Research Of Software Watermarking Technology Based On Dynamic Graph

The illeagal copying and malicious dissemination of software are rampant and the protection of genuine software is urgent.At present,software watermarking is one of the most common and effective ways to solve this problem.However,the robustness of the software watermarking and its resistance to attack are poor,which limits the overall performance of the software protection.This paper proposed a watermarking segmentation algorithm based on Chinese residual theorem and congruence equation set,which is called WSA.The existing algorithm of watermarking segmentation leads to the close relationship between the watermatrk segments.When a topology subgraph is attacked,it will cause the drawback that the extraction of associated topology subgraph is invalid.So this paper proposed the idea of representing the watermark segments that are related to each other by one coding structure.This paper proposed an improved watermarking coding based on PPCT and permutation graph,with the WSA,which is called P-PPCT.The existing software watermarking coding of dynamic graph has poor concealment and robustness.So based on WSA,this paper proposed the P-PPCT coding algorithm.This coding structure expresses one integer of the watermarking segment with the structure of PPCT,and the leaf nodes of PPCT tree was used to express the other integer according to the permutation graph code,which expresses the topology subgraphs with relevance by one coding structure.The experiment showed that the watermarking segmentation algorithm and the P-PPCT coding algorithm can reduce the correlation between watermarking segments and improve the encoding efficiency,concealment and anti-aggression of software watermarking.This paper proposed an improved DES algorithm based on Logistic chaotic system,which is called LDES,because of the poor security of DES algorithm used for code encryption in technology of P-PPCT watermarking tamper-proof.The LDES algorithm established double-key mode by introducing the parameter of Logisitic chaotic system.This paper introduced module of key expansion by the new secret key to confuse the original secret key and reconstructed the S-boxes with the random sequences of the module of key expansion.The LDES algorithm expanded the key space of the DES algorithm twice by introducing key expansion module and reconstructing S-boxes.The experiment showed that the key space is expanded and it enhances the security of DES algorithm,which provides higher security for the P-PPCT dynamic graph watermark based on protection scheme.This paper designed and implentmented a software watermark protection scheme based on P-PPCT dynamic graph watermark for software copyright's certification and protection,based on the above methods.The experiment shows that the seheme can prevent reverse engineering from analyzing the code and attack on the P-PPCT software watermarking further.When the copyright of software needs to be detected,it can extract valid information and identity authentication.This solution provides a new and effective way for software copyright protection.