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The GdNA (German language: Oberkommando des Heeres/General der Nachrichtenaufklärung) was the signals intelligence agency of the Wehrmacht, 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 reorganized into the Headquarters for Signal Intelligence (German language: Leitstelle der Nachrichten Aufklaerung) (abbr. LNA) between 1942 and 1944, until it was finally reorganized in October 1944 into the GdNA.[1][2] 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.



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,[3] a common cryptographic test used as part of deciphering of enciphered message, and invented by Solomon Kullback, but only to the first three letters of the word Chiffrierabteilung (English:cipher department). Chi-Stelle, which was also a short hand for Chi, translates to Cipher Department Location.


Key personnel[]

German Army Signal Intelligence Service Chain of Command for Field Organization. 1944-1945

9 July 1945]]

General Erich Fellgiebel 1931–1932 Chief Code and Cipher Section of German Defense Ministry 1931–1932; Chief Signal Officer Army High Command and Supreme command of Armed Forces. General Fellgiebel was killed in July 1944 after attempt on Hitlers life in the failed 20th July plot.

Lieutenant Colonel Mettig was a signals officer who 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. After the war he was considered such a high-value target that he was moved to England to be interrogated by TICOM.

Major General William Gimmler, (German language: Chef Ag WNV) Chief Signals Officer subordinated to Commander in Chief OB West and Chief of the Armed Forces Signal Communications Office.[4] Gimmler was responsible for coordinating all the cryptographic security studies undertaken by German Armed Forces.[5]

Captain Gorzolla, Head of Group III, OKH/GDNA. Liaison office[6] r between the clearing centre of communication intelligence and the Eastern Intelligence Branch.[4]

Lieutenant Colonel Gotthard Heinrici was on the General Staff and Chief Signals officer for OB West.[4]

Colonel Leo Hepp was a member of the General Staff and was Deputy Chief of Army Signal Communication.[4]

Colonel Walter Kopp was a senior communication intelligence officer for OB West.[4]

Major Marquardt was a liaison officer between the clearing centre of communications intelligence, and the Western Intelligence Branch, Army General Staff.[4]

Colonel Muegge was a communication intelligence officer for an army group.[4]

Colonel Kunibert Randewig was commander of intercept units with various army groups.[4]

Lieutenant Colonel Hugo Seemueller was a communication intelligence officer for several army groups.[4]

Major 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 professionalized,[7] In 1939, he was posted to Army Group Southeast (German language: Heeresgruppe Südost) to take up the office position of Chief of Intelligence Evaluation in Athens, Greece.[8] In 1944, following the reorganisation of the Wehrmacht signals intelligence capability, Fritz Boetzel, now General Fritz Boetzel created 12 Communications Reconnaissance Battalions in eight regiments, with each regiment assigned to a particular Army Group.[9] Fritz Boetzel was considered to be one of the sources for the Lucy spy ring.[7] 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.[7]

Major Major Mang.

Colonel Hugo Kettler

Baron Colonel Rudolf Von Der Osten-Sacken



Little was known about the Signals Intelligence of the German Army during this period. A Codes and Ciphers Section of the German Defence Ministry (German:Reichswehrministerium Chiffrierabteilung) was subordinated to an Army Signal Officer, that had been maintained in skeleton form since the end of World War I.[10] 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 (German:Feste Horstelle) abbv. Feste, and at least seven stations were operating before 1933 in military districts.[11] The second intercept branch was the motorized Intercept Companies (German:HorchKompanien), created by Fellgiebel himself. Six of the stationary intercept stations was 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, Muenster, Koenigsberg, Leignitz and Breslau[12] with the diplomatic traffic intercept station located at Treuenbrietzen.[13] 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 Koenigsberg and Frankfurt, and so on. The assignments were established in the Assignment Plan H-Aufgabenplan. Each assignment was prioritized from 1st to 4th, sometimes absolute, sometimes relative, e.g. Poland was assigned 1st for Frankfurt/Oder stations and a 1st or 2nd for Koenigsberg. Priority could change depending if a country went to war.[12]


During the 1933–1934 period, the Defense Ministry created three more intercept stations: one Feste was at Hersbruck, (that was later moved to Lauf[14]) with the other two located at Striegau and Chemnitz.[15] 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 (HLS) (German language: Horchleitstelle) in 1933/34.[16][17] 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.[18] Diplomatic intercepts were sent to both German War Ministry (German language: Reichskriegsministerium) and to Foreign Office civilian cipher bureau AA/Pers Z S.[11]


Inspectorate 7 Group VI Typed Organisation chart, Autumn 1941, typed by CSDIC 9th July 1945

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

  1. The intercept service mission was narrowed to include only Army Traffic. With the formation of OKW/Chi, the signals intelligence agency of the Supreme Command of the Armed Forces, in 1939, OKW/Chi took over all diplomatic intercept traffic. To help facilitate message interception, the Army transferred two interception stations at Lauf and Treuenbrietzen.[19]
  2. The intercept service expanded. In 1939, the Army established two new branch stations for the intercept of foreign Army communications from the east. The branch stations were created as Graz and Tullin.
  3. Five new Signal Intelligence Regiments (German:Kommandeur der Nachrichtenaufklärung, abbr. KONA) were created.[14] The KONA operated in the theatre as complete intercept and evaluation units, while attached to Army Groups, (e.g. Army Group A).[20] Each KONA unit was numbered from one to five. KONA units 1,2,3 were assigned to the Eastern Front. KONA 1 was assigned to the southern front, KONA 2 to the Central front and KONA 3 to the Army Group on the Northern Front. KONA 4 was not attached to any Army Group, but was subordinated to the commander of the German Armies in the Balkans (German:Befehlshaber Suedost).[21]
  4. KONA 5 was assigned to Army Group B on the Western Front.[22]
  5. In 1939, to cope with the increased demand and difficulty of decryption of enemy Army traffic, a large number of mathematicians and linguists were drafted and assigned to various field units, or intercept stations.[20] When intercept units moved into the field in 1939, no cryptographers were available. Colonel (German:Oberst) Kunibert Randewig, was a veteran of pre-war monitoring of Soviet Union wireless traffic.[23] As commander of all the intercept units in the west, he was tasked with seeking available personnel. Those cryptographers which were available from Y Units around Berlin were reassigned with additional linguists and mathematicians recruited as necessary. As a result, when the German Offensive started in April 1940, a sufficient group of cryptanalysts personnel were available [20]
  6. The Army showed an increased interest in the security of their own key systems. This gave rise, via a concentration of personnel, to a new agency, a math referat[24] that was created in 1939/40, Army Signal Security Agency es Group IV of Inspectorate 7 (abbr. 7/IV). This was subordinated to the Chief of Army Equipment and Commander of the Replacement Army (German:Chef de Heeresriestung und Befehlshaber des Ersatxheeres) (abbr. Chef H Ruest u. Bde). The unit initially had about a dozen mathematician including Dr Hans Pietsch, Steinberg, Friedrich Böhm, Dr Herbert von Denffer, Hilburg, and Dr Hans-Peter Luzius. Most of these were drawn from the statistical offices of insurance companies. Dr Otto Buggisch had his first contact with the group at the end of 1940[25] The group was loose at first, as men could be detached for specific projects in security work, but over time the work gradually split into three functions. This was General Theory – Referat F under Denffer, Hand ciphers under Oblt. Lüders and machine systems with the heading, Referat 13 commanded by Wachtmeister Doering.[25] The German Army Signal Intelligence service in 1939 consisted of the following parts:
    1. At least 10 intercept stations for the interception of foreign traffic (German: Feste Horchstellen, abbr. Feste).
    2. Five Signal Intelligence Regiments (KONA) attached to Army Groups.
    3. An Intercept Control Stations (German: Horchleitstellle) for the evaluation and analysis of foreign Army traffic.
    4. An Army Signal Security Agency, Inspectorate 7/IV for testing and issuing codes and ciphers for the Army.


Inspectorate 7 Group VI Typed Internal Organisation chart, Spring 1943, typed by CSDIC 8th July 1945. Note: War Office Code was a British Cypher.

During the middle of war, the small staff of the intercept and listening stations (German language: horchleitstelle) 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 that was designated as Inspecktorate 7/VI or more simply In 7/VI. It was also commanded by the Chief of the Army Equipment and Commander of the Replacement Army (German language: Chef der Heeresruestung und Befehlashaber des Ersatzheeres Inspektion 7 Gruppe VI). 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 (German language: Leitatelle der Nachrichten Aufklaerung) (abbr. LNA).

Gruppe VI of In 7 (In 7/VI) was organized 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.[26] 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.[26] The cryptographic section would eventually become independent[26]

During the first months of the unit, Russian cryptanalysis was conducted as part of the operational schedule 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.[26] This group would eventually become the nucleus of the organisation: Intercept Control Station East (German language: Horchleitstelle Ost) (abbr. HLS Ost) for Russian 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 In 7/VI and LNA.

In 1942, the responsibility for security testing of existing German Army cryptographic systems had been transferred from In 7/IV to In 7/VI[27] 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.[28]

In the autumn of 1943, In 7/VI 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 (German language: Oberkommando des Heeres/Allgemeines Heeres Amt/Amtsgruppe Nachrichten/Nachrichten Aufklaerung) (abbr. OKH/AHA/AgN/NA). Minor changes in internal organisation were affected, but the function and operation of the agency was not changed.[29]

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 (1,2,3) were supplemented by the addition of KONA 6, which was formed to cover the German campaign in the Caucasus.[30] 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.[31]

The organisation of the German Army Sigint Service in 1944 consisted of the following:[32]

  1. A central cryptanalytic agency for non-Russian traffic: In 7/VI, later AgN/NA.
  2. A central evaluation agency for non-Russian traffic: LNA.
  3. A central cryptanalytic and evaluation agency for Russian traffic: HLS Ost.
  4. Seven Signal Intelligence Regiments (KONA).
  5. An Army Signal Security agency for the distribution and development of Army systems: IN 7/IV.


AgN Nachrichten Abteilung Typed Internal Organization chart, Summer 1944, typed by CSDIC 8th July 1945

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 (later AgN/NA), 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.[33]

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 centralized control in matters of administration and signal intelligence policy.[33] 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,[34] and a Senior Commander of the Signal Intelligence (German language: Hoeherer Kommandeur der Nachrichten Aufklaerung) (Abbr. Hoeh Kdr d NA) was created to coordinate and control KONA 5 and KONA 6.[33] 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.[35] A captured document[36] indicated that KONA 4 had been succeeded by a signal battalion, (German language: Nachrichten Aufklaerung Abteilung) (Abbr. NAA) 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:

  1. The Signal Intelligence Agency of the Army High Command (OKH/GdNA), a central cryptanalytic and evaluation agency for all traffic.
  2. A Senior Commander of the Signal Intelligence (Hoeh Kdr d NA) with control over the KONA stationed in the west and responsibility for all the Signals intelligence activities of the German Army in the west.
  3. 9 Signal Intelligence Regiments (KONA) which were attached to Army Groups or Commanders in the field.

