The Rogue State.

"N.S.A. Gathers Data on Social Connections of U.S. Citizens."-The New York Times.

Since 2010, the National Security Agency has been exploiting its huge collections of data to create sophisticated graphs of some Americans’ social connections that can identify their associates, their locations at certain times, their traveling companions and other personal information, according to newly disclosed documents and interviews with officials.

The spy agency began allowing the analysis of phone call and e-mail logs in November 2010 to examine Americans’ networks of associations for foreign intelligence purposes after N.S.A. officials lifted restrictions on the practice, according to documents provided by Edward J. Snowden, the former N.S.A. contractor.
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The agency can augment the communications data with material from public, commercial and other sources, including bank codes, insurance information, Facebook profiles, passenger manifests, voter registration rolls and GPS location information, as well as property records and unspecified tax data, according to the documents. They do not indicate any restrictions on the use of such “enrichment” data, and several former senior Obama administration officials said the agency drew on it for both Americans and foreigners.
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Almost everything about the [NSA's] operations is hidden, and the decision to revise the limits concerning Americans was made in secret, without review by the nation’s intelligence court or any public debate.
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The agency is not required to seek warrants for the analyses from the Foreign Intelligence Surveillance Court.
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A series of agency PowerPoint presentations and memos describe how the N.S.A. has been able to develop software and other tools — one document cited a new generation of programs that “revolutionize” data collection and analysis — to unlock as many secrets about individuals as possible.
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Phone and e-mail logs, for example, allow analysts to identify people’s friends and associates, detect where they were at a certain time, acquire clues to religious or political affiliations, and pick up sensitive information like regular calls to a psychiatrist’s office, late-night messages to an extramarital partner or exchanges with a fellow plotter.

“Metadata can be very revealing,” said Orin S. Kerr, a law professor at George Washington University. “Knowing things like the number someone just dialed or the location of the person’s cellphone is going to allow them to assemble a picture of what someone is up to. It’s the digital equivalent of tailing a suspect.”

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The N.S.A. documents show that one of the main tools used for chaining phone numbers and e-mail addresses has the code name Mainway...The documents show that significant amounts of information from the United States go into Mainway. An internal N.S.A. bulletin, for example, noted that in 2011 Mainway was taking in 700 million phone records per day.