operational and tactical problem domains were too dissimilar to stimulate effective collaboration. Admiral Karl Dönitz, stated:

Liaison with the Luftwaffe Luftnachrichten Abteilung 350

Before the Luftwaffe established its own Signals Intelligence Agency,, in 1937, the Army fixed Intercept Station, the Feste associated with Army Groups, worked with the corresponding intercepted Air Signals Abteilingen, to intercept traffic. According to Ferdinand Feichtner of the Luftwaffe, the Army did not give air traffic sufficient attention as it was required, and the Luftwaffe became increasingly dissatisfied with the Army's work. In 1936, the Luftwaffe began the formation of its own Signal Intelligence Service, although for three years, it had a close relationship with the Army. Luftwaffe airmen underwent familiarisation training at Feste units and the first Luftwaffe intercept stations were established according to the Army's prototypes. By 1939, the dependence of OKL/LN Abt 350 on the Army was ended.
During the succeeding period relations between the two agencies were particularly good in field operations. This was fostered by such means as unification of signal regulations, a regular exchange of liaison officers, working personnel, equipment, reports, raw traffic and cryptanalytic methods, between the two agencies.
Minutes from a Chi-conference held in October 1944, stated that the OKH/Chi and LN Abt 350 attempted to coordinate their signal regulations. According to the minutes preserved among the papers of Erich Hüttenhain, Generalleutnant Wilhelm Gimmler, Chef AgWNV, stated that one special difficulty in signal communications was the fact that the diverse parts of the Armed Forces used different wireless and cipher phraseology. In response to this, Lt. Col. Schulze of the Luftwaffe stated that by means of far-reaching assimilation of Heer and Luftwaffe regulations, the difficulties arising in those services from different wireless and cipher phraseology would soon be overcome. This attitude of cooperation between the Heer and the Luftwaffe is typical and extended to all echelons.
A regular exchange of liaison officers between the Heer and the Luftwaffe field units was maintained both on the eastern and western fronts. In the west, from 1942, a Luftwaffe liaison officer had been stationed with NAAS 5 of KONA 5 stationed at St. Germain. Major Hentze of KONA 5, stated that the two units worked closely together, and Hentze showed familiarity with the unit there, its complement and its work.
One of the chief duties of the OKH/Chi liaison officer at the Luftwaffe post was to keep the ground situation map up to date from Luftwaffe reports. Of the OKL/LN Abt 350 liaison officer at an OKH/Chi post, among other duties, they passed requests to Luftwaffe for support.
Friendly liaison between commanders and men of units of the Luftwaffe and Heer that were closely associated in the field was a source of contact. Oberst Muegge was commander of KONA 4 and Obsert Rosenkrantz, who was an old friend of Muegge had a Luftwaffe Signals station there. When Muegge moved to Italy in 1943 as commander of KONA 7, Rosenkrantz was also posted to the same location.
Much of the interchange of men and equipment between field units of the Luftwaffe and Heer was caused by the fact that the Heer had no very long distance-finding sets, and depended upon equipment and reports from the Luftewaffe to compensate for this deficiency. Major Franze Oelijeschläger, Chief of III/LN. Rgt. 4, the Signal Intelligence Service of Luftflotte 4 of the Luftwaffe, with about 800 personnel, stated that the KONA regiments willingly detached direction-finding parties to reinforce the Luftwaffe effort and the Luftwaffe was always open to receive Army requests for use of D/F equipment. Muegge told interrogators that as commander of KONA 7 in Italy, he borrowed two Luftwaffe D/F sets with long and short.
The field unit NAA 11 stationed in Finland relied on the D/F reports from the Luftwaffe.
Intelligence of all types were exchanged at every level. Army Group HQ received from the local Luftwaffe office the Immediate Reports, the Daily Reports and the Fortnightly Reports.

Liaison with Pers Z S

There were few examples of collaboration between the GdNA and Pers Z S at the senior administrative level. Dr Otto Buggisch, formerly of Inspektorate 7/VI and later OKW/Chi, gave the only available information to TICOM. Dr Buggisch worked in the French language group in OKH/Chi from November 1941 until August 1942 and during this period he collaborated with Dr Kunze on a five-digit DeGaulle code. He also worked with Kunze regarding the Swiss Enigma General Alfred Jodl, Chief of the Armed Forces Operations Staff stated he did not receive any decodes as they went directly to the Foreign minister, but knew in a general way Pers Z S professionalism and commitment. The general lack of collaboration between Pers Z S and In 7/Vi did not point to lack of coordination at senior administrative function, nor to professional jealously between the two agencies. Essentially the two agencies had two distinct operational foci. Pers Z S was diplomatic and OKH/Chi was a military agency. Therefore, there was little need for detailed collaboration.