Organisation of central agencies[]

Intercept Control Station[]

Before the war, cryptography in the German Army was carried out by OKH/In 7 Listening Position (German language: Horchleitstelle) (Abbr. HLS). 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 which was commanded by Major Dr. Jung.[16] It had a number of fixed intercept stations: Fixed News Service (German:Feste Nachrichten Aufklaerungsstelle) (Abbr. FNAST or Feste). These were staffed by a skeleton organisation and were working to monitor the traffic of neighbouring states.[37]

Inspectorate 7/VI organisation[]

In Autumn 1941, Inspectorate 7/VI was headed by Major Mang, and was divided into the following sections:[38]

Inspectorate 7 / Group Vi Commanded by Major Mang
Function Name Responsible Personnel
Referat Z Captain (German language: hauptmann) Herbrüggen
British Referat Senior Inspector (German language: OberInspektor) Zillman, Senior Inspector Liedtke
French Referat Senior Inspector Kuehn
Italian Referat Captain (German language: Hauptmann) Dr Fialla
Balkan Referat Superior Government Councillor (German language: Regierungsrat) Dr Rudolf Bailovic
Russian Referat War administration inspector (German language: Kriegsverwaltungsinspektor) Oberleutnant Alexis Dettman
Mathematical Referat Oberleutnant Otto Lüders, Special leader (German language: Sonderführer) Dr Hans Pietsch
Linguistic Research Referat Special leader (German language: Sonderführer) Köhler
Training Referat Senior Inspector Kühn

Between 1941 and 1943, the following changes in In 7/VI took place:

  1. The Russian Referat was sent to Loetzen, East Prussia[39]
  2. A Referat for cryptanalysis of USA systems was formed with the entry of the USA into the war on 7 December 1941.[40]
  3. A Referat for cryptanalysis of traffic of agents (foreign and internal) was added in 1943.[41]
  4. The investigation of the security of the current German Army systems was transferred from In 7/VI, the former Army Signal Security Agency, to the mathematical Referat of In 7/VI.[27]
  5. An IBM Referat together with its machinery from In 7/IV was added[27]

In the spring of 1943, In 7/VI organisation was as follows:

Inspectorate 7/ Group Vi Commanded by Major Mettig
British Referat Senior Inspector (German language: OberInspektor) Zillman
USA Referat Senior Inspector Dr Steinberg
Balkan Referat Superior Government Councillor (German language: Regierungsrat) Dr Rudolf Bailovic
French Referat Senior Inspector Kühn
Italian Referat Corporal Manaigo
Mathematical Referat Special leader (German language: Sonderführer) Dr Hans Pietsch
Linguistic Referat Special leader (German language: Sonderführer) Köhler
Training Referat Senior Inspector Kühn
Agents Referat Oberleutnant Vauck
Hollerith Referat Special leader (German language: Regierungsrat) Schenke

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;[42] 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.[43] 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 In 7/VI. In 7/VI was thereupon moved to Jüterbog, where it was located until its amalgamation in November 1944 into GdNA.[44] 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 (German language: Amtsgruppe Nachrichten/Nachrichten Aufklaerun) (Abbr. AgN/NA), the internal organisation was changed. The previously independent sections were organised into a main section (German language: Hauptreferat) 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 In 7/VI. The organisation of AgN/NA is as follows:[45]

Chief of Unit Major Lechner
Main Referat A for Mathematics Lüders
Main Referat B for Languages Rudolf Bailovic
British Referat Zillman
United States Referat Steinberg
French Referat Hans Wolfgang Kühn
Balkan Referat Rudolf Bailovic
Swedish Referat Pfc Rohden
Linguistics Cryptanalysis Referat Kohler
Training Referat Hans Wolfgang Kühn
Hollerith Machinery Referat Schenke

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 (German language: Leitstelle de Nachrichten Aufklaerung) (Abbr. LNA) had sections for evaluating British, USA, Italiam, 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 In 7/VI. This unit size of the LNA was small, and consisted of 75 military personnel.[46]

HLS Ost[]

The Intercept Control Station East (German: Horchleitstelle Ost) (Abbr. HLS Ost) 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 organization, as defined below:[47]

HLS Ost organization in late 1944
Referat Z Administrative
Referat 1 Supply, maintenance, evaluation of captured documents and general research into wireless procedures
Referat 2 Evaluation, compilation of intercept situation report.
Referat 3 Russian cryptanalysis section
Referat 4 Monitoring of inter-Soviet State traffic; Russian radio broadcasts and Reuters and Tass News Agency broadcasts

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 Hitlers life and committed suicide.[47]

Signal Intelligence Agency[]

The three agencies, In 7/VI (lattery AgN/NA), HLS Ost and LNA were amalgamated in November 1944, into the Signal Intelligence Agency of the Army High Command (German:Oberkommando des Heeres, General der Nachrichten Aufklaerung) (Abbr. OKH/GDNA) almost intact.[48] In 7/VI has 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:

Signal intelligence organisation in November 1944
Referat Z Moved into Group Z
Referat 1 (Miscellaneous) Moved into Group V (Miscellaneous)
Referat 2 (Eastern Front Evaluation) Moved into Group III (Eastern Front Evaluation)
Referat 3 (Russian Cryptographic Section) Moved into Group IV (General Cryptographic Section)
Referat 4 (Intercept Service on Soviet Traffic) Moved into Group VI
Group I Wireless and news agency joined Group I

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.[49][50]

  • Headquarters Unit. The HQ unit of OKH/GDNA, was managed by (German language: oberst) Colonel Fritz Boetzel, his (German language: oberstleutnant) Chief of staff, Lieutenant Colonel Andrea, the (German language: Oberleutnant) Adjutant Lieutenant Moravec and staff officer Lieutenant (German language: leutnant) Koebe. As well as all staff being subordinate to the unit, the unit also controlled two intercept stations, Feste 6 and Feste 11 (KONA Unit), who specialized in intercepting high frequency traffic of the Red Army and the NKVD[51] The officers and men of the unit supervised the intercept traffic requirements of the KONA units and their subordinate units, directly in the case of KONA 1, 2,3,7, and 8, and through the Senior Commander of Signal Intelligence (German:Hoeherer Kommandeur der Nachrichten Aufklaeruns) (Abbr: Hoeh, Kdr. d NA) for KONA 5 and KONA 6.[51] In October 1944, the HQ was run by Lieutenant Colonel (German language: oberstleutnant) Andrea, Chief of Staff was Colonel (German language: oberst) Köbe, with Group Z being run by Major (German language: Hauptmann) Hüther.[52]
The authority of the staff was exclusively in matters of intelligence policy and did not extent direct to intercept units in the field. It could however liaise with these through the unit staff. The final responsibility for policy, issue of intercept reports and allocation of work within the groups lay with staff HQ.:[52]
  • Group (German language: Gruppe) I: This unit was directed by Amtmann Bodenmüller and was responsible for two main tasks:
  • The first task was the maintenance of communications between the units of the GdNA.[52]
The signals officer of the group, Inspector Strahlendorf was in charge of a wireless centre and a teleprinter centres of a network connecting to the outlying units of the HQ. Teleprinter was the preferred method of communication unit the end of the war, when radio was used. In the middle of April 1945, a plan was evolved for creating wireless stations in occupied parts of Germany for intercept purposes. Comms with these stations was to be maintained by the wireless centre of the GdNA. The plan was abandoned. Personnel employed by the comms unit were almost exclusively women.[52]
  • The second was wireless monitoring. This section was known as Radio Reception Point (German language: Ic Rundfunkempfangstelle) and was commanded by Wm Pretterebner. This unit had four subsections:
  • Referat Ia: The broadcast monitoring East (German language: Rundfunküberwachung Ost) unit monitored eastern wireless.[52]
Owning to personnel shortage its efforts were restricted to monitoring the Moscow wireless. Latterly, a certain amount of Balkan monitoring was instituted particularly for Turkey and Romania
  • Referat Ib: The broadcast monitoring West (German language: Rundfunküberwachung West) of western wireless.[52]
Due also to personnel shortages this unit only monitored the BBC London Service.
  • Referat Ic: The Plain text monitoring (German language: Helldienst) unit.[52]
This unit was responsible for the intercept activity which concentrated on the Reuters agency.
  • Referat Ic: An evaluation section.
This section was responsible for collating all information from the other three sections and consolidating it into reports. The collated reports were divided into separate parts for political, economic or military news. They were circulated within the departments of the Army High Command (OKH), sometimes with the classification TOP SECRET (German language: German:Geheimkommando-sache) (Abbr. GKdoS). Special news flashed on items of urgent importance were also issued.[49][52]
  • Group II: This unit which was known as End Evaluation (German language: Endauswertung) was commanded by Major Thiel. Formally group II was known as LNA West and was located at the Zeppelin bunker near Zossen, and had a personnel count of around 50 people, producing radio situation reports correlating the information from KONA 5, KONA 6 and KONA 7. Captain Thiel, who was head of this group, had been with the LNA for a long time, and was thoroughly familiar with the problems of western evaluation.[49][52]
  • Group III: Captain (German language: Hauptmann) Gorzolla was responsible for this unit, and was known as final results east, (German language: Endauswertung Ost) This unit undertook evaluation of intercept traffic and cryptanalytic work emanating from Eastern European Front, e.g. Soviet Union.
With the HQ of Group III, there was a special receiving office through which all messages emanating from the forward intercept units and fixed stations were passed. At the reception office, the unit originating the message was identified by the call signs used. Undecipherable messages were thence passed immediately to Group IV for deciphering and messages which were already in plain text were passed to the special evaluation sub-sections according to the nature of the traffic. In addition, deciphered messages were passed back from the Gruppe IV through the reception office for evaluation. The head office of Groupe III kept a central card index in which call signs, cipher indicator groups and contents of messages were registered.[52]
The department was subdivided into the following sections:
  • Referat IIIa: Traffic Sorting Office.
  • Referat IIIb: Northern Sector Evaluation.
  • Referat IIIc: Central Sector Evaluation.
  • Referat IIId: Southern Sector Evaluation.
  • Referat IIIe: People's Commissariat for Internal Affairs (NKVD) Evaluation
  • Referat IIIf: Partisan traffic evaluation
  • Referat IIIg': Swedish traffic evaluation
Sources of information for the evaluation unit were call signs, cipher indicator groups and D/F reports. Using these it was possible to establish a detailed order of battle. Surnames were considered an exceptionally valuable source of intelligence since they were used so infrequently in Russian traffic dealing with promotion and transfer. Surnames about Major were tracked in a card index. The evaluation of NKVD traffic was equally valuable since reinforcements and movements of NKVD traffic normally indicated similar movements in the Red Army Field Army. The also gave a good indication of lines of communication. Partisan traffic was also intercepted, for appropriate countermeasures.[52]
  • Group IV: Major Rudolf Hentze was responsible for all cryptanalytic work done at GdNA. It was one of the largest groups within the GdNA, having been built up from parts of the three former agencies: The defunct In 7/VI, LNA West at Zossen and the HLS East at Lötzen.[52] The HLS East group, which operated in Loetzen, East Prussia, during 1942–1944, intercepted Soviet teletype transmissions. This unit was captured wholesale in May 1945 in Rosenheim, Germany, by the Allies, and transported by TICOM and put to work so their methods could be evaluated. The Allies then either directly copied the German equipment, or built similar models and used them to intercept the internal Soviet network traffic.
The unit was divided into separate Referate according to the origin of the material. Material dealt with in the Group IV, consisted of traffic which the forward intercept units had intercepted but had been unable to decipher. A certain amount of special traffic was also intercepted by the Feste attached to the GDNA.[52]
  • Referat I: The mathematician, Dr Hans Pietsch was responsible for the unit. It was responsible for analytical research. It was the former Mathematical Section of In 7/VI. It was responsible for the security of German Army Systems.[52]
  • Referat Ia: The subsection was headed by Johannes Marquart, was engaged in research on German Army hand cryptanalytic systems.
  • Referat Ia: This subsection was managed by Dr Pietsch handled research on German Army machine systems.
  • Referat II: Headed by the mathematician Dr Alfred Kneschke, it dealt with the cryptanalysis and deciphering of non-Russian traffic. It had three sub-sections:
  • Referat IIa: Cryptanalysis and decoding of British and USA systems.
  • Referat IIb: Cryptanalysis and decoding of French systems.
  • Referat IIc: Cryptanalysis and decoding of Balkan systems.
  • Referat III: This subsection was managed by Lieutenant Alexis Dettman. The section was composed of the cryptanalytic sections of HLS Ost. It dealt with the Russian systems and had four sub-sections:
  • Referat IIIa: Cryptanalysis of NKVD traffic.
  • Referat IIIb: Cryptanalysis of Russian army traffic.
  • Referat IIIc: Cryptanalysis of Partisan traffic.
  • Referat IIId: Cryptanalysis of Russian systems.
  • Referat IV: This unit was the former Hollerith machinery section of In 7/VI. This section performed mainly statistical work. Most of the members of the unit were women used to run the machinery. The section maintained its own repair shop for the machines.
  • Referat V: This unit was the training department of the GdNA where cryptographic and cryptanalytic courses were given under the direction of Inspector Kuehn, who had headed the Training section of In 7/VI. During the last months of the war, the once flourishing section dwindled to a group of 40 students every three months.
  • Group V: This unit was commanded by Amtmann Block. It had a fair wide field of activity. It had a mixed group containing three referat all of which carried out unrelated work.[52]
  • Referat I: This section was named (German language: Beutcauswertung OST) headed by Inspector Zipper, and was engaged in reconstructing Russian, British and USA call signs and call signs systems, and deducing units therefrom. It covered various procedures of enemy wireless traffic and the allocation of wave lengths.
  • Referat II: This section managed specifically by Amtmann Block was responsible for the exploitation of captured Russian documents and manuals of signals interest. Captured manuals were translated and descriptions of Russian equipment examined. By April 1945, the Referat II had completed an up-to-date booklet on Russian abbreviations, which was ready for publication. This book was to have been made available to all forward intercept units.[52]
  • Referat III: This section had two tasks. The first was engaged in supplying the KONA signal intelligence regiments with the necessary intercept equipment and in maintaining a workshop to service the needs of the GdNA HQ itself.
  • Group VI: This unit was located in Potsdam under Captain (German language: Hauptmann) Roeder, and was responsible for intercepting and evaluating special high-grade machine systems.
  • Referat I, with three sub-sections, handled Russian Systems:
  • Sub-Section Ia: This section was responsible for interception and evaluation of Inter-Soviet State traffic, picked up on Baudot traffic.
On the basis of this, the (German language: Wehrwirtschaftsnachr) (Abbr. WWN) bulletins were compiled. These bulletins gave a detailed summary of Russian economic situation, particularly in the areas of Moscow, Baku, Rostov and included production figures and details of supply and labour conditions. About 30 copies of this report were issued. Detailed card indexes were kept, which included names and locations of factories and personalities therein.[52]
  • Sub-Section Ib: Interception and evaluation of Russian Baudot.
The unit consisted of two cryptographers who undertook research into the cipher machines employed for Baudot traffic forward of GHQ Moscow. They also assisted Referat Ic in preliminary evaluation.[52]
  • Sub-Section Ic: Interception and evaluation of Russian Army traffic.
This section picked up Inter-Soviet and Red Army Baudot traffic and dealt with the preliminary evaluation of Ref Army Baudot traffic. Based on this analysis, a situation report was brought out, giving the Order of Battle, personalities, frequencies, call signs and cipher indicator groups used in the traffic. This was passed to Group III for evaluation. Referat Ib carried out joint initial evaluation.[52]
  • Referat II had two sub-sections. Inspector Heller was responsible for this unit.
  • Sub-Section IIa: Interception of western teleprinter and automatic morse traffic intercepts.
  • Sub-Section IIb: Evaluation of the intercepts from section 2a.
  • Group Z: This unit was responsible for general administrative control of all departments with OKH/GdNA. The work was divided into four types:
  • Personnel: A central card index was kept for all personnel employed with the GdNA. The unit was also responsible for all transfers, either interdepartmental or outside the unit.
  • Registry Office (German language: Registratur). This communications unit registered all incoming and outgoing correspondence and was responsible for all courier communications between HT General GDNA and its outlying subordinate units. For local communications, the registry had its own runners, but for long distances, the courier services of the Army High Command (OKH) were used. In addition, the Registry Office duplicated some reports for the individual groups.
  • Paymaster. All of OKH/GdNA were paid by this section.
  • Drawing. This unit managed the production of situation maps and maps of WT radio networks were produced. Mimeograph and Bookbinding activity was also carried on here.[52][53]

