Many of the attendees at DEF CON include computer security professionals, journalists, lawyers, federal government employees, security researchers, and hackers with a general interest in software, computer architecture, phone phreaking, hardware modification, and anything else that can be "hacked." The event consists of several tracks of speakers about computer- and hacking-related subjects, as well as social events and contests in everything from creating the longest Wi-Fi connection and cracking computer systems to who can most effectively cool a beer in the Nevada heat. Other contests include lockpicking, robotics-related contests (discontinued), art, slogan, coffee wars (not currently running), scavenger hunt and Capture the Flag. Capture the Flag (CTF) is perhaps the best known of these contests. It is a hacking competition where teams of hackers attempt to attack and defend computers and networks using certain software and network structures. CTF has been emulated at other hacking conferences as well as in academic and military contexts.
Since DEF CON 11, fundraisers have been conducted for the Electronic Frontier Foundation. The first fundraiser was a dunk tank and was an "official" event. The EFF now has an event named "The Summit" hosted by the Vegas 2.0 crew that is an open event and fundraiser. DefCon 18 (2010) hosted a new fundraiser called MohawkCon. In 2010, over 10,000 people attended DEF CON 18.
DEF CON was also portrayed in the The X-Files episode "Three of a Kind" featuring an appearance by The Lone Gunmen. DEF CON was portrayed as a United States government sponsored convention instead of a civilian convention.
DEF CON was founded in 1992 by Jeff Moss as a farewell party for his friend and fellow hacker. The party was planned for Las Vegas a few days before his friend was to leave the United States, because his father had accepted employment out of the country. However, his friend's father left early, taking his friend along, so Jeff was left alone with the entire party planned. Jeff decided to invite all his hacker friends to go to Las Vegas with him and have the party with them instead. Hacker friends from far and wide got together and laid the foundation for DEF CON, with roughly 100 persons in attendance. The term DEF CON comes from the movie WarGames, referencing the U.S. Armed Forces defense readiness condition (DEFCON). In the movie, Las Vegas was selected as a nuclear target, and since the event was being hosted in Las Vegas, it occurred to Jeff Moss to name the convention DEFCON. However, to a lesser extent, CON also stands for convention and DEF stands for the number 3 on a telephone, a reference to phone phreakers. DEF CON was planned to be a one-time event, a party for his friend, but he kept getting emails from people encouraging him to host again the next year. After a while, he was convinced to host the event again, and the attendance nearly doubled the second year.
A semi-fictionalized account of DefCon II, "Cyber Christ Meets Lady Luck" written by Winn Schwartau demonstrates some of the early DefCon culture.
Noteworthy incidents 
In August 2007, Michelle Madigan, a reporter for Dateline NBC, attempted to secretly record hackers admitting to crimes at the convention. After being outed by DEF CON founder Jeff Moss during an assembly, she was heckled and chased out of the convention by attendees for her use of covert audio and video recording equipment. DEF CON staff tried to get Madigan to obtain a press pass before the outing happened. A DEF CON source at NBC had tipped off organizers to Madigan's plans.
MIT students Zack Anderson, R.J. Ryan and Alessandro Chiesa were to present a session entitled "The Anatomy of a Subway Hack: Breaking Crypto RFIDS and Magstripes of Ticketing Systems". The presentation description included the phrase "Want free subway rides for life?" and promised to focus on the Boston T subway. However, the Massachusetts Bay Transit Authority (MBTA) sued the students and MIT in United States District Court in Massachusetts on August 8, claiming that the students violated the Computer Fraud and Abuse Act (CFAA) by delivering information to conference attendees that could be used to defraud the MBTA of transit fares.
The court issued a temporary restraining order prohibiting the students from disclosing the material for a period of ten days, despite the fact the material had already been disseminated to DefCon attendees at the start of the show.
In 2008's contest "Race to Zero", contestants submitted a version of given malware which was required to be undetectable by all of the antivirus engines in each round. The contest concept attracted much negative attention.
List of venues 
- The first DEF CON was held at the Sands Hotel & Casino in June (9-11) 1993.
- DEF CON 2 was held at the Sahara Hotel and Casino in July (22-24) 1994.
- DEF CON 3 was held at the Tropicana Resort & Casino in August (4-6) 1995.
- DEF CON 4 was held at the Monte Carlo Resort and Casino in July (26-28) 1996.
- DEF CON 5 was held at the Aladdin Hotel & Casino in July (11-13) 1997.
- DEF CON 6 was held at the Plaza Hotel & Casino in July/August (31-2) 1998.
- DEF CON 7 was held at the Alexis Park Resort in July (9-11) 1999.
- DEF CON 8 through DEF CON 13 were also held at the Alexis Park Resort from 2000 to 2005.
- DEF CON 14 through DEF CON 18 were held at the Riviera Hotel & Casino in Las Vegas, Nevada from 2006 to 2010.
- DEF CON 19 and 20 were held at the Rio Hotel & Casino.
See also 
- HNS. "The Vulnerability Economy". Help Net Security. Retrieved 2008-08-27.
- Zetter, Kim (3 August 2007). "Dateline Mole Allegedly at DefCon with Hidden Camera -- Updated: Mole Caught on Tape". Wired Blog Network. Retrieved 2007-08-15. "According to DefCon staff, Madigan had told someone she wanted to out an undercover federal agent at DefCon. That person in turn warned DefCon about Madigan’s plans. Federal law enforcement agents from FBI, DoD, United States Postal Inspection Service and other agencies regularly attend DefCon to gather intelligence on the latest techniques of hackers."
- "DEFCON 15 FAQ's". Retrieved 9 Feb 2011. "Lots of people come to DEFCON and are doing their job; security professionals, federal agents, and the press."
- Jeff Moss (July 30, 2007). The Story of DEFCON. http://www.youtube.com/watch?v=lg6bQMTjHCE. Retrieved 9 Feb 2011.
- Winn Schwartau. "Cyber Christ Meets Lady Luck" (PDF). Retrieved 9 Feb 2011.
- Lamos, Rob (31 July 2005). "Exploit writers team up to target Cisco routers". Security Focus. Retrieved 2004-07-31.
- Cassel, David (4 August 2007). "Transcript: Michelle Madigan's run from Defcon". Tech.Blorge.com. Retrieved 2007-08-15.
- Lundin, Leigh (2008-08-17). "Dangerous Ideas". MBTA v DefCon 16. Criminal Brief. Retrieved 2010-10-07.
- Jeschke, Rebecca (2008-08-09). "MIT Students Gagged by Federal Court Judge". Press Room. Las Vegas: EFF.
- Massachusetts Bay Transit Authority v. Zack Anderson, RJ Ryan, Alessandro Chiesa, and the Massachusetts Institute of Technology (United States District Court District of Massachusetts). Text
- "Race to Zero". Contest concept.
- McMillan, Robert (April 2008). "Security Vendors Slam Defcon Virus Contest". IDG News Service.
- "Legal Threat Pushes Former HBGary Federal CEO Out Of DEFCON". Business Security. Retrieved 8/10/2011.
- "Defcon’s NinjaTel cell network could solve real-world problems". Retrieved 2012-08-02.
- CoffeeWars: 2007 Official contest