Wednesday, July 30, 2014

Compromise of OWI - Office of War Information communications

In 1942 the US government created a new organization called the Office of War Information, headed by Elmer Davis. This organization absorbed the functions of several other government departments such as the Office of Facts and Figures (OWI's direct predecessor), the Office of Government Reports, the Division of Information of the Office for Emergency Management and the Foreign Information Service.

The OWI had representative in countries abroad and participated not only in news gathering activities but also Anti-Axis propaganda and even espionage. Especially in Bern, Switzerland the local station, headed by Gerald M Mayer, cooperated closely with the OSS - Office of Strategic Services station of Allen Dulles.

Monday, July 28, 2014

Svetova Revoluce and the codes of the Czechoslovak resistance

At the end of the First World War the multiethnic Austro-Hungarian Empire collapsed and out of its ruins emerged several new countries. One of these was Czechoslovakia, containing the Czech areas of Bohemia and Moravia together with Slovakia and Carpathian Ruthenia in the east.

In the interwar period Czechoslovakia followed a foreign policy supportive of France and was part of the Little Entente. The country had a stable democracy and its industrial resources were large (based on the Skoda works) for such a small country. However there were two important problems affecting Czech national security. On the one hand the rise of Nazi Germany and its rearmament was a clear security threat. At the same time there were serious problems with the German and Slovak minorities that resented Czech rule.  

Czechoslovakia contained a large number of minorities that were dissatisfied with the ruling Czech establishment. Especially the German minority made up roughly 23% of the population (according to the 1921 census) and a large part of it was concentrated in the border with Germany called Sudetenland. Many of the Sudeten Germans wanted for their areas to be unified with Germany and in the 1930’s Hitler’s Germany supported the demands of the Sudeten German Party. These claims were rejected by the Czech government of Edvard Beneš and as the Czech crisis threatened Europe with a new war a conference took place in Munich between the governments of Germany, Italy, Britain and France 

Without support from Britain and France the Czech government was forced to cede the Sudeten territories to Germany and also lost other disputed areas to Hungary and Poland. Even though Germany had succeeded in absorbing the Sudeten areas and in weakening Czechoslovakia that did not stop Hitler’s offensive plans and in March 1939 German troops invaded and occupied the rest of the country. From then on the country was ruled by Germany and special attention was given to its heavy industry which produced weapons for the German armed forces.
During the war the Czech Government in Exile, headed by Beneš, was based in London and had regular communications with the Czech resistance. The most daring operation of the resistance was the assassination of Reinhard Heydrich, protector of Bohemia and Moravia and former head of the Reich Main Security Office. However after this episode the Germans took many security measures and were generally able to keep the resistance activities under control. In this area they took advantage of the insecure communications between the resistance and the Czech intelligence service, operating from Britain.

Tuesday, July 22, 2014

Compromise of Soviet codes in WWII

Signals intelligence and codebreaking played an important role in WWII. British and American codebreakers solved many important Axis crypto systems, such as the German Enigma machine and the Japanese Navy’s code JN25. 

Historians have not only acknowledged these Allied successes but they’ve probably exaggerated their importance in the actual campaigns of the war.
Unfortunately the work of the Axis codebreakers hasn’t received similar attention. As I’ve mentioned in my piece Acknowledging failures of crypto security all the participants suffered setbacks from weak/compromised codes and they all had some successes with enemy systems. 

Britain, the Soviet Union and the United States did not have impenetrable codes. In the course of WWII all three suffered setbacks from their compromised communications.
After having dealt with the United States and Britain it’s time to have a look at the Soviet Union and their worst failures. 

Move along comrade, nothing to see here
Compromises of communications security are usually difficult to acknowledge by the countries that suffer them. For example since the 1970’s countless books have been written about the successes of Bletchley Park, yet detailed information on the German solution of Allied codes only started to become available in the 2000’s when TICOM reports and other relevant documents were released to the public archives by the US and UK authorities.

In Russia the compromise of their codes during WWII has not yet been officially acknowledged and the archives of the codebreaking organizations have remained closed to researchers. This is a continuation of the Soviet policy of secrecy.
The Soviet Union was a secretive society and information was tightly controlled by the ruling elite. This means that history books avoided topics that embarrassed the regime and instead presented the officially sanctioned version of history. Soviet era histories of WWII avoided references to codes and ciphers and instead talked about ‘radio-electronic combat’ which dealt with direction finding, traffic analysis and jamming (1).