Signal intelligence operations[]

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.[37]


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 (Finnish radio intelligence). That particular code was used by the Russians in the first year of the war with Germany in 1939.[37]


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.[37]


Continuous and significant successes were obtained against the French (Deuxième Bureau) 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.[37]


Very little success was obtained in the reading of British cyphers before the war, principally due to the low quality of the personnel involved.[37]

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. It should be noted however, that whereas 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 (abbr. D/F) information, and the evaluation of call-signs and other items of the wireless traffic procedure.[54]


In 1939, In 7/VI cryptanalysed the mobile cipher which had replaced the peace-time 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.[20] 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.[20]


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.[20]

German Offensive May–June 1940[]


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 and the C-36.[20] 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.[20]

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.[20]

Supplies of cryptanalysts in the west 1939 to 1940[]

When the forward intercept units moved into the field in 1939, no crytanalysts 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 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.[20]

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.[55] 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.[55]

In general, the object of In 7/VI 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.[56][57] To this end, the Russian Referat of In 7/VI 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 (German language: Oberleutnant) Seebaum and Commander of Signals Troops (German language: Kommandeur for Horchtruppen 4) 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.[55]

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 (abbr. OKW/Chi), 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.[55] 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.[55]

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.[55]

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.[55]

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 (German language: Nachrichtenaufklärung Abteilung/ Chief of Heeresrüstung und Befehlshaber des Ersatzheeres abbr(Chef H Rüst U BdE)) was created in Berlin during November 1941.[55] 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.[58] 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, Dr Hans 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 has morphed into the OKH/GDNA, it had been specifically banned from intercepting and attacking German traffic as a security precaution.[58][59]

The main investigation carried out by the Mathematical Referat was a continual enquiry into the security of the main German cipher machines: Enigma machine.[58] 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.[58] 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(abbr. WT) 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 [58] 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 captured Polish cryptanalysts to check this point. No positive confirmation was achieved.[58]

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 (an experience which resulted in the daily cipher, which at the beginning of the Russian campaign was very heavily burdened, being split up into two or three portions). 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.[58]

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 (German language: Kriegsverwaltungsinspektor) 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.[39] 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 (NAAS) 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 on In 7/VI.[39] 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.[60]

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.[60]

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.[60]

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.[60]

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.[60] 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 recognize, from other evidence, which British procedures has 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 (Feste) 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.[60]

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.[60]

Intercept station operations[]

Intercept station operations 1923–1933[]

Assignment of intercept coverage from 1923 to 1933 was made by the Code and Ciphers of the Defense Ministry (German language: Reichwehrministerium Chiffrierabteilung). The division of intercept tasks was established on a geographical basis. The Munich outstation intercepted traffic from Italy, which included the Italian colonies, Yugoslavia, Romania, Hungary, Austria, and Czechoslovakia. The Stuttgart outstation monitored France, including her colonies, Belgium, the Netherlands and Spain. Münster intercept outstation monitored England including colonies and Dominions. The intercept station at Königsberg intercepted Russian traffic. The Breslau intercept station monitored communications traffic from Polish, Czechoslovakian and Russia. The Liegnitz had twice the personnel of the stations.[61]

The personnel of each intercept station consisted of one officer, who was Chief of the station, one radio mechanic, eighteen or twenty Non-commissioned officers and six or eight civilian employees used as clerks, administrators, interpreters and couriers. In 1933, five technicians were added to the personnel. Major Feichtner of the Luftwaffe (German Air Force), Air Signals Regiment 352 (LN Regiment 352), stated under interrogation that these units had no tables of organisation (Order of battle), their personnel being detached from signal battalions and signal platoons of the Infantry and Cavalry. Not until 1932 did the Fixed Intercept Stations (German:Feste Horchstelle) (Abbr. Feste) receive their tables of organisation. Only the finest and most experienced radio operators of the signal battalions and platoons were accepted as intercept operators. The chief of an intercept station, by having the direct support of the Reichswehr Ministry, was certain always to receive the best qualified personnel.[62]

The material intercepted daily was studied by the traffic analysis section, bearings obtained on the stations involved and the results incorporated into a daily traffic analysis report, which was called N.B. – Meldung. All Wireless telegraphy (Abbr. W/T) intercept messages, where the keys were known was done directly at the intercept stations. The contents of the decoded messages were then evaluated. All W/T messages which could not be decoded by the intercept stations (e.g. all diplomatic messages) were sent daily to the Chi-Stelle in Berlin, where they were worked on by a larger and more specialized cryptanalytic staff of the Reichswehr.[63] The Chi-Stelle in Berlin was divided into various sections, each headed by a section leader. The sections or desk each dealt with an individual country. In one instance, when the maneuvers of one of the large foreign powers were being monitored, the head of the desk dealing with the country in question was sent to the appropriate intercept station for the duration of the maneuvers.[63]

The first real military activity that the Munich intercept unit undertook was the monitoring of the Rif War that was fought between 1920 and 1926. The deployment and operational tactics of the Spanish and French were learned in details through the decoding of wireless messages, with the Weimar Republic supplied with regular intelligence reports. In recognition of the excellent performance of the Munich intercept station, its chief was given leave to pursue technical studies at the expense of the state.[64]

Major Feichtner made it clear, that the period prior to 1933 was one of training for the German intercept units.

Intercept station operations 1933–1939[]

In 1933, the OKH assumed general control of the intercept organisation[16] and the Intercept Control Station (HLS) (described above), directed intercept coverage. A program of expansion and improvement was instituted, with the creation of three new fixed intercept stations at Striegau, Hersbruck and Chemnitz.[65] All intercept stations were improved. By 1934, for instance, each had its own building outside city limits where it was free from electrical interference and each was equipped with the latest technical improvements.[66] In 1935, the first mobile Signal Intelligence Companies were activated, and populated from Signals Corps recruits. Officers, NCO's and privates from the fixed intercept stations acted as instructors[67] In selecting this new military personnel, no consideration was given to an individuals background; the only requirement was a certain degree of intelligence. Many difficulties resulted, which had repercussions through the entire German Signal Corps. This policy continued for an excessively long time, around 2 years, in order to bring the companies up to strength. The lack of technically trained personnel, especially amongst the officers remained one of the greatest deficiencies of the German Signals Intelligence units, right up until the end of the war.[66]

At that time, the Army was intercepting all Army, diplomatic and Air Force traffic. The Army traffic was sent for analysis to the Army cryptoanalytic and evaluation agency,[16] the Intercept Control Station (HLS) at Berlin. Diplomatic traffic was passed either to the Codes and Ciphers Office of the Reichswehr before 1935 and later the same office at the Wehrmacht, or the Pers Z S.[68] Technical Sergeant Karl Jering of the Signals Corps of the Air Force High Command, (Order of Battle OKL/LN Abt. 350) noted during his tour of duty, that during this period, the Army intercepted and evaluated foreign Air Force traffic, but he observed time and time again that far less importance was given to the monitoring and evaluation of Air Force traffic, than it gave to ground force traffic.[69] The Air Force was becoming increasingly dissatisfied with the Army intercept work and in 1935, began to organize its own Signals Intelligence Service. For three years however, between 1935 and 1938, the Air Force maintained close relations with the Army. Air Force employees underwent familiarization training at Army Fixed Intercept Stations and the Air Force radio intercept stations, (German language: Wetterfunkenpfangstelle), (W-Stellen) were created according to the Army prototypes[70] By 1939, the break between the Signals Intelligence Service of the Army High Command, and of the Air Force High Command was complete.

At this time the Supreme Command of the Armed Forces, the Oberkommando der Wehrmacht (Abbr. OKW), also created its own intercept service for diplomatic traffic. The Army gave to the OKW two of its intercept stations, Lauf and Treuenbrietzen for the interception of this traffic.[71] From this period on, the Army intercept service confined itself exclusively to the interception of foreign Army traffic.

Intercept station operations 1939–1944[]

Before 1939, the German General Staff has placed very little emphasis upon intercept in the field. Nearly all intercept has been carried out by Fixed Intercept Stations (Feste), With the approach of mobile warfare, however, Germany Army intercept operations also became mobile. The new emphasis on field intercept resulted in the establishment of Signal Intelligence Regiments (KONA, whose mobile component parts were designed to work with units of the Army Group to Army Corps level). The adaption of the KONA regiments to meet the needs of the Field Army was one of the chief accomplishments of the Army signal intelligence service.

