Online anonymity: impossible after four phone calls
INDIVIDUAL human movement patterns mean 95pc of people can be identified from information about just four interactions with mobile networks, researchers have found.
Writing in Nature, an international team led by researchers from the Massachusetts Institue of Technology found that data derived from mobile phone networks, using just the location of radio masts, could identify the vast majority of people from just four pieces of information.
The discovery raises questions over the increasing use by businesses and government agencies of supposedly anonymous data.
A simply anonymized dataset does not contain name, home address, phone number or other obvious identifier, the researchers observed. “Yet, if individual's patterns are unique enough, outside information can be used to link the data back to an individual.”
The study examined data collected over 15 months from1.5million people. It found that “human mobility traces are highly unique”.
“A list of potentially sensitive professional and personal information that could be inferred about an individual knowing only his mobility trace was published recently by the Electronic Frontier Foundation,” the authors said. “These include the movements of a competitor sales force, attendance of a particular church or an individual's presence in a motel or at an abortion clinic.”
“All together,” the paper continues, “the ubiquity of mobility datasets, the uniqueness of human traces, and the information that can be inferred from them highlight the importance of understanding the privacy bounds of human mobility.”
Artificial efforts to coarsen the data were found to have relatively little effect, the researchers wrote.
“Modern information technologies such as the internet and mobile phones, however, magnify the uniqueness of individuals, further enhancing the traditional challenges to privacy. Mobility data is among the most sensitive data currently being collected,” they said.
Jane Frost, chief executive of the market research society, said “The ability to cross social data and deanonymise it is worrying because we haven’t had an open conversation about it.”
She added, however, “A lot of this data is still siloed. The problem is there is no way there for consumers to own this data effectively and to tie it in with their right to be forgotten. People are requesting data privacy more and more but I think there is a time when data will suddenly be out there and people will be very surprised by it. This is the next horsemeat scandal.”