Cipher machines were more secure than the book systems that they replaced and they encoded/decoded faster. The main players in the international market were the well known Enigma machine in its commercial version and the products of Boris Hagelin, mainly the ‘’small Hagelin’’ C-36 and ‘’large Hagelin’’ B-21/211.
The French armed forces purchased a small number of Hagelin machines ( C-36 and B-211 ) in the early 1930’s.These systems proved secure during the period of the Phony war and the Battle of France.
After hostilities ended however the cryptanalysts of the Army signal intelligence agency Inspectorate 7/VI (later OKH/GdNA) managed to acquire these cipher machines and they found ways to break the messages. Although their research was of a theoretical character since no new traffic was intercepted on these systems once the Free French forces of General De Gaulle started using them again they were in a position to benefit from their earlier research.
In the case of the C-36 the methods of solution were successful against field traffic. Messages of the large Hagelin B-211 however could not be solved. The reason was that the French had anticipated the German efforts to read their codes so they physically modified the B-211.Still it seems the Germans were able to read some messages on it due to operator errors :
Thanks to the solution of the C-36 the Germans were able to decode French traffic in North Africa and Italy in the period 1942-44.The Anglo-American authorities however were aware of the insecurity of French codes so they provided the M-209 (American version of Hagelin C-38) to the French forces fighting in Italy :
In Ticom reports the French M-209 is called BC-38.This was a version of the C-38/M-209 with a keyboard.
Apart from the Army agency In. 7/VI the Signal intelligence agency of the Supreme Command - OKW/Chi seems to have successfully solved the C-36 . The methods of solution are given in Ticom I-45 ‘’OKW/Chi Cryptanalytic research on Enigma,Hagelin and Cipher Teleprinter machines’’ (found in Frode Weierud's Cryptocellar)
Details on all the information mentioned so far are available from these sources :
Mettig was head of In. 7/VI from November 1941 to June 1943.Then second in command of OKW/Chi from December 1943 to April 1945.
France
With the opening of the offensive in May 40, the French began to use ciphers in increasing quantities. The Germans soon felt an acute shortage of forward cryptographers and were therefore unable to undertake much work on the French forward ciphers. As a result, the forward units concentrated on the two French cipher machines, the B-211 and C-36. Progress was slow, but as a result of research on two captured C-36 machines, Army Group C was in a position, by Jul 40, to undertake satisfactory reading of the traffic. Likewise it was impossible to break the B-211 machines in time for that information to be of any value.Nevertheless the research undertaken during this period was to justify itself later.
Referat France
This section lost a lot of its importance after the campaign of 1940. It concentrated on watching the communications of the VICHY Government which was supposed to inform the Germans of their cipher procedures. Breaches of regulations committed by the French were reported to the Disarmament Commission at WIESBADEN and rectified. The retention of captured French documents and the further investigation of the French cipher machines C-36 and B-211 justified itself in that the initial de Gaullist WT traffic in NORTH AFRICA for 1942-43 was undertaken through those methods. It was possible to read all these techniques at the start but how far the success was maintained during 1943 PW cannot say.
From I-160 Homework by Sonderfuehreer Kuehn of Gen. D. N. A. On General Organisation and Work of French Referat ,p6
Hans Wolfgang Kuehn was head of the French Referat of In. 7/VI from 1941 to February 1945.
French Machines
1. French "C-36" Machine. This machine was worked on and frequently broken in Wm. Doering's machine section. As far as I know and can judge, the content was moderate, to good, but mostly too old.
2. French "B-211" Machine. This machine was worked on in Wm. Doering’s machine section without, the slightest 'success . This machine was pronounced unbreakable by Doering and his colleagues.
3. French "BC-38’' Machine. This machine was worked on in Wm. Doering’s machine section. According to reports, only messages with the same or nearly the same indicator group were breakable. Under favorable circumstances the appropriate day's traffic could be broken from this. Such compromises were very rare. They were of no particular importance as the messages broken were too old.
From I-58 "Interrogation of Dr. Otto Buggisch of OKW/Chi ,p3 and 5
Otto Buggisch was a cryptanalyst in Inspectorate 7/VI (In 7/VI).Transferred to Wa Pruef 7/IVe in summer 1944
p5:
C-36 - The theoretical analysis of this in 1940 developed two theoretical methods.
1) Based on frequency of K. as word separator.
2) Statistical - various, depending on the most usable feature of the traffic, low, high letters, etc. The studies made by B. et al. were used by Oberinsp. Kuehn to forestall the introduction of the device into the German Army, as advocated by Major JUNG.
