by Henry Landau
Sir Alfred eagerly accepted the assignment. Starting with a staff of five men, he patiently trained them and then added to their number until eventually he had a band of fifty assistants – mathematicians, linguists, and, later, secret ink chemists. Space for Sir Alfred and his staff was found in the Old Admiralty Building in Room 40, and to keep the nature of the organisation secret it was always referred to as ‘40 OB’ (Old Building).
Ewing’s appointment was one of the most judicious ever made at the admiralty. While battles raged at the Front and at sea, this frail, slightly-built man, with his enormous head, bushy eyebrows and dark piercing eyes, tranquilly seated in his peaceful office at the admiralty listening attentively, learned through intercepted and decoded messages what the next moves of the enemy would be. Even though the Germans constantly invented new codes or combined existing ones, he and the men working under him were always able to solve their mystery.
The existence of the British cryptographic service was one of the most jealously guarded secrets of the war. Even some of the British Cabinet ministers did not know of its existence, and many a member of the admiralty never heard of it until long afterwards. But those who were in the know realised that it contributed largely to the ultimate victory of the Allies. The public for the first time heard of it in 1925 when Sir Alfred Ewing caused a sensation by referring to it in an address which he gave at the University of Edinburgh. Shortly afterwards, Lord Balfour made the following declaration: ‘The country owes “40 OB” an immense debt of gratitude, a debt which, for the moment at least, cannot be paid. Secrecy was an essential part of the work and never was a secret better guarded.’
There are hundreds of code and cipher systems, some of which are simple, others so complex as to tax the uttermost ingenuity of the cryptographer. Some are based on a verse or prose passage, or on an intricate combination of numbers, others are as elementary as the prearranged interchange of the letters of the alphabet. Some require the use of ponderous code books; others, in order to prevent their falling into the hands of the enemy, can be committed to memory. The skilled cryptographer must take most of these in his stride.
Cryptography alone, however, could not possibly unravel the secrets of all the German coded messages which crowded both the air and other channels of communication. In the case of a simple code, it was possible for an expert to find the key by studying the words or letters which kept repeating themselves; but in the case of the big German codes, which generally had four or five figure numbers, corresponding to a list of different words and phrases, supplemented by some fixed dictionary to supply words missing from the list, it was necessary to have a copy of the actual code.
The dictionary part was worked by slips having numbers so spaced that they fitted opposite the words on each page; the number of the page was obtained by adding it on to the front or the back of the code number. Thus, for example, if the word ‘jeopardy’ occurred on page 63, and when putting the slip on this page the number 534 came opposite this word, then the code number for jeopardy would be either 63534, or 53463. This could be made more complicated by multiplying this number by a common factor, or adding a fixed sum. As the numbers on the slip were changed continually, and as there are hundreds of dictionaries of all sizes and editions in existence, this dictionary code was undecipherable without a key.
As many of the German coded messages were based on the larger codes, ‘40 OB’ could therefore never have achieved its brilliant success had not many of these codes, by some means or other, fallen into the hands of the British. The difficult task of acquiring them devolved on the British naval intelligence service.
In October 1914, Captain W. R. Hall, who later was knighted and promoted to the rank of admiral, took over from Admiral Sir Henry Oliver the direction of the naval intelligence service. Sir Reginald, or ‘Blinker’ Hall, as he was affectionately known to his intimates, was splendidly endowed for this work. The following estimate of him made by Walter Hines Page, the American ambassador in London, in a confidential letter to President Wilson in 1917, was no exaggeration:
Hall is one genius that the war has developed. Neither in fiction nor in fact can you find any such man to match him. Of the wonderful things that I know he has done there are several that it would take an exciting volume to tell. The man is a genius – a clear case of genius. All other secret service men are amateurs by comparison … I shall never meet another man like him: that were too much to expect.
Apart from Hall’s intimate experience and knowledge of everything pertaining to secret service, he was an uncanny judge of character. One glance was sufficient for him to sum a man up. It was thus that he immediately gauged the qualities of Ewing, chosen by his predecessor, and promptly gave him carte blanche in the running of ‘40 OB’. The rest of his staff were chosen and handled with equal perception. He also had a remarkable ability in cross-examination, which proved the downfall of many a suspected German spy who was snared in the net he laid for him. However watertight their story, as Horst von der Goltz and others found when they had to face him in 1915, he intuitively picked out the flaws in their alibis or defences. ‘He can see through your very immortal soul. What eyes the man has got!’ was the despairing remark of one of his victims. But it was the acquiring of German codes which was Sir Reginald’s special vocation. Under his expert guidance and planning some were stolen by his daring agents; some were recovered from sunken German submarines and warships; others were captured by the British forces in various parts of the world. Although the British diplomatic and fighting services knew nothing about ‘40 OB’ yet, as if attracted by a magnet, all information acquired by them pertaining to German codes found its way to Hall. His net was spun so finely that nothing missed him. To illustrate his methods we will tell how three of the many codes which fell into his hands were obtained.
