Node-Level Differentially Private Graph Neural NetworksDownload PDF

05 Mar 2022, 09:41 (modified: 07 Apr 2022, 08:15)ICLR 2022 PAIR^2Struct OralReaders: Everyone
Keywords: differential privacy, graph neural networks, node-level privacy
TL;DR: We propose the first method to learn node-level differentially private graph neural networks.
Abstract: Graph Neural Networks (GNNs) are a popular technique for modelling graph-structured data and computing node-level representations via aggregation of information from the neighborhood of each node. However, this aggregation implies increased risk of revealing sensitive information, as a node can participate in the inference for multiple nodes. This implies that standard privacy preserving machine learning techniques, such as differentially private stochastic gradient descent (DP-SGD) - which are designed for situations where each data point participates in the inference for one point only - either do not apply, or lead to inaccurate solutions. In this work, we formally define the problem of learning GNN parameters with node-level privacy, and provide an algorithmic solution with a strong differential privacy guarantee. We employ a careful sensitivity analysis and provide a non-trivial extension of the privacy-by-amplification technique. An empirical evaluation on standard benchmarks datasets and architectures demonstrates that our method is indeed able to learn accurate privacy-preserving GNNs, while still outperforming standard non-private methods that completely ignore graph information.
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