树索引数据差分隐私预算分配方法

Differential privacy budget allocation method for data of tree index

树索引空间数据进行差分隐私保护时需要产生噪声,针对现有差分隐私预算采取均匀分配方式,普通用户无法个性化选择的问题,提出等差数列分配法和等比数列分配法两种分配隐私预算策略。首先,利用树结构索引空间数据;然后,用户根据隐私保护度的需要和查询精确度的需要,个性化设置相邻两层分配的隐私预算的差值或比值,动态调整隐私预算;最后,隐私预算分配给树的每一层,实现了个性化按需分配方式。理论分析和实验结果表明,与均匀分配方式相比,这两种方法分配隐私预算更加灵活,且等比数列分配法优于等差数列分配法。

Noise is required in differential privacy protection for spatial data with tree index. Most of the existing differential privacy budget methods adopt uniform allocation, and ordinary users can not personalize their choice. To solve this problem, an arithmetic sequence privacy budget allocation method and a geometric sequence privacy budget allocation method were proposed. Firstly, the spatial data was indexed by tree structure. Secondly, users could personalize the difference or ratio of privacy budgets assigned by two adjacent layers to dynamically adjust the privacy budget according to the needs of privacy protection and query accuracy. Finally, the privacy budget was allocated to each layer of tree to realize personalized and on-demand allocation. Theoretical analysis and experimental results show that these two methods are more flexible in the allocation of privacy budget than the uniform allocation method, and the geometric sequence allocation method is better than the arithmetic sequence allocation method.