Constructing An Obfuscator Based On Control Transformation

Intellectual property protection is one of important parts of digital content protection in Information security. More and more researches concerned about computer security are focusing on software intellectual property protections. Along with the methods of intellectual property attack, certain techniques come into being. Watermarking came along with software piracy attack, tamper proofing came along with tampering attack, and obfuscation came along with reverse engineering attack. Attacker can know about the function of software, even analyze the code and look into hidden information and property information through reverse engineering attack. Obfuscation, which keeps the same behavior of obfuscated programs as the original ones, makes obfuscated program harder to break for the reverse engineering and less readable for the attacker to understand so as to protect the software from being attacked. In this paper we use control transformation to increase program complexities and make the program less readable so as to protect software from reverse engineering and the person who wants to read the source codes. First, we will present you the improved methods of obfuscating the loops and the if-statements, and a new method of obfuscation that is the reforming of flow of execution. Then using above methods we introduce the model of constructing an obfuscator and make it into being. Also functions and performances of the tool are tested. Finally, performances are compared with the similar in the complexity, obfuscating methods, readability, cost and statistical properties. It shows that the obfuscator is very effective in complexity, obfuscating methods and readability.