Exclusive and Updateable Watermarking for Neural Network Model Trading

Neural-network model trading raises two unmet requirements for watermarking: exclusive ownership verification and updateability (transfer/revoke) without retraining. We present a training-time framework that jointly embeds a keydriven dynamic label-mapping and a proactive, self-defending trigger. The label-mapping encodes an owner-specific signature that authorized key holders can verify, update, or transfer by rotating keys; the defensive trigger actively hardens the model against unauthorized backdoor insertion and fakewatermark attempts. Our design yields three properties: (i) exclusivity—only the correct key decodes the watermark; (ii) updateability—ownership can be changed without retraining the backbone; and (iii) robustness—the watermark persists under common post-deployment changes. Across CIFAR-10/100, GTSRB, and Tiny ImageNet on five architectures, the method achieves (> 97%) watermark success rate while preserving original accuracy within 0.5 percentage points, retains (>85%) watermark strength after fine-tuning and (60%) pruning, and reduces fake-watermark success to (95%) on unprotected models). By coupling updateable encoding with proactive defense, our approach offers a practical, scalable path to secure, transferable ownership verification for neural-network marketplaces and model exchanges.