AI 中文总结
本研究提出符合Kerckhoffs原则的PDMarks水印框架，集成于OpenROAD-flow-scripts，在多PD阶段嵌入所有权证据，实验显示其优于现有方法，联合重合概率极低，能有效保护物理设计IP。
AI 中文摘要
物理设计（PD）知识产权（IP）是现代超大规模集成电路（VLSI）实现的重要成果，包含由精心调优的PD流程生成的优化单元布局、时钟分布和布线决策。随着PD工具的访问权限扩大，未经授权的布局布线数据库复用成为日益突出的问题。现有PD水印方法要么仅保护单个PD阶段，要么依赖隐藏的构造细节，易受白盒攻击者攻击。本研究开发了PDMarks，这是一个符合Kerckhoffs原则的水印框架，其安全性仅依赖于密钥。PDMarks在PD流程的多个阶段嵌入所有权证据，包括布局、时钟树综合（CTS）和布线。所有水印实例和目标值均使用HMAC-SHA256从32字节密钥确定性推导而来，确保嵌入和验证的一致性。PDMarks已集成到OpenROAD-flow-scripts中。在NanGate45和ASAP7设计上的实验表明，PDMarks比现有物理设计水印方法提供更强的所有权证据，且PPA（功耗、性能、面积）开销相当或更小。每个评估设计的近似全阶段联合重合概率低于10^-32。错误密钥和攻击评估进一步显示，错误密钥无法复现完整所有权证明，削弱水印需要对受保护实现进行广泛扰动。
英文摘要
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.
