The Woman Who Smashed Codes

by Jason Fagone

and the burst of Polish. Two hours later stations in Berlin were spreading news of the “Polish attack.” The BBC in London reported that “Poles forced their way into the studio.” And while diplomats around the world tried to get a fix on the truth, the Nazis were massing at the border. At dawn on September 1, 1939, the morning after the incident in Gliwice, the Wehrmacht sliced into Poland, forty-two

were planning for the worst. For years now, they had been thinking about the possibility of direct Nazi attacks on the United States. It was obvious that no effective invasion could

to cross the ocean, drop bombs, and return home. But there was a catch in this argument, an unnerving loophole: What if the Nazis got control of South America? South America.

too. And President Roosevelt was convinced that if Nazism took root in South America, even in just a few places, it would pose a clear and present danger to U.S. cities like New York. South America

Omaha.” If Britain fell to Hitler, the thinking went, Nazi ships could move west and set up bases in South America, seizing its rich resources, the metals to make war machines and the food to sustain armies, and then U.S. coastal cities would be within reach of Nazi bombing raids. Some officials dissented from this

the Nazis. The Germans had left a cold country of worthless currency and sailed into the crystalline seas hugging a warm and open continent. A “bewildering abundance” met them ashore. “Everything

site.” Farther south, another great city of the continent beckoned to the Germans: Buenos Aires, Argentina, a polyglot metropolis of four million, a chaos of automobiles and bookshops and neon

Wherever Germans settled in South America, they built German schools (two hundred in Argentina alone), German businesses, German radio stations, German newspapers, and transportation links back to the homeland. Zeppelins floated people and cargo from Berlin to Rio, and

residents spoke only German; parts of southern Brazil became known as Greater Germany. “The German spirit is ineradicably grounded in the hearts

Edmund von Thermann, believed that German Argentines must show “complete subservience” to “the ambitions and desires of the home country. Germans naturally count on these prosperous nuclei to assist eventually in the rebuilding of a new Germany.”

fantasies of revolution. Right-wing parties and radicals on the continent found inspiration in Nazism. Followers of a Brazilian movement called Integralism raised their hands in Nazi-style salutes, wore uniforms of green (the men were “Green Shirts,” the women

regimes had risen to the top of police and military hierarchies; many had gotten their training from German officers. A group of Paraguayan officers formed a secret lodge, the Frente de Guerra, to organize

and Japan, decided to name his son Adolfo Hirohito. In Argentina, a young military instructor with a Cheshire-cat smile, Juan Perón, was studying the leadership styles of Mussolini and Hitler and found much to admire. One Argentine general, Juan Bautista Molina, displayed so much zeal for National Socialism that even Thermann, the Nazi ambassador, found it “embarrassing.”

America. His strongest affinity was for Argentina, which had protected German interests in the First World War while ostensibly remaining neutral. In June

continent after defeating Europe. As Baron von Thermann put it, “Once the war were decided in Germany’s favor, her domination of Latin America would follow without much effort.” This was the Nazi attitude, and it meant that the war in South America

would be the Invisible War. There was a school in Hamburg where SS intelligence officers trained combatants for this war. Male party members were selected to receive a basic

course in espionage tradecraft. They were taught to write letters in secret inks. The SS had developed a disappearing ink that actually looked like ink, bluish in color and carried in a regular ink bottle; a message written with this ink would turn invisible after a few minutes and could only be unmasked with a certain reagent. They learned how to operate a German-invented “microdot” camera that shrunk documents to the size of the dot above an i, allowing

including an ingenious system for exploiting a popular novel, any novel, to generate garbled text. For the purposes of spying, this hand technique was

aroused no suspicion. One in common use was All This and Heaven Too, a period potboiler about a French governess falsely accused of murder. Would the unlucky Henriette Desportes manage to clear her name? Or would the conniving Parisian judge dispatch her to the dungeon? German men abroad pressed their noses to the book, eyes wide, turning the

happened next. The SS instructors taught students how to transmit text in Morse code and how to operate shortwave radio transmitters and receivers. Radio

coil. Portable transmitters in hand, the novice agents were

confiscated. The SS issued all foreign spies two kinds of suicide drugs to ingest in case of arrest. The first was a tablet that caused death by heart failure within ten minutes, and the second was a powder that resulted in “a slow process of general collapse over

out an encrypted message in the dots and dashes of Morse, the signal aimed at a receiving station in Hamburg or Berlin. Sometimes it worked, and the spy could be heard in Germany—there were no atmospheric disturbances, and the signal squeezed through

Elizebeth Friedman’s next mission for America became the biggest secret of her life. She would never speak in detail about what she did between 1940 and 1945, even as an old woman, and the records of her work, the documents that now make it possible to tell the story, were classified after

codebreakers, Robert Gordon, Vernon Cooley, and Hyman Hurwitz, the ones she had originally recruited and trained, were still with her, and a handful of women clerk-typists had also joined the team as support staff. Elizebeth, Gordon, Cooley, and

Hurwitz often worked together at a long table in the office, analyzing the ever-replenishing piles of cryptograms

two minutes before the 4:30 close of the day, and making what Elizebeth called “rapid-fire dictator-sort of requests,” demanding that Elizebeth and her team solve some difficult problem in an impossibly

