Lenore Carol Blum (née Epstein,[2] born December 18, 1942) is an American computer scientist and mathematician who has made contributions to the theories of real number computation, cryptography, and pseudorandom number generation.

Blum was born to a Jewish family in New York City, where her mother was a science teacher.

[4] After completing her doctorate, Blum went to the University of California at Berkeley to work with Julia Robinson[11] as a postdoctoral fellow and lecturer in mathematics.

It was not until 1976, when she was elected as the first woman in the mathematics section of the National Academy of Sciences, did Robinson receive a permanent offer from Berkeley.)

[5] In 1983 Blum won a National Science Foundation (NSF) Visiting Professorship for Women award to work with Michael Shub for two years at the CUNY Graduate Center.

After visiting the City University of Hong Kong in 1996–1998 to work on her book Complexity and Real Computation (during Hong Kong's handover from British to Chinese rule), she became a Distinguished Career Professor of Computer Science at Carnegie Mellon University (CMU) in 1999.

[15] At CMU, Blum co-Directed the NSF seeded ALADDIN Center which promoted the synergy between algorithm theory and practice.

Blum and her co-authors, Michael Shub and Stephen Smale, showed that (analogously to the theory of Turing machines) one can define analogues of NP-completeness, undecidability, and universality for this model.

[5][BSS] In this model, over any field F, the problem of deciding whether or not a finite system of polynomial equations over F has a common zero is NP-complete over F. (F could be the reals or complex numbers or the integers mod 2.)

Along with Felipe Cucker, Mike Shub and Steve Smale, she published a book on the subject,[16][CRC] and in 1990 she gave an address at the International Congress of Mathematicians on computational complexity theory and real computation.[12][5].

[17] In 2005, Blum was a recipient of the Presidential Award for Excellence in Science, Mathematics, and Engineering Mentoring, given by president George W. Bush "for her efforts to mentor girls and women in technology fields where traditionally they are underrepresented".