XKeyscore is a secret computer system used by the United States National Security Agency (NSA) for searching and analyzing global Internet data, which it collects in real time. The NSA has shared XKeyscore with other intelligence agencies, including the Australian Signals Directorate, Canada's Communications Security Establishment, New Zealand's Government Communications Security Bureau, Britain's Government Communications Headquarters, Japan's Defense Intelligence Headquarters, and Germany's Bundesnachrichtendienst.
Slide from a 2008 NSA presentation about XKeyscore, showing the query hierarchy
Slide from a 2008 NSA presentation about XKeyscore, showing the differences between the various NSA database systems
The National Security Agency (NSA) is an intelligence agency of the United States Department of Defense, under the authority of the Director of National Intelligence (DNI). The NSA is responsible for global monitoring, collection, and processing of information and data for foreign and domestic intelligence and counterintelligence purposes, specializing in a discipline known as signals intelligence (SIGINT). The NSA is also tasked with the protection of U.S. communications networks and information systems. The NSA relies on a variety of measures to accomplish its mission, the majority of which are clandestine. The NSA has roughly 32,000 employees.
NSA headquarters in Fort Meade, Maryland, c. 1986
Black Chamber cryptanalytic work sheet for solving Japanese diplomatic cipher, 1919
Protesters against NSA data mining in Berlin wearing Chelsea Manning and Edward Snowden masks
Intercepted packages are opened carefully by NSA employees