apktool

# Apktool - Android APK Unpacking and Resource Extraction

You are helping the user reverse engineer Android APK files using apktool for security analysis, vulnerability discovery, and understanding app internals.

## Tool Overview

Apktool is a tool for reverse engineering Android APK files. It can decode resources to nearly original form and rebuild them after modifications. It's essential for:
- Extracting readable AndroidManifest.xml
- Decoding resources (XML layouts, strings, images)
- Disassembling DEX to smali code
- Analyzing app structure and permissions
- Repackaging modified APKs

## Prerequisites

- **apktool** must be installed on the system
- Java Runtime Environment (JRE) required
- Sufficient disk space (unpacked APK is typically 2-5x original size)
- Write permissions in output directory

## Instructions

### 1. Basic APK Unpacking (Most Common)

When the user asks to unpack, decode, or analyze an APK:

**Standard decode command:**
```bash
apktool d <apk-file> -o <output-directory>
```

**Example:**
```bash
apktool d app.apk -o app-unpacked
```

**With force overwrite (if directory exists):**
```bash
apktool d app.apk -o app-unpacked -f
```

### 2. Understanding Output Structure

After unpacking, the output directory contains:

```
app-unpacked/
├── AndroidManifest.xml          # Readable manifest (permissions, components)
├── apktool.yml                  # Apktool metadata (version info, SDK levels)
├── original/                    # Original META-INF certificates
│   └── META-INF/
├── res/                         # Decoded resources
│   ├── layout/                  # XML layouts
│   ├── values/                  # Strings, colors, dimensions
│   ├── drawable/                # Images and drawables
│   └── ...
├── smali/                       # Disassembled DEX code (smali format)
│   └── com/company/app/        # Package structure
├── assets/                      # App assets (if present)
├── lib/                         # Native libraries (if prese