"Smali" is the intermediate language for Android. Think of it as the assembly language of the Android OS. When you decompile with APKTool, the classes.dex becomes a folder full of .smali files. These are difficult to read but editable.
This is the biggest danger for the general public. When you download a "Modded APK" from a random forum or third-party website, you are trusting a stranger. Malware authors often take a popular app, inject a trojan that steals your contacts or SMS, and repack it. Since Android allows installation from unknown sources, users unwittingly install spyware. apkefor repack
To successfully repack an APK, you generally follow these four high-level steps: "Smali" is the intermediate language for Android
If you don't have a keystore, you'll need to generate one first using keytool . Best Practices for Success These are difficult to read but editable
The gold standard for the initial phase. APKTool can decode resources to nearly original form and rebuild them after modification. It handles the binary XML decoding so you can actually read the Manifest and layout files.