In a move that legal experts said could present a major test of First Amendment rights in the Internet era, a federal judge in San Francisco on Friday ordered the disabling of a Web site devoted to disclosing confidential information.

The site, Wikileaks.org, invites people to post leaked materials with the goal of discouraging “unethical behavior” by corporations and governments. It has posted documents concerning the rules of engagement for American troops in Iraq, a military manual concerning the operation of prison at Guantánamo Bay, Cuba, and other evidence of what it has called corporate waste and wrongdoing.

The case in San Francisco was brought by a Cayman Islands bank, Julius Baer Bank and Trust. In court papers, the bank claimed that “a disgruntled ex-employee who has engaged in a harassment and terror campaign” provided stolen documents to Wikileaks in violation of a confidentiality agreement and banking laws. According to Wikileaks, “the documents allegedly reveal secret Julius Baer trust structures used for asset hiding, money laundering and tax evasion.”

On Friday, Judge Jeffrey S. White of the Federal District Court in San Francisco granted a permanent injunction ordering Dynadot of San Mateo, Calif., the site’s domain name registrar, to disable the Wikileaks.org domain name. The order had the effect of locking the front door to the Wikileaks.org site  a largely ineffectual action that kept back doors to the site, and several copies of it, available to sophisticated Web users who knew where to look.