Cracking the Code

February 11 marked the International Day of Women and Girls in Science, a time to recognize the contributions of women in STEM fields.

It’s also a fitting opportunity to highlight the women cryptologists of World War II — pioneers whose intelligence work helped shape modern computing and national security.

During World War II, a secret army of around 11,000 women worked around the clock, helping to process and decipher enemy messages — work that ultimately helped secure an Allied victory. Their efforts were top-secret for decades, but today, these women, whose contributions laid the groundwork for modern computing and intelligence operations, are recognized as STEM pioneers.

In 2022, the U.S. Postal Service honored their legacy with the Women Cryptologists of World War II stamp.

The design incorporates a World War II–era WAVES (Women Accepted for Volunteer Service) recruitment poster, overlaid with characters from the infamous Japanese “Purple” code. In 1940, Army cryptologist Genevieve Grotjan made a breakthrough that ultimately enabled the U.S. to decipher Purple code messages — an intelligence game-changer.

Art director Antonio Alcalá found inspiration in the National Security Agency’s cryptologic museum, where he saw Grotjan’s original work. “The tour was stunning,” he recalls. “The librarian shared Genevieve’s story and let me look at her actual work deciphering the Purple code. These papers and the code itself gave me the idea for the stamp’s design.”

Fittingly, the stamp itself is a puzzle. Its design hints at secrecy — from the veiled figure of a cryptologist to vintage typewriter-style lettering and cut-out shapes suggesting classified information.

As a final wink to history, Alcalá even included an encoded message in the stamp’s selvage. “If you want to try your hand at breaking the code,” he teases, “you’ll find the cipher to the code on the back of the pane of stamps.”