The National Security Agency (NSA), the Department of Defense and the FBI were among the spy, military and police agencies represented at DefCon, an international gathering of hackers in Las Vegas.
Hackers and computer security professionals made up the bulk of the more than 6,000 people that took part in the three-day conference which ended Sunday, according to founder Jeff "Dark Tangent" Moss.
Games, contests and seminars at DefCon are devoted to breaching computers, Internet websites, software programs and real-world locks.
Throughout the event money is raised for the Electronic Freedom Foundation, a non-profit legal group that defends online rights and privacy cherished by hackers.
Lawyers from the foundation are spearheading litigation accusing the NSA of illegally snooping on e-mail and telephone communications.
NSA vulnerability analysis chief Tony Sager gave a talk at DefCon, saying the agency was increasingly sharing information with the public in the hope computer wizards wherever they may be become allies in cyber security.
"I'm not sure I can convince them to trust me," Sager told AFP.
"I think we are part of a larger community. In the old days it was about what we found was really precious, because what we had was all there was. Now, it's less important what we find and more important what everybody finds."
It takes the brightest technical minds to fight new-age crime and terrorism, and those people shun government paychecks for "big bucks" in private sector jobs, according to federal agents at DefCon. ...
Federal agents at DefCon said their technology "wish list" includes being able to identify who is responsible for what on the Internet.
"The NSA spent decades trying to do things themselves and that didn't work," (Hacker Roger) Dingledine said. "I'm happy they realize other people can help. I think they know better than to show up and say 'Trust us, we're the NSA'."
Sager said he is not sure how to resolve the conflict between public safety and Internet privacy.
"People don't come to the NSA because they want to fly black helicopters and deny people their liberties," Sager said.
"We happen to be in a time that is very volatile -- the whole issue around the war on terrorism and the loss of personal information. I'm not sure there is a logical path right now that will satisfy the majority of the population."