Control of intercept coverage 1939–1944[]

German Army Signal Intelligence Regiment Operations Diagram – Based on KONA 1

Control of intercept coverage during the war stemmed from the Intelligence Officers of the Eastern Armies Branch and the Western Armies Branch[72] As Alfred Jodl stated:

these officers were thoroughly familiar with the general signal intelligence picture[72]

The chain of command was very clear during the last year of the war. The Intelligence officers of the Eastern Armies Branch and the Western Armies Branch briefed the chief of the Understaff of OKH/GdNA, who had control over all the KONA regiments and who issued to them their directives for intercept coverage.[51] In the west, the Understaff worked through the Senior Commander of Signal Intelligence, (German language: Hoeherer Kommandeur der Nachrichten Aufklaerung) (Abbr. Hoeh Kdr d. NA) whose function it was to coordinate the intercept coverage of KONA 5 and KONA 6.[51]

With the other KONA, the chain of command from the Understaff was direct. The Signal Intelligence Evaluation Centre (NAAS) issues the directives for intercept coverage to all units subordinate to the KONA.

In 1941 to 1944, previous to the establishment of the GdNA organisation, the chain of command appears to have been the following:

  • Non-Russian intercept coverage was distributed by the Western Armies Branch through the Control Station of the Signal Intelligence of the Army High Command (OKH/LNA)[73]
  • Russian intercept was directed by the Eastern Armies Branch through the Intercept Control Station East of the Army High Command (OKH/HLS Ost)[47]

Assignment of intercept coverage[]

Assignment of intercept operations was established on a geographical basis; either eastern, south-eastern, western, southwestern. From the beginning of the war eastern, interception was given high priority and KONA 1,2,3 were assigned to eastern coverage. In 1942, KONA 6 and in 1944 and 1945, two other KONAs, KONA 8 and KONA Nord were formed also for the interception of eastern traffic[74] In addition, eastern interception was carried on by three independent Stationary Intercept Companies, Feste 7, Feste 8, 11 and one Long Range Signal Intelligence Platoon, Faz Nord. After 1942, new monitoring of eastern traffic was also done by the Intercept Control Station East (HLS Ost)[75] In contrast, southeastern, western and southwestern interception were covered by one KONA regiment apiece, with one central monitoring agency for all three areas, the Control Station for Signal Intelligence (LNA).

Eastern intercept[]

Order of Battle Hierarchy of signal intelligence intercept units on Russian front on 1 January 1945. Original Diagram created by Lieutenant Colonel (German language: Oberstleutnant) Mettig

The mission of all eastern KONA regiments was the interception and evaluation of Russian Army, Air Force and Partisan traffic. Their intercept coverage differed only in respect to the geographical origin of the traffic. KONA 1, which was during the 1939–1944, attached to Army Group South Ukraine (German language: Heeresgruppe Südukraine) covered the southern part of the Russian front. It operated in the vicinity of Lemberg, Vinnytsia, Poltava, Reichshof, and Nový Jičín. KONA 2 which was attached to Army Group Centre covered traffic on the central Russian front, moved in the vicinity of Warsaw, Borisov, Orsha, Vitebsk, Smolensk, Minsk, Grodno.[76] KONA 3 which was attached to Army Group North, covered traffic on the northern part of the Russian front and in the Baltic states. It was variously at Riga/Dueneberg, Pskov and Courland, where in 1945 it was caught in a pocket by the Russians and captured intact.[76] KONA 6 was formed in 1942 to cover the traffic of the Battle of the Caucasus [30] While in the east, the unit was located at Rostov-on-Don, Novocherkassy and Minsk.[76] After that campaign, it was assigned to the interception of Russian Partisan traffic, and kept this as its intercept coverage until 1944, when it was withdrawn from the east and reassigned to the Western Front.[76]

The four independent Stationary Intercept Companies assigned to work on the eastern front had the following assignments. Feste 11 was assigned coverage of high frequency traffic on the Red Army and the NKVD. Originally this Feste was located at Winniza, latterly at Kiev.[77] The other two Feste 7 and 8, concentrated on special Russian traffic. Feste 7 was the Russian Baudot reception station located at Minsk. In 1942–43, it was moved to Giżycko (Loetzen) where it became part of Section 4 of the HLS Ost and continued to intercept Russian Baudot traffic.[33] Feste 8 was the former Army intercept station at Königsberg. After 1942, this station concentrated on Russian wireless telephone traffic called by the German Russian X-traffic. Attempts were made to pick up this traffic by equipment developed by Army Ordnance, Signal Equipment Testing Laboratory (German language: Waffenpruefung) (Abbr. Wa Pruef 7). The channels monitored ran east of Moscow; the traffic was mainly economic in nature. From 1942 to 1944, this traffic was successfully recorded, but after 1944 the Russian wireless traffic was encrypted, and after unsuccessful efforts to decrypt these communications, the monitoring was stopped.[78]

The Faz Nord operated in Finland after 1941. The mission of this unit was the interception of Russian Army traffic.[79] All Russian Army systems were handled by Faz Nord except five-figure traffic which was sent in encrypted format to the Intercept Control Station.[80]

Section 4 of the Intercept Control Station East (HLS Ost) monitored NKVD Inter-Soviet State traffic, and radio broadcasts of the Tass News Agency from Moscow.[33]

Southeastern Intercept[]

Southeastern intercept was the task of KONA 4, which was the only Signals regiment in the Balkans (Balkan Campaign (World War II)) during the war. For the task of intercepting traffic in this area, the component parts of the KONA were located in strategic positions. NAAS 4 was moved in the summer of 1941 to the Neon Phaleron near Athens,[81] where it remained there until February 1944, when it retreated to Belgrade.[33] From Belgrade it moved back to Graz, where it had departed four years prior.[82] Feste 5, the former Army intercept station at Graz, was moved to Epanomi in Greece.[82] Feste 6, was the former Army Fixed Intercept Station at Tulln, was stationed during this period in Athens, from which it returned to Tulln in 1944.[82] The Close Range Signal Intelligence Platoons NAZ T was located at Kavala on the Thracian Sea. NAZ W was located in Belgrade.[82]

The traffic intercepted by KONA 4 and its components parts was divided into two types:

  • Long range traffic emanating from the Middle East and Africa.
  • Traffic of the occupied Balkan countries.

Long range traffic in the Middle East emanated from Turkey, from the British Ninth Army in Palestine and Tenth Army in Iraq, and from the French Armies in Syria

Interception of Turkish traffic was carried on from 1941–1944 partly by the NAAS 4 at Neon Phaleron[82] but chiefly by the Close Range Signal Intelligence Platoon, NAZ T, stationed at Kavala in Greece, whose sole mission was the interception and decoding of Turkish traffic.[82] Traffic from the British and French troops in Palestine and Syria was intercepted by NAAS 4 at Neon Phaleron.[82]

Traffic of the occupied countries was covered before 1944 mainly by NAZ W, operating from Belgrade. This platoon covered the traffic of the Croatian adversaries, the Serbian partisans and Josip Broz Tito.[82] Feste 5 aided by covering Greek partisan traffic.[82] Feste 6 added Hungarian traffic to its intercept coverage in 1943 by sending a plain clothes detail to Slovakia near Pressburg (now Bratislava), Hungary to monitor this traffic.[83] When NAAS 4 was moved to Belgrade, it concentrated on the traffic of the occupied countries and covered Yugoslavian, Romanian, Bulgarian and Hungarian traffic.[84]

Western intercept[]

The traffic assigned to western intercept emanated from:

  1. The British Isles
  2. The United States, after the entry of the USA into the war
  3. Spain, Portugal and Brazil
  4. Miscellaneous western traffic

The coverage of this traffic was the task of KONA 5 which, until November 1944, was the only Signal Intelligence Regiment in the western area.

  1. Traffic from the British Isles was considered the most important of the western intercepts which were received overall. It had long been monitored intensively since 1939 by the GDNA, and by precursor organisations, when a Long Range Signal Intelligence Company, FAK 620 was sent to the Atlantic coast near Norderney Island to monitor British Army maneuver traffic.[85] Although FAK 620 was sent at a later date to the eastern area,[85] British traffic continued to be monitored by the following units of KONA 5 from 1939 to 1944:
    1. Long Range Signal Intelligence Company, FAK 613. This unit was stationed at Saint-Malo exclusively monitored radio traffic from the British Isles.[86]
    2. Feste 2, a Stationary Intercept Company located until November 1943 in Husum in the Netherlands, after that stationed in Lille. This unit monitored only traffic of the British Isles.[86]
    3. Feste 9, formed in June 1942, in Frankfurt am Main was sent to Norway to monitor British traffic. At first the unit was stationed at Trondheim, later at Bergen, where it remained until the spring of 1944, when it moved to Ski near Oslo, Norway. The unit was tasked to intercept traffic with the point of origin being the British Army in Northern England, Scotland and the Faroe Islands.[87]
    4. Feste 12, was attached to the Evaluation Centre of KONA 5 and located in Louveciennes. Until January 1944, this station monitored traffic exclusively from the British Isles.[88]
  2. Traffic originating in the United States and Iceland, and from American troops in the British Isles was monitored by Feste 3, located at Euskirchen and Feste 9 located at Bergen, Norway. Feste 3 concentrated on traffic from the USA.[89] After the Autumn of 1943, Feste 3 has a special intercept unit for USA non-Morse radio teletype traffic, designated by the Germans as FF5 (German language: Funk Fernschreib 5)[90] From Feste 9 in Bergen, United States traffic intercepts from Iceland was monitored. This unit intercepted short wave radio traffic from London to Washington via Ireland, but without success.[91]
  3. The traffic of Spain, Portugal and the Brazilian Army in Italy was monitored from 1939 to 1942 by Feste 3 at Euskirchen. In early 1943, the Long Range Signal Intelligence company FAK 624, was formed at Montpellier in southern coast of France for the interception of this traffic.[89] In January 1944, the Spanish, Portuguese and Brazilian message intercepts were shared with FAK 624 by Feste 19.[89] In addition to the three main commitments of the western intercept units, two other minor traffic sources were intercepted. These were Swedish Army traffic and the French Police traffic originating in Corsica. The Swedish Army traffic was intercepted by the subordinate unit of Feste 9 in Norway. This unit, known as out-station Halden, Norway (German language: Aussenstelle Halden) was attached for administrative purposes to the Halden Police Battalion.[87] The French police traffic from Corsica was monitored by FAK 624 at Montpellier.[89]

South Western Intercept[]

Before 1943, the German Army (German language: Heer) had no signal intelligence units in Italy. In February of that year, KONA 7 was established with a task of intercepting traffic from Italy and North Africa.[89] The intercepted traffic consisted of British, American, Polish, French and Brazilian Army traffic in Italy and North Africa.[89] There was no specific division of tasks in the various of units of KONA 7; all units intercepted all Army traffic from these countries.

The most southerly location of NAAS 7, the Signal Intelligence Evaluation Centre of KONA 7, was at Rocca di Papa, about 25 km south of Rome.[92] In September 1943, it moved into the neighbourhood of Rome, establishing itself at Vallerano. Later it moved to Vincenza in northern Italy.[92] Feste 1, the former intercept station at Stuttgart, after sundry moves in France from 1940 to 1943 was ultimately stationed in Italy at Genzano, west of L'Aquila.[92] Feste 9, which came to Italy from Norway in November 1944, was located in Breganze and remained there until shortly before the end of the war.[93]

The Long Range Signal Intelligence Company, FAK 621, which was attached to KONA 7, had been originally designated as the Army Signal Company 3 (German language: Horch Nachriten Aufklrg.) (abbr. H NA 56).[83] This unit, which was very active in North Africa, was captured, in part, in July 1942. In May 1943, the entire company was captured in Tunisia.[94] Until the time of its final capture, this unit intercepted traffic of British, French and American soldiers in North Africa and of the Egyptian Army and Camel Corps[84]

Intercept Service 1944-1945[]

Intercept Operation of OKH/GDNA[]

The years 1944-1945 saw the centralization of the German Army Signal Intelligence Service and its catastrophic dissolution in the months prior to the capitulation on 8 May 1945. As part of the movement to centralize the service, the OKH/GDNA assumed responsibility for the intercept and evaluation of the following types of traffic:

Traffic Type Operational Unit and Responsibilities
Foreign Press The intercept and evaluation of foreign press was undertaken by Section 2 of Group I, OKH/GDNA. This section was divided into four subsections:[95]
  1. monitoring of eastern wireless (German language: Rundueberwachung Ost).
  2. monitoring of western wireless (German language: Rundueberwachung).
  3. monitoring of plaintext (German language: Helldienst).
  4. evaluation.

