John Draper

also known as Captain Crunch, Crunch or Crunchman (after Cap'n Crunch, the mascot of a breakfast cereal), is a former phone phreak.
Draper was the son of a U.S. Air Force engineer; he described his father as distant in an interview published on the front page of the Jan 13-14, 2007 issue of The Wall Street Journal. Draper himself entered the Air Force in 1964, and while stationed in Alaska helped his fellow servicemen make free phone calls home by devising access to a local telephone switchboard. He was honorably discharged from the Air Force in 1968 and did military-related work for several employers in the San Francisco Bay Area. He adopted the counterculture of the times and operated a pirate radio station out of a Volkswagen van.
A blind friend of John Draper's named Joe Engressia (later known as Joybubbles) informed him that a toy whistle that was, at the time, packaged in boxes of Cap'n Crunch cereal could emit a tone at precisely 2600 hertz—the same frequency that was used by AT&T long lines to indicate that a trunk line was ready and available to route a new call. This would effectively disconnect one end of the trunk, allowing the still connected side to enter an operator mode. Experimenting with this whistle inspired Draper to build blue boxes: electronic devices capable of reproducing other tones used by the phone company.
“I don't do that. I don't do that anymore at all. And if I do it, I do it for one reason and one reason only. I'm learning about a system. The phone company is a System. A computer is a System, do you understand? If I do what I do, it is only to explore a system. Computers, systems, that's my bag. The phone company is nothing but a computer.”—From Secrets of the Little Blue Box by Ron Rosenbaum, Esquire Magazine (October 1971) 
The class of vulnerabilities Draper and others discovered was limited to call-routing switches that employed in-band signaling, whereas newer equipment relies almost exclusively on out-of-band signaling, the use of separate circuits to transmit voice and signals. Though they could no longer serve practical use, the Cap'n Crunch whistles did become valued collector's items. Some hackers sometimes go by the handle “Captain Crunch” even today; 2600: The Hacker Quarterly is named after this whistle frequency. The expense of sustaining the unbilled phone calls, the redesign of the line protocols and the accelerated equipment replacement due to the blue box is difficult to calculate, or even to separate from something as complex and dynamic as the telephone long-distance network, but it is generally acknowledged to be a huge sum.
The 1971 Esquire article which told the world about phone phreaking got Draper in hot water. Draper was arrested on toll fraud charges in 1972 and sentenced to five years' probation. The article also brought him to the attention of Steve Wozniak. In the mid 1970s he taught his phone phreaking skills to Steve Jobs and Steve Wozniak, who later founded Apple Computer. He was briefly employed at Apple, and created a telephone interface board for the Apple II personal computer. Wozniak has said that the reason that the board was never marketed was that Wozniak was the only one in the company who liked Draper and partially due to Draper's arrest and conviction for wire fraud in 1977. While at Apple, Draper also wrote a cross-assembler used by Steve Wozniak while developing Apple I and Apple II.
Draper wrote EasyWriter, the first word processor for the Apple II, in 1979. According to The Wall Street Journal, he hand-wrote the code while serving nights in the Alameda County Jail, then entered the code later into a computer. However, another account had him writing the code as he served his four-month sentence at the Federal Correctional Institution, Lompoc, California.
Draper's own webpage, and personal communication with him, furnishes a more realistic version of the coding of EasyWriter.
Draper was in prison, in California, at the time, but under a 'work furlough' program. This meant that while he had to spend every night in prison, he spent each day working a regular job, outside prison.
This job was at Receiving Studios, a small band practice studio, and while there he had access to a computer, where he coded EasyWriter. He did take copies of the code 'home' to prison overnight to work on it.
Draper later ported EasyWriter to the IBM PC, beating Bill Gates on the bid for the IBM contract. Draper's company, Capn' Software, posted less than $1 million revenue over six years, and he subsequently sued his software's distributor, Bill Baker, over an unauthorized version of EasyWriter that Baker released. In the 1980s, Draper worked for Autodesk, but was laid off. His eccentric behavior sometimes led to difficulties with potential clients. Shortly after Apple released Macintosh, he taught an online course in Mac programming. Currently he writes computer security software, is senior developer of KanTalk!  VoIP software for teen singer/software model Kandice Melonakos, and host of an internet show, Crunch TV.
Draper is Chief Technical Officer (CTO) for media delivery company En2go, that delivers music, video and other digital content to desktops.
One oft-repeated story featuring Captain Crunch goes as follows: Draper picked up a public phone, then proceeded to "phreak" his call around the world. At no charge, he routed a call through different phone switches in countries such as Japan, Russia and England. Once he had set the call to go through dozens of countries, he dialed the number of the public phone next to him. A few minutes later, the phone next to him rang. Draper spoke into the first phone, and, after quite a few seconds, he heard his own voice very faintly on the other phone. Draper also claimed that he and a friend once managed to place a direct call to the White House and spoke directly with someone who sounded like Richard Nixon; Draper's friend told the man about a toilet paper shortage in Los Angeles. Draper was also a member of the Homebrew Computer Club.
In popular culture
John Draper's story inspired several mentions in popular culture.
Elements of the movie Sneakers recall Draper, including Cosmo's experience of offering phreaking services to criminals while in prison. John Draper is specifically mentioned as Captain Crunch in one scene in Cowboy Bebop: The Movie, in which a hacker mentions that "Cap'n Crunch broke into the national phone system with a plastic whistle." He is portrayed by Wayne Pére in the movie Pirates of Silicon Valley. Captain Crunch is being searched for by Rockford during a murder investigation on the TV show Rockford Files, season 5, episode 5, Kill the Messenger.