Seizing the Enigma (12 page)

Paris contacted the Berlin embassy, and the
Deuxième Bureau
contact there, Maurice Dejean, confirmed that Schmidt had visited him. He added that Schmidt and his older brother, a lieutenant colonel, were both listed as being in the German Defense Ministry. This improved the chances that the approach was real and not a provocation.

The
Service de Renseignements
assigned the task of making the first contacts with Schmidt to its man Friday, who handled all sorts of details for the service—he could get train reservations that Cook’s couldn’t—but who specialized in recruitment and in the puchase of secret codes.

His codename was
REX
, he claimed to have been named von Koenig (“king” in his native German), his legal name was now Rodolphe Lemoine, but he had been born Rudolf Stallmann in Berlin on April 14, 1871. The son of a wealthy Berlin jeweler, he preferred travel—in France, Italy, England, Africa, Chile, and Argentina—to going into his father’s business. Somewhere along the way he met and married a Frenchwoman, whose name he adopted; in 1900, he was naturalized as a French citizen. During World War I, in Spain, he developed a taste for spying, and in 1920 he came to Paris to work full-time for France’s intelligence service. His pay came in the form of protection from the police in his shady dealings and of business concessions abroad that the French government awarded him. These activities he ran out of an office at 27 rue de Madrid in Paris’ fancy eighth arrondissement.

Writing to the Basel address,
REX
arranged to meet Schmidt on November 1, 1931, at the Grand Hotel in Verviers, a town in eastern Belgium some 15 miles from the German border. There he learned much of the would-be spy’s history.

Schmidt, then forty-four, had been born May 13, 1888, in Berlin, the second son of Professor Dr. Rudolf Schmidt and his wife, Johanna. The father, who was thirty-seven when Hans-Thilo was born, taught at the Charlotten school in Berlin. The first son, Rudolf, two years older than Hans-Thilo, had brought honor to the family when at twenty he was accepted into the army as a cadet. Hans-Thilo had had the standard college-preparatory classics education but then had studied business, with an emphasis on chemistry and technology. Both brothers had served in World War I. Rudolf distinguished himself in various signal corps posts, winning the Iron Cross, rising to
captain, and ending the war in the general staff of the Fourth Army. Hans-Thilo, a lieutenant, likewise won the Iron Cross but had the bad luck to be gassed.

Rudolf was retained in the 100,000-man army that the Versailles treaty allowed Germany. Hans-Thilo started a soap factory, but in Depression- and inflation-ridden postwar Germany, the business failed. By the mid-1920s, married and with two children, Hans-Thilo was desperate. He turned to his brother for help. Rudolf, who had no children and was close to his younger brother, prevailed upon a fellow signals officer to give Hans-Thilo a job. The officer was head of the
Chiffrierstelle
(Cipher Center), known as the ChiStelle, and he hired Hans-Thilo in part because Rudolf had been his predecessor. In fact, in one of the most exquisite ironies of intelligence history, Rudolf Schmidt, as head of the ChiStelle, had approved for army use the Enigma cipher machine that his brother was now proposing to betray! Hans-Thilo became a civilian clerk who distributed cipher material and supervised its destruction when it expired. He did his work well.

But he was embittered and rapidly grew more so. Despite his war record, his job paid poorly. His life seemed to be going nowhere. He was living in a furnished room at Lorenzstrasse 17 in west central Berlin, having sent his family to less expensive Bavaria to live with his in-laws. The contrast with his past was striking. His family had had enough money and high status: his mother was a baroness, his father a Professor Doktor—probably the highest nongovernmental standing a civilian could achieve in Germany. And the contrast with his brother’s position was no better. Rudolf had not only been retained in the army, Germany’s most prestigious institution, but had been promoted to lieutenant colonel and, after two assignments in divisional staffs, had been named chief of staff of the signal corps. Like thousands of others similarly disaffected, Hans-Thilo applied for membership in the Nazi party. But this did not immediately ameliorate his situation. And though a desire for more money and a sense of relative failure
must trouble many men who hold state secrets, most do not betray their country. Hans-Thilo, from whatever motives, did.

REX
learned much of this at Verviers. He sized up his man and examined the documents the spy brought with him.
REX
concluded that both the documents and the offer were genuine and directed Schmidt to return to the same place one week hence.

