? The economic viability of the reusable core-based design paradigm depends on the development of techniques for intellectual property protection. We introduce the first dynamic watermarking technique for protecting the value of intellectual property of CAD and compilation tools and reusable core components. The essence of the new approach is the addition of a set of design and timing constraints which encodes the author's signature. The constraints are selected in such a way that they result in minimal hardware overhead while embedding the signature which is unique and difficult to detect, remove and forge. We establish the first set of relevant metrics which forms the basis for the quantitative analysis, evaluation, and comparison of watermarking techniques. We develop a generic approach for signature data hiding in designs, which is applicable in conjunction with an arbitrary behavioral synthesis task, such as scheduling, assignment, allocation, and transformations. Error corre...