The compromise of Polish diplomatic, intelligence service and resistance movement communications 1930’s-1945

 In WWII Poland fought on the side of the Allies and suffered for it since it was the first country occupied by Nazi Germany. In the period 1940-45 the Polish Government in Exile and its military forces contributed to the Allied cause by taking part in multiple campaigns of war. Polish pilots fought for the RAF during the Battle of Britain, Polish troops fought in N.Africa, Italy and Western Europe and the Polish intelligence service operated in occupied Europe and even had agents inside the German High Command.

Although it is not widely known the Polish intelligence service had spy networks operating throughout Europe and the Middle East. The Poles established their own spy networks and also cooperated with foreign agencies such as Britain’s Secret Intelligence Service and Special Operations Executive, the American Office of Strategic Services and even the Japanese intelligence service. During the war the Poles supplied roughly 80.000 reports to the British intelligence services (1), including information on the German V-weapons (V-1 cruise missile and V-2 rocket) and reports from the German High Command (though the agent ‘Knopf’) (2).

The activities of the Polish government departments and intelligence agencies attracted the attention of both Germany and the USA and UK and their codebreakers were able to solve most of the Polish cipher systems.

Interesting article on the German codebreakers of WWII

German mathematicians and cryptology in WWII by Frode Weierud and Sandy Zabell.

Update

In The Japanese FUJI diplomatic cipher 1941-43 I’ve added the following information under the paragraph ‘Pers Z effort’:

More information is available from the TICOM report DF-31B ‘How J.B. 57 Japanese Letter System Was Solved’, written by the cryptanalysts Annalise Huenke and Hans Rohrbach. 

The first break into system JB 57 came through two messages that had the same indicator (meaning they used the same transposition key). Once these were solved the system was identified as a transposed code, using a stencil.

Solution of this indicator led to the decipherment of more messages and dr Kunze (head of the ‘Mathematical Cryptanalytic Subsection’ of Pers Z) was able to use the information recovered in order to solve more message indicators. The inroads made by the solution of indicator groups led to the eventual recovery of the underlying code by the linguistic group and the current exploitation of this traffic.

TICOM report D-83 ‘Summary of Work Done on Typex Traffic by OKH/In 7/VI, 1939-1941’

Uploaded at arcre.com

Analysis of the Czechoslovak STP cipher

Essay on the WWII Czechoslovak STP cipher by Štefan Porubský.

Research Gate link: Application and Misapplication of the Czechoslovak STP Cipher During WWII

Note that I’ve dealt with the ciphers of the Czechoslovak resistance movement in Svetova Revoluce and the codes of the Czechoslovak resistance.

The Abwehr’s Enigma G cipher machine and Procedure 63

The Cryptologia article Mr. Twinn’s bombes is available from the Taylor and Francis website and it has some very interesting information on the Enigma G cipher machine, used in WWII by the German military intelligence service Abwehr.

The Enigma G was different from the version used by the German military since it did not have a plugboard. Also its stepping was more frequent due to the many notches in the rotors.

According to the article it was used by the following Abwehr networks:

1). Berlin, Madrid, Lisbon, Paris, Bordeaux

2). Berlin, Vienna, Budapest, Bucharest, Sofia, Salonika

3). Berlin, Vienna

4). Berlin with stations in Turkey

The device was issued with 3 rotors only (while the military version used 3 rotors from a set of 5). In some networks the rotors were rewired during the war.

Several indicator systems were used in the period 1941-44. Up to August 1942 the message key was enciphered twice on the Grundstellung (basic setting). The 8 letter sequence was the indicator at the start of the message. This was the same procedure used up to 1938 by the German Army and Airforce.

From August 1942 the double encipherment of the message key was dropped and instead it was enciphered on the Grundstellung only once.

In the period late 1943-early 1944 a new indicator procedure was introduced. This was part of new security regulations called Procedure 63 - ‘Verfahren 63’. The new system used two basic settings. One for the network and one for the station. The cipher clerk first enciphered the message key twice on the network’s basic setting and then enciphered the 8 letters again at the station’s basic setting.

It is interesting to note that an OKW/Chi report dated August 1944 says that Procedure 63 was not secure:

D) Agentenverkehr

Die Vorschrift Nr.63 genügt nur dann zeitgemässen Sicherheitsansprüchen, wenn auf jeder Linie nur wenig Verkehr auftritt. Es soll versucht werden eine bessere Vorschrift auszuarbeiten.

Es wird dafür gesorgt werden, dass alle anderen mit Enigma-Maschinen arbeitenden Behörden usw. nur die vom Ausschuss geprüften und zugelassenen Vorschriften benutzen.

Google translation:

D) Agent traffic

Regulation No.63 only meets current safety requirements if only little traffic occurs on each line. A better regulation is to be worked out.

It is necessary to ensure that all other authorities working with Enigma machines, etc., use only the regulations audited and approved by the Committee.

The Japanese TOKI diplomatic cipher 1943-45

During WWII Japan’s Foreign Ministry used several cryptologic systems in order to protect its diplomatic communications from eavesdroppers. In 1939 the PURPLE cipher machine was introduced for the most important embassies, however not all stations had this equipment so hand ciphers continued to play an important role in the prewar period and during the war.

The main hand systems were transposed codes.

Historical overview

The first Japanese diplomatic system identified by US codebreakers was introduced during WWI and it was a simple bigram code called ‘JA’. There were two code tables, one of vowel-consonant combinations and the other of consonant-vowel. Similar systems, some with 4-letter code tables were introduced in the 1920’s.

These unenciphered codes were easy to solve simply by taking advantage of the repetitions of the codegroups of the most commonly used words and phrases. US codebreakers solved these codes and thus learned details of Japan’s foreign policy. During the Washington Naval Conference the codebreakers of Herbert Yardley’s Black Chamber  were able to solve the Japanese code and their success allowed the US diplomats to pressure the Japanese representatives to agree to a battleship ratio of 5-5-3 for USA-UK-Japan. However this success became public knowledge when in 1931 Yardley published ‘The American Black Chamber’, a summary of the codebreaking achievements of his group. The book became an international best seller and especially in Japan it led to the introduction of new, more secure cryptosystems.

In the 1930’s the Japanese Foreign Ministry upgraded the security of its communications by introducing the RED and PURPLE cipher machines and by enciphering their codes mainly with transposition systems.

Japanese transposed codes J-16 to J-19

The J-19 code had bigram and 4- letter code tables similar to the ones used previously by the Japanese Foreign Ministry. According to the NSA study ‘West Wind Clear: Cryptology and the Winds Message Controversy A Documentary History’ it was used from 21 June 1941 till 15 August 1943.

In terms of security the J-19 FUJI and the similar codes J-16 MATSU to J-18 SAKURA, that preceded it in the period 1940-41, were much more sophisticated than the older Japanese diplomatic systems. They had roughly double the number of code groups at ~1.600, these included 676 bigram entries and in addition there was a 4-letter table with 900 entries for ‘common foreign words, usually of a technical nature, proper names, geographic locations, months of the year, etc’.

These codes were enciphered mainly by columnar transposition based on a numerical key, with a stencil being used for additional security. The presence of ‘blank’ cages in the box created irregular lengths for each column of the text.

Examples of the stencils and numerical keys from ‘West Wind Clear’:

Despite these measures the transposed J-series codes were solved cryptanalytically both by the Anglo-Americans and by the German codebreakers (1).

The replacements of J-19 FUJI

In summer ’43 J-19 FUJI was replaced by three new systems. The transposed codes TOKI and GEAM and the enciphered code ‘Cypher Book No1’.

TOKI was used in the period 1943-45 and it was similar to J-19 in that it was a code transposed on a stencil. The TOKI system was used by Japan’s embassies and consulates in Europe (2).

Just like its predecessor it was solved by the Anglo-Americans and the German codebreakers.

Allied exploitation of the TOKI cipher

The US effort

The TOKI transposed code was different from its predecessor J-19 FUJI in that it was used by European posts, while J-19 was used by Japanese diplomatic missions from around the world. Also TOKI was made up of 2 and 3 letter code groups while J-19 had 2 and 4 letter groups. The code groups were arranged in a non systematic manner thus making solution more difficult (3).

