Though black clothing still dominated and clusters of hackers exchanging information was still the norm, the crowd at this year's Def Con was older and appeared to be far more professional.
"It is more laid back this year," acknowledged Jeff Moss, the founder of the conference, now in its ninth year. "It is more a reflection of what is going on in the hacking community."
While the hacking counterculture was still in attendance, its members seemed in the minority at the gathering of 4,500-plus people. Professional security consultants made up a large percentage, and law-enforcement and military officers padded out the majority.
"It is becoming more white-hattish," Moss confirmed, referring to the practice of denoting malicious hackers as "black hats" and security-conscious hackers as "white hats."
Part of the change in the crowd has occurred because computer security is no longer an esoteric subject protected by a technological priesthood. Security has gone mainstream, and Def Con has become the No 1 way to meet others interested in the topic.
"If you wanted to learn something, you needed a mentor," said Moss, who used to be known as Dark Tangent. "Now there are a million books on security and a lot of sites on how to hack."
As the crowd has matured, so have many of the hacking groups.
Even the Cult of the Dead Cow, whose antics at past Def Cons have made headlines, played it straight this year, with a panel discussion on hacktivism and how hackers can help fight for human rights.
Originally, the cDc intended to announce an application, known as Peekabooty, that would create the foundation for an anonymous information-swapping network to help human-rights activists. Peekabooty combines the Internet's distributed file-sharing abilities--similar to those made famous by Napster--with technology to hide the source of data traveling around the network. The program is delayed because of unresolved technical problems.
"The cDc has done a lot of thinking about what (human-rights activists) can do to protect ourselves," said Patrick Ball, deputy director of the Science and Human Rights Program at the American Association for the Advancement of Science. "We have a tremendous need for a program that can do what (the cDc is) aiming to do."
Others at the conference seemed more intent on exchanging Divx copies of movies and grabbing archives of MP3 music.
In one corner of the main hall, 18-year-old Sean Horan set up a server--mounted directly into an old Samsonite suitcase--that offered more than 30GB of MP3 music and 25GB of movies compressed into Divx format.
Anyone who wanted access could ask him for an account on the computer, good through the end of the conference.
Although at the moment downloading a Divx movie--each is compressed to about 1.5GB--would take too long to be viable over even a cable or DSL connection, Horan said the movie industry should be worried.
"If Divx pisses them off, I am happy for it," he said.
Collections of other hackers, many of whom wore the proverbial white hat, were running off copies of Divx movies on recordable CDs.
Not all copying should be considered illegal, Horan said. "There are legitimate uses of compressed formats, like Divx, that (DVD encryption) technology makes impossible to use."
Of course, such encryption technology's nothing that even a newbie hacker can't get around.