Colossus: Breaking the Code

The ability to send secret, encoded communications led to ruthless devastation by Nazi troops early in WWII. Allied mathematicians and engineers rushed to build a machine capable of breaking the codes. Here we pay tribute to “Colossus” for helping to end the war and begin the age of computing.

Breaking the Code

To decipher the enemy’s plans and movements during World War II, Britain assembled an extraordinary team of mathematicians and engineers at Bletchley Park, its Government Code and Cypher School.

Their assignment? Develop machines to crack German codes. Among their triumphs was Colossus, an electronic code-breaking computer that remained classified until the 1970s.

Women’s Royal Naval Service “Wrens” operated many of Britain’s Colossus code-breaking machines. In the US, 600 Navy women, known as “WAVES,” used other machines to break German codes.

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The ENIGMA cipher machine was used by the German military in World War II. Messages typed into the machine were encrypted and then sent by Morse code. Based on earlier Polish code-breaking efforts, special-purpose machines in the US and Britain secretly broke the ENIGMA codes.

This is one of few surviving pieces of the Colossus machines used at Britain’s Bletchley Park to break German Lorenz codes during WWII. Winston Churchill acknowledged that they shortened the war, but ordered the machines destroyed and kept secret.

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Bletchley Park

Learn more about the history of World War II code-breaking including the early Polish contributions at Bletchley Park History.