Examples of recovered code values (4):

The TOKI messages were enciphered using stencils and transposition keys that changed within the same message. Specifically the indicator of the message designated 3 stencils and 3 numerical keys to be used in encipherment. Each table had 250 blocks (25x10) but 50 were crossed out according to a specific system, thus 200 letters could be enciphered. If the message was longer than that then the next stencil and numerical key designated by the indicator was used.

Initially the date of the message and the signature of the originator were used to select null and blank blocks (5). In December 1943 this procedure was changed. Null blocks were abolished and the new procedure for crossing out blocks was the following (6):

‘at the intersection of the column and row; five blanks are inserted; the odd blanks are inserted vertically, the even blanks horizontally, for numbers 1-10 in numerical order. Blanks to be inserted below row 10 are continued at row 1. If a blank is already present in a space to be used for another blank, it is skipped over; always five blanks are inserted for each intersection point, so that the total number of blanks is 50, and the number of letters in the matrix is 200. Three such matrices and three such random sequences are used for each indicator, if the length of the message warrants this. If a message is longer than 600 textual letters, the first sequence is used for a fourth block, the second for a fifth block, etc..’

Examples of stencils and transposition keys (7):

The use of a 2 and 3 letter code together with different stencils and transposition keys made solution difficult. The main method used was to analyze a large number of messages ‘in depth’ (enciphered with the same settings, identified by having the same indicator), then it was possible to use anagramming in order to solve the encipherment and recover the code values.

The report SRH-361 ‘History of the Signal Security Agency Volume Two The General Cryptanalytic Problems’, p283 says about TOKI/JBA:

JBA, a transposition system of a degree of security second only to the Purple machine-cipher system (JAA), was solved by statistical methods within six weeks. This solution is believed to be the first instance of the recovery of an unknown transposition of an unknown code by purely statistical means. Beginning groups, and later, code groups within the body of the text were found by matching stretches of cipher text from several messages with the same indicator. Frequent digraphs were recorded, and eventually the transposition patterns and tetragraphic code groups were recovered despite the presence of occasional trigraphic groups, the use of blanks in the matrix, and the use of the letters of the signature as nulls throughout the message.

Apart from statistical methods it was possible to solve messages by taking advantage of operator mistakes such as sending the same message in two different keys, enciphering the same message on TOKI and GEAM ciphers, having stereotyped beginnings etc

The Gee-Whizzer

During the war traffic on the J-series codes increased significantly and the solution of the daily changing settings became a problem for the small number of people working on Japanese systems, so there was an effort to automate the process. The device built was an attachment for standard IBM punch card equipment called the ‘Electromechanagrammer’ or ‘Gee-Whizzer’.

According to the NSA study ‘It Wasn’t All Magic: The Early Struggle to Automate Cryptanalysis, 1930s – 1960s’, p50-51:

‘The Gee Whizzer had been the first to arrive. In its initial version it did not look impressive; it was just a box containing relays and telephone system type rotary switches. But when it was wired to one of the tabulating machines, it caused amazement and pride. Although primitive and ugly, it worked and saved hundreds of hours of dreadful labor needed to penetrate an important diplomatic target. It proved so useful that a series of larger and more sophisticated "Whizzers" was constructed during the war……………….When the Japanese made one of their diplomatic "transposition" systems much more difficult to solve through hand anagramming (reshuffling columns of code until they made "sense"), the American army did not have the manpower needed to apply the traditional hand tests.

Friedman's response was to try to find a way to further automate what had become a standard approach to mechanically testing for meaningful decipherments……………………………………..Rosen and the IBM consultants realized that not much could be done about the cards; there was no other viable memory medium. But it was thought that it might be possible to eliminate all but significant results from being printed. Rosen and his men, with the permission and help of IBM, turned the idea into the first and very simple Gee Whizzer. The Whizzer's two six-point, twenty-five-position rotary switches signalled the tabulator when the old log values that were not approaching a criterion value should be dropped from its counters. Then they instructed the tabulator to start building up a new plain-language indicator value.

Simple, inexpensive, and quickly implemented, the Gee Whizzer reinforced the belief among the cryptoengineers in Washington that practical and evolutionary changes were the ones that should be given support.’

Importance of the TOKI system

From the available statistics on the solved TOKI messages and the reports issued it is clear that it was one of the high level Japanese diplomatic hand systems (together with JBB/GEAM and JBC/Cypher Book No1) (8).

