How successful were Hitler’s Codebreakers?

Just how successful were Hitler’s Codebreakers during World War 2? It’s a question many visitors ask when they visit Bletchley Park, where our codebreaking operation was situated during the war.

It’s a good question as until now the wartime story of codebreaking has almost exclusively centred around Allied successes, particularly that of Bletchley Park. Anglo-American Sigint (Signals Intelligence) successes played a major part in the winning of the war, and undoubtedly were far more successful than the main Axis powers of Germany, Italy and Japan.

However, the Germans in particular were extremely active in codebreaking and had their successes. But it was not until after the war that the extent or otherwise of their triumphs could be gauged. With the war in Europe at an end, in April-May 1945 British and American codebreaking teams hunted for their German counterparts to find out just how good they had been. There were lessons to be learned for the post-war period for Western intelligence.

Furthermore, just how far had the Germans moved in the field of technological innovation? They did not develop the Bletchley Park equivalent of the bombe – which broke messages enciphered on the Enigma machine – or Colossus and Tunny – which broke messages enciphered on the Lorenz cipher attachment machine, which were transmitted by teleprinter and contained the secret traffic of the German High Command and Hitler personally.


My latest book Hitler’s Codebreakers – German Signals Intelligence in World War 2 is based on European Axis Signal Intelligence in World War II as revealed by ‘TICOM’ Investigations and by other Prisoner of War Interrogations and Captured Material, Principally German and completed in May 1946. This is available on the NSA website. It provides a fascinating insight into the question – how successful were Hitler’s Codebreakers at breaking Allied codes?

Below is the starting point of answering the question by understanding the type of codebreaking operation Hitler had at his command and the Allied effort to uncover just how successful Hitler’s Codebreakers had been.

TICOM – Target Intelligence Committee – was a shadowy Anglo-American organisation set up in October 1944 whose cover name disguised its real purpose – the seeking out in the immediate aftermath of the war of German Sigint staff for interrogation.

TICOM originally planned airborne operations even before the end of the war to seize key German signals intelligence targets. There were four objectives:

  • To learn the extent of the German cryptanalytic efforts against the Allies;
  • To prevent the results of such German cryptanalysis from falling into unauthorised hands;
  • To exploit German cryptologic techniques and inventions before they could be destroyed by the Germans; and
  • To uncover items of signal intelligence value in prosecuting the war against Japan – a conflict that did not end until August 1945.”

The airborne policy was abandoned in spring 1945 because known German signal intelligence agencies were dispersing or retreating in great disorder and pinpointing of locations was not possible. It would not be possible to seize German personnel and material and hold them through the confusion of major battles. So, in March 1945, TICOM setup six Anglo-US target teams to take over and exploit known or newly discovered targets of signal intelligence interest and to search for other signal intelligence targets and personnel. The first team was sent in April 1945 to the Neumünster-Flensburg area in northern Germany and other teams were rapidly dispatched to other areas as soon as they were overrun. As a result of these efforts, 4,000 documents weighing five tons were captured along with many cryptographic devices and machines. There were 196 reports issued by TICOM based on the interrogation of German signals intelligence personnel as well as miscellaneous reports and translations.

TICOM prisoner-of-war interrogations and captured documents, plus interrogations conducted by other Anglo-US agencies, in particular CSDIC – the Combined Services Detailed Interrogation Centre – gave investigators a ‘reasonably complete picture of German signal intelligence.’

Below is an introduction to the six main cryptologic organisations that led Germany to ‘considerable’ success against British medium and low-grade military and naval communications systems. Their cryptanalytic successes against the Russians exceeded that of their efforts against the United States. Successes against the diplomatic communications of Italy, Japan, France, Turkey, Bulgaria, Greece, Portugal, Spain, Switzerland and other smaller nations also achieved important results.

 

Signal intelligence organisations

Germany possessed six main cryptologic organisations with a total strength of around 30,000 people. The total of European Axis Sigint (signals intelligence) personnel was around 36,000. This compared with a total Allied Sigint staffing level of around 60,000 people. Of the six main German organisations, four were military and two civilian.

