Unanswered questions of WWII cryptology – progress report

Back in 2013 I wrote down several cases of WWII cryptologic history that require more research. Since then I’ve spent a lot of time and money trying to find new information. Has the effort paid off? Let’s have a look at each case:

1). US State Department strip cipher

I wrote: How bad was the compromise of the State Department’s high level system? That question is hard to answer because there is limited information available and it doesn’t seem like the Americans were really interested in learning the full extent of the compromise. Some documents that would shed more light on this affair are proving very hard to find…

I’ve been able to find more information on this case, including the way the M-138 strip cipher was used by the State Department, decoded US diplomatic traffic found in the US and Finnish national archives, the exploitation of US traffic by the Japanese in the period 1940-41 and the efforts of the German cryptanalyst Wolfgang Franz at OKW/Chi.

It is clear that Germans, Japanese and Finns were able to solve many alphabet strips both circular and special and thus read State Department messages from embassies in Europe and Asia. The most important intercepted messages seem to have been those from Bern, Switzerland and Chungking, China.

Unfortunately several important reports are still classified by the NSA and we have to wait for the declassification procedure. At the same time I haven’t been able to track down the Carlson-Goldsberry report, detailing the Finnish solution of the State Department strip cipher. This report was written in late 1944 by two US cryptanalysts after interviewing Finnish codebreakers in Sweden. 

Another aspect of this case concerns the messages from the OSS - Office of Strategic Services and OWI - Office of War Information stations in Bern that were also sent via diplomatic channels. It’s not clear why these messages were sent using State department codes and not through their own systems. In this area information is lacking, since the OSS organization doesn’t seem to have officially acknowledged the compromise of their communications during the war.

2). NKVD 5^th Department codebreakers

During WWII the Soviet Union invested significant resources in the interception and exploitation of enemy radio traffic. The internal security service NKVD and the Army’s general staff had codebreaking departments with the former recruiting many talented mathematicians. According to author Matthew Aid  ‘By the end of World War II, the 5th Directorate controlled the single largest concentration of mathematicians and linguists in the Soviet Union.’

So far very limited information is available regarding their war time efforts versus foreign codes (not only Axis but also US, UK and those of neutral countries).

 3). Referat Vauck success

In the period 1942-44 the German Army’s signal intelligence agency Inspectorate 7/VI had a separate deparment (Referat 12) assigned with the solution of the encoded messages of Allied spy groups operating in occupied Europe. Head of the department was dr Wilhelm Vauck, so his unit was also called Referat Vauck. In 1944 they were transferred to the OKW radio defense department so their reports can no longer be found in the files of Inspectorate 7/VI.

I had written about this case: How successful were they during the war? Unfortunately we do not know. The relevant file in the British national archives HW 40/76 ‘Enemy exploitation of SIS and SOE codes and cyphers’ says that postwar files have been retained and my request for the release of the interrogations of dr Vauck has been rejected by the archives staff

Thankfully I‘ve been able to track down the monthly reports of Referat 12 for the period April ’42-February ’44 and I will be writing an essay on them.

An interesting discovery, made while I was trying to find information on Referat Vauck, was that OKW/Chi was also solving Allied agents codes during the war (with significant success it seems). Not much is known about this aspect of OKW/Chi operations…

4). Forschungsamt information

Goering’s Forschungsamt was one of the main German codebreaking/intelligence agencies of the period 1939-45, yet a detailed history of that organization still eludes us. This is another case where it’s up to the NSA to declassify the relevant documents, written by Forschungsamt personnel in the 1950’s.

5). German Enigma investigations

Several authors claim that the Germans never suspected that their Enigma cipher machine was solved by the Allies and that they considered it to be unbreakable.

I had written: The Germans constantly evaluated the security of their Enigma cipher machine. There were many studies on whether the daily key or parts of it could be retrieved through cryptanalysis. Those studies are the TICOM DF-190 to DF-190AN files…..More research is needed to evaluate the German methods and the way they influenced their security measures.

Since then I’ve posted information on case ‘Wicher’ (Polish solution of the Enigma) showing that the Germans knew the device had been compromised in the prewar period and in 1943 they got information from the US regarding the solution of their naval version.  So far it’s clear that the German Navy’s codebreakers found a solution for their 4-rotor machine in late ’44 but we don’t know much about the similar work of the Army cryptanalysts. More research is needed in this case.

6). Japanese Purple and Coral cipher machines

Were the Germans able to solve the cipher machines used by the Japanese foreign ministry and by Japanese military attaches?

I wrote: PURPLE was solved by American and Soviet codebreakers. Did the Germans have any success with it? Until recently the answer was no. 

However it seems there is more to this story.

The Coral machine was used by military attaches and the Anglo-Americans solved it in 1944. In the same year dr Steinberg of the German Army’s signal intelligence agency was transferred to OKW/Chi where he worked on a cipher machine used by the Japanese attaché. Did he manage to solve it? 

TICOM report I-64 ‘Answers by Wm. Buggisch of OKH/Chi to Questions sent by TICOM’ says ‘B. thinks Steinberg (of 209 fame) solved some Jap machine traffic which was difficult but not so hard as Enigma. B. thinks it was traffic of the Jap Military Attache.’

There is scattered information that points towards the solution of an important Japanese code or cipher machine in the period 1943/44 but no conclusive evidence. Maybe more information will become available in the future.

7). Soviet diplomatic code

I wrote: The Soviet Union used a code enciphered with one time pads as its main diplomatic system during WWII. This system if used correctly is unbreakable. 

Were the Germans able to read parts of this traffic? There are some strange statements in Allied and German reports…

The recently declassified TICOM report DF-111 ‘Comments on various cryptologic matters’ by Adolf Paschke (head of the linguistic cryptanalysis group in the German foreign ministry’s decryption department) says that in the years 1927-30 parts of the Soviet diplomatic traffic could be read since the additive pads were sometimes used twice if the message was long enough. Paschke had also identified the use of the same additive tables more than once in some links. Regarding wartime traffic he says that they couldn’t solve any since there were no repetitions but in the report he also added cryptically that Russian material of the Forschungsamt and the High Command’s deciphering department OKW/Chi were destroyed in 1943 during a bombing attack on Berlin.

Although the Germans might have not solved any Soviet diplomatic traffic they did succeed in solving Comintern communications.

8). M-209 decoding device

I wrote: I’m surprised that no one has figured out how this machine worked!

I have to say I’m still surprised that this device has not received any attention from historians and/or the media!