Tag Archives: Flowers

Bill Who? The Lesser Known Codebreaker of Bletchley Park

The work of Bletchley Park during the Second World War is inspirational-numerous codes were broken and incalculable lives were saved. It is important to remember that code breaking at Bletchley Park was a team effort and not something that one person could have achieved alone. However, some people are prominent due to their unique contribution; Bill Tutte was one of those people.
W. T. (Bill) Tutte

W. T. (Bill) Tutte

“Bill who?” Is the standard response I receive whenever I mention his name. If I’m lucky, then the person to whom I am speaking has heard of Bletchley Park and Enigma, and if it is a really good day then they have heard of Alan Turing; but it is rarely the case that they have heard of Lorenz, Colossus, Bill Tutte or Tommy Flowers.
A Naval Enigma Machine

A Naval Enigma Machine

So let me clarify. Alan Turing cracked the Enigma code as used by the German Army, Navy and Air Force. It was a cipher transmitted via Morse code and was an important tactical code to break. The breaking of Enigma is widely remembered for its significance when tackling U-boat threat during the Battle of the Atlantic. When we talk about Tutte, Flowers and Colossus, this is in reference to the Lorenz cipher-an enciphering attachment to a teleprinter machine. Lorenz was used by the German High Command, so a break into Lorenz revealed the strategy of Hitler and his generals-highly significant communications during World War Two.
Lorenz SZ42

Lorenz SZ42

So what was Bill Tutte’s contribution to the breaking of Lorenz?
Very simply, Tutte deduced the structure of the Lorenz cipher through analysis of two pieces of cipher text where the original messages had been enciphered using the same settings, but with slight differences between the texts (e.g abbreviations and misspellings). This meant the encipherment could be removed and then Tutte could look for recurring patterns within the text, eventually deducing the entire structure of the machine. This enabled Tommy Flowers to design and build Colossus, the world’s first digital computer, which was used to break the Lorenz cipher. Tutte’s achievement has been described as the greatest intellectual feat of the Second World War, because unlike Enigma, Tutte deduced the structure of Lorenz with no information about the machine or what it looked like.
Surely that deserves a memorial?
Author: Claire Butterfield
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