SIM had its own codebreakers, but too few of them. Safecracking was quicker.
The two operations complemented each other. If you know how a country builds its codes, and what phrases repeat in its messages, unraveling a code is much easier. The Portuguese legation got a new cipher the year after Talamo’s raid, but the information gleaned from the old cipher helped SIM break the new one.55
In May 1939, the Duce instructed the Servizio Informazioni Militari to pass any new British papers it acquired to Germany.56 Whether or not Talamo’s own commanders told him this, he had acquired a new client.
Three months later, Germany went to war. Mussolini reluctantly stayed out. Talamo stepped up the frequency of thefts from the British embassy.57
ON SEPTEMBER 4, Al Aharam, Egypt’s largest-circulation newspaper, reported that it still had no word from its Rome correspondent on Italy’s intentions. But it put together the clues. Rome radio stations, it said, had carried British prime minister Neville Chamberlain’s speech on going to war. Italian diplomats in Cairo hadn’t been told to close their legation. “The Italian liner Marco Polo is today sailing from Italy to Alexandria,” it reported. All this indicated that “Italy is not yet ready to range herself alongside Germany.”58
As the days passed and that prediction held true, the Foreign Office in London reluctantly accepted Lampson’s view: it wasn’t worth pushing Ali Maher and Farouk to declare war.59 In practice, Britain prepared to defend Egypt as part of the empire. Officially, Egypt was a “nonbelligerent.”60
The morning after Ralph Bagnold got to Cairo, he dropped in at General Headquarters Middle East to see a friend from his days serving there. The friend was now chief signals officer of the British Troops in Egypt.
“Just the man,” his friend said. “Wavell wants to see you at once.”
Bagnold was baffled. As far as he’d known, he was uninvited and unexpected. He couldn’t figure out how General Archibald Wavell knew he was in Egypt or what Wavell himself was doing there.
It turned out that a reporter for the English-language Egypt Gazette had spotted him the evening before. The morning paper reported correctly that the famous desert explorer was back in town, and incorrectly that the War Office had assigned him to the right place. As for Wavell, he’d been appointed to head the new and still mostly theoretical Middle East Command, for the moment consisting of the small British forces responsible for internal security in Egypt, Sudan, and Palestine. Wavell was supposed to turn them into an army, but to be quiet about it and avoid provoking Italy.
The signals officer took Bagnold to a small upstairs office, where he found “a rather stocky man with a grim weatherbeaten face, with one very bright eye.” Wavell asked if he’d like to serve in Egypt, and arranged for the War Office to transfer him. He was sent to Mersa Matruh on the coast, where Britain’s single armored division in Egypt—incomplete, inexperienced, and untrained for desert fighting—was deployed to stop an Italian invasion.61
4
THE MACHINE IS THE FUTURE
Autumn 1939. Bletchley Park–Warsaw–Paris.
A LINE OF trees protected the country estate from the rumble of the trains passing by on the London-Scotland and Cambridge-Oxford lines. A fence ran around the estate—no barbed wire yet—and a sentry stood at the gate when Gordon Welchman drove up. On his first day, his name was most likely on a list for the sentry. After that he’d need the daily password, though the sentries weren’t strict about this once they knew a face.1
Up the drive from the gate stood the mansion, with its improbable collection of gables, arches, stonework, peaked roofs, and a copper dome. A stockbroker who’d been rewarded for his riches by being made a baronet had lived there for over forty years. He’d completed his pose of country gentleman by planting a maze on the grounds and hundreds of trees including a sequoia redwood from California.2
The mansion now housed confusion. MI6, the Secret Intelligence Service, had set up its wireless communication station in an attic. An aerial ran from the top of the house to the towering redwood. MI6 took over the bedrooms on the second floor for its offices. Ground-floor rooms went to the telephone exchange and the teleprinters and to workspace for the people who broke army, navy, and air force codes for the half-euphemistically named Government Code and Cypher School, Britain’s signal intelligence agency. The director of the GC&CS, Alastair Denniston, established his office in the morning sitting room of the lady of the estate, where the picture window looked out on the lawn, the circular carriageway, and the lake.3
