A new concept of watermarking system for IC design IP protection is presented and its advantages against traditional constraint-based watermarking techniques are proposed. Differences and traits of various kinds of watermarking approaches and the design levels in which they are implemented are analyzed. The third part organization needed in a watermarking system is introduced and its main functions are listed. Possible attacks against the watermarking system are discussed. Using the proposed watermarking technique, both the robustness and the easy-detection of the watermark can be guaranteed.