Science Friday - The Black women codebreakers of the Cold War

Episode Date: July 27, 2026

During the early Cold War era, the United States Army and later the NSA began recruiting and training codebreakers and intelligence officers to decipher intercepted Soviet messages. Among those recruits were a group of highly skilled Black women who were employed as cryptologists to decode these messages. But their role in Cold War intelligence operations has been largely overlooked, until now. Host Flora Lichtman talks with historian Sarah Valentine about her book, “Decoding the Devil: Black Women Codebreakers and the Secret War Against Stalin’s Bomb.” Read an excerpt of “Decoding the Devil.” Guest: Dr. Sarah Valentine is the author of “Decoding the Devil: Black Women Codebreakers and the Secret War Against Stalin’s Bomb.” Transcripts for each episode are available within 1-3 days at sciencefriday.com. Subscribe to this podcast. Follow our show on Instagram, TikTok, Facebook, and Bluesky @scifri and sign up for our newsletters. Got a science question that’s keeping you up at night? Call us: 877-472-4374 Hosted by Simplecast, an AdsWizz company. See pcm.adswizz.com for information about our collection and use of personal data for advertising.

Hey, it's Flor Lichtenen, and you're listening to Science Friday. During the early Cold War era, the United States Army and later the NSA began recruiting and training codebreakers and intelligence officers to decipher intercepted Soviet messages. Among those recruits were a group of highly skilled black women who were employed as cryptologists to decode these messages. But until now, their role in Cold War intelligence operations has largely been overlooked. My next guest, Dr. Sarah Valentine, digs into this history in her new book, Decoding the Devil, Black Women Code Breakers, and the Secret War Against Stalin's Bomb. Sarah, thanks for being here. Thanks for having me. How did you come across this story?

So I came across the story kind of by accident. I was looking at a website, and it turned out to be NSA's website, and there was a little history section about this group. It was called Invisible Cryptologists, and it discussed these black code-breaking specialists who learned Russian and were part of this top secret project on Soviet nuclear intelligence. And I thought, I need to know more about this. This was, you know, over 10 years ago, but I never found anything. So eventually, I decided to write the book myself. And you, this is sort of a topic near and dear to your heart, right? because you have a background in Russian language.

Yes. My PhD is in Russian literature, and I taught Russian literature and Soviet history for a long time. I also happened to be a black woman. So when I came upon this subject, I just thought, this is really fascinating. Take us into the so-called traffic processing division where these black women codebreakers were working. So the traffic processing division was in the basement, a warehouse like, space in one of the operations building on Arlington Hall's secret campus near Washington, D.C. And it was very noisy. It was very densely packed. There were over 100 people working in this space.

And they had a white manager who was part of the military, and it was segregated. So the operation was upstairs downstairs. So the white analyst. and the people doing the higher level code-breaking work, they were upstairs. And the traffic processing unit with its loud machine noises, they were in the basement pulling out this data for the analysts to work on further. What they were doing was analyzing Soviet telecommunications that were intercepted. So we had a link to a Soviet telegraph line, and that data just came streaming into our listening station at NSA. And there was no time to translate.

So the women, it was mostly women. There were some men who were doing this too. But they had to read the encoded telegraph strips, which were in Cyrillic and find keywords. They were like the manual Google of their time. They were looking for any words that related to the Russian military, anything scientific, anything that would indicate where the nuclear research was happening. And they went through millions of these communications a week. Millions. I mean, this is big data before big data.

Exactly. And it was considered grunt work because it was they had to separate the wheat from the chat, so to speak, looking for needles in haystacks because maybe 1% or 10% of all of the messages they scanned, had good intelligence in them, but they still had to go through every single one. How did these black women find themselves working there? Were they recruited? They were recruited and it was kind of word of mouth. So some of the women I profile in my book, they had friends who worked at the agency. And maybe they worked in another area of government because many of the middle class black folks in Washington, D.C., worked for the federal government in this era, the 1940s and 50s.

It was one of the best kinds of jobs with benefits, with retirement, which in many parts of the country, black people weren't allowed to get in their jobs. So federal government was kind of a good job to have. I mean, did these women come in with specialized knowledge? Were they learning Russian at the agency? Yes, the agency trained everyone they hired. But if you had a college degree or a master's degree, you were usually trained to be a linguist or a cryptanalyst or, you know, something a little higher level.

