The British Typex cipher machine

In 1926, the British Government set up an Inter-Departmental Cypher Committee to investigate the possibility of replacing the book systems then used by the armed forces, the Foreign Office, the Colonial Office and the India Office with a cipher machine. It was understood that a cipher machine would be inherently more secure than the codebook system and much faster to use in encoding and decoding messages. Despite spending a considerable amount of money and evaluating various models by 1933 the committee had failed to find a suitable machine. Yet the need for such a device continued to exist and the Royal Air Force decided to independently fund such a project. The person in charge of their programme was Wing Commander Lywood, a member of their Signals Division. Lywood decided to focus on modifying an existing cipher machine and the one chosen was the commercially successful Enigma. Two more rotor positions were added in the scrambler unit and the machine was modified so that it could automatically print the enciphered text. This was done so these machines could be used in the DTN-Defence Teleprinter Network.

The new machine was called Typex (originally RAF Enigma with TypeX attachments). The first experimental model was delivered to the Air Ministry in 1934 and after a period of testing 30 more Mark I Typex machines were produced in 1937. The new model Typex Mark II, demonstrated in 1938, was equipped with two printers for printing the plaintext and ciphertext version of each message. It was this model that was built in large numbers and the first contract for 350 machines was signed in 1938. Typex production was slow during the war with 500 machines built by June 1940, 2,300 by the end of 1942, 4,078 by December 1943 and 5,016 by May 1944. By the summer of 1945 about 11.000 (8.200 Mk II and 3.000 Mk VI) had been built (1).

Update

I have added the National Institute for Defense Studies articles ‘Japanese intelligence and the Soviet-Japanese border conflicts in the 1930s’ and ‘Japanese Intelligence and Counterinsurgency during the Sino-Japanese War: North China in the 1940s’ in the sources of Japanese codebreakers of WWII.

Update

I added information from ‘Report on interrogation of Walter Schellenberg 27 June- 12 July 1945’ (which can be found in British national archives folder KV 2/95) in Intercepted conversations - Bell Labs A-3 Speech scrambler and German codebreakers, Reich security service and OKW/Chi reports and Allen Dulles and the compromise of OSS codes in WWII.

Also added information from the report E-Bericht Nr. 3/44 der NAASt 5 (Berichtszeit 1.4-30.6.44) in German intelligence on operation Overlord and The American M-209 cipher machine.

Compromise of US M-209 cipher machine prior to the invasion of Normandy

Sometimes the answer to an interesting question is right in front of us but we can’t see it because we’re not paying attention…

In my essay German intelligence on operation Overlord I said about the M-209 cipher machine:

The M-209 cipher machine was used extensively by the US armed forces in the period 1943-45. Army units in England sent training messages on the M-209 which the Germans decoded.

The USAAF used it in operational and administrative networks.

M-209 traffic together with D/F may have allowed the Germans to discover the concentration of US forces in the South.

After having a look at the report E-Bericht Nr. 3/44 der NAASt 5 (Berichtszeit 1.4-30.6.44) it is clear that the Germans were in fact able to get order of battle intelligence on the US forces in the UK. In pages 2-3 it says:

 

 

Activity report before the invasion

…………………………………………

1). AM1:

Focused on decoding the AM1. Ten absolute settings were recovered, which brought the deciphering of 1,119 messages. This cipher-material, mostly composed by the U.S American Expeditionary Corps, gave valuable insights into the location of enemy groups.

AM1 (Amerikanische Maschine 1) was the German designation for the M-209.

German special intelligence, the M-138 strip cipher and unrest in India

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. Similarly the codebreakers of the Axis nations also had their own victories versus Allied codes.

One of the most important Allied cryptosystems compromised by the codebreakers of Germany, Finland and Japan was the State Department’s M-138-A strip cipher.  This cipher system was used for important messages by US embassies around the world and also by the Office of Strategic Services and the Office of War Information.

Unfortunately accurate information on the compromise of this system is limited and the statements made in some of the available TICOM reports are often contradictory. Still it is clear that from 1940 till late 1944 the Axis codebreakers were able to read a lot of the traffic sent on the ‘circular’ and ‘special’ strips.

In complicated cases like this one the only way to find more information is by checking all the available sources. During WWII there was an exchange of information between Germany, Finland and Japan on the State Department’s strip cipher. Some of these messages were intercepted and decoded by the Western Allies, so it is possible to track the progress of the Axis codebreakers through their decoded messages.

