An important story

Dedicated to those who worked in Building 26, 1942-1946

The mission of this site is to tell the story of hundreds of people who worked at the United States Naval Computing Machine Laboratory, a top secret project in Dayton during World War Two. These people kept their secret for over fifty years. They produced machines which were crucial to the war effort and helped to save the lives of tens of thousands of troops, on land and sea, around the world.

Please take a look–there are hundreds of pages of declassified documents, rosters of personnel, photographs and more. I have added a new bibliography page brought up to date to include burgeoning information about cryptography on the web.

This site originates with and is maintained by Deborah Anderson in Dayton, Ohio. My father was Joseph Desch, Research Director for the NCML. This site is an outgrowth of my own efforts to learn more about the story behind my father’s secret work and a desire to share what I have learned. It also is a resource for the facts behind the documentary Dayton Codebreakers.

I am grateful to the Archive Center at Dayton History, the Wenger Command Display in Pensacola, Florida, friends at the NSA Center for Cryptologic History and the National Cryptologic Museum, and the many veterans–WAVES and sailors– who have been so generous over the years for a share of the photographs presented here.

Thanks for learning about a part of Dayton’s, and the nation’s, history.

Launched 2001

A popular page on my site, The US Navy Cryptanalytic Bombe, now with new photos and a link to a bombe simulator.

Excellent update of a page at Virmuze [network of Virtual Museums] about the US Bombe with information about some components.

Watch a YouTube video from the NCM about the US Navy Cryptanalytic Bombe from the Nat’l Crypto Museum

My favorite page: The incredible amount of production at the US NCML reflected in the By the Numbers page.

Redone page of Cryptanalytic Equipment in operation at Nebraska Avenue, linked to full-size photos.

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  • You Are Here

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  • Sources

    This site has material from many sources. Some are use by permission. Before using, ASK. More specific information here.

  • Inside You’ll Find…

    WHO worked during the war? Find the Personnel section. Also, Joseph R. Desch
    WHAT were their goals? By the Numbers. Also, The US Bombe
    WHY? History of the Bombe Project A contemporary account of the reasons and the plans for their project for the Director of Naval Communications, 1944.
    WHERE was the project: In Dayton, it was in Building 26. In Washington, it was housed at the Naval Communications Annex

    • Recent Updates

    • Stray Thoughts in the Information Age

      General George S. Patton, the legendary commander of World War II, became an astute consumer of communications intelligence (COMINT); he learned its worth in the drive across Western Europe after D-Day and used it well. For example, in mid-August 1944, while Patton’s Third Army was located near the French city of Le Mans, the general and about 40 of his officers attended daily intelligence briefings. Here they would hear regular briefings by the G-2 (Intelligence) and G-3 (Operations), situation reports, and a news report from radio broadcasts. Following each meeting, all but seven officers were dismissed, and the rest stayed for a briefing on the enemy situation as seen in COMINT. This source proved valuable for the Third Army: ULTRA (the codeword assigned to COMINT derived from decryption of high-level German ciphers) material alone predicted a drive by five German Panzer divisions against the Third Army at Avaranches. In another instance, when Third Army headquarters moved near Chalons, an ULTRA message arrived at 0100 hours showing the German order for an attack at 0300. Patton had described the U.S. troops in the attack areas as spread out as “thin as the skin on an egg.” He found means to alert the defending divisions without jeopardizing the security of ULTRA, and the German attack was repulsed.

      One member of Patton’s staff wrote about the value of ULTRA to Patton’s army stating that, “An army has never moved as fast and as far as the Third Army in its drive across France, and ULTRA was invaluable every mile of the way.”

      NSA, Center for Cryptologic History, from 50th Anniversary Brochure, p. 10. URL frequently change but currently this can be found at nsa.gov > History > Cryptologic History > Publications > NSA/CSS. /p>

    This page last updated Last updated: January 2, 2026 at 10:10 am

    © Deborah Anderson. Use of materials by permission. Materials other than those clearly marked as National Archives materials are not in the public domain. More information here. Simple Privacy Policy is here

    HIT A DEAD END?

    I ask that visitors be patient when links or pages disappear or become mangled in the vagaries of PHP and generated code. Frequent additions and updates make for human error — please report any broken links or other problems to Debbie Anderson, site manager–your help is appreciated.

    E-mails are still appreciated, and I will try to respond promptly. Your messages are what make this job worthwhile.