Learning with graphs has attracted significant attention recently. Existing
representation learning methods on graphs have achieved state-of-the-art
performance on various graph-related tasks such as node classification, link
prediction, etc. However, we observe that these methods could leak serious
private information. For instance, one can accurately infer the links (or node
identity) in a graph from a node classifier (or link predictor) trained on the
learnt node representations by existing methods. To address the issue, we
propose a privacy-preserving representation learning framework on graphs from
the emph{mutual information} perspective. Specifically, our framework includes
a primary learning task and a privacy protection task, and we consider node
classification and link prediction as the two tasks of interest. Our goal is to
learn node representations such that they can be used to achieve high
performance for the primary learning task, while obtaining performance for the
privacy protection task close to random guessing. We formally formulate our
goal via mutual information objectives. However, it is intractable to compute
mutual information in practice. Then, we derive tractable variational bounds
for the mutual information terms, where each bound can be parameterized via a
neural network. Next, we train these parameterized neural networks to
approximate the true mutual information and learn privacy-preserving node
representations. We finally evaluate our framework on various graph datasets.

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