Code Girls: The Untold Story of the American Women Code Breakers of World War II

by Liza Mundy

At the time these schools were founded, many considered higher education to be poorly suited for girls. Now the views had changed. Educated women were wanted. Urgently.

The students were called to secret meetings where they learned that the U.S. Navy was inviting them to embark on a field called “cryptanalysis,” a word, it was soon made clear to them, they were never to utter outside the confines of the gatherings. They were being offered a training course in code breaking and, if they passed, would proceed to Washington after graduation, to take jobs with the Navy as civilians. Sworn to secrecy, the women were forbidden from telling anybody what they were doing: not their friends, not their parents, not their family, not their roommates. They were not to let news of their training leak into campus newspapers or disclose it in a letter, not even to their enlisted brother or boyfriend. If pressed, they could say they were studying communications: the routing of ordinary naval messages.

They laid the groundwork for the now burgeoning field of cybersecurity, which entails protecting one’s data, networks, and communications against enemy attack. They pioneered work that would lead to the modern computing industry.

“In the event of total war,” Noyes told her, “women will be needed for this work, and they can do it probably better than men.”

There was furious infighting between the U.S. Army and the U.S. Navy, to a degree that would have been comic if it weren’t taking place in the middle of a war. For several decades the two services had built small and separate code-breaking operations, which were competitive to a point where it sometimes was not clear who the real enemy was. “Nobody cooperated with the Army, under pain of death,” said naval code breaker Prescott Currier. This was an overstatement, but not by much.

That women were considered better suited for code-breaking work—as the letter that Rear Admiral Noyes sent to Ada Comstock suggested—wasn’t a compliment. To the contrary. What this meant was that women were considered better equipped for boring work that required close attention to detail rather than leaps of genius.

Men were seen as more brilliant than women, but more impatient and erratic. “It was generally believed that women were good at doing tedious work—and as I had discovered early on, the initial stages of cryptanalysis were very tedious, indeed,” recalled Ann Caracristi,

The Axis powers never mobilized their women to the extent that the Allies did. Japan and Germany were highly traditional cultures, and women were not pressed into wartime service in the same way, not for code breaking or other high-level purposes.

Women were more than placeholders for the men. Women were active war agents. Through their brainwork, the women had an impact on the fighting that went on. This is an important truth, and it is one that often has been overlooked.

This means that of the Army’s 10,500-person-strong code-breaking force, nearly 70 percent was female.

At least 80 percent of the Navy’s domestic code breakers—some 4,000—were female.

Also after the war, the Joint Committee on the Investigation of the Pearl Harbor Attack noted that Army/Navy signals intelligence was “some of the finest intelligence available in our history” and that it “contributed enormously to the defeat of the enemy, greatly shortening the war, and saving many thousands of lives.” Major General Stephen Chamberlin, who served in the Pacific, announced that military intelligence, most of which came from code breaking, “saved us many thousands of lives” in the Pacific theater alone, “and shortened the war by no less than two years.”

Code breaking required literacy, numeracy, care, creativity, painstaking attention to detail, a good memory, and a willingness to hazard guesses. It required a tolerance for drudgery and a boundless reserve of energy and optimism.

In America in the 1940s, three-quarters of local school boards (like telephone companies and other employers of female labor) had enacted a “marriage bar,” which required that married women not be hired and that a teacher must resign when she did marry, in accordance with the prevailing belief that a wife’s place was at home. By definition, then, many female schoolteachers were single. Schoolteachers were smart, educated, accustomed to hard work, unused to high pay, simultaneously youthful and mature, and often unencumbered by children or husbands. In short: They were the perfect workers.

“What four things were thought by Captain Hitt to be essential to cryptanalytic success?” (perseverance, careful methods of analysis, intuition, and luck) and “What two places in every message lend themselves more readily to successful attack by the assumption of words than do any other places?” (the beginning and the end).

Before the war, a team of Polish cryptanalysts had in fact figured out the workings of the Enigma. Small, vulnerable nations surrounded by big potential enemies—Poland is bordered by Russia and Germany—tend to be hypervigilant about their neighbors, and the Polish Cipher Bureau was remarkably good. The Poles broke the Enigma during the 1930s, in part thanks to a German who passed schematics and decrypted messages to French intelligence, who passed it to them, and to a commercial model they obtained.

I always thought Engima was broken by Alan Turing at Bletchley Park. Turns out he took what the Poles knew and refined their work.