Breaking the Enigma:
One of the single greatest cryptographic accomplishments of all time was the breaking of the enigma. This was considered by western Supreme Allied Commander Dwight D. Eisenhower to have been "decisive" to the Allied victory. It was no small feat, considering that the standard army version had nearly 159 quintillion settings (when used with three rotors being selected from five, and 10 pairs of letters connected via the plug board). Even more amazing was that it was broken without the use of modern computers.
The breaking of Enigma is often credited to Alan Turing, and indeed his contribution was substantial. However, the earliest breakthroughs were made by Marian Rejewski from the Polish Cipher Bureau. The story of how he did it is fascinating and more than can be relayed here. However, one of his more important realizations was that the plugboard (called the steckerbrett) and the rotor systems operated quasi independently. In other words, it was possible to determine the initial rotor configuration without knowing the plugboard configuration.
While the cryptanalysts of the 1930s and 1940s couldn’t directly exploit this weakness, they were able to indirectly exploit this using mechanical enigma simulators called “bombes.” While not technically computers, these machines greatly simplified the process of testing various rotor configurations. The resulting message would still be partly gibberish, but occasionally, fragments of plaintext would emerge which allowed the analyst to guess at the plugboard configuration.
The following message was encrypted using the standard Army Enigma using the following configuration: Rotor Numbers: I, II, III; Starting Configuration: A,A,A (for simplicity); Plugboard (Stecker): used, five pairs swapped. Please use the related webpage and information contained herein to solve.
YKSO MKLT HGDY UAJN PIED TQSS UGGK FPQF DBIZ UBNX WJPH PBNR VGCK GSCP CZFO MRTO EAWK GZNP WBPV IEMM KI
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