The
Service de Renseignements
, now persuaded that Schmidt would really spy for them, gave him, as they gave their other agents, a designation consisting of a group of letters. His was HE, which seems not to have borne any particular significance. In French, this pair is spoken
ahsh-AY
. This somewhat resembles the German word
Asche
(ash), which is sounded
AH-shuh
and which Schmidt himself later chose—with a premonitory shiver about the fate of most spies?—as his codename.

The rendezvous was set for November 8, 1931. The day before,
REX
, accompanied by the stout and sometimes difficult Gustave Bertrand and the
Service de Renseignement
’s photographer, Bintz, arrived at the Grand Hotel, where
REX
had installed himself in princely fashion. Bertrand and Bintz had adjoining rooms with a bathroom between them: if it served as the camera studio, the shutter noise would not be heard in the hall. They spent part of the night adjusting the camera and their portable lights. The next morning they waited in their room for the call from
REX
. It came at 10 o’clock.

In a room filled with cigar smoke and with a radio playing music to deter eavesdropping,
REX
presented Schmidt to Bertrand. Schmidt, a whisky in his hand, smiled and bowed, heels together. Bertrand saw a man who wore a dark gray suit and down-at-the-heel shoes but who seemed to carry himself with assurance and to display the manners of a good upbringing. Bertrand was introduced as Monsieur Barsac. After some pleasantries, he examined the documents that Schmidt produced. They included an organization chart of the ChiStelle, an army hand cipher with its keys, a memorandum on poison gas, which Schmidt claimed to have obtained from his
brother, and—most important—the two Enigma documents. The first was
Gebrauchsanweisung für die Chiffriermaschine Enigma
, the instructions for the use of the machine, numbered H.Dv.g.13 (for
Heeresdienstvorschrift geheim 13
, secret army service regulation 13). The other was the
Schlüsselanleitung für die Chiffriermaschine Enigma
, the directions for setting the keys on the machine, numbered H.Dv.g.14.

Bertrand could not conceal his pleasure, and Schmidt, seeing this, was radiant.
REX
and Bertrand agreed to pay him 10,000 marks, or $4,000 (about $27,500 in 1991 dollars). Bertrand took the documents and, running up the stairs two at a time, brought them to photographer Bintz. The two worked through lunch. About three, Bertrand brought the documents back to Schmidt, whom he found chatting with
REX
. The army officer, in his poor German, asked if Schmidt was pleased with the agreement.

“
Jawohl, meine Herren. Besten Dank. Alles ist in Ordnung
,” Schmidt replied.

He bowed, took his money, and left.

Back in Paris, the elated Bertrand brought the documents to his friend Colonel Bassières, one of France’s finest cryptanalysts, an amusing man with a limp who had honed his talents on German ciphers in World War I. Bassières accepted the papers, but he found that they provided only interesting generalities. H.Dv.g.13, warned, for example, “When putting the rotors on the shaft, be careful that the sides with the flat contact surfaces are always pointing to the side of the shaft that has a ring on its end.” The keying instructions were more useful. They specified that the four elements of a complete key consisted of (1) the sequence in which the rotors were placed in the machine, given in roman numerals, such as III I II; (2) the setting of the alphabet ring on its rotor, given by a letter or its corresponding number, B or 2, for example; (3) the so-called basic setting of the rotors, specified by the letter or number of each rotor’s alphabet ring that should appear in the rotor windows of the machine’s lid at the
Start of the enciphering; and (4) the six plugboard connections, enciphering twelve letters, indicated by a pair of letters or numbers, such as A/O or 4/15.

This information seemed, however, to have little value in the absence of two critical elements not provided by the Schmidt documents: the wiring of the rotors and the actual keys in use on particular days. On Friday, November 20, two work weeks after he had given Bassières the documents, Bertrand went to him to learn how he had made out.

“Impossible to get anything useful from your documents,” Bassières told him. “Too many things are lacking for us to reproduce the machine.” He was referring primarily to the rotor wiring. “And even if we could, we would have to tie ourselves down to a monumental task of finding out the [daily] keys. We just don’t have the means.”

Hopeful that the British, with whom French intelligence had close relations, might do better, Bertrand immediately obtained permission to show them the documents. On Monday the twenty-third, he gave copies to the Paris representative of the British intelligence services. Commander Wilfred (Bill) Dunderdale. Three days later Dunderdale was back with the same judgment Bassières had rendered: the documents did not make it possible to solve Enigma messages.

