Mathematics and Primary Sources: Historic Codes, Ciphers, and Computational Thinking, Part II – the Women Codebreakers of WWII

This post was written by Michael Apfeldorf of the Library of Congress.

Sending and cracking secret messages dates back to the foundation and exploration of the country. But did you know that much of the cryptographic work that helped the United States win World War II was accomplished by female codebreakers? The Library of Congress Veterans’ History Project (VHP) contains numerous oral histories that your students can examine to learn more about these groundbreaking women, and Megan Harris and Lisa Taylor of the Veteran’s History Project highlighted some of them in recent blog posts. By conducting their own analyses of these interviews, students can construct an authentic understanding of what work and life was like for these women, while gaining insights into the mathematical and computational thinking necessary to be a successful codebreaker.

Ann Caracristi

Begin by asking students to listen to excerpts from interviews with Ann Caracristi and Ann Ellicott Madeira, choosing from the sections identified below.

After they have listened to the clips, students can:

  • Record their observations, reflections and questions on the Library’s Primary Source Analysis tool. Remind students that they can pause, rewind, and re-listen to recordings as much as they need to;
  • Research the Library’s collections for insights into what pre-war life was like for college educated women such as those recruited to be codebreakers. Many, for instance, were recruited out of college while studying to become teachers;
  • Write a descriptive piece, including details from their observations and research, showing a “day in the life” of a female codebreaker.

In Part I of this series, we discussed how George Washington and Thomas Jefferson used cryptography.  After reviewing their approaches:

  • Ask students to compare and contrast their methods with the methods discussed by Caracristi and Madeira.
  • Challenge students to send and receive a note using “additives” and “false math” as described in the VHP interviews.
  • Based on their experiences, what insights have students gained about the history and evolution of cryptography?

The stories of numerous other female cryptographers are also available within the VHP, such as Donna Southall, Marjorie Scott, and Elizabeth Bigelow Stewart, offering opportunities for interested students to expand their exploration of the topic.

Let us know in the comments what your students discover!

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