Blackfoot

Name of an operation to bug the French mission to the UN.

Blarney

See Upstream.

Boundless Informant

The National Security Agency's internal analytic tool that allows it to monitor surveillance country by country and program by program.

Bruneau (or Hemlock)

The codenames given to the Italian embassy in Washington by the NSA.

Bluf

Stands for "bottom line up front" – a request from NSA analysts to collect less data from the Muscular program (see below) because it is of no intelligence value.

Bullrun

The NSA's efforts to undermine encryption technology that protects email accounts, banking transactions and official records. The UK has a similar programme, with both codenamed after civil war battles: Bullrun for the NSA and Edgehill for GCHQ.

Cheesy Name

A GCHQ program that selects encryption keys that might be vulnerable to being cracked.

Dishfire

Database that stores text messages, for future use.

DNI (digital network information)

Data sent across computer networks, such as web page requests, emails, voice over IP. (Formally, any information sent as "packets").

DNR (dialled number records)

The metadata around phone calls, including the sending and receiving of phone numbers, call time and duration.

Dropmire

A surveillance method that involves bugging encrypted fax machines. Used to spy on the European Union embassy in New York.

Edgehill

See Bullrun.

Fisa court (Fisc)

The foreign intelligence surveillance court, a secret US court which oversees surveillance under the Fisa Act.

Fairview

See Upstream.

Five Eyes

Britain, the US, Canada, Australia and New Zealand – the club of English-speaking countries sharing intelligence.

GCHQ

Government Communications Headquarters, the UK intelligence agency focusing on signals and communications intelligence.

Genie

An NSA surveillance project to remotely implant spyware into overseas computers, including those in foreign embassies.

Humint

Short for "human intelligence", refers to information gleaned directly from sources or undercover agents. See also Sigint.

Keyhole

Code for images gathered by satellites.

Klondyke

The mission to snoop on the Greek embassy in Washington.

Mainway

The database where the NSA stores metadata of millions of phone calls for up to a year.

Marina

The database where the NSA stores metadata of millions of internet users for up to a year.

Metadata

The "envelope" of a phone call or email, which could include the time, the duration, the phone numbers or email addresses, and the location of both parties.

Muscular

Program to intercept Google and Yahoo traffic, exposed by the Washington Post.

Noforn

"Not for foreign distribution" – a classification of some of the Snowden slides.

NSA

The National Security Agency, the US agency responsible for collecting and analysing intelligence, plus cybersecurity.

Oakstar

See Upstream.

Operation Socialist

The name of a GCHQ cyber-attack on Belgium's main telecoms provider, Belgacom.

Perdido

The codename for the bugging of EU missions in New York and Washington.

Polar Breeze

A technique for tapping into nearby computers.

Powell

The operation to snoop on the Greek UN mission.

Prism

A programme to collect data from internet companies including Google, Microsoft, Facebook and Apple.

Rampart-T

Spying efforts against leaders of China, Russia and several eastern European states.

Royal Concierge

A GCHQ surveillance project to track foreign diplomats' movements by monitoring the booking systems of high‑class hotels.

Sigint

Short for "signals intelligence", or information gathered through the interception of signals between people or computers. See also Humint.

Snacks

The NSA's Social Network Analysis Collaboration Knowledge Services, which analyses social hierarchies through text messages.

Stormbrew

See Upstream.

Tempora

A GCHQ programme to create a large-scale "internet buffer", storing internet content for three days and metadata for up to 30.

Tor

Free software allowing users to communicate anonymously.

Tracfin

Database storing information from credit card transactions

Turbulence, Turmoil and Tumult

Data analysis tools used by the NSA to sift through the enormous amount of internet traffic that it sees, looking for connections to target.

Upstream

Refers to bulk-intercept programs, codenamed Fairview, Stormbrew, Oakstar and Blarney, to intercept data in huge fibre-optic communications cables.

Verizon

One of America's largest telecoms providers, from which the NSA collects the phone records (metadata) of millions of customers.

Wabash

The codename given to the bugging of the French embassy in Washington.

XKeyscore

An NSA program that allows analysts to search vast databases of emails, online chats and browsing histories of millions of individuals, with no prior authorisation.