Reich security service and OKW/Chi reports

Intelligence services collect information from various sources such as magazines, journals, newspapers, government reports, secret agents etc. However the most accurate source has always been the decoded traffic of a foreign state’s diplomatic and military networks. For this reason there has always been a close relationship between a country’s human intelligence and signal intelligence agencies.  

During WWII the British foreign intelligence service benefitted from the successes of Bletchley Park versus Axis military, diplomatic and agents codes. Similarly the German foreign intelligence services received summary reports from the Signal Intelligence Agency of the Supreme Command of the Armed Forces - OKW/Chi (Oberkommando der Wehrmacht/Chiffrier Abteilung).

The Sicherheitsdienst was the security service of the SS and its foreign intelligence department Amt VI (headed by General Walter Schellenberg) had some notable successes during the war. According to Schellenberg and two high-ranking SD officials their agency received daily reports from OKW/Chi, containing important diplomatic messages from Bern, Ankara, Algiers, Moscow and other areas.

Since it seems that most of the OKW/Chi archives were destroyed or lost at the end of WWII these statements are important in evaluating the successes or failures of that organization.

1). General Schellenberg was interrogated postwar by the Allies and in ‘Report on interrogation of Walter Schellenberg 27 June- 12 July 1945’, p30 he said:

The Germans broke the American code. Messages sent by HARRISON, U.S.A. minister in Berne, to Washington, lay daily deciphered on SCHELLENBERG's desk. These messages sometimes contained intelligence service material. SCHELLENBERG also received Turkish, Polish, French, Swiss, South American, Spanish and Portuguese messages which were all decoded.

 
2). SS-Sturmbannführer Dr. Klaus Huegel was an important SD official with knowledge of German spy activities in Switzerland and Italy. In one of his postwar interrogations he mentioned that from April 1943 to March 1944 he had access to the daily reports sent from OKW/Chi to General Schellenberg. The reports often included US diplomatic messages from Bern, Switzerland, British messages from the Bern embassy, De Gaulle traffic from Algiers to Washington and messages from the Turkish ambassador in Moscow.

3). Giselher Wirsing was an accomplished author and journalist, who in 1944 joined the SD foreign intelligence department as an evaluator. Wirsing had come to the attention of General Schellenberg due to his clear headed analysis of the global political situation and of Germany’s poor outlook for the future. Under Schellenberg’s protection he wrote a series of objective reports (called Egmont berichte) showing that Germany was losing the war and thus a political solution would have to be found to avoid total defeat. While writing his reports Wirsing had access to the OKW/Chi summaries sent to the SD leadership. According to him the messages ‘did not reveal any startling news‘ but were useful in assessing  information from other sources. He remembered messages from the US, Japanese, Turkish and Bulgarian ambassadors in Moscow,  State Department messages to Paris, traffic from the US mission in the Balkans and messages from the Polish mission in Jerusalem to their London based goverment in exile.

 

Overall it is clear that OKW/Chi provided valuable information to the Sicherheitsdienst leadership, even though they served different masters (OKW/Chi was subordinated to the military while the Sicherheitsdienst came under the control of the Nazi party).

Sources: CIA FOIA reports HUEGEL, KLAUS No 22 and WIRSING, GISELHER No 16,
British national archives KV 2/95 ‘Walter Friedrich SCHELLENBERG: rose to be No. 2 in the S.D. and was close to Himmler’

Update

In my essay German intelligence on operation Overlord the paragraph

Another German agent in Lisbon said in May 1944: ‘the plan of attack favored by the Allies was an assault on La Manche (Cherbourg) peninsula.’ [Source: ‘British intelligence in the Second world war’ vol3 part 2, p61]

is replaced with:

From Lisbon the agent Paul Fidrmuc sent a report correctly identifying the endangered area ‘the plan of attack favored by the Allies was an assault on La Manche (Cherbourg) peninsula’. According to his postwar interrogation he got this information from his agent ‘TOR’ in the UK.

 

[Sources: ‘British intelligence in the Second world war’ vol3 part 2, p61 and KV 2/198 ‘Paul Georg FIDRMUC, alias FIDERMUTZ, RANTZAU, codename OSTRO’]

Update

I’ve added information from a report titled ‘Penetration and compromise of OSS in Switzerland and Western Europe’ in Allen Dulles and the compromise of OSS codes in WWII.

I’ve also located a very interesting report on tank warfare during the Korean War. There is information on the performance of the T-34 tank from US reports and N. Korean POW interrogations. It seems the T-34/85 had serious shortcomings in Korea…I’ll write more about this in the future.