The reading of this traffic during the years of peace and intrigue did from time to time produce very interesting if not invaluable intelligence. But the proximity of the two capitals did mean that a great deal passed by bag.
c. The only real operational intelligence came from our work on the Soviet traffic. We were able to attack their systems step by step with success from the days of Litvinov’s first visit to Copenhagen, of Kamenev as their first representative in London followed by Krassin, until the famous Arcos Raid in 1927 (?) when HMG found it necessary to compromise our work beyond any question. From that time the Soviet government introduced OTP for their diplomatic and commercial traffic to all capitals where they had diplomatic representatives.
The revolutionary government in 1919 had no codes and did not risk using the Czarist codes which they must have inherited. They began with simple transposition of plain Russian and gradually developed systems of increasing difficulty. The presence of Fetterlein as a senior member of the staff and two very competent girls, refugees from Russia, with a perfect knowledge of the language, who subsequently became permanent members of the staff, enabled us to succeed in this work. We were also able to borrow certain British Consuls who could not return to Russia.
d. The fourth big productive effort was on the Japanese. Here the cryptographic task was for the first ten years almost non-existent so far as diplomatic work was concerned. For the language, which was the main difficulty, we were lucky enough to have recruited Hobart-Hampden just retired from 30 years’ service in the East. But for a long time he was virtually alone, but with his knowledge of the habits of the Japanese he soon acquired an uncanny skill in never missing the important. Probably not more than 20 per cent of the traffic received was circulated, but throughout the period down to 1931 no big conference was held in Washington, London or Geneva in which he did not contribute all the views of the Japanese government and of their too verbose representatives. Sir Harold Parlett, another distinguished officer from the Japanese service, joined him in 1926 and ably seconded him with an equal sense of the essential. Yardley’s ‘Black Chamber’ tells of the American success at the Washington Conference. No one will ever tell how much accurate and reliable information was made available to our Foreign Office and Service Departments during those critical years.
Of the building up of the Japanese naval work, in which both these officers played a part, I will be speaking briefly later.
e. A continued watch was kept on the ex-enemy countries, but here there was little development. Germany was allowed to introduce her new methods, and we soon knew that she was using OTP for all she wished to keep secret. In course of time we knew her method of using pads and how she made them up. We also knew of her second method and diagnosed it as unbreakable.
This second method, nicknamed Floradora, was finally broken in 1942 thanks to three chances:
1. The basic book fell into our hands;
2. Close co-operation with USA;
3. SS work by an able ally who obtained first-hand information and one page of figures from a German cypher officer.
We had in fact reconstructed the basic book during the period 1932-39, but the effort was never profitable as German security rules forbade its use unrecyphered, except for purely administrative telegrams which proved of little interest or value.
The Austrian government had always used reasonably secure methods of recypherment and never used their books plain. Thanks to assistance from Fetterlein we did read them in 1918 and 1919, as there was sufficient traffic. But Trianon produced a small poor country whose communications grew less and less, and ultimately we failed for lack of telegrams.
Austria, Hungary, and the Balkan countries rarely produced sufficient material to justify an attack. The greater part of their telegrams probably passed on the continental landlines which were never available to use in peace.
Hungarian was successfully tackled by Knox, but it is doubtful if the results obtained at that time justified the enormous effort on his part.
Later an increase in the use of W/T and the troublous political situation did enable us to read some of the traffic of these countries but never have we been able to report full legibility, a regular flow of traffic and valuable results.
f. Some of the other powers had already been started in MI 1B or 40 OB, notably Greek, Spanish, Italian, Scandinavian and Persian and where purely alphabetical books were used, telegrams had been read and circulated.
Sections were therefore formed in the new GC&CS to carry on this work. Early in our career the Foreign Office disclaimed any interest in Scandinavian, so this subject was dropped.
Passage of time and changes in the political situation opened up new lines. The various South American republics, Portuguese, Brazilian, were tackled. The Balkans were watched, though little traffic was available as European landlines carried most of it. A Near East Section was envisaged, working in close co-operation with the military station at Sarafand, of which I will write later.
To sum up the cryptographic effort of 20 years on diplomatic traffic: we started in 1919 at the period of bow-and-arrow methods, i.e., alphabetic books; we followed the various developments of security measures adopted in every country; we reached 1939 with a full knowledge of all the methods evolved, and with the ability to read all diplomatic communications of all powers except those which had been forced, like Germany and Russia, to adopt OTP.
The authority who sanctioned our establishment in 1919 clearly never envisaged a complete reading, translation and issue of every telegram received by us.
Such was a physical impossibility for the 30 specialists who composed the main body of the staff employed on the work.
Hence from the outset sections did exercise their own discretion as to what they translated and submitted for circulation. They got guidance from the D and R who in turn received intelligence directives from the Foreign Office, the circulating sections of SIS and the officers who used our material in the Service and other large departments.
During the thirties we did supplement our daily issue by a daily ‘Summary of telegrams decoded but not circulated’, for the benefit of SIS, Admiralty and War Office (occasionally the Foreign Office) and it is noteworthy that it was only a very small percentage that were ever asked for in complete form.
