Tsutomu Shimomura

Tsutomu Shimomura (下村 努, Shimomura Tsutomu, born October 23, 1964) is a Japanese-born physicist and computer security expert. He is known for helping the FBI track and arrest hacker Kevin Mitnick. Takedown, his 1996 book on the subject with journalist John Markoff, was later adapted for the screen in Track Down in 2000.

Shimomura was a founder of semiconductor company Neofocal Systems, and served as CEO and CTO until 2016. Born in Japan, Shimomura is the son of Osamu Shimomura, winner of the 2008 Nobel Prize in Chemistry. He grew up in Princeton, New Jersey, and attended Princeton High School.At Caltech he studied under Nobel laureate Richard Feynman. After Caltech, he went on to work at Los Alamos National Laboratory, where he continued his hands-on education in the position of staff physicist with Brosl Hasslacher and others on subjects such as lattice gas automata.

In 1989, he became a research scientist in computational physics at the University of California, San Diego, and senior fellow at the San Diego Supercomputer Center. Shimomura also became a noted computer security expert, working for the National Security Agency.

In 1992, he testified before Congress on issues regarding the privacy and security (or lack thereof) on cellular telephones. Author Bruce Sterling described his first meeting with Shimomura in the documentary Freedom Downtime:

It was in front of Congress, and I was testifying to a Congressional subcommittee. And here was this guy in sandals and, like, ragged-ass cutoffs, and the rest of us were done up in ties [...] giving our best sort of 'yes, we're in front of Congress' thing and Shimomura is there in this surfer gear.

He is best known for events in 1995, when he assisted with tracking down the computer hacker Kevin Mitnick. In that year Shimomura also received prank calls which popularized the phrase "My kung fu is stronger than yours", equating it with hacking. Shimomura and journalist John Markoff wrote a book, Takedown, about the pursuit, and the book was later adapted into a movie with a very similar name, Track Down. Shimomura, himself, appeared in a brief cameo in the movie.

Shimomura worked for Sun Microsystems during the late 1990s.

Shimomura was a founder of privately held fabless semiconductor company Neofocal Systems, and served as CEO and CTO until 2016.