A few hours after the German occupation of Brussels, the powerful wireless station at the Belgian capital had been converted to German use. As the intercepted messages started coming in to ‘40 OB’, it became immediately evident to Sir Alfred Ewing that the Germans at the Brussels station were making extensive use of one of their large diplomatic codes. Many of the messages defied the efforts of some of his best cryptographers.
British agents, recruited from among the Belgians who remained behind in the occupied territory, were sending a steady stream of spy reports through to Holland. Here, then, was as good a field as any in which to attempt to secure possession of one of the larger German codes. H. 523, one of the best of the British agents, was charged with the mission. Careful observation and inquiry by him yielded results. He discovered that the German coding staff was located in the Kommandantur in Brussels and that it was composed of four coding clerks, one of whom was an Austrian, Alexander Soll, a brilliant young engineer, born in a suburb of London, whose father had moved with him to Brussels several years before the war. Immediately after the occupation of Belgium, the German and Austrian authorities had called to the colours all their nationals of military age residing in the territory, and young Soll had been one of them. His knowledge of the French language and of Brussels had won for him an assignment in the German counter-espionage service, and from there, in the course of time, he had been transferred as a coding clerk to the Kommandantur.
On receipt of agent H. 523’s report, the British secret service was quick to seize on the point that Soll was born in London. A check-up of aliens registered in his suburb revealed that Soll had a relative still living there, that she was employed in an English family, and that, as in the case of so many Austrians, she was violently anti-German. It was not difficult, therefore, to persuade her to write a letter to her brother on fine tissue paper urging him to aid the British by securing for them the code. Her letter was handed to H. 523 on one of his periodical trips across the frontier into Holland.
To approach Soll directly was a dangerous and delicate undertaking, but H. 523 was skilled in the right methods of approach. After winning Soll’s confidence by giving
him news of his relative, H. 523 finally handed him her letter. At first Soll was afraid, but after considerable persuasion he eventually fell in with H. 523’s plans. Soll’s first thought was to steal the code, but H. 523 quickly pointed out to him that this would defeat their object, as the Germans would immediately change it. And so Soll set about the laborious task of secretly copying the code during his hours of service. This took him several months, since he could only do the copying during the odd moments he was left alone in the coding room during the luncheon hour. Finally, however, in April 1915 the task was completed. But to H. 523’s dismay Soll refused to give him the code. He insisted instead on escaping across the frontier with it to Holland. In vain H. 523 pleaded with him that his flight would arouse the suspicion of the Germans that the code had been copied. But Soll was adamant; he had just received confidential information that he was about to be transferred to the Front; and from the firing line, above all, he wished to escape. Therefore, early in April 1915 on a moonless night, the two of them set out for the Belgian–Dutch frontier.
It was the period just after the Germans had completed their formidable barrier along the Belgian–Dutch border to prevent the passage of spy reports and to put a stop to the flow of refugees escaping across the border to join the Belgian Army. A high-voltage electric fence, 8 ft high, sentries every 100 yards, searchlights, police dogs, a horde of secret service Police, and mounted patrols covered the length of the frontier. Arriving near the border, Soll began to regret his decision. The danger was as real as being in the trenches. He was now glad to get rid of the compromising copy of the code by handing it to H. 523.
Equipped with india-rubber gloves and socks to enable them to cross the high-tension electric fence, the two men crouched in the long grass, awaiting the moment when the sentry near them would reach the point on his beat farthest away from them. But their wait was cut short, a police dog started barking, the alarm was given, the searchlights were switched on, and the sentry started shooting. H. 523, experienced in crossing the high-voltage electric fence, made a dash for the border and succeeded in getting across, but Soll turned back and tried to escape. H. 523 brought the code to Colonel Oppenheim, the British military attaché at The Hague; and in due course it was forwarded to Sir Reginald Hall. What happened to Soll will ever remain one of the mysteries of the war.
Soll’s father, who lived with him in Brussels, never heard of his son again. He was convinced that his son got across the frontier; and when after the Armistice he failed to return home, he accused the British of making away with him to prevent the Germans finding out that the British had a copy of the code.
After the war, while in charge of the secret service section of the British intelligence commission, whose function it was to liquidate all the British spy services which had operated behind the German Western Front in occupied Belgium and north-eastern France, I came across some evidence to show that Alexander Soll had been kept in solitary confinement in the Namur prison, that he was tried by court-martial, found guilty of being a deserter from military service, and shot. My informant was a former German soldier who had served during the war as a warder at the prison. This man, born in Silesia, acquired Polish nationality by the Peace Treaty, and remained in Belgium after the Armistice. I am inclined to believe the warder’s story – he had no reason to invent it – but Soll’s father refused to accept it. To him it was just another ruse of the British to keep the truth away from him. On the other hand, if the Germans did shoot Alexander Soll, why did they not notify his father? And why after the war, when the father made inquiry in Berlin, did the German authorities inform him that they had no record of his son’s execution?
Whatever the solution to the mystery, and whatever suspicions the Germans may have had, it is evident that they were not aware that the British had secured a copy of the code, for, except for a few minor variations, it remained unchanged and in active use until the end of the war.
