Claude Shannon: Biography, Achievements & Lasting Legacy

At the University of Michigan, Shannon dual-degreed, graduating with a Bachelor of Science in electrical engineering and another in mathematics, both in 1936. As a 21-year-old master's degree student in electrical engineering at MIT, his 1937 thesis, "A Symbolic Analysis of Relay and Switching Circuits", demonstrated that electrical applications of Boolean algebra could construct any logical numerical relationship, thereby establishing the theory behind digital computing and digital circuits. Called by some the most important master's thesis of all time, it is the "birth certificate of the digital revolution", and started him in a lifetime of work that led him to win a Kyoto Prize in 1985. He graduated from MIT in 1940 with a PhD in mathematics; his thesis focusing on genetics contained important results, while initially going unpublished.

Shannon contributed to the field of cryptanalysis for national defense of the United States during World War II, including his fundamental work on codebreaking and secure telecommunications, writing a paper which is considered one of the foundational pieces of modern cryptography, with his work described as "a turning point, and marked the closure of classical cryptography and the beginning of modern cryptography". His work was foundational for symmetric-key cryptography, including the work of Horst Feistel, the Data Encryption Standard (DES), and the Advanced Encryption Standard (AES). As a result, Shannon has been called the "founding father of modern cryptography".

His 1948 paper "A Mathematical Theory of Communication" laid the foundations for the field of information theory, referred to as a "blueprint for the digital era" by electrical engineer Robert G. Gallager and "the Magna Carta of the Information Age" by Scientific American. Golomb compared Shannon's influence on the digital age to that which "the inventor of the alphabet has had on literature". Shannon is also regarded as the most important post-1948 contributor to the theory. Advancements across multiple scientific disciplines utilized Shannon's theory—including the invention of the compact disc, the development of the Internet, the commercialization of mobile telephony, and the understanding of black holes. He formally introduced the term "bit", and was a co-inventor of both pulse-code modulation and the first wearable computer. He also invented the signal-flow graph.

Shannon joined the Central Intelligence Agency's Special Cryptologic Advisory Group in 1951. From 1956 to 1978, he was a professor at MIT. He also made numerous contributions to the field of artificial intelligence, including co-organizing the 1956 Dartmouth workshop, considered to be the discipline's founding event, and papers on the programming of chess computers. His Theseus machine was the first electrical device to learn by trial and error, being one of the first examples of artificial intelligence.