Research And Implementation Of Key Technologies Of Software Anti Piracy

In recent years,with the continuous development of reverse engineering technology,many criminals illegally cracked software by means of reverse analysis,which caused great losses to software authors.The software developed by Java has a greater risk of piracy,because Java is an object-oriented programming language,which is different from the executable file compiled by C language.The bytecode file compiled by Java has the characteristics of clear structure and standardization.At present,there are many reverse tools for Java projects.Attackers can use tools to easily decompile Java projects into source code without having a deep understanding of professional knowledge.Aiming at the piracy problem of Java software,this paper proposes corresponding solutions from the perspectives of illegal copying and illegal tampering.The specific contents are as follows:Firstly,aiming at the problem of illegal copy of Java software,an improved software watermark embedding scheme is proposed,which disperses the user information into the code and can provide copyright proof at a critical moment.The traditional software watermarking scheme has the problems of low robustness and poor embeddability because the embedded position is too obvious and the watermark information is not preprocessed.Aiming at these problems,this paper designs the coding and splitting scheme of software watermark through RS coding and opaque predicate,which improves the capacity and security of watermark information.The branch statement in the program is selected as the embedding position,so that the watermark has less impact on the original performance of the program.The experimental results show that this method has high robustness and security in the face of a variety of attacks.Secondly,aiming at the illegal tampering problem of Java software,a tamper proof method at the Java virtual machine level is proposed.There is a common vulnerability in traditional schemes,that is,although the target code is protected,the code that performs the protection function is also written in Java and runs together in the software life cycle.Therefore,under the premise that the source code can be easily reversed,these protection methods will also be found and bypassed by attackers.To solve this problem,this paper uses JVMTI(Java Virtual Machine Tool Interface)mechanism to write the decryption method in dll(Dynamic Link Library),so that the encrypted bytecode file can be restored through dynamic decryption before execution,and the algorithm can reach the binary security level.Considering the key security problem of traditional cryptographic algorithms,white box cipher is selected as the encryption and decryption algorithm.In view of the defects of white box cipher table,the import and export logic of the table is modified to further improve the security protection capability of this method.Experiments show that it can prevent source code tampering more effectively without affecting the original functions of the software.