"Android Advanced Advanced" study notes
first six mobile security papers
Chapter 38: Detailed explanation of Android obfuscation mechanism
There are three types of obfuscation in Android: Java code obfuscation, Native (C/C++) code obfuscation, and resource file obfuscation.
1. Confusion of Java code
Generally, Proguard is used for obfuscation, and Java bytecode can be compressed and optimized.
2. Confusion of Native (C/C++) code
A common and relatively simple method is to use flower instructions to make the Native code make mistakes when being disassembled, so that the cracker cannot clearly and correctly disassemble the content of the code.
3. Confusion of resource files
Currently there are two types of Meituan and WeChat .
Chapter 39: Detailed Explanation of Android Decompilation Mechanism
An APP package contains code files and resource files , so the decompilation is divided into two parts accordingly.
1. Decompilation of Java code
- Tool: dex2jar
- Input: dex file
- Output: jar file
2. Decompilation of resource files
Using ApkTool this tool, it can decompile resources.arsc, 9.png and XML files, and can also repackage the modified decompiled files into APK files.
Chapter 40: Research on Client-side Sensitive Information Hiding Technology
Chapter 41: Research on Android Hardening Technology
Android application reinforcement refers to adding a layer of shell outside the APK and encrypting the dex file in the APK. It can effectively prevent the app from being decompiled and is the last line of defense to ensure the security of the app.