Yes, military. Let us not forget that the National Security Agency is a branch of the U.S. military.
You’ve already learned, thanks to the revelation by the Washington Post today, that the most massively armed military on the planet has been collecting tracking information on the whereabouts of hundreds of millions of innocent people, day after day after day, by hijacking their cell phone location data.
The program is called CO-TRAVELER. Why?
An academic paper I stumbled over a few days ago in the Proceedings of the National Academy of Sciences provides a clue. David Crandall and a number of co-authors (2010) report success in in determining which Flickr users have personal relationships with one another by simply looking for pairs of accounts whose photographs occur at the same time and place over and over again. The insight of “geographic homophily” from network sociology explains why this works: ties form among people who are proximate to one another in space, and proximity is also a consequence of preexisting ties.
Imagine the same trick, but instead of photographs, geocodes and time-stamps are provided by cell phones.
Imagine data like this (binary data in which 1 means that a person can be tracked to a particular location at a particular time, and in which 0 means that the person cannot be tracked to a particular location at a particular time):
|Tracking||Location 1||Location 2||Location 3||Location 4||Location 5|
That data can be converted (thanks to a matrix manipulation identified by sociologist Ronald Brieger in 1974) into information describing the overlap between two people in place and time. In the processed matrix below, the number in each cell represents the number of times and places in which two people’s locations overlap:
|Overlap||Person 1||Person 2||Person 3||Person 4||Person 5||Person X|
Who in the above table is most likely to have a social connection to Person X? Person 3, because Person 3 has the most overlaps in time and place with Person X.
Now imagine that the most powerful military in the world has decided to run this kind of analysis to find all the people who are most likely to have a social connection with Person X. Perhaps Person X is a suspected terrorist. Perhaps Person X is a suspected criminal. Perhaps Person X is a person who has been identified in previous surveillance as possibly being a person who knows a suspected terrorist or criminal. Perhaps Person X just says things that the National Security Agency doesn’t like. Using this technique, NSA military spies can track down most of Person X’s friends and add them to the list of suspicious persons to be further tracked. Without a warrant. Without probable cause.
Now imagine that this analysis can draw on a database of 5 billion phone location records scooped up every single day to carry out such an analysis.