Santa Clara Superior Court Judge William J. Elfving issued a preliminary injunction Friday ordering 21 defendants to stop posting code that breaks through the security software of DVDs to their Web sites.

The news came on the heels of a similar ruling in a related federal case in New York. In that case, a judge granted a preliminary injunction against three hackers sued for copyright violation by the Motion Picture Association of America.

Friday's ruling could set the tone for the course of the lawsuit filed in December by the DVD Copy Control Association against 21 named and 72 unnamed hackers and Internet authors who published DeCSS. Though the original author of the software is still in question, the program was originally made available by a 15-year-old Norwegian hacker on the Web in October.

Elfving, who declined to speak about his ruling, surprised the defense with his decision.

The defense thought his earlier ruling denying the plaintiff's request to submit T-shirts bearing the DeCSS code into evidence spelled good things for their case.

"We felt fairly confident, and clearly we were disappointed with the ruling," said Tom McGuire, spokesman from the Electronic Frontier Foundation, which is representing the defendants in this case and in two related federal cases in New York and Connecticut. "But reading between the lines, what we see is a judge trying to act very specifically following the rule of law."

In fact, McGuire, said, the ruling means nothing to the thousands of other people showing the code on their Web sites, none of whom are affected by the ruling.

The sheer scope of the job of trying to remove the code from the Internet was not lost on the judge.

"In granting this injunction this court is mindful of the many potential enforcement problems," his order reads. "However, a possibility or even likelihood that an order may be disobeyed or not enforced in other jurisdictions is not a reason to deny the relief sought."

The open source community has reacted to Friday's ruling with creative disregard. Hundreds of mirror sites posting the code have sprung up all over the Internet, and one group has gone so far as to auction off the code on eBay for $5 a pop.

Jeffrey Kessler, the plaintiff's lead attorney from Weil, Gotshal & Manges said the ruling bolsters the strength of his client's case.

"Obviously, we're delighted with the ruling," he said. "I think this vindicates what we've been saying all along, that this is a narrow case about trade secret theft."

The defense says the hackers are simply open source advocates trying to learn how to play DVDs without the Windows OS –- not about making illegal copies of DVDs.

"Piracy, we all agree, shouldn't be encouraged and allowed to flourish on the Web," said McGuire. "This isn't about piracy. It's about legally and constitutionally appropriate free speech."