German cipher security reports from 1944

I have uploaded the following documents to my TICOM folder:

1). Report titled: ‘Überprüfung der Sicherheit eigener Geheimschriften’ dated 25 August 1944.

Source: Württembergische Landesbibliothek Stuttgart - Kapsel 137 / 14.

2). Report titled: ‘Niederschrift der Besprechung über Chiffrierfragen - 15.11.44’ dated 21 November 1944.

Source: German Foreign Ministry’s Political Archive - TICOM collection – file Nr 1.620 – ‘1938/45 Korrespondenz Dr. Hüttenhain’.

Cipher systems of the German Foreign Ministry

The TICOM report IF-266 ‘DEPARTMENT OF STATE REPORTS ON THE GERMAN FOREIGN OFFICE’ has some information on the codebooks and cipher procedures used by the German Foreign Ministry during WWII:

Pages from the diplomatic codebook No4:

Use of cipher systems by embassy and consulate:

To err is human vol 4

In my essay Rommel’s microwave link I had mentioned that a German speech cipher system was used on a microwave link connecting the German high command with Rommel’s HQ in North Africa.  

According to ‘Spread Spectrum Communications Handbook’ vol1:

'In 1935, Telefunken engineers Paul Kotowski and Kurt Dannehl applied for a German patent on a device for masking voice signals by combining them with an equally broad-band noise signal produced by a rotating generator. The receiver in their system had a duplicate rotating generator, properly synchronized so that its locally produced noise replica could be used to uncover the voice signal. The U.S. version of this patent was issued in 1940, and was considered prior art in a later patent on DSSS communication systems. Certainly, the Kotowski-Dannehl patent exemplifies the transition from the use of key-stream generators for discrete data encryption to pseudorandom signal storage for voice or continuous signal encryption. Several elements of the SS concept are present in this patent, the obvious missing notion being that of purposeful bandwidth expansion.

The Germans used Kotowski’s concept as the starting point for developing a more sophisticated capability that was urgently needed in the early years of World War II. Gottfried Vogt, a Telefunken engineer under Kotowski, remembers testing a system for analog speech encryption in 1939. This employed a pair of irregularly slotted or sawtoothed disks turning at different speeds, for generating a noise-like signal at the transmitter, to be modulated/multiplied by the voice signal. The receiver’s matching disks were synchronized by means of two transmitted tones, one above and one below the encrypted voice band. 

This system was used on a wire link from Germany, through Yugoslavia and Greece, to a very- and/or ultra-high frequency (VHF/UHF) link across the Mediterranean to General Erwin Rommel’s forces in Derna, Libya.'

After having a look at google patents I saw that Vogt was credited with a patent and I thought that this was the speech cipher system but I was corrected by klausis krypto kolumne commenter ‘Thomas’, who linked the Kotowski-Dannehl patent.

Thus in Rommel’s microwave link I’ve added a link and pics to patent US2211132A.

German 80mm Photophone - Carl Zeiss Lichtsprechgerät

One interesting communications device used by the German Armed forces during WWII was the photophone. This was a device that used light waves to transmit speech over long distances.

The photophone models built by the Germans were constructed by the well known Carl Zeiss company. One of these, the 80mm model, was captured by Allied forces in North Africa and it was evaluated by scientific personnel.

The report they produced is called ‘The 80mm German Photophone’ and can be found at the US National Archives and Records Administration.

The file can be downloaded from my Scribd and Google docs accounts.

 

Additional information on the photophone is available from site fieldgear.org and wehrmacht-awards.

The Jellyfish radio-teletype link

During WWII the Germans used radio-teletype machines with automatic enciphering capability for sending high level messages. In 1944 there were several links throughout Europe, connecting the German High Command with Army Groups.

The link Paris-Berlin was called Jellyfish by the people of Bletchley Park. This link was first detected in January ‘44 and it used the Lorenz SZ-42 cipher machine. Jellyfish connected OB WEST-Commander in Chief West with the OKH so this traffic was important for the operation Overlord planners.

The official history ‘British Intelligence in the Second World War’ vol3 part 1 says that this traffic was intercepted since January 1944 and first ‘broken’ in March. Appendix 2 says that ‘in the months before the Normandy landings its decrypts were to be of the greatest value’.