These women had that educational background, But because of the segregation and the times, they were only trained for these lower level jobs. One of the women's stories you tell in the book is of Iris Carr. Tell us a little bit about her and her journey. She was amazing. Iris Carr was a school teacher in Texas in the 1940s. And when the war began, she realized the kind of job she was in, she would not be able to have benefits or retirement because, again, in the Jim Crow South,

black teachers couldn't pay into retirement. So she decided to try her luck in Washington, D.C., and drove herself. This is a time when few Americans had cars. She drove herself to Washington, D.C., got a job in the federal government, eventually ending up at the agency, and worked her way up through the ranks from that traffic processing division into a position where she could really help others improve their careers. A manager? Yes.

Which was very difficult, you know, for someone like her at the time to do. We talk about computing a lot on the show and the history of computing. And I think often we have a very specific image of a person in our heads and he's wearing a turtleneck. These women are working right around the time when computers are introduced. I think, right, in the late 1940s. How are they part of that history? They are really at the foundation of it. They were basically the GPU of this operation,

the general processing unit, and they were doing it all manually. They were being worked as if they were machines, and it was just at the time that the agency was realizing we have to automate these processes because even with the vast amount of intelligence they were producing, the agency still wanted more. There was just an endless kind of hunger and need for this data.

And so they helped to train a program. Again, it was a top secret, you know, early machine learning project called Soap Flakes. And they taught it to be... Soap Flakes? Soap Flakes. It's so random. Okay. And they had a list of 1,500 Russian key.

And that's what they looked for when they were scanning through these, you know, telegram strips, scanning, scanning, and they trained this special purpose machine, wasn't general computing just yet, trained it on these same keywords. You know, engineers were building the machine. They weren't doing that part, but they were helping to train it. And once it got up and running in the mid-1950s, that was the end of the traffic processing unit. They essentially put themselves out. work by training a language machine. It sounds very familiar. It does. Sounds quite familiar. I mean, given that, were these women able to sort of build off of this experience? Or was this just sort of a moment?

The computer made them obsolete and the job was done. For some of them, yes. It was a pathway. And it could have been a pathway for more of them. But at the agency, you know, several people in their interviews because much of the information in the book is based on declassified interviews that I was able to get from NSA that were first person perspectives from the women who did this work. And some of them describe going to work and seeing, you know, lights on in a building nearby and thinking, you know,

what are they doing up there? And it turns out it was the agency giving white people training on the computer that they weren't given access to. So just at the time when technicians and operators and programmers were needed, they helped to build the foundation for it, but many of them weren't given the opportunity to progress in the profession as it developed. I mean, it seems like you had to do your own sort of real intelligence gathering to just tell this story. to write this book. I mean, how much of this information was classified? Much of it. And the information that wasn't classified was buried deep in the National Archives and the personnel records, files that often had never been touched since their declassification

in the 70s or since they were put on the shelves. So I really had to do a lot of digging A funny story is that I was in the National Archives in College Park, and I opened a box and was going through the files. And I took a letter out of its plastic sheet so I could take a photo of it. Now, you're not allowed to do that. I didn't realize. And an archivist came over and, you know, very gently said, oh, you're not. Tackled you. Yeah.

Right. And then they took another look at the letter and they said, wait, whose signature is that? And I said, that's Eleanor Roosevelt. And it was an original note signed by Eleanor Roosevelt. And suddenly there was a crowd of archivists around me because that was a huge find. And one of the archivists said, you know, you are the first person who has opened this box. And it has been here since the 1970s. Wow.

I mean, I'm curious about your own experience. of this too. As a scholar of Russian literature, do you think of translation as a type of code breaking? It is. And I think, well, for a literary translator, for me, that's a very enjoyable experience. I think for the codebreakers, it was incredibly stressful because they were under time pressure. and it was also a series of trial and error. Cryptanalysis is really like trying to solve a New York Times crosswork puzzle with no hints. Sarah, this is such a fascinating history. Thank you for sharing it with us today.

It's my pleasure. Dr. Sarah Valentine is author of Decoding the Devil, Black Women Code Breakers, and The Secret War Against Stalin's Bomb. When's the movie going to get made? Soon, I hope. All the directors and producers listening, give us a call. If you want to read an excerpt from the book, head to sciencefriday.com slash codebreakers. This episode was produced by Shoshana Bucksbaum, and we want to hear from you.

Let us know if there's any scientific history you want us to tell, or if you have burning questions, we can help you find the answers to. Our number is 8774.7-4-Sy-Fri. I'm Flora Lixman. We'll catch you next time.