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Differentially Private Variational Inference for Non-conjugate Models
Proceedings of the 33rd Conference on Uncertainty in Artificial Intelligence, PMLR R15:291-300, 2017.
Abstract
Many machine learning applications are based on data collected from people, such as their tastes and behaviour as well as biological traits and genetic data. Regardless of how impor- tant the application might be, one has to make sure individuals’ identities or the privacy of the data are not compromised in the analy- sis. Differential privacy constitutes a power- ful framework that prevents breaching of data subject privacy from the output of a com- putation. Differentially private versions of many important Bayesian inference methods have been proposed, but there is a lack of an efficient unified approach applicable to arbi- trary models. In this contribution, we pro- pose a differentially private variational infer- ence method with a very wide applicability. It is built on top of doubly stochastic varia- tional inference, a recent advance which pro- vides a variational solution to a large class of models. We add differential privacy into dou- bly stochastic variational inference by clipping and perturbing the gradients. The algorithm is made more efficient through privacy amplifi- cation from subsampling. We demonstrate the method can reach an accuracy close to non- private level under reasonably strong privacy guarantees, clearly improving over previous sampling-based alternatives especially in the strong privacy regime. $*$AH is also with the Department of Mathematics and Statistics and Department of Public Health, University of Helsinki.