This might be an exaggeration. The Jellyfish ‘break’ was a great codebreaking success but it did not have a strategic effect on operations and planning for several reasons. The main one was that the ‘break’ took place too late in the planning process. By March/April the Overlord plan could not be altered, only small changes could be made based on the new intelligence. This problem was compounded by the long delay in decrypting the SZ42 messages. Usually it took a week or more to solve them.

In addition a lot of the Information on the Jellyfish decrypts could not be understood. The Germans used a special form for their strength reports and this could not be ‘decoded’ by the British.

According to ‘British Intelligence in the Second World War’ vol3 part 2 the main contribution of the Jellyfish intelligence was to ensure that the Fortitude deception was successful and in late May to change the landing sites for the aerial landings by the US airborne divisions so they would not fall directly on top of German occupied areas.

I’ve already given my opinion on the Fortitude operation here. As for the airborne operation in practice the transport planes were unable to drop the paratroopers in the correct positions, so the outcome was the same.

The people of Bletchley Park ran out of luck in June. On June 10 they lost access to Jellyfish and in July they also lost the Berlin-Rome link. They would manage to solve them again in September. This setback was caused by an improvement in the German security procedures (P5 limitations and daily change of the internal settings).

Sources: ‘British Intelligence in the Second World War’ vol3 part1 appendix 2, ‘Decrypted Secrets: Methods and Maxims of Cryptology’, ‘The Normandy Campaign 1944: Sixty Years On’ chapter 14

Acknowledgements: I have to thank Marek Grajek for pointing out that the loss of Jellyfish was not only attributable to ‘P5 limitations’ but mainly to the daily change of machine settings for the SZ42 (positions of the pins in the wheels). Prior to June the internal settings were changed monthly.

German microwave communications of WWII

During WWII the Germans used microwave communications in areas where it was not possible to have landlines. This was either due to geography or for military reasons (partisan interference etc).

There were several types of microwave equipment. The main types were:

1.     Michael - DMG 4,5 (one speech plus 3 teletype channels)

2.     Rudolf -DMG 3aG  (9 channels)

3.     Stuttgart I and II - Fu G 03 (10 channels)

These types could be used together with carrier frequency equipment which allowed for several teletype links to be passed on each channel.

A good source on the German comm equipment is cdvant.org

The microwave equipment was used in all theaters. After the German forces in Stalingrad were surrounded it was this type of equipment that allowed for voice communications with the outside world.

The equipment used had a max range of 40km so in order to extend this to 110km it was necessary to find the highest possible location. The Germans built a tower on a hill near Nizhnyaya Chirskaya and during the night they raised the microwave tower and communicated with the encircled forces. During the day however they dismantled the tower because the Soviet airforce would destroy it.

This link was used by general Paulus to communicate with general von Manstein and other high level personnel.

Voice communications were not available after 22 December ’42 due to the withdrawal of the German front. [Source: FMS D-271 ‘The Battle of Stalingrad. Signal Communications in the Pocket of Stalingrad and Communications with the Outside’]

Other examples are available from FMS P-132 ‘Signal Communications in the East. By General der Nachrichtentruppen Albert Praun’, (available through fold3.com)

Athens-Derna

Norway

Belorussia

Greece

Courland

Rommel’s microwave link

The North African campaign provides authors and researchers of signals intelligence with many interesting cases of ‘broken’ codes and compromised communications. Just as the German and British forces went back and forth like a see-saw the same thing happened in the field of intelligence.

Initially it was the Germans who had the upper hand and from mid 1941 to summer 1942 they benefited greatly from codebreaking. From then on however it would be the British who would succeed at reading their enemy’s codes (while keeping their own secure).

An exception to this story is something i found out about recently. Apparently Rommel had a microwave link from Derna, Libya to Athens, Greece and using it he could communicate with Higher Headquarters in Athens, Rome and Berlin.

Here is a map of the communication link, from FMS P-132 Supplement: ‘Signal Communications in the East: The Balkans and Finland’, p34

Apart from being difficult to intercept the traffic on this link was enciphered by cipher teletype, probably the Siemens and Halske T52 type. Voice communications were also enciphered with a prototype speech privacy system, at least for a time.

As far as I am aware there is no evidence that the British were able to intercept this traffic much less decrypt it.