For the story of the second code we must now switch to another part of the world. One of the principal sources of oil supply for the British fleet was the oil wells of the Anglo-Persian company in Persia. These oil wells, situated several hundred miles inland, were connected to the Persian Gulf by a pipeline. The protection of this vital artery of supply became a supreme necessity. The task was a difficult one, owing to the length of the pipeline and the barren nature of the country through which it ran. The whole length of it could not be guarded at the same time, and the surveillance had to be entrusted to mounted patrols. Not only had these patrols to watch out for marauding bands of Turks and Kurds, who knew the terrain much better than the British, but Persia itself was a hotbed of German intrigue; and, as was the case in other neutral countries, it was overrun by German agents, who, in most cases, were directed by some German official enjoying diplomatic immunity.
Von K–– the German consul at Shiraz, was specially active, and of this fact the British intelligence service was fully aware. In fact, so well were they posted as to his activities, and so closely was he watched, that the British knew several days ahead of time of a raid on the pipeline he planned to carry out with the help of Kurdish irregulars.
The date and the locality of the raid being known, an ambush was laid for Von K–– and his band of Kurds. It was a surprised German consul who found himself surrounded and forced to surrender before more than a shot or two had been fired. Pleased as the British were with their haul, they were even more delighted and surprised when they discovered an important German code in the possession of Von K––. So sure had he been of success that with characteristic German thoroughness, he had brought the code along with him. He had wished to lose no time in sending through to the Turkish lines, for wireless transmission to Berlin, a coded message announcing the details of his coup.
The code was promptly forwarded to Sir Reginald Hall. It was the German code number 13040. It proved later to be one of the biggest scoops of the war.
Even though the Germans heard of the capture of Von K––, it never dawned on them that he could have been so foolish and indiscreet as to have permitted the code to fall into the hands of the British.
Several codes were also recovered from German warships sunk by the British Navy. Of these the code from the cruiser Madgeburg was one of the most important. Within a few minutes after a British torpedo struck her, she went to the bottom, and only a handful of the crew were saved. Days afterwards a British torpedo boat patrolling the area sighted a floating body. It turned out to be the commander of the Magdeburg. Buttoned securely in his tunic was the code book. Some of the survivors later testified that when last they saw their commander, he was standing on deck with the code book clasped in his hands.
Such, then, was the organisation which Hall had brought to perfection. Not only was there ‘40 OB’, which was capable of mastering every German cipher, but also Sir Reginald’s network spread throughout the world, which was able to acquire by theft or capture every important German code. This combination of skilled cryptographers and the actual possession of the large German codes enabled Sir Reginald and his organisation to decipher every German coded message which came into their possession.
To pick up the German wireless messages, receiving stations were erected at Lowestoft, Lerwick, Murcar, and York. These stations not only sufficed to intercept the messages for dispatch to ‘40 OB’, but they served also as radio goniometric stations to furnish bearings for triangulating the position of any German vessel using its wireless.
Not satisfied with intercepting every German wireless message which flashed through the air, agents were actively employed in all neutral countries to secure copies of coded telegrams and cables sent out by German diplomatic representatives over neutral telegraph and cable lines.
Long before the war Germany had seen the necessity of establishing a complete wireless system throughout the world. In accordance with this plan she had in 1911 erected a wireless station at Sayville, Long Island. This foresight had permitted her throughout t
he first two months of the war to have untrammelled wireless communication with her representatives in the United States. But in September 1914 the United States government seized the station, realising that it was being used to direct movements of German commerce raiders still at sea and was thereby infringing American neutrality. At the same time a censorship was enforced and the sending of coded messages was prohibited.
German ingenuity, however, soon found a means of evasion. Receiving the incoming messages sent out every morning at 3 a.m. from the powerful German station at Nauen, near Berlin, was simple. Many of the interned German ships, although forced to take down their regular antennæ, re-rigged them in funnels or other places of concealment. Several secret receiving stations were also erected in private homes. The sending of messages, however, was more difficult. One method was to use prearranged key phrases embedded in apparently innocent commercial telegrams; but for messages important enough to demand the use of one of their large codes they availed themselves chiefly of neutral channels, especially those provided by Sweden. The Swedish Foreign Office was notoriously pro-German, and German messages were frequently put in Swedish cipher and sent to Swedish ministers in other countries for delivery to their German colleagues. Incredible though it may seem, Germany also occasionally beguiled the state department on one pretext or another into forwarding her messages.
The British network of agents in the neutral countries picked up most of these cables, however; and even those forwarded through the state department were intercepted in London, as the cable lines from the United States to Europe passed through the British Isles. In Holland, one of the British agents was specially assigned to procure through secret connections of his in the Dutch telegraph office, copies of all telegrams sent to Berlin by the German minister at The Hague. Such a telegram, intercepted by a British agent in neutral Chile and decoded by ‘40 OB’, gave the British Admiralty the information that Admiral von Spee and his squadron were about to sail from Valparaiso for the Falkland Islands. This permitted the admiralty to draft the plan which led to the sinking of von Spee’s ships by Admiral Sturdee. Proof of the efficiency of the British network was that a telegram which was sent through four different routes to von Eckhardt, the German minister to Mexico, was picked up by the British in each case.
