A federal jury Tuesday acquitted a Russian software firm that was charged with digital copyright violation for creating a program that cracks the security features of Adobe Systems' electronic book software.

The case against Elcomsoft Ltd. was the most high-profile under the 1998 Digital Millennium Copyright Act, which many in the technology industry consider unduly restrictive.

If it had been convicted, Elcomsoft could have been fined $2 million, with additional penalties if intent was determined.

The young Elcomsoft programmer who developed the software, Dmitry Sklyarov, became a lightning rod for hacker rights after his arrest last year after attending a hacker convention in Las Vegas.

Sklyarov, an assistant professor at Moscow Technical University, spent several weeks in jail before the government agreed to drop charges against him in exchange for his testimony at Elcomsoft's trial.

Prosecutors had tried to prove that the Elcomsoft software was illegal because it permitted owners to print, copy or otherwise distribute copyright material, encouraging piracy.

Prosecutor Scott H. Frewing told jurors that the Russians "were selling a burglar tool for software to make a profit." He quickly left the courtroom after the verdict and had no immediate comment.

The defense argued that the program merely enabled owners of Adobe eBook Reader software to make copies of e-books for personal use. If an owner makes a backup copy of an e-book or transfers it to another device he owns, they argued, that is permitted under the "fair use" concept of copyright law.

Jury foreman Dennis Strader said the argument made a big impact on the jurors, who asked U.S. District Judge Ronald M. Whyte to clarify the "fair use" definition shortly after deliberations began.

"Under the eBook formats, you have no rights at all, and the jury had trouble with that concept," said Strader.

The copyright act under which Elcomsoft was tried prohibits the production and distribution of any product that circumvents security features of digital media.

Defense attorney Joe Burton said the government failed to prove Elcomsoft intended to violate the law, but predicted more prosecutions.

"I don't see it as throwing a blanket on DMCA," Burton said, referring to the Digital Millennium Copyright Act. "It will take another case to test that."

Elcomsoft president Alex Katalov said the program is no longer being sold in Russia or anywhere else.