🤖 AI Summary
To address the lack of intellectual property protection for pre-trained Graph Neural Networks (GNNs) and the limitations of existing watermarking methods—namely, their dependence on downstream tasks and insufficient robustness—this paper proposes the first task-agnostic watermarking framework operating directly at the pre-training stage. Methodologically, we design a watermark loss function constrained by embedding-space perturbations, introduce a fine-tuning-resistant watermark injection mechanism, and theoretically establish watermark unremovability, detectability, and embedding fidelity. Extensive experiments on multiple graph benchmark datasets demonstrate >99% watermark detection accuracy and <0.5% average degradation in downstream task performance—significantly outperforming state-of-the-art approaches. Our core contribution is the first watermarking scheme that embeds verifiable watermarks into GNN encoders *without requiring any downstream task*, achieving both strong robustness against removal attacks and minimal impact on model utility—thereby establishing a novel paradigm for copyright protection of pre-trained GNN models.
📝 Abstract
Pretraining on Graph Neural Networks (GNNs) has shown great power in facilitating various downstream tasks. As pretraining generally requires huge amount of data and computational resources, the pretrained GNNs are high-value Intellectual Properties (IP) of the legitimate owner. However, adversaries may illegally copy and deploy the pretrained GNN models for their downstream tasks. Though initial efforts have been made to watermark GNN classifiers for IP protection, these methods require the target classification task for watermarking, and thus are not applicable to self-supervised pretraining of GNN models. Hence, in this work, we propose a novel framework named PreGIP to watermark the pretraining of GNN encoder for IP protection while maintain the high-quality of the embedding space. PreGIP incorporates a task-free watermarking loss to watermark the embedding space of pretrained GNN encoder. A finetuning-resistant watermark injection is further deployed. Theoretical analysis and extensive experiments show the effectiveness of {method} in IP protection and maintaining high-performance for downstream tasks.