Cika wannan jumlar: Marian Rejewski (1905<unk>80), masanin lissafi ɗan Poland, a watan Disamba na 1932 ya warware na'urar Enigma mai amfani da plugboard, babban na'urar ɓoye ɓoye da Nazi Jamus ke amfani da ita. Nasarar cryptologic na Rejewski da abokan aikinsa masu ilimin lissafi Jerzy Różycki da Henryk Zygalski, sama da shekaru shida da rabi daga baya, sun fara karatun Enigma na Burtaniya a Yaƙin Duniya na Biyu; bayanan da aka samu, mai suna "Ultra", ya ba da gudummawa, watakila da gaske, ga
Rashin nasarar Jamus.