Research Of Dynamic Graph-Based Software Watermarking

With the development of Internet, users can obtain the digital products that they desiredeasily through the network. However, due to the non-standard network sharing system, theillegal sharing can do a lot of serious damage to the legitimate rights and interests of digitalcopyright holders. The software is a typical digital product. Software watermarkingtechnology is used to protect the Copyright of software owner.The information included ownership of the software, user identity and proof of whoseCopyright, is embedded into the program through a certain algorithm, which is calledsoftware watermarking. The software watermarking can be divided into static watermark anddynamic watermark in accordance with the timing of the watermark loaded. And the dynamicgraph watermarking technology belongs to dynamic watermark. The watermark is embeddedin the topology map generated by the program dynamic. This is the center idea of the dynamicgraph watermarking algorithm. The pointer was introduced when the topology map isgenerated, which makes the structural analysis of embedded watermark program moredifficult. So robustness has been greatly improved.The common dynamic graph watermarking algorithm mainly have Radix-K codingscheme and the PPCT coding scheme. Radix-K coding scheme has a simple topologystructure and is easy to implement. Otherwise, it is embedding data rate is relatively high.However, the disadvantage of attacked easily is also very obvious. The PPCT topologystructure of the PPCT coding scheme has been improved based on the binary tree. One PPCTgraph structure with n leaf nodes contains n-1nodes and a generator node. PPCT topologygraph structure has good stability and self-healing. But it also has the drawbacks. Not only it’sembedding data rate is not high, but also the resistance of the pointer to change the node is nothigh. This article combines the advantages of the Radix-K coding scheme and PPCT encodingscheme. Meanwhile it introduces a tamper-resistant technology, and presents the K-PPCTcoding scheme based on the tamper-resistant constant.The K-PPCT topology structure in this scheme improves the pointing of the right pointerof the leaf nodes which is in the PPCT topology structure. This can make all the leaf nodesand generate nodes constitute a circular linked list, which is similar to Radix-K codingscheme. Then code watermarking digital according to the circular linked list. Thus we canassociate the structure of the encoded watermark digital with the entire program. So, the entireprogram will not be able to function properly, when the watermark topology structure isdestroyed. I will introduce the specific implementation scheme of the K-PPCT coding scheme basedon the tamper-resistant constant detailedly in this article, and do a simulation experiment onthe Sandmark platform. Embedding and identification of the watermarking digital have beenachieved by this platform. In addition, a series of simulation experiments have been carriedout using the tools of confusion attack, viewing tools of Byte code and API interface. Andthen statistical experimental results are compared with the performance of the Radix-K codingscheme and the PPCT coding scheme.Finally we can come to the conclusion that coding structure of the K-PPCT dynamicgraph has a good concealment and reliability based on the tamper-resistant constant. Howeverthe embedding data rate is still below the Radix-K coding scheme, it has been improvedsignificantly compared with PPCT encoding scheme. The K-PPCT dynamic graph encodingscheme based on the tamper-resistant constant has a good performance, which combined withthe stability、repair and tamper-resistance of the new program.