满足本地化差分隐私的众包位置数据采集

针对位置数据众包采集中个人位置隐私泄露的问题，提出了一种满足本地化差分隐私的位置数据众包采集方法。首先，使用逐点插入法构造维诺图，对路网空间进行分割；然后，采用满足本地化差分隐私的随机扰动的方式对每个维诺格中的位置数据进行扰动；再次，设计了一种在扰动数据集上进行空间范围查询的方法，获得对真实结果的无偏估计；最后，在空间范围查询下进行了实验验证，并与保护隐私的轨迹数据采集（PTDC）算法进行了对比，算法查询误差率最坏不超过40%，最好情况在20%以下，运行时间在8 s以内，在隐私保护度高于PTDC算法的前提下，上述参数优于PTDC算法。

Crowdsourcing location data collection for local differential privacy

To solve the problem of privacy leakage in crowdsourced location data collection, a locally differentially private location data collection method with crowdsourcing was proposed. Firstly, a Voronoi diagram constructed by point-by-point insertion method was used to partition the road network space. Secondly, a random disturbance satisfying local differential privacy was used to disturb the original location data in each Voronoi grid. Thirdly, a designed spatial range query method was applied to noisy datasets to get the unbiased estimation of the actual result. Finally, experiments were carried out on spatial range queries to compare the proposed algorithm with PTDC (Privacy-preserving Trajectory Data Collection) algorithm. The results show that the query error rate is no more than 40%, and less than 20%in the best situation, and the running time is less than 8 seconds, which are better than those of PTDC algorithm while the proposed method has a higher degree of privacy preserving.