Manuel Blum

By Erik J. Larson, PhD

Areas of Specialization: Computational Complexity Theory
Manuel Blum is the Bruce Nelson Professor of Computer Science at Carnegie Mellon University. Born in Venezuela, Blum has had an impressive career working on the theoretical underpinnings of programming and algorithms, notably computational complexity theory (roughly, how long it takes a program to solve a problem), cryptography (code making and breaking), and program verification and checking, an area of immense importance to practical software development.

Blum received his bachelor’s and master’s degrees in electrical engineering and computer science (EECS) from Massachusetts Institute of Technology (MIT). His supervisor was the late Marvin Minsky, a pioneer of Artificial Intelligence and a founding member of the group that launched AI in the 1950s. He spent nearly four decades as a professor of computer science at the University of California, Berkeley, until 1999. He then joined the faculty of computer science at Carnegie Mellon, where he has developed his early research on complexity theory into practical results that have proven immensely important for algorithm design and study: the compression theorem, the gap theorem, and the Blum speedup theorem. Blum’s interest in cryptology has also yielded important results. Perhaps best known are CAPTCHAs (Completely Automated Public Turing test to tell Computers and Humans Apart), the ubiquitous challenge-response quizzes that appear on web pages when users access or sign up for content. Blum and three other researchers coined the term in 2003, though there has been some dispute about who originated the idea.

Blum won the Turing Award in 1995 for his work on computational complexity theory, and in 2002 he was elected to the Academy of Sciences in the United States.

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