Sunday, December 15, 2019

Overview of 2019

In 2019 I was able to research some cases of cryptologic history plus there were some interesting articles and presentations that presented new information.


1). In The American M-209 cipher machine I added info on the unit NAASt 7 and the compromise of the M-209 machine during the invasion of Sicily in 1943.

3). I updated my essay The French War Ministry’s FLD code with information from the Bulletin de l’ARCSI’ articles: Essai d'historique du Chiffre (Add. N°3) and Essai d'historique du Chiffre (N°5) by Général Ribadeau-Dumas. Also added info from the TICOM documents 3612, 3684, 3661.

4). I added a link to the HistoCrypt 2019 proceedings.

6). I added a link to the report ‘Technik und Verfahren der Spionagefunkdienste’  (link from

7). I added links to the following interesting academic articles:

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

Enigma G: The counter Enigma’ by David Kenyon & Frode Weierud

8). I uploaded the following documents to my TICOM folder:

Unfortunately, there were some setbacks:

1). The authorized history of GCHQ Behind the Enigma: The Authorised History of GCHQ, Britain’s Secret Cyber Intelligence Agency’ has been delayed till October 2020.

2). My two FOIA cases (TICOM report I-40 from the NSA and the Henriksson report from the State Department) are still in review.

Hopefully in 2020 my FOIA cases will be processed. Apart from that I don’t have any active research projects on crypto history.

Monday, October 28, 2019


In the essay The French War Ministry’s FLD code I’ve added the following information:

Identifying the FLD codes

We can try to identify the cryptosystems used in the FLD radio network by looking at Huettehnain’s statements and various TICOM documents.

According to Army cryptanalyst dr Buggisch (7) the designations F90 and F110 referred to French Army ciphers, read during the period 1939-1940:

F90 and F110 were German designations for French Army cipher systems before and during the campaign in FRANCE. Both were based on a four figure code, in one case the recipher consisted of a periodic adder [or subtractor] of length 11; in the other it was ordinary transposition, the transposition key being obtained from a key word which itself was taken from the code and shown by an indicator group. Both systems were being read from the winter of 39/40 to the end of the French campaign. Solution was by methods generally known in cryptanalytic circles. One of the codes turned, up again for a short period in De Gaullist traffic.’

Note that Buggisch’s description of the systems is similar to Huettenhain’s from ‘Einzeldarstellungen aus dem Gebiet der Kryptologie‘.

In the TICOM collection of the German Foreign Ministry’s Political Archive there are documents that have more information on the ciphers F90 and F110:

1). The TICOM documents T3611 and T3612 (8) have information on cipher F90, however document T3611 is not available due to deterioration.

According to document T3612 the cipher F90 was a 4-figure code enciphered with short additive sequences of 5, 7 or 11 digit length. It seems that the codebook consisted of 20 pages, each with 100 entries, totaling 2.000 code groups.

This system was used by the network FLD (Paris) in communications with stations fla, flb, flc, flf, flg, fak, fam, flq and others and it was solved thanks to a major cipher clerk error committed in September 1937.

It seems that the same message was sent twice, first without encipherment (so only the code groups were transmitted) and then with additive encipherment. Clearly this gave the German codebreakers an opportunity to identify the basic code groups and then solve the additive sequence used for encipherment. This success allowed them to correct their own relative code findings (from previous decipherments) into the actual French code values.

The information in TICOM document T3612 matches Huettenhain’s statements about a high level code enciphered with short additive sequences being solved completely in the years prior to WWII.

2). The TICOM document T3684 (9) describes system F110 (F4ZCW110 - French 4-figure code with simple transposition) and it says than from February 1938 the radio network of the French 14th Army, with stations in Lyon, Grenoble, Modane, Briancon, Chambery, Jausiers and Beurg-Saint-Maurice, started using this transposed code. The indicator was 55555 and the transposition key was created from the plain meaning of one of the codegroups. The example given in the report was:

p   e   r   m  i  s   s   i  o  n   o  n   n   a   i   r   e 
13 2 14  7  4 16 17  5 11  8 12  9 10  1  6 15  3

The details in the report match Huettenhain’s statements about a French military district adjacent to Italy using a transposed code, with the transposition keys being created from the codegroups of the codebook and the first breakthrough coming in 1938.

The successors to systems F90 and F110

From the available TICOM documents it seems that in September 1939 both systems were changed. Cipher F90 was replaced by a new 3-figure code plus additive, while cipher F110’s successor used the same underlying code but with a new encipherment procedure.

1). TICOM document T3661 (10) contains a report by the cryptanalyst dr Ludwig Föppl, dated 18 December 1939. In the report Föppl says that the code F90, which was used in the military command radio network FLD (Paris), was changed in September and replaced by a new system.

The new system was a 3-figure code enciphered by additive sequences. It seems the encipherment consisted of a 20-digit number that was composed of two 10-digits parts. A peculiarity of the encipherment was that each 10-digit number was composed of all the ten digits from 0 to 9 used only once (11). This system was solved and it seems that the German designation for it was F135.