After the fall of the Soviet Union several important government archives were opened to researchers and this information has been incorporated in new books and studies of WWII. However similar advances haven’t taken place in the fields of signals intelligence and cryptologic history. Unlike the US and UK that have admitted at least some of their communications security failures the official line in Russia is that high level Soviet codes were unbreakable and only unimportant tactical codes could be read by the Germans. Even new books and studies on cryptology repeat these statements (2).
However various sources such as the TICOM reports, the war diary of the German Army’s signal intelligence agency Inspectorate 7/VI and the monthly reports of the cryptanalytic centre in the East Horchleitstelle Ost clearly show that the Germans could solve even high level Soviet military and NKVD codes.

Monday, July 21, 2014


I have uploaded TICOM report DF-111 ‘Comments on various cryptologic matters’. Acquired through the NSA’s FOIA office. Available from my Google docs and Scribd accounts.

I have rewritten Soviet Diplomatic Code 26 and the elusive Dr Roeder using information from DF-111.

Friday, July 18, 2014


I have uploaded TICOM report DF-105 ‘Determination of the Absolute Setting of the AM-1 (M-209) by Using Two Messages with Different Indicators’. Acquired through the NSA’s FOIA office.

Available from my Google docs and Scribd accounts.

Monday, July 14, 2014

Compromise of Soviet codes in WWII – the good, the bad and the unexpected

After covering the cryptologic failures of the United States and Britain in WWII, i’m currently writing a summary of the compromise of Soviet codes in WWII, however there are some good news and some bad news regarding the available sources.

The good news
The war diary of the German Army’s signal intelligence agency Inspectorate 7/VI and the reports of the cryptanalytic centre in the East Horchleitstelle Ost (later named Leitstelle der Nachrichtenaufklärung) are available for the period 1941-43. Also summaries on the solution of Soviet codes are available for the period October 1944-March 1945.

The bad news
I haven’t been able to find the reports of Horchleitstelle Ost for the second half of 1941 and for the period February- September 1944.

The unexpected
According to a recently declassified TICOM report the Germans were able to read the first version of the Soviet diplomatic one time pad code in the 1930’s and the codes of the Comintern. In the first case their success was due to the fact that the system was not true one time pad in that one additive page was assigned to each message. If the values were not enough to encipher the entire message then they were reused.

In the case of the Comintern it seems that the main system used by Communist Parties around the world was a numerical code used together with a letter to number substitution table. The table was used as a ‘key’ generator for additive sequences used to encipher the coded message. A common book would be used for this purpose and the user would identify through the indicator the page and line that the sequence would start from.  In one such case the Germans solved the ‘encipherment sequence of about five million digits’ and identified the five books used as cipher.

Wednesday, July 9, 2014

The French War Ministry’s FLD code

In May 1940 Germany shocked the world by defeating the combined forces of France, Britain, Belgium and Holland in a short land campaign. Unlike World War I that had ended in millions of deaths and a stalemate in the West, this time the German forces were able to quickly defeat their opponents. After France’s defeat several theories were promoted, trying to explain this strange outcome. Some focused on the supposed superiority of the Germans in manpower and armaments, while others tried to point to the German Panzer divisions that supposedly had a big advantage over the similar French units.

General Gamelin who commanded the French forces told Churchill that the defeat was due to: ‘Inferiority of numbers, inferiority of equipment, inferiority of method’. In fact both sides had roughly similar strength in troops and aircraft while in tanks it was the Franco-British alliance that had the advantage, both in terms of numbers and of quality.
However the German were able to overcome their tank inferiority by grouping their armored divisions together, supporting them with ample airpower and providing them with dedicated infantry, anti-tank, artillery and communication units. At the same time their radio communications system was much more advanced than the French Army’s and orders could be dispatched quickly and securely to all units.

The German leadership also took a big risk by attacking through the Ardennes area with the purpose of cutting off the northern part of the Allied front.
Another area where the Germans had the advantage was in signals intelligence. Unfortunately historians have focused almost exclusively on the German Enigma cipher machine and its solution by the codebreakers of Bletchley Park thus neglecting the many successes of the German codebreakers 

The German victories during the period 1939-1942 in France, N.Africa, Atlantic and in the Eastern Front were achieved at least in part thanks to their ability to read their enemies communications.
French military codes and the Battle of France

The French military and civilian authorities used for their secret communications several codebooks, both enciphered and unenciphered. Individually these systems did not have a very high degree of security but it seems that the French strategy was to overwhelm enemy codebreakers through the simultaneous use of a large number of different codebooks. (1)
In addition to the codebooks a number of Hagelin B-211 and C-36 cipher machines had been ordered in the 1930’s. These cipher machines proved secure in 1940 but it doesn’t seem like they were available in large numbers since the codebooks continued to be used on important French communications links.