In the period 1943-45 the main Japanese diplomatic systems decoded and forwarded to the Military Intelligence Service were the Purple cipher machine (JAA), the ciphers TOKI (JBA), GEAM (JBB), Cypher Book No1 (JBC) and the unenciphered code LA (JAH).

The Australian effort

In Australia the Diplomatic Special Section (D Special Section) of the Australian Military Forces HQ in Melbourne decrypted Japanese diplomatic ciphers. This unit was headed in the period 1942-44 by A.D. Trendall, Professor of Greek at Sydney University. Despite the small size of the unit considerable success was achieved in the solution of Japanese communications (9).

According to the report ‘Special Intelligence Section report - Japanese Diplomatic ciphers’ (10) the TOKI cipher was the first of the new Japanese Foreign Office ciphers to be broken.

The system was quickly compromised by the Japanese Ambassador in Lisbon Morishima Morito. The report says that he committed a fatal mistake by sending the same message in two different keys. This allowed the two messages to be solved and a few code groups to be identified.

More codegroups were recovered when some messages were sent both in the TOKI and GEAM ciphers. Since GEAM (JBB) was easier to solve it was then possible to identify the equivalent groups in solved TOKI (JBA) messages. When the cipher was modified in December 1943 it was possible to break in again by solving two messages sent in the same key.

Regarding the content of the messages the report says:

‘BA was used only to a moderate extent and the material it contained was of varying interest ranging from general Tokyo circulars upon international happenings to dull routine matters about couriers. Most BA messages from Russia were on the subject of couriers, visas and rations. However Stockholm was in the habit of sending all his chōhōsha (spy reports) in BA and much information was obtained therefrom. Although the second system of BA cypher might well have proved unbreakable the Foreign Ministry did not regard it very highly and issued instructions that it was to be used only for routine matters; more confidential material was to be sent in the recyphering tables. This was satisfactory from our point of view as we encountered far more difficulty in breaking and reading the second BA system than we did in recovering recyphering tables’.

The German effort

Foreign diplomatic codes and ciphers were worked on by three different German agencies, the German High Command’s deciphering department – OKW/Chi, the Foreign Ministry’s deciphering department Pers Z and the Air Ministry’s Research Department - Reichsluftfahrtministerium Forschungsamt.

OKW/Chi effort

At the High Command’s deciphering department - OKW/Chi, Japanese diplomatic systems were worked on by a subsection of Referat 13, headed by 1st Lieutenant dr Adler. About 15 people were employed by the unit (11) and according to Reinhard Wagner (a member of the section) the TOKI cipher was solved by the department.

Wagner said in his postwar interrogation report (12):

(3) A transposition procedure (Wuerfelverfahren), on which WAGNER did not work himself and which he knew only through having translated messages passed in the system. He could say of this system only that there was a daily changing keyword, and the reciphering process was complicated by Raster. The system remained valid until August 1943.

(4) The successor to the above transposition procedure, which WAGNER helped to solve, employed a basic 2 and 4 letter code book. Transposition was done in a width of 25 and a depth of 10. The keyword was changed arbitrarily. Not all the fields in the transposition square were employed but gaps (Loecher) were left. For example, the first square in the first column was to be left blank, the second square down in the second column, and so forth up to ten. In the eleventh column the top five squares down might be left blank, and in the twenty-first column the bottom five squares. In January 1944 the procedure was complicated by causing blank squares to be left vertically and horizontally. E.g., in column one, starting from the top down five squares were to be left blank. In column two, starting with the second. square down, five squares horizontally were to be left blank. In column three, starting with the third square down, five squares vertically were to be left blank, etc. The referat was successful in breaking this system.

At OKW/Chi they not only solved the Japanese transposed codes but also built a specialized cryptanalytic device called the ‘Bigram search device’ (bigramm suchgerät) for recovering the daily settings. EASI vol3, p65 says:

‘FUJI, a transposition by means of a transposition square with nulls applied to a two and four letter code. This system was read until it ended in August, 1943. It was broken in a very short time by the use of special apparatus designed by the research section and operated by Weber. New traffic could be read in less than two hours with the aid of this machine.’

