Every day, the NSA collects almost five billion records tracing the movements of hundreds of millions of cell phones from around the world, according to report in the Washington Post based on an Edward Snowden-provided classified document.

A giant database stores the information, which the NSA gathers by tapping into cables that connect cell phone networks in the U.S. and internationally. While the NSA does not target U.S. citizens, information about millions of Americans' using cell phones abroad is collected "incidentally."

"[T]here is no element of the intelligence community that under any authority is intentionally collecting bulk cellphone location information about cellphones in the United States," Robert Litt, general counsel for the Office of the Director of National Intelligence, told the Post.

The programs used by the NSA, collectively called CO-TRAVELER, analyzes the bulk data—the vast majority of which is taken from cellphones owned by people of no national security interest to the NSA— in order to discover the associates of established intelligence targets.

From the Washington Post:

Still, location data, especially when aggregated over time, is widely regarded among privacy advocates as uniquely sensitive. Sophisticated mathematical techniques enable NSA analysts to map cellphone owners' relationships by correlating their patterns of movement over time with thousands or millions of other phone users who cross their paths. Cellphones broadcast their locations even when they are not being used to place a call or send a text.

CO-TRAVELER and related tools require the methodical collection and storage of location data on what amounts to a planetary scale. The government is tracking people from afar into confidential business meetings or personal visits to medical facilities, hotel rooms, private homes and other traditionally protected spaces.

"One of the key components of location data, and why it's so sensitive, is that the laws of physics don't let you keep it private," Chris Soghoian, the principal technologist at the American Civil Liberties Union, told the Post.

Even using disposable cellphones or turning off your phone between calls triggers CO-TRAVELER, which can track when a new cellphone is activated immediately or shortly after another is disconnected.

"[T]he only way to hide your location is to disconnect from our modern communication system and live in a cave," Soghoian said.

[Image via AP]