PRISM is a clandestine program launched in 2007, under which the National Security Agency (NSA) collects internet communications of foreign nationals from at least nine major US internet companies.
PRISM is a government code name for a data-collection effort known officially by the SIGAD US-984XN. The Prism program collects stored Internet communications based on demands made to Internet companies such as Google Inc. under Section 702 of the FISA Amendments Act of 2008 to turn over any data that match court-approved search terms. The NSA can use these Prism requests to target communications that were encrypted when they traveled across the Internet backbone, to focus on stored data that telecommunication filtering systems discarded earlier, and to get data that is easier to handle, among other things.
It is a SIGAD operated under the supervision of the United States Foreign Intelligence Surveillance Court pursuant to the Foreign Intelligence Surveillance Act (FISA).
The existence of the program was leaked by NSA contractor Edward Snowden and published by The Guardian and The Washington Post on June 6, 2013.