Intellectual Property Protection (IPP) is one of the most important challenges for digital design development. Intellectual Properties (IP) and their reuse are usual today, but the use of IP design is raising design security issues. Watermarking is one of the efficient methods to detect an unauthorized use of an IP. A lot of interesting works have been proposed, but only a few of them combine watermarking process with the synthesis process. This article presents a new solution of watermarking embedded in a high level synthesis process.