文摘
According to the rule of activity of most users, we introduce LSA by using the historical data. For the attack, we give out two methods to preserve user’s privacy. We divide the regions in the map into different PLs according to the privacy requirement. We design algorithm to make the regions of high level to be dummies at a high rate and the regions of low level at a low rate. The problem that the attacker can violate the privacy of a particular region by analyzing the historical data is solved. We analyze the ability to preserve user’s privacy by entropy. The internal relation among the frequency of user’s LBS query, the division of regions in the map, and the length of the interval of historical information collected is discussed.