Kevin Mitnick

American computer hacker, world famous. He is not only noted for expert computer break-ins but is a "phone phreak," a term for someone who electronically breaks into the phone system. For all his years of hacking - dating back to the '70s, - he never used his ability for nefarious purposes: never stole money, never sold or made public any of the information he found through hacking, never used the information to stalk anyone. He just did it "for the challenge," he says, and out of curiosity. Nevertheless, he spent upwards of six years in federal prison, including over four years of pre-trial detention (kept in prison but not brought to trial) between February 1995 and 1999, of which eight months was solitary confinement. He was also imprisoned in the late 1980s for hacking, and afterwards, when he realized that he was being set up again for another hacking arrest by an FBI informant, he went underground for a couple of years living under several different assumed names. In 1999 he was released under a plea agreement that restricted his ability to use computers, but is now free to use them again. Mitnik now makes his living as a security consultant, and just published a book called "The Art of Deception," about how companies and people can improve their security. Link to Wikipedia biography