The Research And Implementation Of Static Software Watermarking

At present, domestic and international research on software watermarking mostly is focusing on the design of dynamic software watermarking algorithm. Dynamic software watermark is normally built during the process when the host program is running. Different from dynamic watermarking, the static software watermark can be embedded into host program directly and will not change in the process of execution. Through the analysis of the PE (Portable Executable) file format, it is believed that well-designed static software watermarking can achieve better concealment and robustness. Static software watermark is normally embedded into the target software after it is finished. In this regard, the programmer can concentrate on the design of software. This kind of advantages can't be ignored.According to the principle of Software Watermarking, It can be applied to validate the software copyright reserved. The method is that the information of software copyright is converted to watermarking and embedded into the executable file which is regarded as carrier. When analyzing that the executable file exists some free storage space, the watermarking can be encrypted and embedded universally and strategically into these free space which can as well be constructed. At the same time the relevant data of characteristics of the executable file should be modified in order to achieve the invisibility of watermark embedded. The watermark can be extracted and decrypted in order to state the software copyright.In order to fully understand the characteristics of the executable file, in this paper, loading and running features of the executable file are analyzed. The loading process of shelling software is elaborated, including API function calls and SHE(Structured Exception Handling) mechanism. According to the running characteristics of executable files, the related shelling technology can be used to embed the static software watermark, together with shell program code into target software. Therefore, the relationships between the static watermark and the program code are established, by which the security like dynamic software watermark is even achieved.Under normal circumstances, software watermarking should be detected by a third-party program, but this approach is inconvenient to the practical application. Software can detect the watermark that is embedded in its own program file. The method is to make a piece of executable code that should be embedded along with the watermark and which can execute with the priority and detect the watermark. Therefore, It's achievable to fulfill the software watermarking with self-test.