A US court has exposed the content of the controversial FBI National Security Letters (NSLs) used to compel ISPs to hand over customer data.
The use of NSLs expanded rapidly after the introduction of the US Patriot Act following the terrorist attack on 9/11, but the exact contents have remained secret.
However, former ISP owner Nicholas Merrill has been granted permission to disclose the content of an NSL and talk about his experiences after a New York federal judge ruled that the ban against Merrill speaking was unjustified. The ruling followed an 11-year court battle with the FBI.
The letter shows that the FBI can request a long list of content about those it targets for online surveillance, including DSL account information, Internet Protocol addresses, and all billing related to account and subscriber day/evening telephone numbers.
Merrill was running a now-defunct ISP called Calyx Internet Access when he first received the letter in 2004.
US district judge Victor Marrero ruled in September that, despite protests from the FBI, there was little reason to withhold the content and the 90-day appeal period officially expired this week.
The ruling revealed that the FBI no longer requests this sort of information using the letters but still wanted to keep the details secret so as to not tip off criminals to the agency's surveillance techniques.
However, Marrero spoke out against the idea. "The government has not satisfied its burden of demonstrating a ‘good reason' to expect that disclosure of the NSL attachment in its entirety will risk an enumerated harm," he said.
"It strains credulity that future targets of other investigations would change their behaviour in light of the currently redacted information, when those targets, which, according to the government, include 'sophisticated foreign adversaries', have access to much of this same information from other government divisions and agencies."
Merrill said after the ruling: "I feel vindicated today. But there's a lot more work to be done."
Civil rights groups including the Electronic Freedom Foundation have long campaigned against the use of NSLs.
John Pistole, who was deputy director of the FBI at the time, revealed in March 2007 that the agency sent 40,000 to 60,000 NSLs a year.
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