Research And Implementation Of Static Watermarking Technology For Android Application

In recent years, with Android smart devices and Android applications being popular, the problems of Android application copyright infringement occur frequently, this not only seriously endangers the interests of application developers, but also brings a huge threat to the user's mobile phone security. As a branch of digital watermarking,software watermarking technology embeds information related to software copyright and identity authentication in the program, and extracts the information in the event of infringement to prove the copyright attribution of the software, so as to solve the problem of copyright dispute and protect the interests of copyright owners. Software watermarking plays an important role in the problems of software anti-piracy and copyright information proving.Static software watermark has certain advantages in operating cost,performance overload and data rate, has certain research value and use value. At present, the research on static watermarking of Android application is still limited. The existing watermarking scheme mainly uses the executable file Dex as the watermark carrier, but because the structure of Dex is compact, the data rate is easy to be limited, thus affecting the integrity and reliability of watermark information. In addition, most of the selection methods of watermark embedding points are random selection, but the machine can not determine the importance of the selected watermark embedding points in the whole program, which has a certain impact on the robustness. In view of the above problems,this paper puts forward a static software watermarking scheme for Android application, which integrates the software watermarking technology and the Android application characteristic. The main work of this paper is as follows:1. Study the file structure of Android applications, the generation and decompilation of APK files, found that the structure of Android application executable file is compact and has limited redundant space,which easily leads to the limited amount of embedded watermark information. To solve this problem, this paper chooses the JAR file as the watermark carrier, and on this basis, the software watermarking algorithm is studied and selected.2. Combined with the software watermarking technology and the characteristics of Android applications, a static software watermarking scheme for Android application based on JAR file is proposed. The watermarking scheme uses an opaque predicate algorithm to embed watermarks, for the enhancement of data rate, watermarks were embedded into JAR files and then indirectly added into APK files. When embedding watermarks, a watermark segmentation algorithm is introduced to improve the stealth of the watermark. And when selecting the watermark embedding point, the watermark embedding point of the algorithm is selected in the context of the calling function of the system component which plays an important role in an Android application,thereby to enhance the robustness of the watermark.3. Design and implement a static software watermarking system for the Android application which use the JAR file as watermark carrier. The system can embed and extract software watermarks, and record the operation information of embedded and extracted modules in the form of logs, so as to analyze the stability of the system. Through the simulation and performance analysis, it can be concluded that the scheme designed in this paper has a certain improvement on the data rate of Android static watermark, and has good robustness and low performance load.