Design And Implementation Of Multi-level Privacy Protection System For Android Platform

In recent years,the number of Android devices has grown rapidly due to the continuous improvement of the performance and functions of the Android system.However,there are a large number of malicious applications that steal users' private information to obtain illegal profits.These applications cause serious threats to the sensitive data of Android users.There are many reasons of privacy leak in the Android system,such as the unpromised quality of third-party applications,the lack of privacy protection mechanisms in Android,and abuse of permissions for normal applications.Therefore,researching the privacy protection technology in Android system is of great significance to ensure the security of the privacy of Android users.The research focus of this thesis is privacy leak detection and privacy protection of Android platform.The main research contents are as follows:(1)propose a privacy leak detection algorithm(PLDDDFT),to deal with the privacy leak detection problem of Android system.The algorithm traces and analyzes the leakage path of privacy data from the network layer,system layer,and application layer,and can accurately determine the source and target of data in a privacy leak event.The experimental results show that,compared with common algorithms based on taint analysis,the proposed algorithm can effectively detect the leakage of private data,even with packing and obfuscation techniques.(2)propose PPMLBM,a privacy protection scheme based on multi-level behavior monitoring,to solve the privacy protection problem of Android.The program monitors application behavior from multiple levels,to prevent privacy leaks.We also introduce the concept of behavioral sensitivity,and propose a calculation method based on statistical analysis,to evaluate the security of application behavior from multiple dimensions.With behavioral sensitivity,the deviation between the tested application and normal applications is measured.The experimental results show that the method can dynamically intercept the privacy leak events in the Android system,with higher accuracy and lower false positive rate.Based on the above research,this thesis designs and implements a multi-level privacy protection prototype system for Android platform.The main functional modules are designed and implemented,and the system is tested.The test results prove that the privacy protection method designed in this thesis can effectively prevent privacy leakage,and has little impact on the use of normal applications.