The annual Def Con hacking convention has asked the federal government to stay away this year for the first time in its 21-year history, saying Edward Snowden's revelations have made some in the community uncomfortable about having feds there.

"It would be best for everyone involved if the feds call a 'time-out' and not attend Def Con this year," Def Con founder Jeff Moss said in an announcement posted on Wednesday night on the convention's website.

An irreverent crowd of more than 15,000 hackers, researchers, corporate security experts, privacy advocates, artists and others are expected to attend the Las Vegas convention that begins on Aug 2.

Moss, who is an adviser on cybersecurity to the Department of Homeland Security, told Reuters that it was "a tough call", but that he believed the Def Con community needs time to make sense of the recent revelations about US surveillance programs.

Tension defusing

"The community is digesting things that the feds have had a decade to understand and come to terms with," said Moss, who is known as The Dark Tangent in hacking circles. "A little bit of time and distance can be a healthy thing, especially when emotions are running high."

He said that the move was not designed to create tension, but to defuse it. "We are not going on a witch hunt or checking IDs and kicking people out," he said.

In previous years the conference has attracted officials from federal agencies including the CIA, National Security Agency, FBI, Secret Service and all branches of the military.

Last year, four-star General Keith Alexander, head of the National Security Agency, was a keynote speaker at the event, which is the world's largest annual hacking conference.

The audience was respectful, gave modest applause and also asked about secret government snooping. Alexander adamantly denied that the NSA has dossiers on millions of US citizens, as some former employees had suggested before the Snowden case.

"The people who would say we are doing that should know better," Alexander said. "That is absolute nonsense."

Alexander is scheduled to speak in Las Vegas on July 31 at Black Hat, a smaller, two-day hacking conference that was also founded by Moss. It costs about $2,000 to attend and attracts a more corporate crowd than Def Con, which charges $180.

Moss said that he believes Alexander will still speak at Black Hat and that his call for a "time out" only applies to Def Con. Officials with the National Security Agency and Department of Homeland Security could not be reached for comment late on Wednesday.

The feds have previously always been welcome at the event.

Moss says he invited them the first year because he figured they would come anyway. They politely declined, then showed up incognito, he said. And they have attended every year since.

"We created an environment where the feds felt they could come and it wasn't hostile," Moss said in an interview a year ago. "We could ask them questions, and they wanted to ask the hackers about new techniques."

Some feds have even worked among the motley crew of Def Con volunteers who run the conference and walk around wearing T-Shirts that identify them as "goons".

Reuters