PrivGNN: High-Performance Secure Inference for Cryptographic Graph Neural Networks
Fuyi Wang, Zekai Chen, Mingyuan Fan, Jianying Zhou, Lei Pan, Leo Yu Zhang
TL;DR
PrivGNN tackles the challenge of privacy-preserving graph neural network inference in cloud settings by introducing a lightweight offline–online 2PC framework that leverages additive secret sharing and function secret sharing. It provides secure building blocks for matrix multiplication, polynomial evaluations, and nonlinear activations (DReLU, piecewise polynomials) and integrates them into a cohesive MP-NN workflow with three secure components (PrivMF, PrivUF, PrivRF). Theoretical security is established under a semi-honest model via sequential composition, and extensive experiments on MNIST, CIFAR, CIFAR-100, and QM9 demonstrate substantial online speedups (up to 1.2×–73.6× faster) with accuracy close to plaintext baselines. The results indicate PrivGNN’s practical potential for secure, scalable graph-centric services in domains such as drug discovery, where protecting graph structure, features, and model weights is critical.
Abstract
Graph neural networks (GNNs) are powerful tools for analyzing and learning from graph-structured (GS) data, facilitating a wide range of services. Deploying such services in privacy-critical cloud environments necessitates the development of secure inference (SI) protocols that safeguard sensitive GS data. However, existing SI solutions largely focus on convolutional models for image and text data, leaving the challenge of securing GNNs and GS data relatively underexplored. In this work, we design, implement, and evaluate $\sysname$, a lightweight cryptographic scheme for graph-centric inference in the cloud. By hybridizing additive and function secret sharings within secure two-party computation (2PC), $\sysname$ is carefully designed based on a series of novel 2PC interactive protocols that achieve $1.5\times \sim 1.7\times$ speedups for linear layers and $2\times \sim 15\times$ for non-linear layers over state-of-the-art (SotA) solutions. A thorough theoretical analysis is provided to prove $\sysname$'s correctness, security, and lightweight nature. Extensive experiments across four datasets demonstrate $\sysname$'s superior efficiency with $1.3\times \sim 4.7\times$ faster secure predictions while maintaining accuracy comparable to plaintext graph property inference.
