Research On Dynamic Graph Encoding Based Software Watermarking

The rapid advance of network has promoted the spread of digital products.However, it also brings a severe challenge with respect to the copyright protection ofcomputer software faces. There are three kinds of attack that threat copyrightprotection most: malicious tampering, reverse engineering, and unauthorized usage.In order to solve this problem, a new software protection method named softwarewatermarking technology has been introduced in recent years. This moderntechnology embed the copyright information and user identity in computer programsto indicate issuers, authors, legitimate users, owners, etc., and bring along theiridentity and copyright information. It can also identify the illegal copying andsoftware products stealing. Researchers put forward a number of different softwarewatermarking schemes to meet the different demands of copyright protection requestion.In the research of software watermark, dynamic watermark technology is widelyrecognized and well received. The watermark encoding scheme is a key part of thedynamic figure watermark, which is also a hot research field. However, there are stilltwo problems within the existing dynamic graph watermark schemes, including slowrunning speed and limited data rate of coding scheme.In this thesis, different dynamic watermark schemes are intensively researchedand their advantages and disadvantages are completely summarized. For the problemslow running speed, we proposed a new coding scheme of dynamic graph watermark:AB-PPCT. This method combines the stability and robustness of PPCT with thefeature of Radix-K in high data rate. By applying array index to mark the coefficientof coding items, the merit of Radix-K can be effectively added in PPCT. Then wepropose a new efficient watermark embedding scheme. In this method, Chineseremainder theorem is adopted. The related coding acheme is introduced to the processof watermark embedding. Experimental results show that the proposed codingmethod has a higher robustness and better data rate. Meanwhile, the new watermarkembedding scheme is farely fairly effient.