This adds another layer in the intelligence war between Bletchley Park and Berlin and definitely diminishes the effects of reading Rommel’s Enigma ‘keys’ in the second half of 1942.

The information I’ve used comes from the following sources:

Microwave link Derna-Crete:

From FMS P-132 Supplement , p33 :

A permanent Ultra-short-wave radio communication channel operated by the Army Ordnance office later extended the Athens-Crete decimeter lines as far as Derna in Africa. By means of this channel the German Africa Corps could communicate by telephone and teletype over the permanent Balkan lines with the Italian Supreme Command in Rome, the German Luftwaffe Command in Sicily (later in Rome), the Luftwaffe units in Crete and Greece, and the Wehrmacht High Command. The line established communications between the outermost wing of the eastern Front and the Afrika Korps in Libya.

More details are given in FMS B-644 ‘Luftwaffe Communications (Greece and Crete)’ By Generalmajor Walter Gosewisch. 1947, p30

During the German drive on El Alamein one advance command post of the Commander in Chief South had been established at Derna (Libia). From here orders were issued daily by means of radio to the X Air corps stationed on Herakleion, (Crete). Owing to the danger of interception any concentrations of radio messages had to be avoided and consequently extension of the ground radio network became a matter of necessity. It was impossible, due to excessive diffraction, to transmit communications between Crete and Africa across the Mediterranean, a distance of 370 kilometers, by means of standard beam-microwave equipment which operated on a wave length of 53 centimeters.

An attempt was made, therefore, to accomplish this by installing extra powerful ultrashort wave transmitters operating on a wave length of about seven meters and by using intensely focused directional antennas. These transmitters made it possible to establish a sufficiently reliable connection which could be used for telephone and teletype traffic. The danger of interception was considerably greater when operating on a 7-meter wave length than on decimeter wave range and therefore this line was used mainly for teletype traffic by means of self coding teletype machines. (Geheimfernschreiber)

Speech privacy system:

From TICOM I-46 ‘Preliminary Report on Interrogation of Dr. Otto Buggisch (of OKH/Gen.d.NA) and Dr. Werner Liebknecht (employed by OKH and OKW as tester of cryptographic equipment) 23  June 1945’ , p3

Voice cipher machines:


C. Superimposing noise of electrons on speech and taking it out by 180 degree phase; A fixed noise level was not at all successful, but a variable number when employed had some small degree of success. This plan was actually employed back in the North African Campaign when communication from Athens, Greece to Derna, North Africa via Crete was maintained. A noise level of 1 to 4 was employed; however, the problems involved outweigh the advantages derived and the equipment was destroyed by fire and never replaced.

From  ‘Spread spectrum communications handbook, Volume 1’  , p49 [Reference found via historykb user eunometic]

The Germans used Kotowski’s concept as the starting point for developing a more sophisticated capability that was urgently needed in the early years of World War II. Gottfried Vogt, a Telefunken engineer under Kotowski, remembers testing a system for analog speech encryption in 1939. This employed a pair of irregularly slotted or sawtoothed disks turning at different speeds, for generating a noise-like signal at the transmitter,to be modulated/multiplied by the voice signal.The receiver’s matching disks were synchronized by means of two transmitted tones, one above and one below the encrypted voice band. This system was used on a wire link from Germany, through Yugoslavia and Greece, to a very  and/or ultra-high frequency (VHF/UHF) link across the Mediterranean to General Erwin Rommel’s forces in Derna, Libya.

The speech cipher device is described in the US patent US2211132A (found via klausis krypto kolumne commenter ‘Thomas’).

Exploding telephone poles in the Eastern front

One of the systems employed by the German forces for their telephone/teletype communications was the drehkreuz lines. When used together with frequency carrier equipment they carried a large number of voice and teletype channels.

However in the Eastern front there was a serious problem for German wire communications. The Soviet partisan movement attacked the telephone poles daily, especially in the area of Army Group Centre.

In order to protect their communications the Germans used strong points , pursuit detachments and  telephone poles filled with explosives. Once someone tried to cut them down the explosives went off.

The last measure  had the expected result but only for a while. The partisans overcame the problem by forcing villagers who lived nearby to cut the poles.

Source: Foreign Military studies : P-132  ’’Signals Communications in the East – German experiences in Russia’’ – 1954  ,p219-20 (available in the fold3 site)