Liaison with the Forschungsamt

Liaison between the Forschungsamt and In 7/VI was characterised in general by narrowness of approach and mutual animosity of feeling. This was true, apparently at every level. Generaloberst Alfred Jodl, Chief of Operations of the Armed Forces, told interrogators that he knew little of Hermann Göring's Research Office of the Reich Air Ministry :
Buggisch of In 7 stated that this was because Mettig, Director of In 7/VI from 1941 to 1943, was opposed to the Storm Trooper taint of the Research Bureau. Sauerbier of the RLM/Forschungsamt, claimed that narrowness of the Directors of the Forschungsamt, affected relations of that organisation with other bureaux, including the GdNA.
Whenever liaison did occur, it was via a single representative, and never involved any exchange of visits. Klautsche, who was the RLM/Forschungsamt liaison officer after 1943, maintained an office at the OKW/Chi and passed material to the B-Dienst, Luftwaffe and German Army. Klautsche is said to have passed on intelligence material to the Army General Staff, Western Armies Branch and Eastern Armies Branch.
The lack of contact between personnel of the Forschungsamt and the GdNA was very apparent from interrogations. Fricke, who was a prominent mathematician in OKH/Chi who was later transferred to OKW/Chi, stated that he had never seen any personnel from the Forschungsamt until the war was over and they turned up in prison camps. Kurt Sauerbier of the Forschungsamt stated under interrogation that he did not know a single person in another cipher bureau.
There are a few instances of cooperation between the two agencies, but Otto Buggisch insisted it was very rare. One of the outstanding instances of effective collaboration occurred was when the Forschungsamt was having difficulty with a Turkish diplomatic code. The problem of solution and reading was turned over to OKH/Chi. Traffic was intercepted by KONA 4 in Athens and relayed to the Balkan section, run by Bailovic, where it was solved and read until the capitulation. Solved messages were forwarded to the FA.
Buggisch did state that they were exchanges of results between the FA and the In 7/VI in connection with some work of the FA on a Soviet secret teleprinter in 1943. This was the Bandwurm, the so-called Russian FISH, the Soviet Big machine. The FA had analysed the machine, and recognised that it was similar to the German SZ-40. When the Soviets altered their system, the FA communicated its results to the OKH/Chi mathematical department, Group IV and was given in return, a report on the solution of a German secret teleprinter, probably a version of the T-52 teleprinter. No more details of the incident are known, but Buggisch emphasises the fact that this exchange of results was a very rare occurrence.
Evidence indicates that if under pressure, the Forschungsamt reported to the GdNA and its predecessors for help in intercept solutions, and editing of difficult traffic, but in general held itself aloof and disaffected.

Liaison with Finland

The main Finnish unit was the RTK, the Radio Telepgraf Kompanie. Liaison with Finland was always close, both at HLS Ost, and in the eastern field units. Formal liaison at HLS Ost was maintained by a Finnish liaison officer stationed there, in Giżycko. This officer from 1942 onwards was a Lt. Mikko, and he was succeeded by Oberleutnant Ohn. The Finnish General Staff is said to have passed a copy of the Soviet 5-Figure cipher book to Germany, that was used in the first year of the war. OKH/Chi had a high opinion of Finnish cryptanalysts. Alexis Dettman stated that he had visited Finland in 1942, and had a very high opinion of the cipher bureau. Dettman had exchanged technical letters ever since that time. Liaison in the field is known in some detail from the reports of NAA 11, when it was subordinated to a unit in Finland. The first German Liaison officer to Finland was Hauptmann Johannes Marquart, who would later be Director of Referat Ia of Group IV of the GdNA and was later succeeded by Oberleutnant Riemerschmidt, stationed at Sortavala. Riemerschmidt had a direct link to NAA 11.
Liaison on all cryptographic matters was excellent. The liaison between NAA 11 and the Finns was divided into several types, including traffic liaison, cryptographic liaison and technical liaison. Results were exchanged every two or three days and NAA 11 varied its cryptographic priorities to give full attention to any special links required by the Finns, the request coming via Riemerschmidt. The Finnish crypt personnel were considered outstanding and the exchange of great benefit to NAA 11. Riemerschmidt also passed to NAA 11 information and solutions received at Sortavala from the LNA itself, and on one occasion,, this was faster than the direct transmission from LNA to NAA 11. The Finns solved 3Z and 4Z code extensively with emphasis on NKWD material. The Finns has no success with 5Z traffic and never captured any copies of these codes.
Finnish traffic analysis was rated less highly. It was thought that this was due to the Finnish success with solving codes. Although they had about 20 men in the sector, they did not work systematically nor were they adept at grasping intelligence from the analysis of small amounts of traffic. Thus NAA 11 was able to give more than they got in this respect.
Technical liaison was also handled by Riemerschmidt and was far more helpful to RTK than to NAA 11. Finnish equipment was mostly German, with some British and American receiver units. Germany gave the Finns much advice but no physical help. On one occasion they put their own apparatus and men at the disposal of a Russian offensive, but otherwise there was no pooling or sharing of equipment. Much of the Finnish equipment was pre-1939, and old Marconi D/F equipment.

Liaison with Italy

Liaison between Germany and Italy was negligible as Germany had a complete lack of confidence in the Italians. There was no exchange of information or intelligence when the GdNA was so apprehensive of the Italian Servizio Informazioni Militare, that they thought it not competent enough to institute changes in cipher procedures, even if the Italians desired to do so.

Liaison with Japan

According to all evidence, there was very little liaison between the Army and Japan. In 1943, two Japanese officers visited HLS Ost at Giżycko for about half a day. According to Lt. Alexis Dettmann, of Referat III of Group IV, they were given a polite reception but shown very little of anything and were give no hints as to what solutions the OKH/Chi had reached on Russian traffic. The Japanese officials stated that they had solved the Russian OKK 6 and OKK 7 but just what help they provided the OKH/Chi, on these systems was not mentioned. Buggisch emphatically stated that he had never seen any Japanese in the flesh and knew of no liaison with Japan.
At the end of the war, Germany had decided to send a cryptologic mission to Japan by submarine. Including among the officers were Major Opitz, a German intercept officer, Schubert of HLS Ost and Morgenroth, a B-Dienst cryptanalyst. How little they knew about the Japanese Intelligence agencies is shown by the fact that they did not know whom they were to contact when they arrived in Japan, but were to ask the German Counter Intelligence unit in Japan for further instructions. The plan was not carried out due to the end of the war.

Military