XKeyscore is a classified 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, Germany's Bundesnachrichtendienst, and the Danish Defense Intelligence Service, the latter of which proceeded to use it to spy on the UK, Germany, and other key allies for the US.