The NSA Can Track Who Our Friends Are, and Much More

Photo: Paul J. RichardsPAUL J. RICHARDS/AFP/Getty Images2006 AFP

In the latest revelation from Edward Snowden's not-so-secret-anymore NSA files, the New York Times on Saturday reported new details on how the agency uses the metadata we already knew it collected to map out people's social circles and activities, whether they're American or not. While the agency isn't supposed to listen in on the phone calls nor read the e-mails of Americans, it can analyze the information about the locations, time, and participants in calls and e-mails. And analyze it does! A 2011 memo outlined the policy shift that allowed the agency to track data connections that included U.S. citizens, who had previously been off-limits. "The agency was authorized to conduct 'large-scale graph analysis on very large sets of communications metadata without having to check foreignness' of every e-mail address, phone number or other identifier, the document said."

The tool the agency uses to analyze this data even has a catchy code name: Mainway. And Mainway is hard at work, the Times reports:

An internal N.S.A. bulletin, for example, noted that in 2011 Mainway was taking in 700 million phone records per day. In August 2011, it began receiving an additional 1.1 billion cellphone records daily from an unnamed American service provider under Section 702 of the 2008 FISA Amendments Act, which allows for the collection of the data of Americans if at least one end of the communication is believed to be foreign.

So just what kind of information can the agency glean from this kind of large-scale metadata analysis? Conveniently, Ars Technica explored that very question on Friday, with help from a declaration filed on behalf of the ACLU by Princeton computer science professor Edward Felten:

The metadata gets more powerful as you collect it in bulk. For instance, showing a call to a bookie means a surveillance target probably made a bet. But "analysis of metadata over time could reveal that the target has a gambling problem, particularly if the call records also reveal a number of calls made to payday loan services."

NSA analysts still have to provide a foreign intelligence justification if they want to trace the contacts of Americans, the Times notes: "That could include anything from ties to terrorism, weapons proliferation, international drug smuggling or espionage to conversations with a foreign diplomat or a political figure."

It's not totally clear exactly what data the NSA is analyzing. Agency head General Keith Alexander this week avoided questions over whether the agency was using cell-phone location data. But one of the new documents showed it was using queries that established people's relationships to one another, such as "travelsWith, hasFather, sentForumMessage, employs," the Times reports. Sounds a bit like a top-secret Facebook for spies.