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'Bombe' Replica Code-Breaking WW2 Computer Was Used To Decipher Message Scrambled By An Enigma Machine (bbc.com)
An anonymous reader quotes a report from the BBC: Computer historians have staged a re-enactment of World War Two code-cracking at Bletchley Park. A replica code-breaking computer called a Bombe was used to decipher a message scrambled by an Enigma machine. Held at the National Museum of Computing (TNMOC), the event honored Polish help with wartime code-cracking. Enigma machines were used extensively by the German army and navy during World War Two. This prompted a massive effort by the Allies to crack the complex method they employed to scramble messages. That effort was co-ordinated via Bletchley Park and resulted in the creation of the Bombe, said Paul Kellar who helps to keep a replica machine running at the museum. Renowned mathematician Alan Turing was instrumental in the creation of the original Bombe.
For its re-enactment, TNMOC recruited a team of 12 and used a replica Bombe that, until recently, had been on display at the Bletchley Park museum next door. The electro-mechanical Bombe was designed to discover which settings the German Enigma operators used to scramble their messages. As with World War Two messages, the TNMOC team began with a hint or educated guess about the content of the message, known as a "crib," which was used to set up the Bombe. The machine then cranked through the millions of possible combinations until it came to a "good stop," said Mr Kellar. This indicated that the Bombe had found key portions of the settings used to turn readable German into gobbledygook. After that, said Mr Kellar, it was just a matter of time before the 12-strong team cracked the message.
For its re-enactment, TNMOC recruited a team of 12 and used a replica Bombe that, until recently, had been on display at the Bletchley Park museum next door. The electro-mechanical Bombe was designed to discover which settings the German Enigma operators used to scramble their messages. As with World War Two messages, the TNMOC team began with a hint or educated guess about the content of the message, known as a "crib," which was used to set up the Bombe. The machine then cranked through the millions of possible combinations until it came to a "good stop," said Mr Kellar. This indicated that the Bombe had found key portions of the settings used to turn readable German into gobbledygook. After that, said Mr Kellar, it was just a matter of time before the 12-strong team cracked the message.
During WW2, the Ministry of Defence searched everywhere for cryptogramists (experts in code breaking), but accidentally hired a cryptogamist (expert in algae and other spore-distributing plants), Geoffrey Tandy, whose expertise turned out to be useful in restoring a water logged codebook.
https://en.wikipedia.org/wiki/...
What is seldom mentioned is that the British sent the design for the Bombe to the US where hundreds were built and did the bulk of the decrypting work. This is nicely presented at the NSA museum at Ft. Meade, which also has several Enigma machines, including a pre-war commercial version, and a section of a Bombe on display.
using data given to them by the French
AIU it was the other way round. The Polish team developed the codebreaking method using their own resources (notably, they were able to reconstruct the rotor wiring just by analyzing coded messages). They approached the French because they wanted to share their knowledge before the country was overrun. Also, changes made by the Germans meant the problem had become more complex and vastly more machines and personnel were needed to break the new codes with any regularity - resources the Polish cypher bureau didn't have.