<P> Around December 1932 , Marian Rejewski of the Polish Cipher Bureau used the theory of permutations and flaws in the German military message procedures to break the message keys of the plugboard Enigma machine . Rejewski achieved this result without knowledge of the wiring of the machine , so the result did not allow the Poles to decrypt actual messages . The French had a spy with access to German cipher materials that included the daily keys used in September and October 1932 . Those keys included the plugboard settings . The French gave the material to the Poles , and Rejewski used some of that material and the message traffic in September and October to solve for the unknown rotor wiring . Consequently , the Poles were able to build their own Enigma machines , which were called Enigma doubles . Rejewski was aided by cryptanalysts Jerzy Różycki and Henryk Zygalski , both of whom had been recruited with Rejewski from Poznań University . The Polish Cipher Bureau developed techniques to defeat the plugboard and find all components of the daily key , which enabled the Cipher Bureau to read the German 's Enigma messages . Over time , the German cryptographic procedures improved , and the Cipher Bureau developed techniques and designed mechanical devices to continue breaking the Enigma traffic . As part of that effort , the Poles exploited quirks of the rotors , compiled catalogs , built a cyclometer to help make a catalog with 100,000 entries , made Zygalski sheets and built the electro - mechanical cryptologic bomb to search for rotor settings . In 1938 , the Germans added complexity to the Enigma machines that finally became too expensive for the Poles to counter . The Poles had six bomby , but when the Germans added two more rotors , ten times as many bomby were needed , but the Poles did not have the resources . </P>
<P> Around December 1932 , Marian Rejewski of the Polish Cipher Bureau used the theory of permutations and flaws in the German military message procedures to break the message keys of the plugboard Enigma machine . Rejewski achieved this result without knowledge of the wiring of the machine , so the result did not allow the Poles to decrypt actual messages . The French had a spy with access to German cipher materials that included the daily keys used in September and October 1932 . Those keys included the plugboard settings . The French gave the material to the Poles , and Rejewski used some of that material and the message traffic in September and October to solve for the unknown rotor wiring . Consequently , the Poles were able to build their own Enigma machines , which were called Enigma doubles . Rejewski was aided by cryptanalysts Jerzy Różycki and Henryk Zygalski , both of whom had been recruited with Rejewski from Poznań University . The Polish Cipher Bureau developed techniques to defeat the plugboard and find all components of the daily key , which enabled the Cipher Bureau to read the German 's Enigma messages . Over time , the German cryptographic procedures improved , and the Cipher Bureau developed techniques and designed mechanical devices to continue breaking the Enigma traffic . As part of that effort , the Poles exploited quirks of the rotors , compiled catalogs , built a cyclometer to help make a catalog with 100,000 entries , made Zygalski sheets and built the electro - mechanical cryptologic bomb to search for rotor settings . In 1938 , the Germans added complexity to the Enigma machines that finally became too expensive for the Poles to counter . The Poles had six bomby , but when the Germans added two more rotors , ten times as many bomby were needed , but the Poles did not have the resources . </P>
who broke the code of the enigma machine
who broke the code of the enigma machine
Marian Rejewski
Marian Rejewski