With personal satisfaction I maintain that GC&CS did during those 20 years fulfil its allotted function with success, with exiguous numbers and with an absence of publicity which greatly enhanced the value of its work.
4. Clandestine
Peacetime GC&CS did have one experience of successful work on clandestine traffic. This, unlike the diplomatic, necessitated close cooperation between interception, T/A and cryptography before the final results were made available only to a small select intelligence section of SIS.
Some time around 1930 our stations picked up a mass of unusual and unknown transmissions, all in cypher except for the ‘operators’ chat’, which was all of the international amateur type. The analysis of this traffic was studied closely, and from it emerged a worldwide network of clandestine stations controlled by a station near Moscow. It turned out to be the Comintern network. Brigadier Tiltman has written up the story of the cryptography attack which met with complete success. Control of interception, including D/F, was left to Kenworthy and Lambert, and their successful effort to locate a room in a house in a terrace in a suburb of London was perhaps the earliest example of this type of work, and proved in the early days the value of co-operation between interception, T/A and cryptography.
I can imagine that there was a considerable amount of clandestine wireless from 1935 onwards, during the Abyssinian and Spanish wars, and various episodes of Hitler’s aggression, but lack of technical facilities prevented any attempt at interception.
One other clandestine network was observed and studied by us in the prewar days, namely that organised by the German Foreign Office. As we were aware that already our own Foreign Office and SIS were taking steps
to ensure communications with our embassies and posts abroad in the event of a breakdown of the normal routes, we were not surprised when Denmark Hill in 1937 and 1938 obtained obvious German diplomatic traffic broadcast from an unlisted station in Germany to unknown recipient call-signs as well as obvious replies from unknown stations.
As previously stated, we could not read the traffic, but it could not be mistaken: it was not disguised. Interception, T/A and direction finding enabled us, even in those days, to be certain that every German embassy and legation and many German consulates were equipped with W/T gear for reception and transmission. Denmark Hill was able to make preliminary studies of all the methods of changing frequencies, call-signs, etc, used to disguise as far as possible the originators and the services, so as to avoid interception and identification. When later during the war it became necessary to obtain all this material, these early studies by Denmark Hill proved of very great help.
5. Services
GC&CS, as an office, had no means of obtaining W/T traffic. Admiralty and War Office had set up a large number of intercepting stations during the war, from which DNI (Admiral Sinclair) persuaded the Signal Department to retain two, Scarborough and Pembroke, and the Military Directorate in the War Office to retain one at Chatham. Naturally the first duty of these stations was to watch the service traffic of other powers, but they also undertook to spend part of their time watching the big commercial transmitters in foreign countries with a view to obtaining such government cypher traffic as they heard. I propose to go more fully into this question in section D. But it had to be mentioned here as one reason for the creation of a Naval Section.
Admiralty. The beginning of the Naval Section is obscure in my memory. Clarke, who became the head of the section, did not join until 1921 as he was engaged in writing up the naval history of the Great War. But the Admiralty did lend certain officers, first German, then Italian linguists. There was of course very little German naval material in the early years: there was no German navy to speak of. There was a small amount, but it was soon apparent that we could not read it. The Armistice Commission and the Peace Treaty had made no demands. So far as I remember we concluded that a machine recypher had been applied to the 4-letter code book with which the German navy finished the war, but at that time we knew nothing of the German development of the Enigma machine. It is possible that in 1923-25 they were already using it.
In any case there was no navy, and consequently little traffic, and so interception was dropped.
The Italian navy was also watched, and here we were lucky. There was a navy and consequently a fair amount of traffic, and in early days we did reconstruct the main naval code book because of the delightful Italian habit of encyphering long political leaders from the daily press. As can be imagined in those years and with such habits, the Intelligence value of the effort was slight, but we did build a foundation which proved of value from 1934 onwards.
But even in the early twenties the Admiralty did evince an interest in Japan. But GC&CS only obtained diplomatic and attaché material - no Japanese naval traffic could be intercepted in this country. We knew the Japanese cryptographic methods to be low-grade - the language was the difficulty and linguists were hard to find. The Admiralty, however, had a certain number of interpreters, some of whom were for one reason or another no longer essential for active service. From 1922 onwards we had always one naval officer working in the Japanese Section, reading the diplomatic and naval attaché telegrams. By 1925 we even had officers still on the active list and a scheme was arranged whereby such came to us for two years and then joined the China Squadron in a ship where there were facilities for local interception. Thus a first start was made on Japanese naval traffic.
From then onwards there was a flow of traffic by bag to London where the various codes were segregated and broken as far as possible, and a return flow of officers with skeleton books to carry on the work locally. I believe that by 1930 they were able to be of definite use to the C-in-C, China. Finally the Admiralty sent out Captain Tail (then DDNI) to study the Far East question, and in consequence of his report, set up a small bureau for interception and cryptography at Hongkong (moved to Singapore in September 1939) where Captain Shaw, now retired, headed the first party to exploit Japanese naval signals, to which was added the beginning of Japanese military. The Diplomatic Section had followed the diplomatic and attaché developments, including the introduction of mechanical devices, successfully, and thus it can be maintained that in early 1939, GC&CS had full control of diplomatic and attaché traffic, were reasonably fluent in their reading of all the main naval cyphers and knew quite a lot about Japanese army cyphers as used in China.