Owing to the personal shortage during the years of 1944-1945, Section 2 was not able to cover its commitments to any large extent. Eastern monitoring was confined for the most part to the Moscow wireless, although in the later months, a certain amount of Balkan monitoring was confined to the BBC London Service. News monitoring was confined to the Reuters and TASS Agencies

Special high grade machine ciphers The interception and evaluation of special high grade machine ciphers of the Soviet Union, Britain and the United States were assigned to Group VI of OKH/GDNA, which was located at Potsdam. Section 1, dealing with Russian traffic, had three subsections:[96]
  1. Interception of Inter-Soviet State traffic.
  2. Interception of Russian Baudot traffic.
  3. Interception of Russian Army traffic.

The interception of Russian Baudot traffic (called by the Soviets, Z-traffic) was carried on by the same personnel who had manned the Russian Baudot station at Minsk in 1942-1943. In 1943, the Russian Baudot station was moved to HLS Ost at Giżycko, where it was absorbed by the OKH/GDNA, the Baudot station became Section 1b of the OKH/GDNA.[97] Section 2 of Group IV was employed with the interception (2b) and the evaluation (2a) of British and American high grade machine ciphers.[97] The interception of this traffic has been carried on by Feste 3 at Euskirchen until the establishment of the GDNA, when the responsibility was transferred to the central agency.[98]

Wireless photography The interception of wireless photography, called by the Germans Y-traffic, was carried on by a special unit of Section I of Group VI. This unit intercepted traffic from all over the word but the non-Russian channels are said not to have yielded any valuable information. Photos intercepted from internal Soviet traffic, however, often contained technical diagrams and charts.[99]
Intercept Service in the field[]

The intercept service in the field during the last year of the war, maintained its geographical distribution: eastern, south-eastern, western, and southwestern. Paralleling the changes in the war situation, meant there was an increasing emphasis on western intercept and a corresponding decreasing emphasis on south-eastern intercept in the war situation.

With the pressure of the Allied invasion, of necessity, western intercept assumed a position of greater importance. KONA 6 was reassigned at this time from eastern to western intercept and the western KONA regiments, KONA 5 and 6 were subordinated to a Senior Commmander of Signal Intelligence (Hoeh Kdr d NA) who was responsible for all signals operations in the west.[100] Upon these two KONA's fell the task of intercepting the traffic of the invading Armies.

KONA 6 monitored traffic for Army Group H and Army Group B which were stationed in the northern part of the Western Front. Army Group H was stationed in Netherlands and in Nordrhein-Westfalen. KONA 5 montitored the traffic of Army Group G, which was stationed in the southern half of the Western Front.[100]

One member of the Long Range Signal Intelligence Company, stated that his unit's original mission was the interception of traffic of the 1st French Army and the USA 7th Army. Later it intercepted the USA 1st Army, 3rd Army and 9th Army.

The decreasing emphasis on southeastern interception was manifested by the disbandment of KONA 4. The component parts were apparently reassigned to various fronts. South-eastern intercept and evaluation was carried out by KONA 4's successor, the newly formed NAA 16.[101]

The situation on the Eastern front and Southeastern Front remained, for the most part, much as it had been in the previous year. To the eastern front were assigned two new KONA's, KONA 8 and KONA Nord,[101] and to KONA 7 in Italy and one new intercept unit, Feste 9, which moved from Norway to Italy.[101]

A German Army report on the intercept situation about January 1945, gives the following picture of the units and their coverage:[101]

Front Unit Coverage
Eastern Front
  • KONA 8 for Army Group South
  • KONA 1 for Army Group Centre
  • KONA 2 for Army Group Weichsel
  • KONA Nord for Army Group Kurland
  • NAA 11 for 20th Mountain Army
  • Russian front traffic
  • Radio nets of NKVD
  • Romania
  • Roving bands in Poland and Ukraine
  • Espionage units in operational areas
Southeastern Front NAA 16 for Army Group E
Western Front
  • Senior Commander of Signal Intelligence
  • KONA 6 for Army Groups H and B
  • KONA 5 for Armt Groups G and Army Group Oberrhein
  • English, American, French front traffic
  • British traffic from the British Isles
  • USA traffic from the United States
  • French traffic from France
Southwestern Front KONA 7
  • English, American, French front traffic
  • Allied traffic from the western Mediterranean and North Africa
  • Italian bands in Northern Italy
Disintegration of Intercept Operations[]

It may be safely assumed that the constant movement of the German Armies and their intercept units during the last months of the war prevented continuous and orderly interception of enemy traffic. A brief resumé of the KONA regiments illustrates the confusion of these last months.[102] KONA 1 withdrew from the eastern front into Czechoslovakia and was found by the invading forces at Nový Jičín. KONA 2 retreated from the vicinity of Grodno to Ortelburg in Prussia, Gdańsk (Danzig), Pregolsky Microdistrict (Holstein) and finally to the Wismar area. KONA 3 was caught in the Courland Pocket and captured. KONA 8 withdrew first into Romania, then Croatia and finally to Lantsch/Lenz. KONA 5 in the west withdrew from Louveciennes in mid-August, 1944 and went first to Viggingen near Metz. At the beginning of September, it moved to Krofdorf-Gleiberg near Giessen, where it stayed until March. From there it moved to Rhoen and finally to Dischingen. One of its units, FAK 611 moved in the spring of 1945 from the Netherlands to Flensburg.[84] Feste 3 moved from Euskirchen into the Black Forest.[103] The southwestern unit, KONA 7 and its subordinates, retreated to northern Italy. Concerning southeastern intercept in the last months of the war, it is known only that NAA 16 remained as the only unit in the area.[101] The constant shiftings of the KONA and in the late months of the war, the disruption of internal communications between various parts of the KONAs and between the KONAs and the GdNA had a disastrous effect on the whole problem of enemy intercept.

During the last months of the war, the internal intercept units of the GdNA were also disrupted. The units of Groups I and V moved with the other Groups of the GdNA to Erfurt and then to Bad Reichenhall[104] The intercept unit of Group VI which had been covering high grade machine traffic at Potsdam was moved to Stuttgart and from there to Rosenheim[104] The equipment was buried in the cellar in the surrounding neighbourhood of a house, the Pioneer-Kaserne in Rosengeim, where it was later found by TICOM interrogators.[105]

Soviet cryptanalysis[]

Organisation of Cryptanalytic effort against Soviet Union[]

Review of Central Office Organisation[]

Prior to 1939, the Intercept Control Station [Ref 5.1] had a section for handling Russian traffic, but little was known of its operation or achievements.[106] Early successes against Russian cryptography were evidenced by cryptanalysis of 2,3, and 4-figure codes[107] with a 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.[108] When HLS was replaced in 1941 with the new agencies: In 7/VI and HLS [Ref 5.2], the Soviet (Russian) evaluation section was moved to LNA and the cryptanalysis unit for Soviet (Russian) 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.[108] This section formed the nucleus for the third central agency, the HLS Ost [Ref 5.5]. 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.[109]

For a breakdown of Russian signals intelligence activities, Group II under Captain (German language: Hauptmann) Gorzolla and Group IV under Major Rudolf Hentze were the principal units with the GdNA which worked on Russian systems [Ref 5.6.2].

Review of Field Office Organisation[]

The KONA (German language: Kommandeur der Nachrichtenaufklärung) (abbr. KONA) was the basic element of the field organisation of the German Army (Wehrmacht) signal intelligence organization during World War II. Due 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,[110] 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 Easter front signal intelligence regiments, and activated in late 1944 and early 1945.

Cryptanalytic effort against Soviet Union[]


Survey of Successes in Cryptanalysis at KONA 1

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.

Russia 2-Digit Codes
Name of Code Introduced Classification Design and Use
PT-35 Unknown Substitution cipher According to Alexis Dettman, who ran the Russian Referat and Sergius Samsonov who was head of Referat IIIa of Group IV, the first 2-figure operational system used over a long period by the Army and Air Force of the whole Soviet Union was PT-35, a code with 100 values, re-enciphered daily within each individual network.
PT-39 Code Late 1939 Substitution cipher

Fig I. PT-39 Recypher table.png

The PT-39 Code (Russian: Peregovornaa Tablica) meaning conversation table, a 2-digit code placed in a 10 x 10 square and then enciphered by substitution through a 2-digit 10 x 10 Latin square, with no figure being repeated in any row or column, and can be classified as the original, or fundamental 2-digit code.[111][112] From 1940-1942, it was used by Army Groups, Armies down to Divisions. The identification of the latin square used for encipherment enabled the GDNA to establish which Russian front or army the wireless station using it belonged, or whether it was an Army or Air Force Station. Since the squares could easily be checked (which appears to have been hardly necessary, since the rows and columns could be solved) with a minimum of 15 to 20 groups. The messages were of a technical signal or tactical nature, the latter more prominent after the beginning of the Russian campaign in June, 1941. This code was used from the extreme south to the extreme north of the eastern front, and far as the Caucasus, middle Asia and North Persia.[112]

Technical Description

The alphabet lay in three columns, the figures 1 to 0 in one column, the remainder of the square consisting of words and phrases such as CO, Chief of Staff, WT Station, We are changing to frequency. The latter groups had alternative meanings consisting of such phrases. In order to differentiate the two meanings, the first column contained two groups, one meaning Read letter and the other read words. E.g. of a 2-digit message: S.D = Rifle Division.

17 86 CO 80 37 32 56
Read Words KONA 3 6 Read Letters S D

The recipher was carried out using the 10 x 10 Latin Square, i.e. no figure repeated in any one column or line. A line or colum of this square was allotted to each day of the month.

Template:Framebox Ex: 7th, 12th, 19, 18 May Line A

   1st, 9th, 13, 29 May Line G
   3rd, 6th, 10, 19 May Column E


The recipher of the bigrams 17, 86, 00, 80 on 7 May would be according to Figure I be 10, 54, 99, 59.[113]

PT-42, PT-42N 1942 Substitution cipher

Fig II. PT-42 Recyphering Table

Fig III. PT-42N Recypher table

PT-42 was similar to PT-39 in construction except that the distribution of values in the basic square was made random, and variants for values (as many as four for common letters such as 'o', 'e'. 'i', 'a') were introduced. The enciphering method was the same as for PT-39, but because of the random nature of value assignment in the basic square, the solution of a row (or column) of the enciphering square now required about 30 groups. PT-42 was restricted for use in Army Groups, Armies or Corps. For divisions or regiments, PT-42N was used (Fig II). It was smaller, with a square of 7 x 10 instead of 10 x 10, but its construction was the same as PT-42. As in the case of PT-42, encipherment was performed by rows, but these were rarely derived from the Latin square. It was used most exclusively from division forwards and remained in force in some cases until 1944.[114] During interrogation by TICOM, Alexis Dettman stated this code produced large amounts of tactical information. Fig. II is the recyphering table.
PT-43 1943 onwards. The PT-42 and PT-42N were superseded by the PT-43, which was the last general purpose 2-digit code used and which remained in force up to the capitulation of Germany. Unlike the basic square in PT-39, PT-42 and PT-42N, it contained no letters. PT-43. was used for addresses, particularly by the Air Force and the Anti Aircraft Defense (PWO).[115] PT-43 came in about 1.5 years late, at which rate PT-45 would have arrived in 1946.[116]
Home-made 2-digit Unknown Small independent special units, such as Combat Engineer Brigades, Motor Regiments and Artillery Brigades, had their own home-made 2-figure codes, which were often in use for only short periods and which, besides the letters of the alphabet and numbers, contained specialized expressions appropriate to the unit concerned.[115]

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.[117] For Lieutenant Alexis Dettman, who stated that solving PT codes was:

merely a form of crossword puzzle[118]

Dr. Wilhelm Gerlich of NAAS 1, stated that 1 or 2 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,[112] however other evidence would seem to 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.[119][120]

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 (Eastern Front (World War II)). 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.

