New documents published by The Daily Beast earlier this week reveal that AT&T required this corrosive secrecy. Specifically, the contract AT&T prepared for police seeking access to Hemisphere provides:
[T]he Government agency agrees not to use the data as evidence in any judicial or administrative proceedings unless there is no other available and admissible probative evidence. The Government Agency shall make every effort to insure that information provided by the Contractor is non-attributable to AT&T if the data is provided to a third-party.In other words, the first rule of Hemisphere is: you do not talk about Hemisphere. more