Kerckhoffs-Compliant Watermarking for Physical Design IP Protection: From Placement to Routing

Physical design (PD) intellectual property (IP) is a valuable artifact of modern VLSI implementation. It includes optimized cell placement, clock distribution, and routing decisions produced by carefully tuned PD flows. As access to PD tools expands, unauthorized reuse of placed-and-routed databases becomes an increasing concern. Existing PD watermarking methods either protect only one PD stage or rely on hidden construction details, leaving them vulnerable to a white-box adversary. In this work, we develop PDMarks, a Kerckhoffs-compliant watermarking framework whose security depends only on a secret key. PDMarks embeds ownership evidence across multiple stages of the PD flow, including placement, clock tree synthesis (CTS), and routing. All watermark instances and target values are deterministically derived from a 32-byte secret key using HMAC-SHA256, enabling consistent embedding and verification. PDMarks has been integrated into OpenROAD-flow-scripts. Experiments on NanGate45 and ASAP7 designs show that PDMarks outperforms prior physical design watermarking methods by providing much stronger ownership evidence with comparable or smaller PPA overhead. The approximate joint all-stage coincidence probability is below 10^{-32} for every evaluated design. Wrong-key and attack evaluations further show that incorrect keys do not reproduce the complete ownership proof and that weakening the watermark requires broad perturbation of the protected implementation.

Source: arXiv:2608.05055v1 - http://arxiv.org/abs/2608.05055v1 PDF: https://arxiv.org/pdf/2608.05055v1 Original Link: http://arxiv.org/abs/2608.05055v1