Fig IV. Example of 3-figure code book

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.[121] 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.[122] The first 3-digit ciphers were very simple in form, consisting of several pages, 10 at most, and contained alphabetically semi-hatted or completely hatted, the numbers 1 to 0 and punctuation marks. See Fig IV.[122]

Fig V. Example of 3-figure alphabetic code book

Soon afterwards the letters of the alphabet were put in their alphabetic position in the book.See Fig V.[122]

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

Fig VI. Example of 3-figure semi-alphabetic code book

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.[122] 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.[123] If the codes were smaller than 1000 groups, alternatives were given either to pages or first figures of the lines.[124] 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 1 month, although with the Air Force, it sometimes lasted longer.[124] 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.[124]

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:

736 1) Read the initial letter
737 2) Read the whole word

Fig VI. Example of 3-figure syllabic code book

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.[125]

3-digit code R3ZC which was mentioned by Corporal A. Faure of NAA 11 and was discovered as part of the Norway codes.[126] 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.[126]

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 (with a 2-digit latin square encipherment) was used.[127] KONA 1 personnel stated that every Army Group down to Battalion had its own 3-digit code.[128]

It is curious to note that a good deal of plaintext was inserted into the 3-digit enciphered code as it was transmitted.[129] 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[130] 3-figure traffic was only slightly more secure that 2-digit code traffic and was 80% readable.[131] 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 1 week to 1 month. However, all 3-digit codes were readable[132] 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.[39]

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 2 or 3, 3-figure groups allotted to it. As in the case of the former code, anything not in the codebook was sent in plaintext.[133] 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 (abbr. 4/F) 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 Mechanized 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.[134]

Lt. Schubert of KONA 6 stated under interrogation that: The Russian [Soviet] Army keys are 3 or 4-digit systems. The basis is the same.[135] 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.[128] with the book length being described as either 6 or 7 pages[135] 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.[136] 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.[136]

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 (in comparison to single-letter substitution in the case of 3-difit codes), combinations of these two, abbreviated figures in the substitution, and others.[136] Uffz. Corporal Karrenberg, who was GDNA cryptographer, and was a specialised on Russian Baudot stated while under interrogation, in his discussion of the Russian Cryptanalysis course given for field training, stated that 3-digit or 4-digit could also be reciphered on an adder. For this purpose a text chosen at random is enciphered (likewise by the code) and the code text added to or subtracted from (non carrying).[137] 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 (2-figures) and encipherment of the last 2-digits by various means, including 2-digit Latin square.[138]

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.[139]

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 war, and OKK 6, 7, 8 later. Dettmann and Samsonov stated:

All these systems, however, recovered by cryptanalysis before their capture and were made completely and currently readable.[140]

Ltn. Harry Loeffler of Feste 10 stated that a:

General army 4-digit cipher was last observed in use in Tajikistan (North Persia) in the winter of 1941-42. It had 50 pages, each designated by two alternative Bigrams and 100 lines to each page.[136] There was no indication in interrogations that 4-digit codes were either less or more frequently employed.[141] In 1944, 4-digit Signal Codes, of the same form as the 3-digit Signal Codes, appeared, and were used by army groups.[142] and probably superseded in great part, if not wholly, the 4-digit codes discussed above.

4-digit codes were changed less frequently than other codes[143] but Dr Wilhelm Gerlich's of NAAS 1 of KONA 1 who stated, the change in encipherment was not quick enough to make decipherment impossible [by Germany].[144] Certainly the 4-digit codes gave Germany cryptanalysts a certain amount of trouble, as a large amount of material to absolutely necessary and the majority of unsolved 4-digit codes and ciphers were abandoned because of an insufficient number of messages.[144]

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 (ground/ground) stated that they were only 60% readable.[145] 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.[146]

In the interrogations of KONA 1 members, the following 4/F codes were listed as solved:[147]

  • 4-digit code of VI Guards Mech. Corps of 1st Ukrainian Front from January 1945 to end of war.
  • 4-digit code of 152 Tank Brigade of 60th Army of the 1st Ukrainian Front.
  • 4-digit code of Tank Supply and Administration Authorities of the 1st Ukrainian Front.
  • 4-digit code of the 76th Regional Air Base (Russian 76 RAB)
  • 4-digit code of Supply Units of 13th Army of 1st Ukrainian Front.
  • 4-difit code of 3rd Guards Tank Army

Lieutenant (German language: Oberleutnant) Horst Schubert of GDNA simply stated:

"We broke Army 3 and 4-digit re-enciphered books. These were enciphered on a conversion table. Early in the war we read most of this traffic, but by the end only 40% to 50%."[148]

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 (Russian: Narodny Komissariat Oborony), 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 In 7/VI, Lt. Col. Mettig, stated glibly:

The breaking of the Russian 5-digit recyphered code...was the most outstanding cryptanalytic achievement of In 7/VI.

The Soviet 5-digit code was broken chiefly by War Administration Inspector German language: Kriegsverwaltungsinspektor) Lieutenant Alexis Dettman.[149] 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.[150] 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 In 7/VI 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 (German language: uffz) A. Althans of the KONA 1 stated that cryptanalysis of 5-digit codes was only possible with the following conditions:

  1. There was a number of messages, at least 3, which had the same additive applied.
  2. The 5-digit code had been captured.[151]

Dettmann and Samsonov[152] stated that codes 011-A, 023-A, O45-A, 062-A and 091-A used successively from the beginning of Word War II to the end, did prove difficult from a pure cryptanalytic solution. They stated:

"It is interesting to point out that during the course of the war all the newly appearing versions of each cipher were captured through fortunate circumstances and always so soon that the originals were almost always in the hands of the cryptanalysts at the instance of their being put into use by the Soviets.[152] Of course, this 'contentious capture' was an aid in solution, under such circumstances because of the One-time pad encipherment. The individual tables offer almost complete security against breaking."[153]

In the reports of personnel from NAA 11, a Captain Schmidt stated that:

with regard to Russian [Soviet] traffic, the Abteilung [Battalion] did everything up to and including 4-digit. 5-digit they considered insoluble and forward these to the GdNA.[154]

One Corporal Karrenberg, of GdNA,while under interrogation discussed 5-letter and 5-digit codes used for operational orders, stated:

These were so-called Blocknot codes, which were only used once and were therefore unbreakable.[155]

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.[156][157]

In 1943, KONA 1, for a period, undertook 5-digit cryptanalysis independently of GdNA,[158] 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:

even at the GdNA HQ, very little attention was give to 5-digit messages and very little enthusiasm displayed in working on it. Only the preambles were used to identify units, from Blocknots and indicator groups.[159]

Finally Lt. Schubert, when questioned on possible success on 5-digit codes replied:

In the Finnish campaign the book was captured and the Russians used the one-time pads over again. Because of this we had considerable success. Recently the Russians used the [one time] pads correctly and only very few messages were read, these through re-encodements.[148]
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.[151]

Corporal Althans stated that Succesful Cryptanalysis is possible only if:

  1. There are a number of messages, at least three, which have had the same additive applied.
  2. the 5-figure code was captured.

Cryptanalysis starts from the mathematical rule that the difference between 2 code groups remains constant if both have have the same additive row applied to them. For example:

Code Group Additive Cipher Group
39214 20186 59390
98315 20186 18491
Difference 41909 41909

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 (positionen) 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 (Herman Hollerith) machines and entries made on the catalogue as follows:

"41909 17-32" which means:
Number 17 u 39214
Number 32 TUPE 98315
Difference 41909

As stated previously, in 1943 KONA 1, for a period did 5-figure cryptanalysis independently, of GdNA. For this purpose a difference catalogue of 200 clear groups (which equals 19900 differences) was compiled by hand. A calculation aid, in the form of a wooden frame with 5 paper belted wheels I to V, where 1 wheel represented each digit of the 5-figure group, was used.[151] 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.[160] 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 (Lotzen) 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.[160] 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:

The 5-figure code books contained about 25,000 out of a possible 100,000 groups, the pages being numbered 000 to 999 with a hundred lines on each page. The Germans never broke a book and any examples they had were captures.[161] The books were alphabetic at first but then became "semi-hatted", i.e. all groups with the same initial letter were grouped together but not alphabetically, nor were the initial letters alphabetic with reference to one another.

Alphabetic at first, the 5-digit codebooks later became partially alphabetic. The contained:

  1. Single letters
  2. Words
  3. Phrases
  4. Two-figure numbers
  5. Types of units
  6. Specific units of the Red Army
  7. Full stops and commas on every page
  8. Add designations of types, such as Types of Tanks, ammunition, wireless stations (W/T), transport etc.

The encipherment was effected by applying additives taken from enciphering pads known at BLOCKNOTS, that were a variable of sheets on which 50-100 5-figure groups appeared. Each pad had a 5-figure number, and each sheet had a 2-figure number running consecutively. There were five different types of Blocknots:

  1. I - Individual: 50 pages, additive read off in one direction only.
  2. Z - Circular: 30 pages, additive read off in either direction.
  3. OS (?)
  4. Notblock: Used in an emergency
  5. Blocknot: Used for passing on traffic.[162]

The distribution of Blocknots was carried out centrally from Moscow to Army Groups to Armies. The Army was responsible for their distribution to those units which were subordinated to that specific Army. Occasionally, the same Blocknot was distributed to two units on different parts of the front, with the result that a depth was established. Records of all BLOCKNOTS used were kept in Berlin and when a repeat was noticed a BLOCKNOT ANGEBOT was sent out to all German S.I units. The second condition for successful cryptanalytic success established by Corporal Althans was fulfilled: Depth was established.

