| With the continuous advancement of mobile technology,many people use mobile phones.The open source feature of the Android system has made it favored by a large number of mobile phone manufacturers,and has gradually developed into the most dominant mobile operating system.The Framework layer of the Android system is implemented by the Java language.The open source feature of the Java language makes Android applications very easy to be reversed,maliciously modified,and repackaged before being released.In order to prevent the application from being easily cracked,it needs to be effectively protected.As an effective means to protect Android applications,reinforcement is a popular research topic in the direction of mobile phone application protection.The proguard technology provided by Google can protect the code to a certain extent through obfuscation,but the difficulty of cracking is relatively low.As a technical means to effectively prevent decompilation,hardening has always attracted people’s attention.At present,the research direction in the industry mainly focuses on virtual machine customization solutions.The process of this scheme is to extract part of the functions of the DEX file and map them into custom instructions,and then use the custom virtual machine to restore the instructions when the functions in the DEX file are executed.However,with the release of Android 5.0,the Android virtual machine was replaced by Dalvik with ART.The custom virtual machine solution faces great challenges in terms of compatibility.In addition,the design that can only strengthen some core functions is also very limited.The promotion and use of the third-generation program.So as to solve the problems mentioned above,this article analyzes the underlying security operation mechanism of Android and the core principles of Android’s two-generation virtual machines(Dalvik and Android Runtime).It starts with preventing static code theft and dynamic debugging and analyzing code,combined with anti-repackaging,Anti-runtime debugging and other technical solutions,designed and implemented an Android application reinforcement system based on method instruction extraction,which effectively solved the problem that systems above 5.0 cannot be reinforced.After system testing,use the reinforcement scheme of this paper to reinforce unreinforced applications,and cooperate with the processing of the command whitelist to ensure 100% success rate of opening applications after reinforcement.At the same time,it is impossible to crack the application after reinforcement by using the current static and dynamic analysis tools in the industry,which has a good effect on the application.In terms of performance,after the application of reinforcement,the package volume has increased by 10%,the startup time has increased by 30%,the memory usage has increased by 5%,and the three performance loss indicators are below the industry average. |