The ‘Bigram search device’ is called ‘digraph weight recorder’ in the US report ‘European Axis Signal Intelligence in World War II’ volume 2. In pages 51-53 details are given on the operation of this device:

‘The digraph "weight" recorder consisted of: two teleprinter tape reading heads, a relay-bank interpreter circuit, a plugboard ‘’weight’’ assignor and a recording pen and drum.

Each head read its tape photoelectrically, at a speed of 75 positions per second.’

The machine could find a solution in less than two hours and did the work of 20 people, thus saving manpower.

Pers Z effort

At the Foreign Ministry’s deciphering department Pers Z Japanese systems were worked on by a group headed by Senior Specialist dr Rudolf Schauffler. This section successfully solved the Japanese diplomatic transposed codes, including the TOKI cipher which in Pers Z reports was designated as JB-64.

Dr Schroeter, a cryptanalyst of the mathematical research section who worked on Japanese ciphers, said in TICOM report I-22, p17

136. Dr. Schroeter: Had joined the organization comparatively later (Spring 1941) and had no intention of ‘staying on'. He was a lecturer in mathematical logic at the University of Münster. He had joined Dr. Kunze’s party and worked independently on Japanese recypherments.

137. He started work on simple transposition recypherments of codes; they were single transpositions with nulls over two-letter books. In the autumn of 1942-43 he worked on a Japanese 'Greater East Asia‘ traffic consisting of single transposition over a two-letter book systematically constructed, groups consisting of cv. The cage was 6 letters long and 5 or 10 letters deep with blanks evenly distributed throughout; there were three keys.

138. The system used with European posts consisted of transposition with a 25 place stencil. The stencil changed sometimes as often as three times within the message. The blanks in the stencil were filled out with the originator's signature, e.g. SHIGEMITSU. The basic book was more difficult and employed groups of two or three letters. The system was broken largely-owing to a twelve part message from Moscow with similar beginnings to each part. This system, known as 'JB 64’, is still current, though the stencil changes more frequently. Dr. Olbricht used to work on it. Dr. Schroeter sketched a specimen stencil.

It is interesting to note that a cryptanalytic device called ‘Spezialvergleicher’ was used to solve the Japanese transposed codes (13).

In the TICOM collection of the German Foreign Ministry’s Political Archive there are several folders containing worksheets of solved JB-64 messages for the period 1943-45 (14).

For example (15):

Forschungsamt effort

At the Air Ministry’s Research Department Japanese systems were worked on by Abteilung 7 (USA, UK, Ireland, South America, Spain, Portugal, Turkey, Egypt, Far East). The department had about 60-70 workers.

Unfortunately at this time there is limited information on the Forschungsamt cryptanalytic effort. In TICOM report I-25, p7 dr Martin Paetzel (deputy director of Main Department IV - Decipherment) said that a Japanese transposed code was worked on in the middle of 1943 but it was not read currently. It is possible that he was referring to TOKI.

Messages from the Japanese embassy in the Soviet Union

The Germans were particularly interested in the communications of the Japanese diplomats in the Soviet Union. It seems that this embassy was either not given a PURPLE machine or perhaps they had to dismantle it in 1941, so they relied on hand ciphers for their most important messages.

During WWII Japan fought on the side of the Axis but was careful to avoid a confrontation with the Soviet Union. War between the SU and Japan finally broke out in August 1945 but during the period 1941-45 Japanese diplomats were free to collect and transmit important information from the SU on military and political developments as well as their discussions and negotiations with Soviet officials. These messages were a prime target for the Allied and German codebreakers.

In the period 1943-45 the messages of the Japanese ambassador clearly showed the deterioration of Soviet-Japanese relations. Some of these messages were used in a series of reports prepared by Giselher Wirsing, an accomplished author and journalist, who in 1944 joined the Sicherheitsdienst foreign intelligence department as an evaluator.

Wirsing had come to the attention of General Schellenberg (head of SD foreign intelligence) 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 (16).

In his postwar interrogations Wirsing mentioned the decoded messages of the Moscow embassy that he used in his reports:

‘Japanese ambassador in Moscow to his Government. Occasional telegrams were deciphered which indicated clearly that the Japanese were having increasing difficulties in maintaining friendly relations with the USSR. Through this source came confirmation from an Amt VI Far East V-man regarding a secret meeting of Japanese and Russian emissaries somewhere in SIBERIA’.