2). In the notes of dr Huettenhain there is a report from November 1939 that describes the solution of the successor to system F110 (12):

‘Report on the attachment to Army Group C evaluation section

On 2 September 1939 the French Army Code F110 was replaced by a new code so that traffic could no longer be broken currently.

On 3 September 1939 I was seconded to FRANKFURT-ON-MAIN in order to take part in the task of breaking this new code. The task was accomplished at the beginning of October so that all the September material could be read retrospectively.

This success was made possible in such a short time by the fact that

1) the necessary data (Code etc) was obtained by months of work in peace time, chiefly by Herrn TRAPPE (Chi OKW) and SCHMIDT (Chi OKW)
2) a close co-operation between the above named gentlemen and me could be established.

It was therefore, still possible in October to work on the October material with success. In addition to the above named gentlemen Herr Professor Dr. FOPPL was of great assistance in the solution of this system.

As the system was not changed on 1 November 1939 this code could be read currently again from the date when the October key was broken. On 3 November 1939 at the finish of my attachment in FRANKFURT-0N-MAIN I was sent to BERLIN.’

From Huettenhain’s report it seems that the underlying code remained the same (as in system F110) but the encipherment procedure was changed. By having the code the German codebreakers only needed to attack the encipherment and this was quickly achieved according to Huettenhain.

Friday, October 18, 2019

GCHQ official history delayed?

It seems that the upcoming book ‘Behind the Enigma: The Authorised History of GCHQ, Britain’s Secret Cyber Intelligence Agency’ has been delayed till October 2020.

Saturday, August 10, 2019

The case of the Rote Kapelle

I have uploaded the British report KV 3/349 ‘The case of the Rote Kapelle’ (only parts 1 and 2).

Friday, August 9, 2019


In the essay French Hagelin cipher machines I made a correction regarding the solution of the Hagelin C-36 by the German Army codebreakers. 

I had written that the device proved secure in 1939-40 but in TICOM report I-78 Mettig (head of the Army’s codebreaking department for the period 1941-43) stated that it was read by July 40 (thanks to captured machines).

I’ve also added the following paragraph at the end of the essay:

Solution of the Hagelin C-36 at OKW/Chi:

The Hagelin C-36 cipher machine was not a secure device and it seems that in the 1930’s the codebreakers of OKW/Chi (codebreaking department of the Armed Forces High Command) developed methods of solving it.

According to the NSA report ‘Regierungs-Oberinspektor Fritz Menzer: Cryptographic Inventor Extraordinaire’, p21 in 1936 Fritz Menzer developed two methods for solving the C-36.

Also in TICOM report I-31, p7 dr Huttenhain (chief cryptanalyst of OKW/Chi) stated that the French C-36 type could be solved cryptanalytically (without the use of stereotyped beginnings).

Unfortunately, there is no information on the work they did on the C-36 during the late 1930’s and in 1940. Considering their statements on the security afforded by the device it is possible that at OKW/Chi some French Hagelin C-36 traffic was solved during that time.

Saturday, August 3, 2019

Still waiting for the FOIA reports

I requested TICOM report I-40 from the NSA back in 2015. It’s August 2019 and it has not been reviewed yet….

I requested the Henriksson report from the State Department in June 2018 and as of August 2019 this case has not been processed (apart from assigning a case number)…

Let’s hope I don’t have to wait years for these files to be released.

Monday, July 22, 2019

New finding aid for the TICOM collection in the Political Archive of the German Foreign Ministry

Some time ago I posted the finding aid for the TICOM collection in the Political Archive of the German Foreign Ministry (excel file).

Now a new finding aid is available with a short description of each file (in pdf format). I have uploaded it to my Google Drive account.

Tuesday, July 16, 2019

Cryptologic history Symposium 2019

The program for the NSA’s Cryptologic history Symposium has been posted.

There seem to be some interesting presentations about WWII and the Cold war period. For example:

Dr. George Lasry Modern Codebreaking of Siemens and Halske T52

Mr. Jock Bruce What Happened Next? British Army Sigint, 1919-1939

Mr. Tony Comer GCHQ Centenary History

Dr. John Ferris GCHQ during the Cold War

Mr. Richard R. Lonergan Re-Evaluating the Cryptological Dividends of the Battle of Nomohan at 80: The Impact of Soviet Breakthroughs into Japanese Code and Cipher Systems

Dr. Francis Jordan-Rozwadowski What the Metadata Say: A Study of OKW/Chi Decrypts of Polish Intelligence Traffic

Dr. David Kenyon How Fishy was ULTRA? – The Role of Encrypted Teleprinter Traffic in the Intelligence for Operation OVERLORD

Mr. Marty Busse COMSEC Lietuvos Partizanų

Dr. Paul A. Thomsen Terminating the Signal: How SIGINT Turned the Tide against Axis Submarine Predation in World War II

Mr. Robert J. Hanyok Answering the Age-Old Commander’s Question: What the Hell is Going on out There? – The U.S. Army’s Signal Information and Monitoring Units and the
Phantom Service

I hope that they decide to publish their proceedings online, like Histocrypt did.

Saturday, June 22, 2019

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’.

Histocrypt 2019 proceedings

Saturday, May 25, 2019

Histocrypt 2019 program

The program for the International Conference on Historical Cryptology 2019 has been posted.

