On January 30, a team of scientists claimed in the published paper on the American journal of Science that they can basically make clear of all consumption records of a cardholder if 4 set of relatively accurate payment time, name of business and transaction amount are provided, with an accuracy rate of 90%. Researchers analyzed a data set containing the anonymous credit card consumption information of 1.1 million people in 10000 merchants. Only by comparing space, time and consumption ability, they are capable of linking some consumption record with a certain user ID. The paper's first author had already published a similar paper with his colleagues in 2013. In that paper, they pointed out that with 4 locations and corresponding time of the same cell phone, they are able to position a user with 95% rate of accuracy. These studies show that in the "age of big data," to protect individual privacy is becoming increasingly difficult.endprint