‘When STALIN delivered his famous address on 7 November 1944, singling JAPAN out as an aggressor nation, WIRSING, in a special report written at the request of SCHELLENBERG, read into this sentence the accomplished fact of a fundamental change of Russian policy towards JAPAN. Again SCHELLENBERG demurred. Then, approximately three weeks later, a report by ambassador SATO to his government was intercepted in which he related a conversation he had had with MOLOTOV in connection with a Japanese note expressing concern over anti-Japanese utterances by a Russian colonel in a public address. MOLOTOV, according to SATO, availed himself of this opportunity to advise the Japanese Government not to mistake rhetorical exuberance for an expression of the considered policy of the Kremlin. However, MOLOTOV added, the time would come when certain outstanding questions of a more fundamental nature would have to be thrashed out between the two nations.‘

It is reasonable to assume that some of these messages were enciphered with the TOKI system.

Notes:

(1). The Japanese J-19 FUJI code

(2). TICOM report I-22, p17 and US report ‘The solution of the Japanese transposed code JBA’, p1 (NARA - RG 457 - Entry 9032 – NR 2828)

(3). US report ‘The solution of the Japanese transposed code JBA’ (NARA - RG 457 - Entry 9032 – NR 2828)

(4). US report ‘Master JBA trigraph charts‘ (NARA - RG 457 - Entry 9032 – NR 2458)

(5). The procedure as described in ‘The solution of the Japanese transposed code JBA’ was as follows. The cipher clerk would take the stencil, write the numerical key at the top and then add the letters of the signature of the originator (for example SATOAMBASS) at the blocks on row 1-column 1, row 2-column 2, row 3-column 3 etc.

The blank blocks were selected from a key table which identified the columns to be crossed out for each day of the month.

(6). US report ‘The solution of the Japanese transposed code JBA’ (NARA - RG 457 - Entry 9032 – NR 2828)

(7). US reports ‘Report on Japanese diplomatic systems 1944’ (NARA - RG 457 - Entry 9032 – NR 3095) and ‘The solution of the Japanese transposed code JBA’ (NARA - RG 457 - Entry 9032 – NR 2828)

(8). US report 'Foreign Cryptographic Systems, 1942-1945' (NARA - RG 457 - Entry 9032 - NR3254)

(9). Breaking Japanese Diplomatic Codes David Sissons and D Special Section during the Second World War, chapter 1

(10). Australian National Archives - NAA: A6923, 1/REFERENCE COPY - (barcode 12127133)

(11). TICOM I-124, p3 and TICOM I-150, p4

(12). TICOM I-90 ‘Interrogation of Herr Reinhard Wagner (OKW/Chi) on Japanese systems’, p3

(13). TICOM I-22, p18

(14). German Foreign Ministry’s Political Archive - TICOM collection - files Nr. 2.465-2.471

(15). German Foreign Ministry’s Political Archive - TICOM collection - file Nr. 2.471 - Japan 1944/45   ‘JB64, 1481-1644’, Diplom. Briefverkehr

(16). British national archives KV 2/140 ‘Giselher WIRSING: Journalist and author’

Sources:

‘European Axis Signal Intelligence in World War II’ volumes 2,3,6,7 , TICOM reports I-22, I-25, I-90, I-124, I-150,  DF-187B , ‘The Codebreakers’, ‘Breaking Japanese Diplomatic Codes David Sissons and D Special Section during the Second World War’, United States Cryptologic History Series IV: World War II Volume X: ‘West Wind Clear: Cryptology and the Winds Message Controversy A Documentary History’, United States Cryptologic History, Special Series, Volume 6, ‘It Wasn’t All Magic: The Early Struggle to Automate Cryptanalysis, 1930s – 1960s’, NSA interviews of Frank Rowlett 1974 (National Cryptologic Museum Library), Australian National archives: ‘Special Intelligence Section report - Japanese Diplomatic ciphers’, NARA reports: ‘The solution of the Japanese transposed code JBA’, 'Foreign Cryptographic Systems, 1942-1945', ‘Report on Japanese diplomatic systems 1944’, ‘Master JBA trigraph charts‘, NSA report SRH-361 ‘History of the Signal Security Agency Volume Two The General Cryptanalytic Problems’

Acknowledgements: I have to thank Rene Stein for identifying several of the NARA JBA reports.