B. says the statistical method was later used in practice and needed 300 letters. He makes general statements about considerable later success with C-36, from 1942 on. (Not pinned down on this.)
B-211 - B. studied this in 1942 in detail, using the traffic of two years before. A theoretical solution was developed and back traffic actually solved. However, the method did not work in practice when B211 traffic was again encountered actually, and B, did not mention any new methods devised or any idea of how the machine may have been changed.
The modification is mentioned In ‘’European Axis Signals Intelligence’’ vol1 chart 1-2 : Cipher machine employing fractionation, substitution and recombination (used 5x5 square,had 6 wheels and 2 sets of plugs , ‘’modified’’ version had 10 wheels and 4 sets of plugs)
p3 :
Roughly end of 42 or beginning of 43. Reappearance of C 36 messages in De Gaulle traffic. Decoding by means of the method developed earlier by Dr. Denffer; likewise B 211 messages appear, which however do not decode according to the theoretically worked out method.
Winter 43/44 ……C-36 messages with complicated encyphering technique, solved in the spring (Le zouave du pont d'Alma a dit).
From I-92 Final Interrogation of Wachtmeister Otto Buggisch (OKH/In 7/VI and OKW/Chi) ,p3
3. Complications in C36. Buggisch could recall no "complicated enciphering device," unless he had meant to refer to the new indicator method introduced in January of 1944. The old indicator system, changed in its details in 1942, had been a letter substitution table, which had been simple. The new system was based on numbers, but he could give no details. Relative internal settings continued to be recovered and a high percent of the traffic solved on cribs and statistics (for any message over 400 letters) until the indicator system was broken in the late summer of 1944. About the same time in 1944 the French had adopted a system of sending internal settings by mean of an ordinary sentence for each wheel, of which the first so many non repeating letters gave the active lug positions. This system was first reported in a broken code message; the knowledge that it existed was of academic interest only, as no keys wore gained from other systems.
Buggisch spoke especially of the successful solution of C36 in 1943, on de GAULLE traffic to CORSICA. He also said that the Southern France landings were largely given away as to date and strength of force by broken C36 traffic.
I-23 Interrogation of Major Ernst Hertzer, German Army Signals Intelligence Service (KONA 1) ,p2
'’The French Hagelin C-36 was read in it’s entirety ‘’
I-18 Interrogations of Oberst Muegge, O.C. of NA 4 and NA 7 of German Army Sigint Service ,p5
Muegge was asked about work of NA 7 on the large French Hagelin. He knew nothing about this, but said they "had captured a small French Hagelin and therefore were able to read all the traffic". This was used on the big links only, in the summer of 1943. They had good success but the content was not interesting. He believed they read all the traffic. We asked what methods were used, and Dr. FRICKE broke in to say that they could read all messages from 1940 on in Berlin, and they sent the keys out to NA 7. They did not need depths, as they knew the common beginnings and K was used as a word spacer. This machine was the C-36 with fixed lugs on the drum. For the American Hagelin with moveable lugs, depth was needed. The American machine was broken only occasionally.
Finally report FMS P-038 ‘’German radio intelligence’’ mentions the C-36,BC-38 and B-211 although not by name :
XI. Sicily and Italy (1943 - 45)
………………………………………………………………………………………………………………………………
Only the French went their own way in cryptographic matters, and their systems could be easily solved. They used a small cipher device, probably of Swedish origin, the results of which were not difficult to solve. It was even possible to break the large French cipher device under certain circumstances
The large Hagelin is definitely the modified B-211 .It seems that some messages could be read probably as a result of operator mistakes ( messages in depth?) .
The small Hagelin was the C-36 in 1943 and the C-38/BC-38 in 1944.According to report ULTRA/ZIP/SAC/G.21 the Allies equipped the French Forces in Italy with the M-209 (US version of C-38) in 1944.
In conclusion we can say that the French did not fare well in the cryptologic field during WWII .The Germans considered their methods outdated and the western Allies were constantly irritated by their security compromises.
In conclusion we can say that the French did not fare well in the cryptologic field during WWII .The Germans considered their methods outdated and the western Allies were constantly irritated by their security compromises.
During the 1930’s and up to the Battle of France their high level codes were read by the Germans. In N.Africa and Italy their low and mid level codes compromised Allied plans. Moreover it seems that they continued to use weak cryptosystems even after the end of the war up to the 1960’s.
The best thing that can be said about the French is that although they lost the cryptologic war ,by facilitating the Polish success with the Enigma they fatally compromised the basis of German communications.
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