It seems that depths of up to 8 were established at the beginning of the Russian Campaign, but that no 5-figure was broken after May 1943.[163]

Prisoner stated definitely that each of the figures 'a - 9' occurred the same number of times on any one page of a BLOCKNOT and that if a count of the figures in the cipher text was made the frequency of each figure always lay between 9 and 11%.[163]

The two indicators of the BLOCKNOT were placed 'en clair' (in plaintext) usually within the first ten groups of the text or sometimes at the end. One indicator was the BLOCKNOT number and the at her consisted of two random figures, the figure representing the type, and the remaining two, the page of the BLOCKNOT being used.[163]

In long messages 00000 was placed in the message when the end of a page had been reached.[163]

Address Codes[]

Soviet Address Codes (2-digit, 3-digit, 4-digit) 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:

Unit Name Comment
In the FAK 15 to 20 people were adequate for company cryptanalysis. (Cryptanalysis in the KONA) Special procedures such as Signal Codes (3-figure and 4-figure) and word codes and address codes (3-digit) were studied by chosen by cryptanalysts.[164] The strength of the various sections was modified to cope with developments on the Russian side: namely the shifting of emphasis from 2-digit to 3-difit and then to 4-digit traffic. Special procedures, such as Signal Codes (3-digit and 4-digit), Word Codes and Address Codes (3-digits), were studied in the appropriate section by specially chosen cryptanalysts, for the most, also sometimes by the chief cryptanalyst. The average working time to recover a new code varied a great deal and depended on the difficulty of the procedure.[164]
In the NAAS

Liaison with other agencies on Russian Cryptanalysis[]


Training Operations[]

Until 1942, the work of the Training Referat was not fully exploited and only a small beginners course was in progress.[58] Suffering from an acute shortage of cryptanalyst personnel which the German Defense Ministry encountered, it was found that the practice of pushing forward groups of cryptanalysts to key areas did not of itself provide adequate signals intelligence, particularly as the front lines were getting further away from Berlin.[58]

As a result, Commanders of forward intercept units were allowed to create their own cryptanalysts teams. Two difficulties were encountered in this connection; firstly, a lack of technical knowledge, and secondly the entry into the cryptographic service of personal who were untrustworthy from the security point of view. In two cases in KONA 2 in Smolensk personnel were unearthed who were guilty of espionage.[58] As a result of this a security vetting for all security, translators and cryptanalysis personnel was introduced.[39]

Once the forward cryptanalysis units had been set up, and eventually became the Long Range Intelligence Company (NAZ), they were attached to various Close Range Intelligence Company (NAK) which coordinated intelligence and forwarded the raw flow of intercepts into the Signal Intelligence Evaluation Centre (NAAS). It was agreed to allot the NAZ units investigation of forward lines of communication traffic which could be solved in the field. In 7/VI remained, however, responsible for all army cryptanalysis work and concentrated on the most difficult and unsolved procedures.[39]

As a personnel establishment for these forward cryptanalysis units, it was found necessary to have two or three linguists and one to three mathematicians. Such personnel were trained at a six weeks' course by In 7/VI. 200 cryptanalysts were trained successfully and included such individuals as Major Dr Hentze, Lieutenant (German language: Oberleutnant) Lüders and Lieutenant Schubert.[39] The results of this work in 1941 and 1942 was to enable In 7/VI to concentrate on research into more difficult procedures.[39]

Training Classification[]

Training of signal recruits[]

The Signal Intelligence Replacement and Training Battalion (German language: Nachrichten Aufklärung Ersatz und Ausbildungsabteilung) (abbr. NAEUAA) that was located in Frankfurt, was responsible for the training of German Army Signal recruits. It had control over Signal Intelligence Replacement and Training Companies in each Service Command District (German language: Wehrkreis) where basic training and some training in signal matters were given to the recruits.[165] In time of peace, basic training lasted one year, signal training being taken up after the first three months. During the war, the time of basic training was shortened in order to place more troops more quickly in the field. Recruits were trained in direction-finding, teletype operation, and simple field codes, and they were sent out into field units.[166] No special courses were conducted in the Replacement and Training Companies.

Training of signal technicians[]

Most of the signal technicians were trained in specialist academies of various sorts. Academies for carrier frequency, switchboard operators, repair men, etc., were established by the Army and Division and Corps Signal Battalions and at Army Signal Depots.[166] Instructors were mainly non-commissioned officers who had experience in the field.

Training of specialists[]

The Signal Interpreter Replacement and Training Battalion (German language: Nachrichten Dolmetscher Ersatz und Ausbildungs Abteilung) (abbr. NDEUAA) was located in Halle[167] This battalion was responsible for the training of signals interpreters who were to be employed in signal intercept units for radio and wireless monitoring. The battalion was divided into three companies: company one was for Romance languages, company two for Slavic languages, and company three for Germanic languages. For matters of administration, the battalion was divided into the following 5 platoons:[168]

  1. Cadre platoon (German language: Stammzug) comprising cadre personnel and instructors in military and intelligence technical matters.
  2. Instructor platoon (German language: Lehrzug) comprising teachers and members of the instructor group.
  3. Training platoon (German language: Ausbildungszug)comprising the students who were under instructions in some language.
  4. Alert platoon (German language: Marschzug) comprising men who have passed their final examination and who are expecting to be sent into action.
  5. Pool (German language: Auffangkorporalschart) comprising newcomers waiting for their entrance examination.

A rough estimate of the personnel shows that in 1944, there were about 350 to 400 men attending the various languages classes. After the courses which lasted 6 weeks, the men were given a final examination. According to the results of this examination, they were assigned to one of the three following categories:[169]

Personnel Categories Comment
S – Speakers (German language: Sprachmittler) These were people who spoke well and were able to make themselves understood, but who did not master the language in speaking and writing correctly.
U – Translators (German language: Uebersetzer) These were people who mastered the foreign language in writing, but were only fair in speaking.
D – Interpreters (German language: dolmetscher) These were people who spoke and wrote the foreign language correctly and fluently and whose general education was up to a corresponding standard.

Employment was assigned according to the category to which each person was assigned.

For persons of category S, a special course in monitoring Allied radio communication was organised at Leipzig for English speaking personnel only. The course consisted of three weeks daily instruction in the following subjects:[170]

  1. USA and British organisation of signal units.
  2. USA and British radio sets used at all levels.
  3. USA and British radio call signs.
  4. USA and British authorized abbreviations.
  5. USA and British message forms.
  6. USA and British fixed station and net operational methods.
  7. USA and British Army terminology.

Each of the subjects was taught for one hour a day and had a brief examination. In most cases, the lectures were conducted in English to facilitate practice in this language.

Training of signals officers[]

The Army Signal Academy located in alle (German language: Heeres Nachrichten Schule) (abbr. HNS), conducted the course for officer candidates of the Signal Corps.[171] Emphasis here was in the first months evenly divided between technical and military subjects. The officer candidates were selected by their commanders in the field after having proved themselves in combat or in outstanding work in their specialty. All enlisted men were eligible, although the racial origin evidently played some part in the selection. One prisoner, for instance, states that he was not allowed to become an officer candidate, because of his Jewish grandmother.[172]

After their selection, the men were given a four weeks course in tactics, Army regulations, customs, technical subjects. Those who passed this preliminary course were sent to the Armed Forces Signal Troop Academy (German language: Führungs Nachrichtentruppen Schule) (abbr. FNS) where they were trained for three months in Signal Corps work.[173] From there they were sent into the field for a probation period as leaders of platoons. During this period of training, Colonel Grube states, many of the candidates lost their lives. A final three months at the Signal Academy in Halle brought, with graduation, the rank of Leutnant (second lieutenant).

Training of German Army cryptanalysts[]

Nothing is known of the training of Army cryptanalysts before 1939. Mettig states that when the KONA regiment moved into the field in 1939, no cryptanalysts were available.[174] Colonel Kunibert Radewig, the commander at that time of all intercept stations in the west, however, was able to procure a number of cryptanalysts from the Feste around Berlin, and to this force he added a few mathematicians and linguists.[20] As a result, when the German offensive began in April 1940, the KONA units had a moderate supply of cryptographic personnel. The early war years clearly showed that additional personnel were needed. A Training Section in In 7/Vi was established under the leadership of Kuehn, but Mettig stated that the work in the unit was not fully exploited until 1942.[58] The Training Section was located at Matthäikirchplatz 4 in Berlin until November 1943, when it was moved with the rest of the Agency to Jüterbog because of the Allied bombings. In November 1944, the Training Section 7 of In 7/VI became Referat 5 of Group IV of the GDNA.[96] The training academy consisted of about 20 officers with 120 men, and about 12 women as Stenographers.[175]

The course, which lasted 10–12 weeks[96] ran during the morning and for two to three afternoons per week. A brief history of Cryptograhy was studied from a syllabus, and included a general picture of the methods of encipherment, details of various means of encipherment and decipherment. During the remaining afternoons, the students evidently specialized in whatever field to which they were to be assigned. One prisoner of war, Gerd Coeler, stated that during the afternoons, he studied English military terms and abbreviations, including the history and organisation of the British Empire and the geography of England.[176] Corporal Karrenberg[177] outlines the course given for those who were specializing in Russian cryptanalysis. Participants were selected from the personnel of the Signal Interpreter Replacement and Training Battalion, which knew Russian. After the most capable interpreters had been selected they were given a course in Russian cryptography, which included all types of Russian systems. For practice in this course actual Soviet (Russian) military intercepts were used, to gradually accustom the men to Russian field problems.

Evaluation of Signal Training[]

The training of cryptanalysts by the Army appears to have been eminently successful. The classes the men used at the Training Section of In 7/VI passed most of the men who would later become outstanding in the field of cryptanalysis either in the KONAs or in the central agencies. The following soldiers were trained at the unit:[39]

  • Major Dr. Rudolf Hentze, who was head of cryptanalysis at KONA 5 in Paris and later Head of Gruppe IV of the GDNA.
  • Dr (German language: Oberleutnant) Wilhelm Vauck was head of the Agents of In 7/VI from 1942-1945.
  • First Leutnant (German language: Oberleutnant) Lüders head of one of the subsections of the mathematical section of In 7/Vl.
  • First Leutnant (German language: Oberleutnant) Schubert, head of cryptanalysis at HLS Ost.

The training of signal troops in the field, appears to be less successful. Throughout the TICOM documentation, attention is drawn to the acute shortages in the Field Army of personnel who were well trained in signal intelligence operations. This was particularly true in the late years of the war when courses became more disorganised and less effective. The central agencies recognized this weakness and attempted to remedy it by publishing field manuals on security and having lectures given at the Army Signals School in Halle (German language: Heeres-Nachrichten-Schule II) by members of In 7/VI. Despite these efforts, however, the Field Army remained, according to Walter Fricke, pitifully ignorant of the principles of security. Ignorance undoubtedly lay at the bottom of the non-cooperative attitude of the Field Army in regard to the adoption of systems considered more secure than those in use by the Army. Conditions were aggravated at the end of the war by the necessity for sending all able-bodied men into the front line and by the general confusion of the Army. Very little training could be carried on by the Field Army during the late months of the war since their schools were taken over by the operational agencies they used to train. For example, the Army Signal School at Halle had been used by the In 7/IV since November 1943 for the preparation of Army keys, and after March 1945 it housed a considerable section of the OKW/Chi, including service personnel and civilians. It may be safely stated that, after 1944, little if any signal training was carried out by the Army.

TICOM publications[]

The Target Intelligence Committee was a project formed in World War II by the United States to find and seize German intelligence assets, particularly signals intelligence and cryptographic ones. The following documents are referenced in this article.

Missing TICOM documents[]

The following TICOM documents are not currently available on the open inter-networks but may be available on the external link below at National Archives and Records Administration. If they are not available there, then they are still considered Top Secret but may be available via an NSA FOIA request.

  • TICOM I-85 P. O. W. Interrogation Report on Reg. Rat Flicke, Tech, Insp. Pokojewski, Stabsintendant Hatz of OKW/Chi
  • TICOM I-96 Interrogation of Oberstlt. Mettig on the Organization and Activities of OKW/Chi.
  • TICOM IF-123
  • TICOM IF-126
  • TICOM IF-127
  • TICOM IF-171 Report on Further Information obtained from Uffz. Kotschy and Uffz. Boscheinen both of Festungs art Abt 1518, deserted at Diffenbach 22 November 1944.
  • TICOM IF-190 The Organization and History of the Cryptographic Service Within the German Army.


