80 years later, GCHQ releases new images of Nazi code-breaking computer

An image of the Colossus computer as seen in 1963, merged with the UK flag.

80 years later, GCHQ releases new images of Nazi code-breaking computer
Ars Technica, January 18, 2024
Cracking the Lorenz cipher
By Benj Edwards

“GCHQ unveils new docs on Colossus, a 1943 marvel that let allies “read Hitler’s mind.””


On Thursday, UK’s Government Communications Headquarters (GCHQ) announced the release of previously unseen images and documents related to Colossus, one of the first digital computers. The release marks the 80th anniversary of the code-breaking machines that significantly aided the Allied forces during World War II. While some in the public knew of the computers earlier, the UK did not formally acknowledge the project’s existence until the 2000s.


Colossus was not one computer but a series of computers developed by British scientists between 1943 and 1945. These 2-meter-tall electronic beasts played an instrumental role in breaking the Lorenz cipher, a code used for communications between high-ranking German officials in occupied Europe. The computers were said to have allowed allies to “read Hitler’s mind,” according to The Sydney Morning Herald.


A photo of a surviving Colossus computer in 1963. - GCHQ
A photo of a surviving Colossus computer in 1963. – GCHQ

The technology behind Colossus was highly innovative for its time. Tommy Flowers, the engineer behind its construction, used over 2,500 vacuum tubes to create logic gates, a precursor to the semiconductor-based electronic circuits found in modern computers. While 1945’s ENIAC was long considered the clear front-runner in digital computing, the revelation of Colossus’ earlier existence repositioned it in computing history. (However, it’s important to note that ENIAC was a general-purpose computer, and Colossus was not.)


GCHQ’s public sharing of archival documents includes several photos of the computer at different periods and a letter discussing Tommy Flowers’ groundbreaking work that references the interception of “rather alarming German instructions.”

Read the Full Article »

About the Author:

Benj Edwards is an AI and Machine Learning Reporter for Ars Technica. For over 16 years, he has written about technology and tech history for sites such as The Atlantic, Fast Company, PCMag, PCWorld, Macworld, How-To Geek, and Wired. In 2005, he created Vintage Computing and Gaming, a blog that pioneered tech history coverage online. He also hosted The Culture of Tech podcast and contributes to the Retronauts podcast. In his free time, he writes and records music, collects vintage computers, and enjoys nature. He lives in Raleigh, NC.

See also: