Kevin David Mitnick was an American computer security consultant, author, and convicted hacker. He is best known for his high-profile 1995 arrest and five years in prison for various computer and communications-related crimes.
Mitnick's pursuit, arrest, trial, and sentence along with the associated journalism, books, and films were all controversial. After his release from prison, he ran his own security firm, Mitnick Security Consulting, LLC, and was also involved with other computer security businesses.
Mitnick in 2010
A security hacker is someone who explores methods for breaching defenses and exploiting weaknesses in a computer system or network. Hackers may be motivated by a multitude of reasons, such as profit, protest, information gathering, challenge, recreation, or evaluation of a system weaknesses to assist in formulating defenses against potential hackers.
Bruce Sterling, author of The Hacker Crackdown