  1. "Volume 4 – Signal Intelligence Service of the Army High Command" (PDF). NSA. Retrieved 12 November 2016.  This article incorporates text from this source, which is in the public domain.
  2. David Joyner (6 December 2012). Coding Theory and Cryptography: From Enigma and Geheimschreiber to Quantum Theory. Springer Science & Business Media. p. 33. ISBN 978-3-642-59663-6. 
  3. David Kahn (5 December 1996). The Codebreakers: The Comprehensive History of Secret Communication from Ancient Times to the Internet. Simon and Schuster. p. 574. ISBN 978-1-4391-0355-5. 
  4. 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 "GERMAN RADIO INTELLIGENCE (BY ALBERT PRAUN, FORMER LT. GEN.); DEPT. OF THE ARMY OFFICE OF THE CHIEF OF MILITARY HISTORY. INCLUDES NSA MEMO AND COMMENTS ON REPORT" (PDF). NSA (Albert Praun). March 1950.  This article incorporates text from this source, which is in the public domain.
  5. Meyer, Joseph A. Der Fall WICHER: German Knowledge of Polish Success on ENIGMA. TICOM. p. 11. Retrieved 10 February 2015. 
  6. Meyer, Joseph A. Der Fall WICHER: German Knowledge of Polish Success on ENIGMA. TICOM. p. 27. Retrieved 10 February 2015. 
  7. 7.0 7.1 7.2 Nigel West (12 November 2007). Historical Dictionary of World War II Intelligence. Scarecrow Press. p. 201. ISBN 978-0-8108-6421-4. Retrieved 1 July 2017. 
  8. Jeffery T. Richelson (17 July 1997). A Century of Spies: Intelligence in the Twentieth Century. Oxford University Press, USA. p. 128. ISBN 978-0-19-511390-7. Retrieved 1 July 2017. 
  9. Nigel West (31 August 2012). Historical Dictionary of Signals Intelligence. Scarecrow Press. p. 105. ISBN 978-0-8108-7187-8. Retrieved 1 July 2017. 
  10. I-96,p. 2
  11. 11.0 11.1 I-85, page 2
  12. 12.0 12.1 Major Jeffrey S. Harley (6 November 2015). Reading The Enemy’s Mail:: Origins And Development Of US Army Tactical Radio Intelligence In World War II, European Theater. Pickle Partners Publishing. p. 23. ISBN 978-1-78625-409-2. 
  13. I-62, p. 6
  14. 14.0 14.1 Peter Matthews (2 September 2013). SIGINT: The Secret History of Signals Intelligence in the World Wars. History Press. p. 142. ISBN 978-0-7524-9301-5. 
  15. I-85, Page 3 – P. O. W. Interrogation Report on Reg. Rat Flicke, Tech, Insp. Pokojewski, Stabsintendant Hatz of OKW/Chi.
  16. 16.0 16.1 16.2 16.3 I-78, p. 2
  17. Bernd Wegner; Germany. Militärgeschichtliches Forschungsamt (January 1997). From Peace to War: Germany, Soviet Russia, and the World, 1939–1941. Berghahn Books. p. 226. ISBN 978-1-57181-882-9. 
  18. IF 181, p. 15
  19. I-85, p. 3.
  20. 20.00 20.01 20.02 20.03 20.04 20.05 20.06 20.07 20.08 20.09 20.10 I-78, p. 4
  21. IF-171, p. 1
  22. IF 127
  23. Bernd Wegner; Germany. Militärgeschichtliches Forschungsamt (January 1997). From Peace to War: Germany, Soviet Russia, and the World, 1939–1941. Berghahn Books. pp. 232–. ISBN 978-1-57181-882-9. 
  24. I-92, p. 6
  25. 25.0 25.1 I-92, p. 6 Section 13.
  26. 26.0 26.1 26.2 26.3 I-78 p. 5
  27. 27.0 27.1 27.2 I-78, p. 6
  28. I-36, p. 2
  29. IF-190B, p. 4
  30. 30.0 30.1 DF-18, Page 81
  31. IF-172, p. 2
  32. Peter Matthews (2 September 2013). SIGINT: The Secret History of Signals Intelligence in the World Wars. History Press. p. 141. ISBN 978-0-7524-9301-5. 
  33. 33.0 33.1 33.2 33.3 33.4 33.5 IF-123, pp. 5-11
  34. I-76 Appendix, Chart I
  35. I-76, p. 7
  36. T-1402
  37. 37.0 37.1 37.2 37.3 37.4 37.5 I-78, pp. 7–8
  38. IF-190, B. Appendix 3
  39. 39.0 39.1 39.2 39.3 39.4 39.5 39.6 39.7 39.8 I-78, p. 8
  40. I-78, p. 10
  41. I-115, p. 3
  42. I-58, p. 2
  43. IF-126, pp. 6-7
  44. IF-126, p. 6
  45. IF-190 B App 5
  46. IF-111, Annex 1 and 2
  47. 47.0 47.1 47.2 IF-123, p. 4
  48. IF-123, pp. 5–6
  49. 49.0 49.1 49.2 I-113
  50. IF-123 – All material concerning the organisation of the GDNA was derived from the interrogation of Major Hentze, who was head of Group of Referat IV.
  51. 51.0 51.1 51.2 51.3 IF-123, p. 6
  52. 52.00 52.01 52.02 52.03 52.04 52.05 52.06 52.07 52.08 52.09 52.10 52.11 52.12 52.13 52.14 52.15 52.16 52.17 52.18 52.19 "CsdicSir1717 neral der Nachrichten aufklärung (Army Intercept Service)". C.S.D.I.C (UK) S.I.R 1717. 16 August 1945. Retrieved 2 June 2017. 
  53. IF-123, pages 6–13
  54. I-78, p. 3
  55. 55.0 55.1 55.2 55.3 55.4 55.5 55.6 55.7 I-78, p. 5
  56. John Ferris (7 May 2007). Intelligence and Strategy: Selected Essays. Routledge. p. 220. ISBN 978-1-134-23334-2. Retrieved 1 August 2017. 
  57. "The organisation and history of the cryptographic within the German Army OKH/AHA/In 7/VI later Ag N/Nachr Aufkl.". TICOM. 2 April 1945. p. 6. Retrieved 1 August 2017. 
  58. 58.00 58.01 58.02 58.03 58.04 58.05 58.06 58.07 58.08 58.09 58.10 I-78, p. 7
  59. Glenmore S. Trenear-Harvey (20 November 2014). Historical Dictionary of Intelligence Failures. Rowman & Littlefield Publishers. p. 78. ISBN 978-1-4422-3274-7. Retrieved 2 August 2017. 
  60. 60.0 60.1 60.2 60.3 60.4 60.5 60.6 I-78 p. 9
  61. IF-181, p. 2
  62. IF-181, p. 3
  63. 63.0 63.1 IF-181, p. 4
  64. IF-181, p. 5
  65. I-185, p. 3
  66. 66.0 66.1 IF-181, p. 9
  67. IF-181, p. 10
  68. I-85, p. 2
  69. IF-181, p. 13
  70. IF-181, p. 14
  71. I-85, p. 3
  72. 72.0 72.1 I-86, p. 2
  73. I-196, p. 10
  74. I-19g, p. 1
  75. IF-123, Page 8
  76. 76.0 76.1 76.2 76.3 I-116, p. 8
  77. IF-123, p. 12
  78. IF-123, p. 14
  79. I-55, p. 5
  80. I-55, Page 9
  81. IF-171, p. 2
  82. 82.0 82.1 82.2 82.3 82.4 82.5 82.6 82.7 82.8 IF-171, p. 3
  83. 83.0 83.1 IF-126, p. 10
  84. 84.0 84.1 84.2 I-74, p. 2
  85. 85.0 85.1 I-76, p. 3
  86. 86.0 86.1 IF-127, p. 5
  87. 87.0 87.1 IF-120, p. 6
  88. IF-127, p. 4
  89. 89.0 89.1 89.2 89.3 89.4 89.5 IF-127, p. 3
  90. I-149
  91. I-78, Page 10
  92. 92.0 92.1 92.2 IF-172, p. 1
  93. IF-144, p. 2
  94. I-78, p. 9
  95. IF-123, pp. 7-8
  96. 96.0 96.1 96.2 IF-123, p. 9
  97. 97.0 97.1 I-123, p.11
  98. IF-123, p.5
  99. IF-123, p. 15
  100. 100.0 100.1 I-76, Appendices
  101. 101.0 101.1 101.2 101.3 101.4 DF-9
  102. I-116, p.8
  103. I-76 p. 11
  104. 104.0 104.1 IF-123, p.12
  105. IF-15
  106. IF-181, p.4
  107. I-78, p.3
  108. 108.0 108.1 I-78, p.8
  109. The amalgamation was necessitated by the retreat of HLS Ost to the Zeppelin bunker near Zossen, where In 7/VI and LNA were located. This move was one of operational rather and cryptanalytic expediency: the Soviets were advancing; HLS was retreating, and when the home office and the field cryptanalytic and evaluation offices were all close together, it was certainly more expedient to combine them. The result was the GdNA.
  110. Nothing is known from TICOM sources of the crypanalytic activities of HLS OST before its amalgamation into the GdNA except a brief statement of Mettig in I-78, p.8
  111. I-191 p. 1
  112. 112.0 112.1 112.2 I-19c p. 1
  113. I-19c, p. 2
  114. I-19c, pp 1,2
  115. 115.0 115.1 I-19c p.2
  116. I-106 p. 2
  117. I-106, p.2
  118. IF-5, p. 6
  119. I-191 p.4
  120. See Also DF-18, p. 47
  121. I-19c p. 2
  122. 122.0 122.1 122.2 122.3 I-19c p. 2,3
  123. I-26, p. 2
  124. 124.0 124.1 124.2 I-19c p. 3
  125. I-19c p. 4
  126. 126.0 126.1 I-55, p. 12
  127. I-173, pp. 10-11
  128. 128.0 128.1 I-19c, p. 4
  129. I-26, p.2
  130. I-191, p. 7
  131. I-75, p.10
  132. I-75, p. 6
  133. I-19c, p.4
  134. I-19b, p. 11
  135. 135.0 135.1 I-26 p. 2
  136. 136.0 136.1 136.2 136.3 I-19c, p. 5
  137. I-166, p. 7-8
  138. I-173, pp 10-11
  139. I-19c, pp. 5-6
  140. DF-18, p. 55
  141. Ltn. Harry Loeffler stated that only a 4-digit code was used by the VI Guards Mechanical Corps 1st Ukrainian Front from January 1945 to the end of hostilities, that was captured in January 1945.
  142. I-19c, pp 5-6
  143. I-19c p. 8
  144. 144.0 144.1 I-191, p. 8
  145. I-75 p. 10
  146. I-75, p. 8
  147. I-19c, pp 6-8
  148. 148.0 148.1 I-15, p. 1
  149. I-111, p. 2
  150. I-128, p. 2
  151. 151.0 151.1 151.2 I-19b, report 25, p. 43
  152. 152.0 152.1 DF-18, p. 59
  153. DF-18, p.61
  154. I-55, pp. 9-11
  155. I-173, p. 6
  156. I-166, p. 78
  157. I-75, p. 10
  158. I-19b, Report 25, p. 43
  159. I-166, p. 79
  160. 160.0 160.1 I-79, p. 8
  161. I-19c, p. 8
  162. I-190, p. 9
  163. 163.0 163.1 163.2 163.3 I-19c, p. 10
  164. 164.0 164.1 I-19b, Report 6, p.11
  165. IF-250,Page 2
  166. 166.0 166.1 IF-250, p. 3
  167. IF-105, p. 5
  168. IF-105, p. 3
  169. I-96
  170. IF-131, p. 4
  171. IF-205, p. 5
  172. IF-127, p. 1
  173. IF-250, p. 6
  174. IF-78 p. 4
  175. IF-127, p. 2
  176. IF-122, p. 2
  177. I-166

See also[]

The following were the main Signal Intelligence Agencies and cipher bureaus of the German forces during World War II.


  • OKW/Chi: The highest cryptologic bureau for the Wehrmacht supreme command.
  • Luftnachrichten Abteilung 350: was the Signal Intelligence Agency of the German Air Force, the Luftwaffe and part of the high command of the Luftwaffe.
  • B-Dienst: (Observation Service) was Department of the German Naval Intelligence Service (German language: Marinenachrichtendienst, MND III) of the OKM, that dealt with the interception and recording, decoding and analysis of the enemy, in particular British radio communications.
  • Abwehr: Military intelligence gathering and cipher bureau from 1941 to 1944.


  • AA/Pers Z S: (AA) Auswärtiges Amt (Foreign Office Personnel Department) (Pers Z) Sonderdienst (Special Service of Unit Z) The Foreign Office cipher bureau decrypting diplomatic signals.
  • RSHA: The Reichssicherheitshauptamt (Reich Security Main Office), the main cipher bureau for Hitler's personal staff including the SS.
  • RLM/Forschungsamt: The signals intelligence and cryptanalytic agency of the German Nazi Party from 1933 to 1945. Part of OKL and Göring's personnel cipher bureau.

External links[]

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