基于云原生数据库的许多应用场景需要处理海量的数据流.为了实时分析数据流中的群体趋势信息而又不泄露单个用户的隐私,这些应用需要在每个时刻都可以为数据流中的最近数据集快速创建可以安全发布的差分隐私直方图.然而,现有的直方图发布方法因缺乏高效数据结构,导致无法快速提取关键信息以确保数据的实时可用性.为解决此问题,深入分析数据采样与隐私保护之间的关系,提出基于采样的数据流差分隐私快速发布算法SPF(sampling based fast publishing algorithm with differential privacy for data stream).SPF首创高效数据流采样草图结构(efficient data stream sampling sketch structure,EDS),EDS对滑动窗口内数据进行采样统计估计,并过滤不合理数据,实现了对关键信息的快速提取.然后,证明EDS结构输出的近似值理论上等效于对真实值添加差分隐私噪声.最后,为了满足用户所提供的隐私保护强度,并且避免正确反映原始数据流的真实情况,提出了一种基于高效数据流采样的自适应加噪算法.根据用户的隐私保护强度和EDS结构所提供的隐私保护强度之间的关系,通过隐私分配的方式自适应生成最终可发布直方图.实验证明,相较于现有算法,SPF在保持相同数据可用性的前提下显著降低了时间和空间开销.
Abstract
Many cloud native database applications need to handle massive data streams.To analyze group trend information in these data streams in real time without compromising individual user privacy,these applications require the capability to quickly create differentially private histograms for the most recent dataset at any given moment.However,existing histogram publishing methods lack efficient data structures,making it difficult to rapidly extract key information to ensure real-time data usability.To address this issue,we deeply analyze the relationship between data sampling and privacy protection,and propose a sampling based fast publishing algorithm with differential privacy for data stream(SPF).SPF introduces an efficient data stream sampling sketch structure(EDS)for the first time,which samples and statistically estimates data within a sliding window and filters out unreasonable data,enabling rapid extraction of key information.Then,we demonstrate that the approximations output by the EDS structure are theoretically equivalent to adding differential privacy noise to the true values.Finally,to meet the privacy protection strength provided by the user while reflecting the true situation of the original data stream,an adaptive noise addition algorithm based on efficient data stream sampling is proposed.According to the relationship between the user-provided privacy protection strength and the privacy protection strength provided by the EDS structure,the algorithm adaptively generates the final publishable histogram through privacy allocation.Experiments show that compared with existing algorithms,SPF significantly reduces time and space overhead while maintaining the same data usability.
维普
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