One of the main factors that contributed to the success of the Allied cryptanalysts over the German cryptographers was the secrecy that surrounded the Allied code breaking efforts.


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The Allies were able to keep their code breaking efforts shrouded under a curtain of secrecy and so even when a breakthrough occurred in Bletchley Park, the Germans remained unaware that their codes were broken and continued to send message through their “secure” system. For example, the Allies had exploited the fact that the Germans embedded their key twice at the beginning of their messages to avoid error, and used this information to help identify the settings of the Enigma machine. Had the Germans known earlier that their key transportation scheme actually hurt the security of their communication system, they likely would have changed the way they provided the key and made it harder for the cryptanalysts to make breakthroughs in deciphering their messages.

The Allies swore all who worked in Bletchley Park to secrecy for good reason. The secrecy gave the Germans a false sense of security in the strength of their system, buying the Allies more time to decrypt messages as well as experiment with new deciphering techniques in case the Germans changed their system upon learning that it was not as impenetrable as they had believed.