The French War Ministry’s FLD code - More clues…

I’ve written about the compromise of the French War Ministry’s FLD code by the codebreakers of the German High Command's deciphering department – OKW/Chi, however up to this point I hadn’t been able to find the official designation of this cryptosystem.

Recently I’ve discovered some clues that might clear things up.

According to the available sources this cryptosystem was used for ‘the cypher traffic between the French War Ministry and the army groups, armies and home authorities’.

The new finding aid to the TICOM collection of the German Foreign Ministry’s Political Archive has certain entries that read:

NR 3684 – ‘F4ZCUW 110’ German notes on the above French Defense Area cipher

NR 3615 – F4ZCUT’ German notes, 1931, on French code as above, used by the Defense Areas HQ’s from Schliersee.

The finding aid also mentions the French code F-90 which might have been the predecessor to F-110.

The French code F-110 is mentioned in one of Erich Huettenhain’s reports:

What was the French designation for the system that the Germans called F-110?

Possibly Code R.A.

The finding aid says:

NR 1736 – Code RA, French military code sheets and instructions for use. Various dates 1933-39 March and July 1940-42 from Schliersee.

Why do I think that Code RA was used by the French War Ministry and the Army Groups?

In the book ‘KODY WOJNY. Niemiecki wywiad elektroniczny w latach 1907–1945’, p1.046 there is a copy of a French report dated 16 April 1940.

It says:

Un code R.A. avec additif et son procede de surchiffrement (clef ZERO S.2.) pour permettre de correspondre a l'Intérieur de la Métropole avec les Autorités et Etats-Majors dotés de ce document (notamment commandants d' armes).

Google translation:

R.A. a code with additive and process for its super-encryption (key ZERO S.2.) To allow a match the interior of the metropolis with the authorities and with staffs of this document (including commanders of weapons).

I hope my friends in France will look into this case. I can’t solve everything by myself!

Overview of reports on compromise of Allied communications in WWII

When researching WWII signals intelligence and codebreaking operations it is important to track down all the available sources of information, from POW interrogations and captured documents to detailed reports summarizing Allied cipher policy, decisions and compromises.

It is reasonable to assume that in the postwar era all the Allied countries tried to assess the extent of the compromise of their communications during WWII. Thus I’ve tried to track down these reports. In the following space i’m going to list the reports I know of and give a short summary of each one. I’ve used most of them in my essays but there are some that I haven’t been able to locate (yet).

USA

Military cryptosystems

1). The ‘European Axis Signal Intelligence in World War II’ volumes are available from the NSA’s website. They are dated May 1946 and have a lot of information on German cipher machines, the German codebreaking agencies and their major achievements. Unfortunately I don’t think that the EASI volumes are entirely accurate.

2). The report Special conference on M-209 security is dated 1950 and looks into the German exploitation of the US M-209 cipher machine. It is difficult to explain why the people involved looked only at the available TICOM reports and not the actual files of the German Army’s codebreaking agency Inspectorate 7/VI. These had been retrieved in 1947 from a camp in Austria.

Overall it seems to me that US reports are not as thorough as they should be.

State Department

I am not aware of any State Department communications security report written after the end of WWII. The ones available were produced during the war and submitted to the US Joint Chiefs of Staff.

1). The reports of June 1941 and November/December 1943 are available online via the NSA’s Friedman collection.

2). The report of June 1944 can be found in the US National Archives and Records Administration - collection RG 457- Entry 9032- box 1384 - 'JCS Ad hoc committee report on cryptographic security of government communications'.

The problem is that these reports only have theoretical evaluations of the State Department cryptosystems, not information on their compromise by the Axis powers.

OSS

The Office of Strategic Services was the predecessor of the CIA and during WWII its overseas stations gathered military and political intelligence on the Axis powers. For example in Bern, Switzerland the local OSS station (headed by Allen Dulles) kept in contact with members of the German Resistance.

According to an OSS veteran a report on WWII crypto security was prepared but I don’t have any details.

