Twelve years ago today, the wreckage of the World Trade Center was still smoldering, and among the ruins were the remains of the suicide hijackers who had brought the towers down with jets full of civilians. Everyone wanted to know everything about where these men–or future attackers like them–had been and with whom they’d met.
Cell phone location records can help. Even the cheapest phone records its general location; because all phones “ping” cellular towers as they pass by. If two phones are in the same general area, and moving between the same tower coverage areas over some time period, it becomes more likely that it’s not a coincidence. This is one way to find previously unknown accomplices.
More recently, location data from phones has emerged a potent, but largely untapped, data source for good works. When you know how millions of people are moving around and who has been in the same general area with whom, this is a great basis for figuring out how best to stop malaria and other diseases from spreading. Such data can also aid in disaster response by helping predict where masses of refugees are likely to flee, based on past travel habits (see “Big Data From Cheap Phones”).
Now come the latest revelations from the National Security Agency’s former contractor, Edward Snowden. It turns out the NSA is doing its best to regularly collect data on the locations of hundreds of millions phones around the world, according to a story today in the Washington Post. It is doing so by tapping the cables of mobile carriers, through which these location pings are apparently available in huge quantities, according to the paper.
“The NSA is gathering nearly 5 billion records a day on the whereabouts of cellphones around the world, according to top-secret documents and interviews with U.S. intelligence officials, enabling the agency to track the movements of individuals — and map their relationships — in ways that would have been previously unimaginable,” the Post writes. The paper describes this practice in tones of worry, pointing out that “location data, especially when aggregated over time, is widely regarded among privacy advocates as uniquely sensitive.”
The Snowden documents have shown lots of evidence of overreaching (see “Bruce Schneier: NSA Spying is Making Us Less Safe”). But what we don’t have, so far, is much evidence of oppressive use of the data. Of course there are very serious and legitimate privacy concerns. But it will help to acknowledge the beneficial uses of this data–for fighting terrorist plots and for stopping deadly diseases–so that we can somehow get beyond these concerns and make sure these datasets, which are already held by the carriers, can be used for the wider good.