One of the main reasons the cryptanalysts at Bletchley Park were successful could be contributed to the German overconfidence in the Enigma machine. Their hubris blinded them, and this blinding trust in the strength of Enigma ultimately led to the German downfall. However, certain individuals also contributed to the ultimate defeat of the Germans - Hans-Thilo Schmidt and Marian Rejewski. These individual contributions would prove invaluable throughout the war.
Schmidt's story shows the effects of the negative German culture. Because he was deemed unworthy, he was forced to leave his position on the army. In addition, his failed business and his descent into poverty left him resentful toward Germany. Had the Germans simply decided not to cut him from their ranks, they could have potentially avoided the Allies' cracking of Enigma. Disillusioned with his country, he sought revenge. Without Schmidt's treachery, the Allies would never have obtained a functioning Enigma machine that could function similarly to the German military machines.
Rejewski's work at the Biuro Szyfrow introduced the importance of mathematics and logic into cryptanalysis. With his famous Rejewski Chains, he was able to crack the earlier version of Enigma before the Germans added more scramblers and plugboards to make it more difficult. His work proved that mathematics and logic were extremely important once cryptography became mechanized. The work of linguists analyzing patterns was no longer enough. Despite Rejewsi's work being essentially useless as Schmidt had given up the German keys for months, his work made it possible for the Allies in the future war efforts to crack the new and improved German Enigma machine. This crucial information gave the Allies a head start and the confidence that Enigma could be beaten.
Without these two individuals, the Allied cryptanalysts may never have achieved victory over the Germans. Although there are many factors that contribute to their victory, the influence of brilliant individuals cannot be ignored.