The Electronic Frontier Foundation (EFF) is representing some unnamed communications companies in their fight against national security requests that are so secure that they cannot be discussed in any detail at all.
The requests are so-called National Security Letters (NSLs) and are part of the arrangement between technology firms and the government agencies that seek information on users.
The EFF went to court on behalf of the comms organisations this week. During the hearing, a Justice Department lawyer argued that the government would lose "an extremely useful tool" if the court upholds the ban on NSLs, according to The Intercept.
But one of the judges queried the current setup. "It leaves it to the poor person who is subject to those requirements to just constantly petition the government to get rid of it," said judge N Randy Smith.
NSLs are issued as part of counter-terrorism investigations, and their issuing and demands are kept private. This means that firms cannot count them in their transparency reports and data disclosures, which has proved contentious.
The EFF court papers argue that the FBI should be able to get the information in a more transparent manner, and with some sort of judicial oversight.
"The statutes governing NSLs empower the FBI, without prior judicial authorisation, to demand customer records directly from internet and telecommunication providers and to issue permanent gag orders that prevent the recipients from disclosing anything about the government's demand," read the EFF's filed papers.
Oral arguments have also been released online by the courts, in which the FBI, the Department of Justice and the EFF make their cases.
The details of the communications companies in this case are sealed, but there are some vocal opponents in the industry.
Last year Twitter, Google, Microsoft and Facebook said that they wanted the right to disclose more information about the data requests that came their way.
This insistence, which followed Edward Snowden's revelations, has carried on, and this week Twitter began proceedings to sue the US government.
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