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 Nachrichtenaufkl√§rung) 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.