Scientists at MIT and the Université catholique de Louvain in Belgium analyzed 15 months of mobility data for 1.5 million individuals who the same mobile carrier. Their analysis, “Unique in the Crowd: the privacy bounds of human mobility” showed that data from just four, randomly chosen “spatio-temporal points” (for example, mobile device pings to carrier antennas) was enough to uniquely identify 95% of the individuals, based on their pattern of movement. Even with just two randomly chosen points, the researchers say they could uniquely characterize around half of the 1.5 million mobile phone users. The research has profound implications for privacy, suggesting that the use of mobile devices makes it impossible to remain anonymous – even without the use of tracking software.
For their research, they studied anonymized carrier data from a “significant and representative part of the population of a small European country.” In the study, the researchers used sample data collected between April 2006 and June 2007. Each time a user interacted with their mobile phone operator network by initiating or receiving a call or a text message, the location of the connecting antenna was recorded, providing both a spatial and temporal data point.
“We show that the uniqueness of human mobility traces is high, thereby emphasizing the importance of the idiosyncrasy of human movements for individual privacy,” the researchers write. Given the amount of information that can be inferred from mobility data, as well as the potentially large number of simply anonymized mobility datasets available, this is a growing concern.”"