Colossus

Colossus was a set of computers developed by British codebreakers in the years 1943–1945 to help in the cryptanalysis of the Lorenz cipher. The Colossus machines were used by British codebreakers at Bletchley Park during World War II.

Development

The design of Colossus was led by Tommy Flowers, an engineer at the Post Office Research Station at Dollis Hill. The first version, Colossus Mark I, was operational by early 1944. It was followed by an improved version, Colossus Mark II, which became operational in June 1944.

Technical Specifications

Colossus was the world's first programmable digital electronic computer. It used a large number of vacuum tubes (thermionic valves) to perform its calculations. The machine was capable of reading up to 5,000 characters per second from a punched tape and could process data at a rate of 25,000 characters per second.

Operation

Colossus was used to break the Lorenz cipher, a high-level German cipher used by the Wehrmacht during World War II. The machine's primary function was to determine the settings of the Lorenz SZ40/42 cipher machine, which encrypted teleprinter messages.

Legacy

The work done by Colossus and the codebreakers at Bletchley Park significantly contributed to the Allied victory in World War II. The existence of Colossus was kept secret for many years after the war, and its contributions were not widely known until the 1970s.

Related Pages

• Bletchley Park
• Lorenz cipher
• Tommy Flowers
• World War II
• Cryptanalysis
• Vacuum tube
• Wehrmacht