Freeman Spogli Institute for International Studies Program on Energy and Sustainable Development Stanford University


Publications




MetaPhone: The NSA Three-Hop

Opinion Piece/Newspaper Article

Authors
Jonathan Mayer - Stanford University
Patrick Mutchler

Published
December 9, 2013


First paragraph of the article:

MetaPhone is a crowdsourced study of phone metadata. If you own an Android smartphone, please consider participating. In an earlier post, we reported how automated analysis of call and text activity can detect private relationships.

Does the National Security Agency have court authority to pour over your phone records? Quite possibly.

According to declassified documents, the NSA operates under a rote legal procedure for querying domestic phone metadata. The agency begins by identifying a “seed” number, with reasonable and articulable suspicion of terrorist activity. Next, the NSA has discretion to follow up to three degrees of calling separation (“hops”). The NSA is authorized to retrieve a complete set of phone records at each hop, and just one call in the past five years appears sufficient to make a hop.