Research And Implementation Of Software Protection Technology Based On Code Obfuscation

With the change and development of science and technology,computers and Internet are changing with each passing day,and become an important part of human society and even human civilization.As the direct carrier of these technologies,the importance of software is beyond doubt,and the growing software market has become an important driving force for economic and social development.However,as an intangible product,software is also facing unprecedented threats.All kinds of reverse cracking behaviors not only infringe the intellectual property rights of developers,but also cause incalculable economic losses to developers and users,and even threaten the healthy development of society.Nowadays,although the source code and the product have been compiled,encapsulated and packaged layer by layer,for the sake of the quality and efficiency of the software and the convenience of subsequent maintenance,there are a lot of useful information left in the software,which can be easily used by attackers to complete reverse analysis and obtain valuable sensitive information.Although some experienced and conscious developers will introduce some security measures,there is no mature software protection system at present.All kinds of protection schemes are mixed,and some of them have not played a protective role,but have brought great negative impact on software.Therefore,it is very necessary to study and design a code protection system that takes into account both security and efficiency,and it is also the focus of current academic research.Based on the research of various relationships and data in control flow diagram,this thesis summarizes the advantages and disadvantages of existing schemes,and finally puts forward software protection technology based on code confusion.The scheme puts forward feasible concrete measures for the protection of control flow information and data information.In the aspect of control flow information protection,the implicit jump of control flow is realized by analyzing the control flow graph and constructing the state transition model,which fundamentally blocks the static analysis of the control flow graph.At the same time,on the basis of implicit jump,the relationship between function call and variable reference in the program is implicitly transformed to protect this information.Finally,aiming at the problem of ciphertext duplication of the same object,a ciphertext salt treatment scheme is proposed to further reduce the exposure of sensitive information.In the aspect of data information protection,by comprehensively analyzing the advantages and disadvantages of several current technologies,a data obfuscation scheme based on chaotic mapping is proposed.With the help of appropriate chaotic mapping,the key is constructed at runtime,thus improving the data security.In addition,according to the characteristics of data in practical application,the scheme also incorporates the mode of string merging and encrypted block linking,which solves some defects of the current scheme in practical application,and hides the information of string length,which is not available in other schemes.Through the protection of control flow information and data information,they complement each other and jointly build a feasible software protection system.Finally,this thesis gives the detailed composition and implementation of the system,and verifies the feasibility and effectiveness of this scheme through specific experiments.Experimental results show that the scheme proposed in this thesis can provide comprehensive protection for software in an acceptable range,whether it is the protection of control flow information or data information.Compared with various popular protection schemes at present,the scheme in this thesis has certain optimization and improvement in performance and file size after confusion.