National Security Agency Surveillance

Much of what is known about surveillance by the National Security Agency (NSA) on telecommunications has come from classified documents leaked by former CIA employee and NSA contractor Edward Snowden. Both the CIA and the NSA focus on overseas intelligence gathering, with the CIA mainly focusing on human intelligence, and the NSA targeting signals intelligence (SIGINT). Snowden was working for Booz Allen Hamilton, a private defense contractor, in 2013 when he fled to Hong Kong and shared confidential NSA files with journalists Glenn Greenwald, Ewen MacAskill, and Laura Poitras.

Revelations that came out of the Snowden documents include a secret order by the Foreign Intelligence Surveillance Court (FISC, or FISA Court) requiring Verizon to hand over records on all telephone calls in its systems, and the ...