APK Reverse Engineering

An APK is a ZIP file with the whole app inside it — compiled code, resources, and a manifest. Reverse engineering it is two jobs: reading what the app does, and changing it. jadx reconstructs readable Java so you can read; apktool unpacks the bytecode into editable smali so you can patch and rebuild. This walks the dex-to-smali pipeline, how to find and edit the right instruction, and the full rebuild, re-sign, and reinstall loop on an app you are scoped to test.