From recently released TICOM reports and various books it is clear that the Germans could read French Army tactical codes (2), the Navy’s main cipher system (3) and the Airforce’s ‘Aviation Militaire’ (4). By exploiting these systems the Germans obviously got valuable intelligence. However their main success that directly contributed to their victory in 1940 was achieved against a high level enciphered code used by the French War Ministry.

Monday, July 7, 2014

Case ‘Wicher’ – Information from the war diary of Inspectorate 7/VI

In the Second World War the Allies and the Axis fought battles not only with tanks, aircraft and infantry but also in the fields of signals intelligence and cryptology. Both sides tried to protect their communications from outsiders by using complicated cipher procedures and their codebreakers made every effort to solve enemy codes and thus gain valuable intelligence.

The Anglo-Americans were able to gain information of great value from reading their enemies secret communications. In Britain the codebreakers of Bletchley Park solved several enemy systems with the most important ones being the German Enigma and Tunny cipher machines and the Italian C-38m. Codebreaking played a role in the Battle of the Atlantic, the North Africa Campaign and the Normandy invasion. In the USA the Army and Navy codebreakers solved many Japanese cryptosystems and used this advantage in battle. The great victory at Midway would probably not have been possible if the Americans had not solved the Japanese Navy’s code.
However the Axis codebreakers also had their successes and they were also able to compromise various Allied crypto system both low and high level.

One interesting question that often comes up in history books is whether the Germans ever suspected that their Enigma cipher machine was being read by the Allies and how the war could have taken a different turn had they managed to discover that it was not secure.
The truth is that the Germans never considered the Enigma to be unbreakable and in fact they had discovered in 1939 that the Poles had solved messages. During the war they continued to investigate the Polish solution of the Enigma, which they called case ‘Wicher’. (1)

Wednesday, July 2, 2014

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

Nazi Germany had several codebreaking agencies both military and civilian. The armed forces had separate agencies for the Army, Navy and Airforce plus there were codebreaking departments in the Foreign Ministry, in Goering’s Forschungsamt and in the Supreme Command of the Armed Forces. This last department operated on civilian lines even though it was subordinated to the military.

The OKW/Chi agency
OKW/Chi - Oberkommando der Wehrmacht/Chiffrier Abteilung was the Signal Intelligence Agency of the Supreme Command of the Armed Forces. It had been established as a separate agency in 1920 and in the interwar period it was able to solve the codes of many foreign countries. Initially the focus was on philological research but the introduction of more complex codes and ciphers led the Germans to invest in mathematical research in the field of cryptanalysis.

The person who orchestrated this change in priorities was Wilhelm Fenner. Fenner started working for the department in 1921 together with his friend Fedor Novopaschenny, a former Tsarist codebreaker and in 1922 became an official employee. In the beginning he didn’t know much about solving codes but he learned mathematical techniques from his Russian friend and came to realize that the agency would need to make organizational changes in order to solve the more difficult foreign cryptosystems.
Since Fenner quickly became head of the cryptanalysis department he was able to carry out his plan to reorganize the agency. First he introduced a more rigorous training program for analysts and concentrated on the scientific analysis of cryptologic history and systems.

The next step in the 1930’s was to hire mathematicians.
Professor Huettenhain and OKW/Chi’s mathematical research department

The first mathematician hired by Fenner was Erich Huettenhain. In the mid 1930’s Huettenhain worked at the observatory of the University of Münster and came to Fenner’s attention when he contacted Chi with some of his proposals for cryptographic systems. Although his systems were ‘unusable without exception’ he was offered a job at Chi and he accepted.
Huettenhain became responsible for mathematical analysis of more difficult cipher systems and in the early years of WWII new personnel were hired to form a separate mathematical research department.

During the war they solved several difficult foreign cipher systems. Weber was successful with a Japanese diplomatic code transposed on a stencil, Witt solved the stencil subtractor frame used by the Polish diplomatic and intelligence service and Franz was responsible for the exploitation of the State Department’s strip cipher.
Apart from the aforementioned individuals, two more mathematicians, Karl Stein and Gisbert Hasenjaeger were hired to work in the cipher security department.