The prewar staff had moved into Bletchley Park in mid-August. In early September, after Britain went to war, new people kept arriving, asking where they were supposed to go and looking for other people they knew, as if GC&CS really were a school and this was the start of the term. Space ran out in the mansion, despite it having twenty-three bedrooms, and in the cottage behind the stable yard, probably the former home of the groom. MI6 bought the small private grammar school that neighbored the estate, and the section that worked on diplomatic codes moved in.4
The year before, when the Sudentenland crisis boiled over, MI6 director Admiral Hugh Sinclair had decided his agency needed a location safer than central London. When people in Britain thought of war with Germany, they thought of Guernica, the town that the German air force had shattered in a single day during the Spanish Civil War. So Sinclair went looking for real estate in the countryside. The widow of Bletchley Park’s baronet had died, and his son had sold the place to a developer. Sinclair found it before the new owner had time to tear down the mansion and start building houses. The War Office and the Foreign Office each thought the other should pay. Sinclair felt greater urgency, and put out £7,500 of his own money, a fortune, and bought the estate in his own name. (Sinclair respected agency traditions: his predecessor’s last initial had been C, so Sinclair went on using that letter as his alias; his predecessor wrote in green ink, so he did too.)
The administrative officer of MI6, Captain William Ridley, directed a trial run of moving from London to Bletchley in September 1938. Staffers from MI6 and GC&CS moved into hotels around Bletchley Park and said they were part of “Captain Ridley’s shooting party,” out for a hunt. The plan was that if war broke out, everyone would stay. The mix of young female secretaries and Great War veterans led locals to guess all the wrong secrets. Then came the Munich Agreement, and everyone returned to London.5
One story that grew around Sinclair’s purchase of Bletchley said that he was attracted by the junction of the London rail line with the Cambridge-Oxford track. This may be myth; Sinclair may simply have taken the first country estate he found on the market.6 Still, the midpoint between the two universities was precisely where GC&CS belonged, physically and in spirit.
IN 1929 IN America, President Herbert Hoover had picked Henry Stimson as his secretary of state. Stimson discovered that the State and War departments were jointly funding a tiny codebreaking agency, officially called the Cipher Bureau and unofficially known—at least by its flamboyant director, Herbert Yardley—as the Black Chamber. Eight years before, Yardley and his crew had broken Japan’s diplomatic codes in time for a conference between American, British, Italian, French, and Japanese representatives on limiting the sizes of their respective navies. The Black Chamber decoded the message from Tokyo to its negotiators telling them that their rock-bottom offer should be that Japan would have 60 percent of the battleship tonnage of the US Navy. American negotiators naturally refused every offer from Japan until its representatives lowered their demand to this number.
Stimson regarded the Black Chamber as a violation of diplomatic ethics. He immediately cut his department’s funding, and the bureau shut down. Stimson later explained, “Gentlemen don’t read each other’s mail.”7
The six employees of the bureau found themselves jobless just as the American economy collapsed. Five nonetheless kept their silence. Yardley, however, wrote a tell-all book, American Black Chamber. Besides its English-language success, it sol
d thirty thousand copies in the Japanese version. “The jolt which his book gave to Japanese cryptographers,” according to a secret US report eleven years later, led “them out of their blissful ignorance” and caused them to develop their own Enigma-type cipher machines.8
Stimson’s puritanical stuffiness never afflicted his British counterparts. Another kind of stuffiness did. Their recruiting policy has been aptly described by a historian as “Only gentlemen should read each other’s mail.”9
Codebreaking, that is, was a job for people of the proper class, and sufficiently brilliant gentlemen were to be recruited at Cambridge and Oxford. This practice dated back to the Great War, when the Royal Navy’s codebreaking office, informally known as Room 40 for its place in the Old Admiralty Building, enlisted classicists and linguists, on the theory that if you could make sense of faded handwritten ancient Greek or Latin, you could unravel a German military or diplomatic code.
