论文标题

贝叶斯数据综合下的全球差异隐私机制

Mechanisms for Global Differential Privacy under Bayesian Data Synthesis

论文作者

Hu, Jingchen, Williams, Matthew R., Savitsky, Terrance D.

论文摘要

本文介绍了一种新方法,该方法嵌入了用于生成合成数据并将其转换为差异私有(DP)机制的任何贝叶斯模型。我们建议对模型合成器的改动来利用[$ \ exp(-ε/ 2),\ exp(ε/ 2)$]的上限和下限的审查可能性,其中$ε$表示DP保证的级别。配备$ε-$ dp保证的这种审查机制将通过将分布变平或将分布转移到弱信息性的事先之前,从而引起关节参数后验分布的失真。为了最大程度地减少可能性检查后的后验分布中的失真,我们将矢量加权伪后验机制嵌入了检查机理中。伪后验是通过选择性地减小每个可能性贡献与其披露风险成比例的贡献来提出的。伪后机制本身会产生渐近差异隐私(ADP)保证的弱。嵌入了审查机制后,DP保证变得严格,因此不依赖渐近药。我们证明,伪后验机制以较弱的ADP保证的价格创建最高效用的合成数据,同时将伪后验机制嵌入所提出的审查机制中,以较强的,非迅速的DP保证,以略有降低的实用性成本,以更强大的非空组化DP保证产生合成数据。包括扰动的直方图机理以进行比较。

This paper introduces a new method that embeds any Bayesian model used to generate synthetic data and converts it into a differentially private (DP) mechanism. We propose an alteration of the model synthesizer to utilize a censored likelihood that induces upper and lower bounds of [$\exp(-ε/ 2), \exp(ε/ 2)$], where $ε$ denotes the level of the DP guarantee. This censoring mechanism equipped with an $ε-$DP guarantee will induce distortion into the joint parameter posterior distribution by flattening or shifting the distribution towards a weakly informative prior. To minimize the distortion in the posterior distribution induced by likelihood censoring, we embed a vector-weighted pseudo posterior mechanism within the censoring mechanism. The pseudo posterior is formulated by selectively downweighting each likelihood contribution proportionally to its disclosure risk. On its own, the pseudo posterior mechanism produces a weaker asymptotic differential privacy (aDP) guarantee. After embedding in the censoring mechanism, the DP guarantee becomes strict such that it does not rely on asymptotics. We demonstrate that the pseudo posterior mechanism creates synthetic data with the highest utility at the price of a weaker, aDP guarantee, while embedding the pseudo posterior mechanism in the proposed censoring mechanism produces synthetic data with a stronger, non-asymptotic DP guarantee at the cost of slightly reduced utility. The perturbed histogram mechanism is included for comparison.

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