Numbers came easily to Angeline Nanni. As a girl of 12 in rural Pennsylvania during the Great Depression, she kept the books in her father’s grocery store. In high school, she took all the accounting classes on offer. Enrolled in beauty school after graduation—cosmetology being one of the few fields open to women in the 1940s—Angie focused on the business side while her sisters, Mimi and Virginia, learned to style hair. Before the war, the three Nanni sisters had opened a beauty parlor in Blairsville, Pennsylvania, and Angie ran it. So yes, numbers were her calling.
But the numbers on this test were like nothing she had ever seen.
Angie—intent, graceful, unflappable—was seated in a small classroom in a large, ill-built temporary structure. The year was 1945, and World War II was over. The Nanni sisters had moved to Washington, D.C. to take jobs in the war effort, but now the beauty shop in Blairsville beckoned. Angie, though, wanted to stay. This test would determine whether she could.
It was being administered at a secret government facility in Arlington, Virginia. Around Angie were eight or nine other women, all contemplating the same set of numbers, wearing various expressions of alarm. Most, Angie thought nervously, had attended college. She had not. On a piece of paper before her were ten sets of numbers, arranged in five-digit groups. The numbers represented a coded message. Each five-digit group had a secret meaning. Below that row of 50 numbers was another row of 50, arranged in similar groups. The supervisor told them to subtract the entire bottom row from the top row, in sequence. She said something about “non-carrying.”
Angie had never heard the word “non-carrying” before, but as she looked at the streams of digits, something happened in her brain. She intuited that the digit 4, minus the digit 9, equaled 5, because you just borrowed an invisible 1 to go beside the top number. Simple! Angie Nanni raced through, stripping out the superfluous figures to get down to the heart of the message.
“I don’t know how I did it,” says Angie, who was 99 years old when we talked in March. “I just said, ‘Oh, that’s going to be easy.’” The supervisor came around and saw that she had finished before anybody else. “That’s right, Angie! That’s right!” she cried. Then she ran out of the room to tell her superiors they had a new candidate for the Russian code-breaking project.
That moment—and Angie Nanni’s instinctive grasp of an unusual form of math called non-carrying addition and subtraction—changed the trajectory of her life. It also helped seal the fate of other Americans, such as Julius and Ethel Rosenberg, executed in 1953 for passing atomic secrets to the Soviet Union. Their conviction was based in part on the work of Angeline Nanni and a group of other extraordinary American women.
Their persistence and talent brought about one of the greatest counterespionage triumphs of the Cold War: Venona, the top-secret U.S. effort to break encrypted Soviet spy communications. For nearly 40 years, Angie and several dozen colleagues helped identify those who passed American and Allied secrets to the Soviet Union during and after World War II. Their work unmasked such infamous spies as the British intelligence officer Kim Philby, the British diplomat Donald Maclean, the German-born scientist Klaus Fuchs and many others. They provided vital intelligence about Soviet tradecraft. Their work was so highly classified that President Harry Truman likely did not know about it.
In 1995, when Venona was declassified, the public face of the project was male. The most celebrated name was that of a man, Meredith Gardner, a linguist who deciphered names and words, working closely with FBI agent Robert J. Lamphere. But in the cryptanalytic unit—where the tough analytic math was done, where the messages were prepared and matched, where the breakthroughs happened, where the numbers were so painstakingly stripped—the face of Venona was different: “Most of the people working on it were women,” says Robert L. Benson, a retired historian for the National Security Agency.
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Even now, talking about her career makes Angie Nanni nervous: “I still don’t if I can help it,” she says. She and her colleagues—young women from rural towns—were privy to some of the most closely held secrets of Cold War espionage. In the 1950s and ’60s, as the Soviets attempted to learn about U.S. weapons and America was convulsed by the toxic chaos of McCarthyism, these women were among a tiny handful of Americans who knew the truth.
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In 1945, the American intelligence establishment began to grasp the scope of Soviet spying against the United States. Igor Gouzenko, a Soviet code clerk working the GRU system, defected and told Canadian authorities that the Soviets had penetrated the Manhattan Project. Under interrogation by the FBI, Whittaker Chambers, a former GRU agent, named Americans spying for the Soviets. By November the Truman administration knew of allegations against Lauchlin Currie, a White House aide; Duncan Lee, executive assistant at the Office of Strategic Services, forerunner of the CIA; and assistant treasury secretary Harry Dexter White. Around the same time, a former Soviet agent, Elizabeth Bentley, gave the FBI a stunning 107-page statement detailing spies in the State and Treasury departments, the OSS, the Pentagon, even the White House.
The problem was that Bentley had a lot to say, but no documentation to back it up. That is where Venona came in.
By the time Angie Nanni was brought on in the fall of 1945—one of the few non-college-educated staffers—the section was in high gear. The Russian unit comprised a traffic section, two “reading” sections and a “back room,” a high-level troubleshooting section where Gene Grabeel was now one of the most experienced workers. “We all loved Gene,” says Angie, who worked in traffic. “She was very nice—very quiet….A lot of times, if we weren’t sure about something, we felt free enough to go to her.”
