Alan Turing is a British mathematician and computer scientist often regarded as the “Father of Computer Science.” His work established the groundwork for the computer on which you’re most likely currently reading this.
Turing stands apart from the rest of the candidates on this list because of his contributions during World War II. While working at the renowned Bletchley Park, Turing is widely regarded as one of the most influential figures in the development of techniques for breaking the German Enigma cipher.
The Allies used the approach he devised to build the Bombe. This gigantic electromechanical machine cracked the Enigma on an industrial scale, allowing them to read practically all of the German communication. In this way, he is considered one of the founding fathers of contemporary cryptanalysis. He is widely regarded as having played one of the most important roles in the Allies’ victory in the Battle of the Atlantic.