Professors Franz and the State Department’s strip cipher
According to the recently declassified TICOM report DF-176 ‘Answers written by professor doctor Wolfgang Franz to questions of ASA Europe’ Wolfgang Franz primarily studied mathematics in the period 1924-1929, during 1930-1934 worked as an assistant at the mathematical seminar at the University of Marburg and in 1937 moved to the University of Giessen as an assistant. When at the beginning of WWII the University of Giessen was closed down he spent a semester as a substitute at the University of Gottingen.

Franz’s area of expertise was topology.
Thanks to a friend of his who knew Huettenhain he was able to get assigned to the OKW Cipher department in Berlin in 1940. The initial training program consisted of solving simple codes and ciphers and as Franz was easily able to cope with these he moved on to real traffic.

The first systems he worked on were a Mexican and a Greek code and he was able to solve them. The most important system solved by Franz was the US diplomatic M-138-A strip cipher, called Am10 by the Germans:
‘Especially laborious and difficult work was connected with an American system which, judging by all indications was of great importance. This was the strip cipher system of the American diplomatic service which was subsequently solved in part.’

According to DF-176, p6 Franz had started his own investigations into this system and was able to make some limited progress when he received the ‘circular’ strips 0-1 and three ‘special’ strips used between Washington and Helsinki, Tallinn and Reval. Using these strips messages could be solved and his investigations could move forward.
Thanks to the success of the department is solving the strip cipher dr Huettenhain was able to hire more mathematicians and expand the research section.

Regarding the strip cipher 70 ‘different traffics’ (links?) were identified and 28 solved plus 6 numerical keys.

It is interesting to note that a special cryptanalytic device called the ‘Tower-Clock’ was used to solve the strip system. Franz says in pages 9-10:

In addition, there was built at my suggestion at the Bureau an electric machine which permits determining a number of repetitions of letters in a polyalphabetic substitution on a width of 30 with a depth of 20 to 80 lines, taking one line at a time, which naturally is fundamental for problem (f) above.

According to EASI vol2 ‘Notes on German High level Cryptography and Cryptanalysis’   , p56-57               
c. Statistical "depth-increaser." - The "Turmuhr," or "Tower-Clock  was a device for testing a sequence of thirty consecutive cipher letters statistically against a given "depth" of similar sequences, to determine whether the former belonged to the given depth. It was used "primarily for work on the U.S. strip cipher, when cribbing which was generally employed was impossible. It cost approximately $1,000.00.

The apparatus consisted of a single teleprinter tape reading head (speed 1 1/2 symbols per second); a storage means, by which any one of five different scores could be assigned, on a basis of frequency, to each of the letters in the 30 separate monoalphabets that resulted from the 30 columns of depth; a distributor that rotated in synchronism with the tape stepping, and selected which set of 30 scores was to be used as basis for evaluating the successive cipher letters; and a pen recording device.

The German codebreakers were only able to exploit the strip cipher to such a degree thanks to serious mistakes in the use of the system by the State Department. Franz acknowledged this in page 6 of the DF-176 report:

This strip cipher system, when rightly employed, doubtlessly has great advantages .It appears to me, however, that it was not used with sufficient caution. Only through carelessness, in part through lack of care in setting up, was it possible to break into the system as far as we did. Only after the Americans had obviously noticed that many of their messages were being read was the application so modified that although the basic idea was the same the possibilities of breaking in were materially reduced.  

Postwar career
In the postwar period professor Franz returned to teaching at Frankfurt University where he eventually became dean of the newly established Department of Mathematics. Also in 1967 he became president of the German Mathematical Society.

In the end It might give some comfort to the Americans to know that their strip cipher was solved by a real gentleman, as report DF-176 says: ‘Personal contact with Dr Franz indicated that he was a gentleman of unusual scholarship and integrity, an impression confirmed by the report’.
Sources: TICOM reports DF-187 A-G and DF-176, ‘European Axis Signal Intelligence in World War II’ vol2


I have uploaded TICOM report DF-176 'Answers written by professor doctor Wolfgang Franz to questions of ASA Europe' - 1949. Acquired through the NSA’s FOIA office.

Available from my Google Docs and Scribd accounts.

Upcoming essays

After finally receiving the documents I was waiting for I can write a detailed essay about the compromise of Soviet codes in WWII. Within the month I’ll also try to cover other interesting cases such as the German investigations on the solution of the Enigma by the Polish codebreakers and the FLD code used by French War Ministry in the period 1939-1940.

In the news

Cryptome has a kickstarter campaign. If you can support them, do so!

Nigel Askey, author of the essay ‘The T-34 in WWII: the legend vs. the performance’ has updated his very interesting website Check it out if you’re interested in analysis of weapon system effectiveness and wargaming simulations.