Unwilling to give up without trying every avenue, Bertrand sought approval to give the information to France’s ally Poland. Bertrand may have known, from a 1928 booklet describing Polish cryptanalytic successes in 1920, that the Poles had a good background in code-breaking. Approval was granted, and Bertrand himself was delegated to go to Warsaw. So that he would not be carrying anything compromising or risk losing the documents and so their secret, he sent photographs of the two booklets ahead by diplomatic pouch. He arrived Monday, December 7, 1931, and picked up the photos at the French embassy. At 9
A.M.
the next day, he was in the office of the head of the Biuro Szyfrów, where he was warmly received. The chief, Major
Gwido Langer, who had succeeded Pokorny, scanned Schmidt’s offering, then exploded with joy. He ran out of the room and returned a few moments later with his boss, Colonel Stefan Mayer, the general staff’s head of intelligence, and with Ciȩżki, head of BS-4. Mayer congratulated Bertrand warmly on his feat and asked for forty-eight hours to study the pamphlets.

At 4
P.M.
on Thursday, Bertrand met Mayer and Langer in Mayer’s office. This time the atmosphere was more temperate. The Poles explained that the documents showed that the machine had three rotors with movable alphabet rings on them and that the reflecting rotor did not turn during encipherment. The documents had further revealed the presence of the plugboard, which did not exist in the commercial Enigma. The Poles could not thank Bertrand enough. But, they explained, they did not know the rotor wiring, the rotor order, or the plugboard connections for a keying period. They did not know the alphabet ring positions on the rotors and therefore did not know the rotor positions for each message. All this could be determined by analysis, they said, but it would take much time. If Bertrand’s informant could provide these details, and if the French could give the Poles specifics of their cryptanalytic progress on the basis of the new information, years of work could be saved.

Bertrand, embarrassed by his country’s cryptanalytic ineffectualness, admitted that both French and English efforts on the Enigma had not produced as much as Langer presumed.

Langer sought to ease his chagrin. “You don’t have the same motivation as we do,” he said generously. And on that note the two parted, with promises of further cooperation.

The next weekend, December 19 and 20, Bertrand and
REX
again met Schmidt in Verviers. The German had by then been admitted to the Nazi party with membership number 738,736. This demonstration of nationalistic orthodoxy did not keep him from delivering the keys that gave the daily settings for the machine for December 1931. Nor did it prevent him from meeting with Bertrand and
REX
three times during 1932: on May 8 in Verviers, on August 2 and 3 in Berlin, and on October 19 and 20 in Liège, Belgium. At each meeting, in addition to other information, Schmidt provided keys: for May, for September and October, and for November and December. Bertrand brought the keys to Warsaw.

The complexity of the Enigma problem led Ciȩżki to expand the plan he had instituted in 1929 of employing mathematicians to attack the new electromechanical forms of encipherment. The three young mathematicians he had brought to Warsaw from Poznán had gained experience in at least two different systems. Ciȩżki placed Marian Rejewski, the oldest and most apt, alone in a room on the third floor of the north wing of the general staff building, overlooking the tomb of Poland’s Unknown Soldier. He gave Rejewski the photographs of the two instructional pamphlets from Schmidt and some obsolete key lists and in October 1932 assigned him in the greatest secrecy to solve the Enigma.

Rejewski read the stolen pamphlets and the few sheets of paper in the archives from earlier attempts and examined a curious equivalent of the commercial Enigma: a 2-foot-square frame with mobile vertical rods studded with nails that could be joined by multicolored threads to reproduce the wiring of the rotors. Then he picked up where his predecessors had left off: by analyzing the six-letter indicators with which each Enigma message started.

In these messages, all one day’s indicators that had a particular letter, say, R, in the first position invariably had a certain letter, say, V, in the fourth position. The same held for the second and fifth and for the third and sixth positions. Rejewski saw that this pattern derived from the German keying method, which he knew from one of Schmidt’s documents, H.Dv.g.14. The method utilized a three-letter key, say MGK, that was repeated: MGKMGK. (The repetition assured the person receiving the message that the key had not been garbled in transmission. If the triads differed, the recipient
could determine the right one in three trials.) The three letters were chosen at random by the cipher clerk for each message so that every cryptogram would have a different key. The recipient had to be told what this key was, but the information could not be transmitted in the clear and so was enciphered.