Dynamic Mapping Software Watermarking Algorithm Based On Tamper-resistant Technology

As the phenomenon of software piracy being more and more serious, software watermarking technology has attracted more and more concern.In recent years, lots of software watermarking algorithms has been designed to protect software, such as algorithm of dynamic graph watermarking. Several techniques of dynamic graph software watermarking has been told in this paper, and their advantages and disadvantages has been analyzed.Then, this paper proposes two modified dynamic graph software watermarking algorithms.Main research work of the paper is summarized as follows.(1)Four coding methods of dynamic graph software watermarking has been told in this paper,and this paper has analyzed the advantages and disadvantages of the four coding methods.Based on the tamper-proof technique of watermarking,it has proposed an algorithm of dynamic graph software watermarking based on PPT(Parent-Pointer Tree) in this paper.Using the technology of number system conversion,a large watermark has been split into a set of small watermarks,this is preprocess watermarking.Then,these small watermarks has been represented as a set of graphs,which has beeen embedded into object program dynamically.The experimental results has shown that this algorithm should had strong advantages in concealment and recoverability.In comparison to PPCT(Planted Plane Cubic Tree),this algorithm has a higher data rate,and the watermark coding is more simple and more convenient.(2)Under the permissible complexity of watermark system, the improved points of the watermarking algorithm based on PPT has been analyzed.Then ,this paper has proposed an algorithm of dynamic graph software watermarking based on tamper-proof technique of variables.This algorithm has two improvements.One is watermark coding, the data rate of watermark can be improved;Second is that it has enlarged the application range of tamper-proof function,with the tamper-proof technique of watermarking.The experimental results has shown that this algorithm has a best anti-attack ability of watermarking,and it has a higher data rate than enhanced PPCT. This algorithm is more complicated than the first algorithm, but the performance of watermark system is better.(3)A summarize has been given to full text, and next research direction of software watermarking has been proposed. The two algorithms are improved algorithms not only in the performance of robustness but also in the field of data rate. The future researchs are how to improve the representation of the watermark, the preprocess's method, and the function of tamper-resistant.