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At about the same time, a bright young home economics teacher was becoming discontented with the charms of rural southwest Virginia. Gene Grabeel, 23, had grown up in Lee County. Her hometown, Rose Hill, had 300 people, a grocery, a church and a service station. Her mother raised chickens and sold eggs, and her father farmed tobacco and worked a variety of jobs. The Grabeels had a tradition of sending their girls to college. Gene went to Mars Hill, a two-year school in North Carolina, then to State Teachers College (later called Longwood) in Farmville, Virginia.
At the time, the only job a female college graduate could reliably expect was teaching school, and Gene taught home economics to teenage girls in Madison Heights, Virginia. When she told her father she hated it, he urged her to find work that made her happy. At a holiday dance in her hometown during the Christmas season in 1942, she chatted with a childhood acquaintance, Frank Rowlett, who was now a top official in the Signal Intelligence Service. Rowlett confided that there was better work in Washington.
By that time, the Army had sent a handful of officers out to seek recruits for its code-breaking operation. Since most of the men were off fighting, the recruiters focused on women. (Ninety percent of Arlington Hall code breakers would be women.) Grabeel traveled to the post office in Lynchburg to hand her application for war work to a recruiter named Paavo Carlson. He offered her a job—doing what, he could not say, because nobody had told him, either—and asked her to head for the capital as soon as she could. Grabeel’s father agreed she would be happier in Washington “shuffling paper” for six months—her likely task, they both assumed—so she took the job. On Sunday, December 28, 1942, she arrived by train and took a cab to Arlington Hall, where she was given hasty training in the art and science of breaking codes.
At Arlington Hall, most work focused on Japanese Army codes, but Grabeel, four weeks after arriving, was directed to attack the Soviet intercepts, an immensely secret and sensitive task even in that secret and sensitive place. It’s likely she was chosen because Rowlett knew her as a solid citizen with an unimpeachable family background. Her code-breaking partner was Second Lt. Leonard Zubko, a 1942 Rutgers graduate fresh out of infantry school at Fort Benning. Eager to command troops, Zubko later figured he got this desk job because he knew Russian. He did not enjoy it. He and Grabeel were seated in one corner of a room and told to speak only in whispers. The other occupant was a British liaison officer—an odd allotment of office space, as the British were not to know what was going on.
And so Venona began: two junior analysts laboring at a table in a building that was alternatively hot and cold and always crowded, with huge open bays occupied by teams working on other projects. The first thing Grabeel and Zubko did was try to get a grip on what, exactly, they had. They began sorting the tangle of messages by date as well as by “lane,” the communications circuit over which they had been sent. Before long, Zubko was replaced. Other men came and went. Grabeel stayed put.
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The Soviets’ code system was widely considered unbreakable because it had so many layers. To encode a message, a clerk would consult a code book, a kind of dictionary that provided a four-digit code group. Each code group stood for a word or letter. To make snooping much more difficult, those numbers were converted into five-digit figures (see “How to Cipher Like a Soviet,”) and then enciphered by adding a second set of numbers, known as “key” or “additive.” (This is where the non-carrying arithmetic came in.) The Soviets drew their additives from a “one-time pad”: pads of pages, each containing about 50 random additives, each page never to be reused.
The one-time pad was believed to make the system watertight. That’s because breaking a complicated code requires “depth,” which is the term for lots of messages enciphered using the same page from an additive book. It is depth that enables code breakers to locate patterns and find a way in. With a one-time pad, there is no depth, no ability to compare.
But Arlington Hall had such huge success breaking Japanese and German codes that officials were optimistic. Over the summer of 1943, they funneled fresh recruits into the tiny Russian unit.
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In October 1943 the code breakers began doing “machine runs” under the supervision of Mary Joe Dunning, a studious, short-haired woman who had been working for the Army code-breaking operation since the late 1930s and knew everything there was to know about how machines could simplify and hasten even the most daunting code-breaking challenge. At this early, laborious, “brute-force” stage, they used IBM punch-card machines to compare early code groups in thousands of messages that had been sent over trade channels. Thanks to this repetitive, painstaking analysis, the team began to realize that there was, in fact, a tantalizing trace of “depth”: Some pairs of messages appeared to have been enciphered using the same pad. This insight was the core achievement of Venona: The Soviets had used some of their one-time pads twice.
How could the Soviets, so expert at espionage, have committed such a basic blunder? After the Germans invaded Russia on June 22, 1941, entire factories’ worth of equipment were packed up in Moscow and put on trains to the Urals. Amid the chaos, resources became scant. In desperation, someone decided to manufacture, briefly, some duplicate sets of pads.
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The extent to which the Venona code breakers were quarantined stood out even in the top-secret environment of Arlington Hall and, later, the NSA building in Fort Meade. No one was permitted to enter the Russian unit except for those who worked there. And even that level of security wasn’t enough.
William Weisband, a native Russian speaker who had become a U.S. citizen, worked as a “linguistic adviser” to the unit. He had a tendency to look over his colleagues’ shoulders. “When I saw him coming, I would put things over anything” she was working on, Nanni says. “He stopped at my desk, and I said, ‘May I help you?’ He took off.”
Her suspicion was well founded: Weisband was, in fact, an NKVD agent. He was identified and suspended in 1950—but never prosecuted for espionage, to preserve what was left of Venona’s secrecy. He sold insurance until he died, in 1967.