To revert to European affairs, the period of dull slackness of naval affairs and traffic, noted in the opening paragraphs of this section, continued with slight alarms and excursions consequent upon naval reviews and visits until around about 1934, when the Italian governments probably began to plan the Abyssinian Campaign. From then onwards, Italian naval traffic was obtained in increasing quantity with increased security measures. The section kept pace with it all, though by 1935 increased numbers and more room had to be provided. Throughout the campaign and in the tenser moments aroused by the threat of sanctions, the section was able to keep DNI fully informed of the strength and activities of the Italian navy. When in the Spanish war the Italians, not content with their own reasonably secure hand methods, introduced the commercial Enigma machine for all their secret naval communications, this proved a heaven-sent opportunity for us to explore machine encypherment. Knox led the party and younger men, such as Bodsworth and Twinn, had their first experience with him, a fact which proved invaluable after 1939.
It was not until the summer of 1936 that any interest was taken in the German navy. But when they appeared that year in the Mediterranean, all our stations were inundated with frequent repetitions of their naval broadcasts. Work began at once under Knox and by this time we were quite aware that the Enigma machine, with the special attachment known as the ‘Stecker’, was the basis of their service signals. Strong efforts were also made by our naval stations to supplement the broadcasts by ship signals and local coast stations in Germany to try to find lower grade traffic. Lack of gear and men prevented this. Knox made considerable progress in his diagnosis until April 1937, when the Germans introduced the new method of indication [4 bigrams] to which he had to admit defeat. Captures in the spring of 1940 showed the correctness of this diagnosis. In 1937 we had no access to mechanical devices which alone enabled this system of indication to be overcome.
But correct diagnosis does not read messages, so the German naval signals were submitted to another process which we called W/T from which we hoped to learn something of German naval activities. Even in the Great War during 1917 and 1918, when new books were introduced and the cryptographers of 40 OB were not in production, the ‘plotting’ section, with the unread signals before them, did continue to produce daily a reasonably accurate situation report. But no German naval signals had been read for 20 years, and it was hardly to be hoped that the Nazi German navy had preserved the habits and routines of the imperial navy. Nevertheless, from 1937 onwards, such an effort was made by officers lent to GC&CS by the Admiralty, reinforced by available members of GC&CS. We had no accurate checks by the cyphers becoming legible; but out of this effort grew the art now called, I think, T/A, which from 1940 onwards has proved a most valuable adjunct to cryptography, quite capable of acting as a trustworthy substitute when the cryptographer is temporarily unproductive.
To sum up the situation of the Naval Section in 1939, including the Japanese branch in Hongkong: they exercised a very fair measure of control of all Italian and Japanese naval cyphers; they had only seen German signals by the Enigma machine and this they could not read; they had started an intensive professional study of raw German traffic with a view to extracting any available intelligence.
Military. Unlike the NID, MI 1 always maintained a personal interes
t, not only in interception and result but also in cryptography. Before there was any question of a Military Section, officers were sent to us with the definite object of training, while the Admiralty lent officers to assist us in producing results. As stated above, the War Office had, during the war, maintained posts abroad, and early in the twenties decided to set up a permanent intercepting station in the Middle East, and about 1923 Sarafand in Palestine was selected and started to function. In addition to interception, they also intended to read the traffic which affected the area. Therefore at Sarafand Arabic was a primary concern, while French and later Italian were also exploited. I visited there in 1925 and am glad to think that the liaison between GC&CS and Sarafand has been maintained for 20 years. Many army officers worked in both places. MI 1 was also our liaison with a bureau which the Indian army had founded during the war to handle the problems (Persian, Afghan, Russian) which affected India.
Throughout the twenties the military officers who joined us went to sections where their language was used or in which the War Office was interested, because there was no purely military traffic. But very early in the thirties the War Office decided to regularise this somewhat haphazard form of training, and the Military Section was formed to which all army officers with us were attached. Tiltman was made the head of the section, receiving the position of senior assistant on the War Office civil establishment. Members of the Military Section conformed to the routine and discipline of the GC&CS, but MI 1 had the right to dictate their requirements as to training and type of work. At a later date the War Office also recruited civilians on the same lines as GC&CS. Thus was laid the foundation of the very large Military Wing of the war period. Originally the Military Section took over certain of the normal commitments of GC&CS, but with the increasing threat of war, gradually the subject and the traffic on which the sections worked became more definitely military. The Far East began to send back bags of Japanese military material, the Japanese military attachés in Europe began to assume importance. Then the Abyssinian and Spanish wars produced large quantities of Italian military material. All of this latter was tackled successfully, and consequently the section became well trained to face their operational task in 1940.
Thirty Secret Years Page 12