Monday, January 13, 2014

Acknowledging failures of crypto security – British, Soviet and American historiography

In the course of WWII 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.
These events have gained great publicity and countless books have been published about them. People like Friedman and Turing are widely known to readers of WWII history.

While there are countless books on Bletchley Park and the American codebreakers, there are only a handful dealing with the operations of the Axis codebreakers. This would be natural if there wasn’t much to write about. Yet the exact opposite is true. German, Italian, Japanese, Finnish and Hungarian codebreakers were able to exploit many important enemy codes and their successes directly affected important campaigns and battles of the war.
For example:

Without the B-Dienst the U-boats would not have been able to locate Allied convoys in the Atlantic.

Rommel’s successes in N.Africa owed a great deal to the information he received daily from his signals intelligence unit NFAK 621 and the decoded messages of colonel Fellers.
In the Eastern Front the Germans were able to exploit a large part of the enemy codes, including the systems of the NKVD and  the high level military ones in 1941-42.

The radio-telephone conversations between Churchill and Roosevelt were decoded and sent to Hitler during the period 1941-44.
The State Departments high level strip cipher was solved during the period 1942-44.

The solution of various Allied codes may have compromised operation Overlord.
British, Polish, Czech and Soviet intelligence communications were decoded by Referat Vauck.

Italian, Japanese, Finnish and Hungarian codebreakers also had their own successes during the war.
Why haven’t the Axis codebreakers received the attention they deserve?

There are probably several reasons. Winners get to write history, so it makes sense that the Allies would not want to publicize their failures. Especially in Britain the successes of Bletchley Park are a source of national pride.
At the same time there is the issue of reliable sources. Historians need documents and official sources to put in their books. This creates a problem since many of the relevant documents were either destroyed/lost at the end of WWII or they were seized by the Allies and kept under lock and key till recently.

For example many of the German signal intelligence archives were captured by the Anglo-American at the end of WWII but large parts were destroyed by the Germans. In Japan they mostly destroyed their material before surrendering. The Finnish archives were moved to Sweden in 1944 and sold off to Japanese, Swedish, German and American officials. The Hungarian archives were moved at the end of the war to Eggenfeld, Germany where they were recovered by a TICOM team.
After the war the surviving participants were understandably weary of talking about their wartime exploits versus Allied codes.

Different archives, from different organizations, in different languages and with parts missing meant that the information they contained was fragmented. If this was not enough the material seized by the Anglo-Americans has only recently been released to the UK and US national archives.
All these problems mean that the exploits of the Axis codebreakers have not been fully recognized by historians.

Still a lot of information has reached mainstream books. It’s interesting to see how different countries have dealt with the failures of their crypto security during WWII.
Soviet Union/Russia

As I understand it during Soviet times WWII histories did not mention codebreaking. There were references to ‘radio-electronic combat’ but these dealt only with D/F, traffic analysis and jamming.
The situation seems to have remained basically the same in Russia. There are some new books that have come out and have more information on Soviet codebreaking operations but the relevant archives are still closed to researchers.

From what I’ve seen the official line is that Soviet codes were unbreakable.
United States

The situation in the US is the exact opposite of Russia. Instead of pretending that their codes were impenetrable they were the first to admit to the most important cases of compromise. The cases of the Bell Labs A-3 speech scrambler, the Fellers messages and the M-209 cipher machine have received attention from historians.
The cases that haven’t received much attention concern the military strip ciphers M-94 and M-138 and the State Department version.

However two important cases are virtually unknown to historians. These are the OSS Berne compromise and the IBM Radiotype case.

Somewhere between Soviet denials and US openness lies the ‘official’ British stance.
On the one hand the official histories ‘British Intelligence in the Second World War’ are careful not to exaggerate the importance of signals intelligence during the war. Regarding Allied cipher security they accurately describe the most important compromises, especially in N.Africa and in the Atlantic.

Volume 2 appendix 1 ‘British cypher security during the war’ has a summary of the main British cryptosystems and their exploitation by the Germans. For some reason this information doesn’t seem to be widely known as it is not mentioned in popular history books.
One of the reasons is probably that there isn’t much analysis of how these British cryptosystems were used during the war,  how secure they were and how much information the Germans got from them.

Important cases that have received no attention are the compromise of SOE codes, low level codes prior to operation Overlord , the code of Prime Minister Chamberlain, the German research on Typex and its possible compromise.
In upcoming essays i will look into the cryptographic failures of each of these countries in more detail.


  1. not to mention the codebreaking successes of some supposidly neutral countries which were in reality anything but. this might be of interest to you

    1. I’ve covered Irish codes and codebreakers here: