| Chunk Type | Purpose | |------------|---------| | RES_TABLE_TYPE | Header; contains package ID (usually 0x7f for app, 0x01 for Android framework). | | RES_STRING_POOL_TYPE | A pool of all UTF-16 strings used in resources (keys and values). | | RES_TABLE_PACKAGE_TYPE | Defines a package (e.g., your app’s package name). | | RES_TABLE_TYPE_SPEC | Specifies the types of resources (layout, drawable, string, etc.). | | RES_TABLE_TYPE_ENTRY | Actual key-value pairs: resource ID to value. | | RES_TABLE_TYPE_CONFIG | Configuration variation (e.g., values-en-rUS-land ). |

Start with Apktool for quick, reliable results. If you need programmatic access, use ARSCLib (Java) or Androguard (Python). Avoid online tools for proprietary code.

from androguard.core.androguard import APK a = APK("app.apk") for pkg in a.get_packages(): print(pkg.get_name()) for res in pkg.get_resources(): print(res.get_key(), res.get_value()) Security researchers writing automated scanners. 4. jadx (with resource decoding) Jadx focuses on DEX decompilation, but its resource decoder can output resources.arsc as res/values/strings.xml .

This is done by mapping the package ID (0x7f), type ID (0x03 for string), and entry ID. Modern obfuscators like ProGuard can rename resources (e.g., ic_launcher → a ). The ARSC decompiler still shows the obfuscated name, but the ID mapping remains correct. Dealing with Overlay Packages (Runtime Resource Overlay - RRO) Android 10+ uses overlays to theme apps. Some ARSC decompilers now support splitting overlay packages and merging them with base resources. Part 6: Writing Your Own Minimal ARSC Decompiler in Python Let’s write a toy decompiler to solidify concepts.

def read_uint32(self): val = struct.unpack("<I", self.data[self.pos:self.pos+4])[0] self.pos += 4 return val

def parse_string_pool(self): chunk_type = self.read_uint32() # should be 0x0001 chunk_size = self.read_uint32() string_count = self.read_uint32() # Simplified: skip style count, flags, etc. self.pos += 20 offsets = [] for _ in range(string_count): offsets.append(self.read_uint32()) for off in offsets: # Strings are UTF-16, but we'll read until null str_pos = self.pos + off end = str_pos while self.data[end:end+2] != b'\x00\x00': end += 2 raw = self.data[str_pos:end].decode('utf-16le') self.string_pool.append(raw)

An is a specialized tool designed to parse, decode, and reconstruct this binary file back into human-readable formats—usually strings.xml and R.xxx definitions.