Right now, there is a good chance your phone is tracking your location -- even with GPS services turned off. That's because, to receive service, our phones reveal personal identifiers to cell towers owned by major network operators. This has led to vast and largely unregulated data-harvesting industries based around selling users' location data to third parties without consent. For the first time, researchers have found a way to stop this privacy breach using existing cellular networks. The new system protects users' mobile privacy while providing normal mobile connectivity.