The experiment proved the theory. Room 40’s successes included decoding the telegram in which German foreign minister Arthur Zimmermann offered Mexico an alliance against the still-neutral United States. Mexico was to regain Texas, Arizona, and New Mexico as the payoff. The message was sent in January 1917 to the German ambassador in Washington in Germany’s most sophisticated diplomatic code, but the British intercepted it. From Washington, the German embassy forwarded it to the German legation in Mexico in an older code, and in slightly different words. Britain didn’t turn over the telegram to the US ambassador in London till it could steal a copy of the reworded version in Mexico City, in order to keep anyone in Germany from guessing that the newer code was now an open book. The telegram did not propose that Mexico get California, perhaps because Zimmermann also proposed adding Japan to the alliance and was saving some booty for that country. Once published in America, the telegram helped bring America into the war.10
The Royal Army had its own unit for reading the mail of officers and gentlemen. When the war ended in 1918, the two units were merged to create the GC&CS and were put under the control of the Secret Intelligence Service. The money-saving merger gave Britain an edge over other countries: its codebreakers weren’t divided into separate agencies working for competing branches of the military that didn’t want to talk to each other. In its first years, GC&CS devoted its energies to the diplomatic messages of ever more countries—a task made easier because British companies owned much of the worldwide web of telegraphic cables. The cable firms had a quiet, gentlemanly arrangement, authorized by the 1920 Official Secrets Act, to turn over to the British government copies of messages between ambassadors, attachés, and their capitals.11
As far as Alastair Denniston was concerned, the Munich Agreement meant only that he had peace for a little more time. He used it to recruit geniuses from Oxbridge, and added mathematicians to his list of candidates. So a letter came in the post one day in late 1938 for Gordon Welchman, politely and unexpectedly inviting him to join the Government Code and Cypher School. The next March, just after Hitler dismembered Czechoslovakia, Welchman went to London for a two-week introduction to the arts of cryptography—that is, creating codes—and cryptanalysis, breaking them.12
John Tiltman taught some of Welchman’s classes. Tiltman really had been a schoolteacher once, until the Great War pulled him from the classroom to France, where he was badly wounded. War takes those who survive, whirls them around, and flings them in directions they never imagined. A bit of Russian he’d picked up landed Tiltman in the business of breaking Soviet codes.
From there he went on to creating new codes for Britain. Unlike many in that line of work, he searched out the weak points in his own codes and used them as clues for how to solve those of other countries. While insisting he was bad at languages, he taught himself Japanese and broke Japanese codes, including the one used by military attachés. He did it over and over, because the Japanese kept changing their codebooks. In 1939, Tiltman headed the military section—which, in British terms, meant specifically the army section—of GC&CS. One thing he hadn’t accomplished was deciphering German Enigma messages.13 No one could do that, as far as anyone in Britain knew.
A photo from that time or soon after shows Denniston and Tiltman on a London street. Denniston’s suit is tailored tightly to his narrow build; the brim of his homburg casts a shadow that hides his eyes; the crown of his hat reaches Tiltman’s shoulder. Tiltman wears the tartan trousers of the Scottish infantry unit in which he fought on the Somme, with a wide leather belt around a military jacket that looks at least one size too small for him, or perhaps he is two sizes too big for the street. He swings his arms as he strides toward the camera.
One man looks like a whisper; the other, a gale.14
After the London course, Welchman got five more months of Cambridge calm. The day he reported to Bletchley Park, he was sent to the cottage behind the stable yard. The cottage was the kingdom of Dillwyn Knox, head of the Enigma section of GC&CS. It was a small kingdom, and drab. The rooms of the cottage were whitewashed; if you rubbed against the wall, you’d find a splotch of white powder on your clothes. A closet connected the two downstairs rooms. Dilly Knox regularly limped into the closet when he meant to go outside. Dilly had a poor sense of direction in the physical realm and an inclination toward accidents. His love of motorcycles had ended with him alive but with one leg permanently damaged. In 1939 he was fifty-five years old, tall, with unkempt black hair retreating from his high forehead. His black-framed glasses seemed to serve as a divider between the world and his thoughts.
