
Heterogeneous Graph Neural Network for
Privacy-Preserving Recommendation
Yuecen Wei†‡, Xingcheng Fu§¶, Qingyun Sun§¶, Hao Peng§, Jia Wuk, Jinyan Wang∗†‡ and Xianxian Li∗†‡
†Guangxi Key Lab of Multi-source Information Mining & Security, Guangxi Normal University, Guilin, China
‡School of Computer Science and Engineering, Guangxi Normal University, Guilin, China
§Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing, China
¶School of Computer Science and Engineering, Beihang University, Beijing, China
kSchool of Computing, Macquarie University, Sydney, Australia
Email: weiyc@stu.gxnu.edu.cn, {fuxc,sunqy,penghao}@act.buaa.edu.cn,
jia.wu@mq.edu.au, {wangjy612,lixx}@gxnu.edu.cn
Abstract—Social networks are considered to be heterogeneous
graph neural networks (HGNNs) with deep learning technological
advances. HGNNs, compared to homogeneous data, absorb vari-
ous aspects of information about individuals in the training stage.
That means more information has been covered in the learning
result, especially sensitive information. However, the privacy-
preserving methods on homogeneous graphs only preserve the
same type of node attributes or relationships, which cannot
effectively work on heterogeneous graphs due to the complexity.
To address this issue, we propose a novel heterogeneous graph
neural network privacy-preserving method based on a differential
privacy mechanism named HeteDP, which provides a double
guarantee on graph features and topology. In particular, we
first define a new attack scheme to reveal privacy leakage
in the heterogeneous graphs. Specifically, we design a two-
stage pipeline framework, which includes the privacy-preserving
feature encoder and the heterogeneous link reconstructor with
gradients perturbation based on differential privacy to tolerate
data diversity and against the attack. To better control the
noise and promote model performance, we utilize a bi-level
optimization pattern to allocate a suitable privacy budget for the
above two modules. Our experiments on four public benchmarks
show that the HeteDP method is equipped to resist heterogeneous
graph privacy leakage with admirable model generalization.
Index Terms—privacy-preserving, recommendation, differen-
tial privacy, heterogeneous graph
I. INTRODUCTION
The heterogeneous graph is an extraordinary information
network, which consists of multiple node types and multiple
relation types [1]. Social relations are one of the networks
that are most complex and closest to people’s lives. According
to their interactions and inter-dependencies, recommendation
predicts the products the user will purchase while inferring
the user’s implicit tendency [2], [3]. Therefore, heterogeneous
information networks (HINs) [4] are widely used in recom-
mender systems due to their enriched heterogeneous data. For
example, in movie recommendation, entities have not only
users and movies but also stores, and the relationship has
collections in addition to purchases [5], etc. For adapting
the non-Euclidean structure of HINs, existing works leverage
high-level information [6]–[10] by other platforms sharing
∗Corresponding author.
Fig. 1. An example of privacy risk from a homogeneous graph to a
heterogeneous. Change (1) represents general privacy-preserving measures
for nodes on the homogeneous graph. Change (2) indicates that the former
method has a poor protection effect on heterogeneous graphs because more
node types are considered.
(e.g., logging in with a third-party account) [11]–[14] or
semantic-level information from multiple entities [1], [15],
[16]. In this way, these works always fuse the social network
data and other side information of the users and items as a
unified heterogeneous graph to improve model performance.
However, while HINs boost recommendation capabilities, they
also bring an additional risk of privacy leakage.
Graph neural networks (GNNs) are widely used to im-
plement heterogeneous graph learning and achieve remark-
able results, as a popular and powerful graph representation
model [17]–[21], such as recommended systems [22]–[25].
However, most existing works focus on how to improve the
representational power of graphs and ignore the security issues
of sensitive information in graph data. For user privacy, some
non-Euclidean data may more intuitively discover the relation-
ships between users and some sensitive information [26], such
as social relationships [13], behavioral trajectories [27]–[29],
and medical records. While people benefit from the conve-
nience of the recommendation, they are faced with recorded
behavior data and learned and used all aspects of information
that would bring a series of privacy leakage risks. In the real
social world, some malicious people can obtain individuals’
sensitive characteristics from enriching recommendations [5],
such as identification and phone number, address, and even
social relationships. The privacy leakage risk of this hetero-
geneous information is reflected in both feature and topology
levels.
Recently, to address privacy problems in graph data, some
arXiv:2210.00538v2 [cs.LG] 9 Oct 2022