Summary: | 碩士 === 國立臺灣海洋大學 === 資訊工程學系 === 104 === As the pirated software is more and more rampant than the past, the cases of illegal infringement are sustained increase. In Asia, there are over 60 percent of software, which has copyright, are used illegally [27]. In order to prevent software pirating, we will use undeniable and irremovable method to prove the copyright of software such as the software watermarking technique. The purpose of this paper is to design a watermark scheme using cryptographic method and increase the effectiveness of digital watermarks in legal level. First, use the part of original program to produce a digital signature, and treat it as the seed to generate the pseudorandom sequence. Second, analyze the target program by a static way, and embed the sequence generated in above step into the program as the watermark. The pseudorandom sequence is unpredictable; thus, this method can enhance the robustness of the watermark. Once the illegal user remove 30 percent of watermark, this method still can prove that no one can fake that pseudorandom sequence over 60 percent. Moreover, this method will build the only relation between target program and the copyright holder. In conclusion, using this method can prove the ownership of software indeed, then restrict the pirated software to intmidute software piracy.
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