Soviet Union

Both in the Soviet era and today in modern Russia the files and archives of the signal intelligence organizations remain closed to researchers. This makes it very difficult to find information on Soviet cryptosystems and on whether the Soviet authorities evaluated their communications security during WWII.

According to Anatoly Klepov's “The historical truth” of Beria and Suvorov about cryptography and radio intelligence, there were evaluations of Soviet cryptosecurity in 1941, in 1943 and at the end of WWII. These investigations came to the conclusion that Soviet ciphers had not been compromised by the Germans but that they were theoretically solvable. This led to the introduction of new, more secure systems.

UK

Army

There are files dealing with British Army communications at the National Archives, collections WO 219 and WO 193. However these deal with cipher policy, not cipher compromises.

Navy

The report ADM 1/27186 ‘Review of security of naval codes and cyphers 1939-1945’ is available from my Google docs and Scribd folders. It is dated November 1945 and it was written after examining the files of the German Navy’s codebreaking agency B-Dienst. Thus it has an excellent analysis both of Royal Navy cipher policy and the compromise of RN codes and ciphers.

RAF

The report AIR 20/1531 ’R.A.F. signal communications: security’ can be found in the National Archives but the information on the compromise of RAF systems is only based on decrypted German messages, not other sources.

SOE

The Special Operations Executive was an intelligence organization created during WWII. I don’t know if a report on the compromise of SOE codes was ever prepared. The British authorities certainly had the available information, since they captured the War Diary of Inspectorate 7/VI in 1947 and this included the summary reports of Referat 12 which dealt with Allied agents’ codes.

The report HS 7/41 ‘Section II: field cyphers; appendices L, M, N and O’ has a file titled S.O.E. FIELD CIPHERS which is available from the Arcre website. This file points out theoretical and practical problems with SOE cipher security but does not have information on the compromise of said systems by enemy codebreakers. 

France

French military high level codes were solved by the Germans in the 1930’s and up to the Battle of France. Unfortunately I am not aware of any French report summarizing their cryptosystems and their compromise during the war.

Czech Republic

During WWII the communications of the Czech resistance movement were solved by the Germans. It seems that at the end of the war the Czechoslovak government found out about this case and personnel of the Defense Ministry prepared the report ‘Dopady lúštenia šifrovacieho systému čs. londýnskeho MNO z rokov 1940-1945 na domáci odboj’.

I requested this report from the Czech Defense Ministry’s history department but they were not able to locate it. Let’s hope that some Czech researcher will be able to find it.

Poland

Polish military, diplomatic, resistance movement and intelligence service codes were read by the Germans during WWII. I don’t know if there are detailed reports in the Polish government archives but the following sources have valuable information.

1). The Cryptologia article ‘From the Archives: Polish Interwar MFA's Cipher Compromised?’ by Jan Bury presents two reports written in 1940 and 1947 by the intelligence officer Major Tadeusz Szumowski, concerning the security of the Polish diplomatic Code 45.  According to Szumowski this codebook had been compromised and the Germans could read the Polish diplomatic traffic since the leadership of the Polish Foreign Ministry chose to keep using it despite his warnings. Szumowski was correct about this case.

2). Recently the book KODY WOJNY. Niemiecki wywiad elektroniczny w latach 1907–1945 a losy polskich, sowieckich, alianckich kodów i szyfrów has been published by Marian Zacharski. I don’t know if the author has information on the Polish ciphers from Polish sources but he has uncovered material from the recently released TICOM files on the extensive compromise of Polish cryptosystems during the war.

Conclusion

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 Axis 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.

I’ve listed some reports that deal with the compromise of Allied codes but I hope that researchers will be able to locate more. Specifically:

1). State Department postwar reports on WWII compromises (especially the M-138-A strip cipher case)

2). The OSS report on WWII cryptosecurity.

3). The Soviet reports of 1941, 1943 and postwar period.

4). Reports similar to ADM 1/27186 for the British Army, RAF and SOE.

5). French reports on their WWII cryptosystems.

6). The Czech report ‘Dopady lúštenia šifrovacieho systému čs. londýnskeho MNO z rokov 1940-1945 na domáci odboj’.

7). Polish government-in-exile reports on their codes and ciphers.