Backdoor-Resilient Graph Federated Learning via Structural Prototype Alignment and Consistency Constraints
Keywords:
graph federated learning, backdoor resilience, prototype alignment, consistency constraints, structural robustness, socio-technical infrastructureAbstract
Graph federated learning enables multiple institutions to collaboratively train graph neural networks without sharing raw graph data, but it remains critically vulnerable to backdoor attacks where malicious participants embed hidden triggers into their local models to cause targeted misclassifications at inference time. Existing defenses often rely on anomaly detection of model updates or adversarial training, yet they struggle to generalize across non-IID graph distributions and often degrade utility. This paper proposes a backdoor-resilient framework based on structural prototype alignment and consistency constraints. The approach centers on establishing a shared set of structural prototypes that capture essential topological patterns across clients, forcing local models to align their learned representations with these prototypes while enforcing consistency constraints across different views of the same graph. By decoupling the global model into a structural encoder and a prototype-based classifier, the framework mitigates the impact of backdoor triggers that distort local feature distributions without affecting the underlying graph structure. We analyze the system-level trade-offs among robustness, communication efficiency, and fairness, and discuss architectural choices for deployment in socio-technical infrastructures such as healthcare networks and financial systems. The proposed method offers a governance-compatible pathway for federated graph learning under adversarial conditions, with implications for regulatory compliance and long-term sustainability.
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