The four military organisations were:

  • Army High Command (OKH/GdNA): Located at Jüterbog, about 60 miles south-west of Berlin, it comprised about 12,000 people handling Allied Army traffic, and was the main unit of the German Army signal intelligence unit in 1945.
  • Naval High Command (OKM/4SKL III): Navy Sigint was responsible for traffic analysis, cryptanalysis and evaluation of British, American, Russian, French and Swedish naval traffic. It had a staff of around 1,000 and had operational control of a field organisation of about 2,500 individuals.
  • Air Force High Command (OKL/LN Abt 30): his was the principal Luftwaffe Sigint service. It had eight field units: three autonomous Sigint regiments comprising eight battalions and five autonomous signal intelligence battalions, in total employing 13,000 individuals. TICOM describes the codebreaking efforts of these units against the RAF and the USAAF as ‘outstanding’ and providing a ‘comprehensive and continuous picture of the battle order and deployment of USAAF and RAF units in the UK, in the Mediterranean theatre and, after D-Day, on the Continent.’
  • Armed Forces Supreme Command (OKW/Chi):  This service employed around 800 people and had three main functions: first, it intercepted, studied and evaluated diplomatic, military attaché and ‘agent’ traffic. Second, it monitored and evaluated commercial radio traffic and news broadcasts, and third, it made security studies of the codes and ciphers used by the OKW, the three armed Services and government departments, vetoing – after 1944 – the use of those it deemed insecure.

 

The two civilian organisations were:

  • Foreign Office Cryptanalytic Section (Pers Z B): This department had two cryptologic sections – the cryptanalytic section, Personal Z Sonderdienst des Auswärtigen Amtes (Pers ZS) and the cryptographic section, Personal Z Chiffrierdienst des Auswärtigen Amtes (Pers Z Chi), of which the former was the senior agency, and had been organised in 1919 or before, and had a staff of about 200. It was involved in the solving of foreign diplomatic codes and ciphers, and had one small intercept station at Dahlem. The rest of its intercept services were provided by OKW/Chi, Goering’s FA and the German Post Office. Also handled diplomatic traffic whether Allied, neutral or friendly;
  • Goering’s Research Bureau (FA): A Nazi Party agency formed in 1933 and, in addition to non-military cryptanalysis, it monitored telephone conversations in Germany and later in Austria, Denmark and ‘German’ Poland. It had access to all messages sent over German commercial teletype and telegraph facilities, and had investigators in all main postal censorship offices. During the war it liaised closely with the Abwehr – military intelligence – and later Himmler’s Reich Security Head Office (RSHA), and served the latter body as a cryptanalytic agency for Russian agent messages. It also monitored worldwide broadcasting organisations, particularly the BBC. It operated six wireless intercept stations, one for intercepting foreign diplomatic and commercial traffic.

A story that puts Hitler’s codebreaking successes into perspective is that in 1938, during the Munich Conference between Germany, Italy, Britain and France, the FA is said to have solved the British system which carried Prime Minister Neville Chamberlain’s messages to London. TICOM states: ‘Hitler once delayed a conference with Chamberlain for several hours in order to get such decodes.’

Cryptographic collaboration

The Germans never developed an inter-Service single codebreaking organisation such as Britain’s Government Code and Cypher School (GC&CS), based at Bletchley Park during the war. However, prior to 1943, there was some sort of collaboration between the various branches of the German armed forces in cryptographic matters.

TICOM says that, in general, co-operation between the FA and OKW/Chi SIA ‘were not overly cordial’ and that the Navy High Command ‘maintained a traditional navy reserve in dealing with other agencies. There was no high-level Sigint co-ordination, and there was frequent overlapping and duplication of effort between the agencies dealing with diplomatic cryptanalysis’. However, there seems to have been as much liaison and co-operation as was necessary, particularly with military field organisations.

Even with this difficulty with collaboration, it is clear from the TICOM material how the Germans understood that the Enigma cipher machine had its weaknesses, and that they had various ingenious machines either manufactured or under development to strengthen their security as the war drew to a close.

Lack of resources – and running out of time – put paid to any major operational deployment of this machinery, but underlines the fact that German ingenuity came close to a situation where they could have made Bletchley Park’s task almost impossible.

 

This article is a modified except from John Jackson’s book, Hitler’s Codebreakers – German Signals Intelligence in World War 2. You can purchase it at Amazon, at Bletchley Park Museum bookshop and it is available to download as a PDF from Scribd. The Kindle e-book will be available shortly. All author royalties from Hitler’s Codebreakers are donated to the Bletchley Park Trust.

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