The sheer quantity of communications that XKEYSCORE processes, filters and queries is stunning. Around the world, when a person gets online to do anything — write an email, post to a social network, browse the web or play a video game — there’s a decent chance that the Internet traffic her device sends and receives is getting collected and processed by one of XKEYSCORE’s hundreds of servers scattered across the globe.
In order to make sense of such a massive and steady flow of information, analysts working for the National Security Agency, as well as partner spy agencies, have written thousands of snippets of code to detect different types of traffic and extract useful information from each type, according to documents dating up to 2013. For example, the system automatically detects if a given piece of traffic is an email. If it is, the system tags if it’s from Yahoo or Gmail, if it contains an airline itinerary, if it’s encrypted with PGP, or if the sender’s language is set to Arabic, along with myriad other details.
This global Internet surveillance network is powered by a somewhat clunky piece of software running on clusters of Linux servers. Analysts access XKEYSCORE’s web interface to search its wealth of private information, similar to how ordinary people can search Google for public information.
Based on documents provided by NSA whistleblower Edward Snowden, The Intercept is shedding light on the inner workings of XKEYSCORE, one of the most extensive programs of mass surveillance in human history.