For me the more interesting presentations (based on the titles) are:

4. Eugen Antal, Pavol Zajac and Otokar Grošek: Cryptology in the Slovak State During WWII
5. Dermot Turing: The Typex Scare of 1943
6. George Lasry: A Practical Meet-in-the-Middle Attack on SIGABA

I hope they post their proceedings at their site like last year.

Sunday, May 19, 2019


In the essays French Hagelin cipher machines and The French War Ministry’s FLD code I added information from the Bulletin de l’ARCSIarticles  Essai d'historique du Chiffre’. Specifically in the paragraphs ‘French Army codes and ciphers’ and ‘French military codes and the Battle of France’.

Thursday, May 9, 2019

Saturday, March 23, 2019


In Compromise of State Department communications in WWII I made the following correction. I had written that the M-325 SIGFOY cipher machine was introduced into service in the second half of 1944, however that was not correct.

According to NARA - RG 59 - Purport Lists for the Department of State Decimal File 1910-1944 – microfilm 611 - 119.25 MC-325 the device was distributed to foreign posts in the second half of 1944 but the keylists were for the period January-June 1945. Thus the device could not have been used in 1944 by the State Department.

Wednesday, March 6, 2019

Information on State Department codes and ciphers

NARA has uploaded the microfilms containing entries on WWII era State Department codes and ciphers.

The entries dealing with cryptology are the 119.25.

Wednesday, February 27, 2019

The missing NAAst 5 reports

Although I’ve given up on getting these files (for reasons that have already been mentioned) I will post this information in the hope that someone else will succeed.

At the US national archives, in the NSA transfer group TR-0457-2016-0017, box 45, folder 3953 there is a file titled ‘KOMMANDEUR DER NACHRICHTEN AUFKLARUNG 5, 1944 (S-013,494)’.

It is possible that this file contains the missing NAASt5 reports. Maybe someone can get hold of this file and solve the mystery.  

Tuesday, February 12, 2019

HistoCrypt 2019

Information on this year's International Conference on Historical Cryptology:

The International Conference on Historical Cryptology (HistoCrypt) is an annual conference on historical cryptology. The 2019 edition will be held from June 23-26, 2019 in the Mundaneum, Mons, Belgium.


HistoCrypt addresses all aspects of historical cryptography and cryptanalysis. The conference's subjects include, but are not limited to:

the use of cryptography in military, diplomacy, business, and other areas

analysis of historical ciphers with the help of modern computerized methods

unsolved historical cryptograms, including the Voynich Manuscript

the Enigma and other encryption machines

the history of modern (computer-based) cryptography

linguistic aspects of cryptography

the influence of cryptography on the course of history

teaching and promoting cryptography in schools, universities, and the public

Participation in the conference is mandatory for at least one author of each accepted paper. 

Submissions from those who are new to the field, particularly students, are very welcome.

We are looking forward to seeing you in Mons, Belgium

The Organizing Committee of HistoCrypt 2019


Wednesday, January 9, 2019

Analysis of the Asia Minor campaign of 1919-1922

Impressive analysis of the Asia Minor campaign of 1919-1922 (in Greek):

I’ve always been interested in the Asia Minor campaign but unfortunately the books I’ve read so far tended to lack an in depth analysis of why the Greek forces failed to defeat the weakened Kemalist army.

The essays posted at the aforementioned site clearly point out the underlying problems of the Greek armed forces: the lack of professionalism of the officer corps, the rigid planning at the operational and strategic level and the lack of support between infantry, artillery and cavalry.

Great stuff!

Sunday, January 6, 2019


In The American M-209 cipher machine I added info on the unit NAASt 7 and the section:

Invasion of Sicily

In July 1943 US and British troops invaded the island of Sicily and after more than a month of fighting defeated the Axis forces and captured the island. However the German forces were able to avoid a total defeat by retreating in an orderly fashion through the Strait of Messina.

It seems that during the fighting in Sicily the Germans managed to capture a valid keylist of an M-209 network and thus read current US military traffic (14). 

The war diary of Inspectorate 7/VI says that in July ’43 the captured material allowed the continuous decryption of the traffic with indicator ‘ID’ and the results were communicated to NAAst 7.

The report of August ’43 says that messages of the ‘ID’ network could be decoded till mid month and after that it was still possible to find several cases of indicator reuse and thus solve the traffic of those days cryptanalytically.

Tuesday, January 1, 2019

The plan for 2019

After spending quite a lot of time and money researching these cases I think it’s time to wind things down.

During the year I’ll be checking books and articles on WWII history and cryptology but I will not embark on any new projects. Nor will I post as often as in past years.

Instead I’ll wait for the processing of my remaining FOIA cases with the NSA and State Department.

The two files are the TICOM report I-40 (from the NSA) and the Henriksson report (from the State Department).

There will also be a conference in late 2019, the NSA’s 2019 Symposium on Cryptologic History.

There might be some interesting presentations in this event.

Sometime during the year the first authorized history of GCHQ will be published. It seems that archival material will also be released to the UK national archives.

I will keep an eye out for interesting information.