In the realm of obscure symbols, on the other hand, Dilly had a supernatural sense of direction. As a young Cambridge scholar, he’d dedicated himself to deciphering a set of papyrus fragments bought by a British Museum scout from tomb robbers in Egypt. The fragments bore the lost, lewd work of the obscure third-century-BCE Greek poet Herodas.
In 1915, Room 40 had needed him more than Cambridge did. Actually, Dilly worked in Room 53, the only one in the Old Admiralty Building with a bathtub. Hot water helped him think. He unraveled the code used by the commander of the German navy. He and a colleague decoded the Zimmermann Telegram. After the Great War, Dilly completed his translation of Herodas but went on working for GC&CS. He acquired an early commercial Enigma machine, though a British expert analyzed the device and decided Britain shouldn’t use Enigma for its own communications. Other countries did adopt the Enigma. Dilly Knox spent years on their messages.15
Dilly’s Enigma section numbered just four people when it moved into the cottage, out of the 110 GC&CS prewar staff who came to Bletchley Park. A year earlier, the Enigma section had consisted only of Dilly and his secretary.16 Size was a statement. The resources devoted to a particular code depend on the value of the information sent in it—but also on the odds that investing people’s time will pay off with a break. Enigma carried freight trains full of German secrets. But could anyone crack the riddle?
Dilly did find his way into the versions of Enigma that the Spanish Nationalists used during the Civil War and those that Italy’s navy used. These were older, simpler machines. Germany’s upgraded Enigma remained impenetrable. Peter Twinn, a twenty-three-year-old Oxford mathematician who started working with Dilly in February 1939, was “not sure whether [Dilly] had any chance of success.” But it was hard to know since Dilly Knox was “notorious for being very secretive.” Knox treated a code as a puzzle to be solved alone—one more reason for his small team. Denniston, though, had enough hope to bring in Twinn, Turing, and Welchman.17
When Welchman came to the cottage, someone showed him a copy of a German Enigma machine with the correct wiring and explained the format in which messages were sent. The machine and the explanations, he was told, came from “the Poles.” He wasn’t told any more details. Dilly didn’t take to Welchman. He gave Welchman “some sort of test and appeared annoyed that I passed.” In fact, Dilly was suffering from a chronic stomach illness. Besides, he generally did not like men. He preferred the company of women.18
Sinclair was in much worse health, dying of cancer. Nonetheless, he sent a chef to Bletchley Park at his own expense. Until the staff grew and war rationing set in, everyone ate lunch in the mansion’s dining room, at tables laden with chickens, hams, and beef puddings, with sherry trifles and bowls of fruit for dessert. They were billeted in the countryside, in private homes and tiny inns. Welchman and Patrick Wilkinson, a mathematician working on Italian naval codes, were given rooms in a pub called the Duncombe Arms, down a country road, on a hillside with a view of a wide green valley. In the pub’s billiards room, they spent their evenings with friends from work. In the daytime, they lived in a strange world, trying to work magic on incomprehensible missives from a far-away war, forbidden to speak a word of what they did to anyone outside.19
WELCHMAN WAS SOON moved from the cottage to a classroom in the old school at the edge of the estate. He connected the move to Dilly’s hostility. The room was furnished with a few wooden chairs, a long table, blank walls, and much empty space. Bundles of German radio messages were piled on the table. On the lower part of each slip of paper, the coded message was written—rows of block letters in pencil that looked like gibberish, as if a schoolchild had recopied a text pounded out by the mythical monkey at a typewriter.20
Above the rows were a few shorter lines of letters and numbers, not enciphered by Enigma but nearly as opaque. They contained instructions for Enigma operators. Welchman’s job was to see if he could squeeze meaning out of the top lines, known as the preamble. At first he shared the classroom with Alex Kendrick, a member of Dilly’s tiny prewar staff whose trousers were dotted with holes burned by ash that fell from cigarettes or a pipe while Kendrick’s mind focused on a problem. Welchman and Kendrick felt “a bit lonely” in the big room. Then Kendrick was transferred to a different job and Welchman was totally alone.
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