Morgenthau’s request, in 1938, the unit began to analyze the wireless messages of British cruisers and German merchant vessels. Elizebeth broke the codes of Nazi captains as they tested the limits of U.S. neutrality and provoked tense confrontations. In December 1939, a German freighter flying the swastika

confusion, Elizebeth realized that the messages hadn’t been sent by smugglers at all. The plaintexts were in German. They contained sensitive information about the routes of U.S. and British ships and the capacities of U.S. factories. And according to the bearing fixes, the signals originated from unknown radio stations in Mexico, South America,

built by Nazi spies to share sensitive information with their bosses in Germany, transmitting and receiving dots and dashes of encrypted text at the speed of light. A pair of stations exchanging wireless signals formed a “circuit,” and each circuit was protected by a different code or cipher that had to be broken before the messages could be read. These were clandestine circuits, meant to stay invisible,

and it became Elizebeth’s goal to pry them out of the dark while remaining invisible herself—an essential part of the job. She knew that if the spies discovered

after the war, “because it dealt with counterespionage.” Counterespionage, counterintelligence—these are the formal terms for what Elizebeth was beginning to do. She was counterspying on foreign spies, serving as America’s eyes and ears in the invisible world of fascist espionage. Today there are large sections at CIA and FBI that perform foreign counterintelligence, teams

adulterations of commercial codes like the ABC code and the ACME code. These were solved in a snap. The key for one circuit was found to be 3141592, the first seven digits of the mathematical constant pi. Elizebeth called this circuit “the pie circuit.” Sometimes the Germans sent the key at the start of the message and in groups of three or four letters instead of five, indicating that there was something special about these letters and giving away that they were a key. When an unfamiliar system was encountered, and

3 E U X Now the columns were in a different order, and this new order gave a clue to the structure of the underlying cipher that allowed her to break it. Essentially, Elizebeth’s goal was to look at these daunting mountains of nonsense and chart a route up the slope in small discrete steps, each of which was like a little game—not quite child’s play but not totally

instance, on January 1, 1940, she received her first intercept from a wireless circuit that linked Mexico with a radio tower in Nauen, Germany. The messages contained only eleven letters of the alphabet: N, R, H, A, D, K, U, C, W, E, and L. One message began UHHNR

different number combinations.) These frequent letters gave her a start, and when able to solve the code in full, Elizebeth identified the names of two known Nazi agents in Mexico, MAX and GLENN, who would appear in other messages in the future, linked to agents in the United States and South America. The two Nazi spies were reporting to Berlin on the movements of U.S. and British ships, making those ships vulnerable to U-boat attacks. Elizebeth solved their book cipher without needing to see the book and did the same with messages

using a copy of the romantic novel All This and Heaven Too and a sophisticated process that generated messages full of garbled letters instead of numbers. Each spy had been assigned a unique identification number, such as 7. To encrypt a message, the spy would take that day’s date, add the number of the day and the month to his identification number (for a January 10 message he would add 1 + 10 + 7 = 18) and turn to the resulting page

unindented lines going down the page. To solve the messages, Elizebeth first had to deduce that All This and Heaven Too was the novel these particular spies had chosen. To do this she went through the same process of reverse engineering that she and William applied in 1917 to solve the Hindu messages. Then she bought her own copy of All This and Heaven Too and kept it on her

twenty-five years, encountering tens of thousands of messages, Elizebeth had solved so many different kinds of puzzles that she knew how to find shortcuts, to identify patterns in fields of text that were like signatures telling her what to do next. She was a kind of human computer in this sense. Today, if you want a computer to recognize certain patterns, you can train it through a process of “machine learning.” How do you get a computer to recognize

intimidated. Enigma was a straightforward idea expressed in a diabolical device. In the simplest sense, it was a box that cranked out poly-alphabetic ciphers. Remember the secret messages that eight-year-old Barbara Friedman sent her parents from summer camp? A=B, B=C, C=D. That’s a MASC, a mono-alphabetic substitution cipher. One cipher alphabet encrypts the whole message. Enigma was poly instead of mono, using multiple cipher alphabets per message. Poly-alphabetic ciphers date to the sixteenth century

Instead, Enigma did the job with three or more rotating

The choice of variables comprised the machine’s key—the starting configuration used to encrypt all messages on a particular day, week, or month, depending

possibilities. Clearly, shortcuts had to be discovered, and by the late 1930s, finding these shortcuts—and conquering Enigma—was the biggest problem facing Allied intelligence. After Polish mathematicians made some early breaks into the device, the Germans kept changing its design and how it was used, so the battle over Enigma was ongoing, a cryptologic

components and subtleties intended to make Enigma codes absolutely unbreakable. Different Nazi organizations developed their own variants. Germany withheld knowledge of these alterations from the enemy, as if Enigma were a submarine or a bomb. To extract useful intelligence from an Enigma system,

services. If you found an Enigma key in the morning, you might go to bed at night and get locked out again in your sleep, and the next day you had to find the key again if you wanted to read the new day’s messages. There were too many Germans using too many Enigmas with too many

of the first digital computers, too. Automation. Polish codebreakers were the first to solve Enigmas and automate the process of

Later, the British mathematician Alan Turing discovered how to make bombes dramatically more powerful, based on mathematical principles and previously solved bits of text known as “cribs”—a crib might be the name of a Nazi officer, the time of day, or “Heil Hitler.” His solutions were essentially search algorithms, ancestors of the Internet search algorithms

jobs, and were billeted in large country houses. The Enigma codebreaking program would come to be known as ULTRA; Enigma decrypts were stamped with the imposing phrase TOP SECRET ULTRA

subtle art. It can be done with clever guesswork and trial-and-error, and it can also be done by applying the principle of the Index of Coincidence, William Friedman’s fundamental insight about the relationships

Before long, then, the coast guard codebreakers were able to identify frequent letters in the columns and use those letters to piece together the plaintexts for most of the first batch of messages. The words seemed to be in German. Elizebeth and her colleagues still didn’t know what