Research On The Model Design Of Obfuscator Based On Java Language

Java program is spreading quickly on the Internet for its platform-independent characteristics, but it also faces two serious software security issues: first, the copyright problem. Java compiler compiles every Java class file into a single file, this feature makes it easy to infringe on using Java class files; second, the decompiling issue. Now, de-compilation technology of the Java byte-code is becoming mature, with many Java de-compiler and de-compilation tools appearing, which enables Java byte-code de-compilation to be compiled into Java source code.In the application software based on Java language, the analysis of Java files is what reverse engineers must do. Through the analysis of documents on Java, the core classes and software Java code can be understood, so the key to protect Java software is to protect Java files. Class files compiled by the Java code contain all the information source (not including notes), especially when a debug information is included, so Java class files compiled according to normal mode can be easily decompiled. In order to avoid this situation, and to protect the laboring fruits of developers, the Java obfuscation techniques have been developed.In order to protect the safety of Java program, a method of protecting Java byte-code is introduced in this paper, and a model of obfuscated Java language is proposed as well, so as to protect intellectual property of the Java program. Obfuscated Java byte-code can confuse internal information while keeping the Java program semantic, so that the reverse engineer could hardly understand the de-compiling Java source code, which even can not be recompiled correctly.The software code obfuscation technique as a rising and an important branch of the immature software security protection technology draws more and more scholars and the enterprises' attention. Especially Java language being widely used attracts many experts and scholars'interest to study the obfuscation techniques. Because the application software based on Java language is released by the byte-code irrelevant with platform, and the software code in this way is similar with its own source, so it's much easier to be attacked by the static analysis, reverse engineering or distorting technique etc than the general binary code.The analysis of the types and evaluation criteria of the obfuscation transformation is given in detail, and the knowledge related with Java class files is also elaborated. A theoretical model to protect Java program is provided as well. Specific content includes:(1) Firstly, the importance of software protection is introduced simply, and the research status and the development trend of obfuscation techniques are analyzed. (2) The principle of obfuscation is introduced in detail, the types and the corresponding usage of the obfuscation transformation are discussed, and the evaluation standard of obfuscation techniques is also given in the second part.(3) The structure of Java class files is introduced in detail, and a protection model of Java program is given in the third part.(4) Finally, a model design of obfuscation system applied into Java language is proposed and the design of the main modules is analyzed.