[Game Ripping Tutorial] Ikemen Vampire Android APK
A video walkthrough is available at the end of this post.
Step 1. Export data files from the Android emulator
I use NoxPlayer as my Android emulator.
Enable root access in NoxPlayer’s setting so we have superuser access to reading and writing files between the emulator and our computers.
I use Cx File Explorer as my Android file explorer because it’s easy to enable root access in this app.
Export base.apk
In Cx File Explorer:
Copy the base APK file into the following folder shared with the computer:
From the Terminal command line:
open Library/Application Support/NoxAppPlayer/Nox_share
Now we can copy these files to the desktop of our computers.
Export additional content downloaded from inside the game
The Google Play Store limits the APK size. That’s why we’ll have to wait through another 1.5GB of downloads the first time we launch our game. We can grab these files and copy them over to share with our computers using the same method as above.
Step 2. Decode encoded data
I’ve covered a lot of the decoding techniques in my previous tutorial and in my video tutorial, so I will keep them concise in this post.
Unpack CPK using QuickBMS
These raw data files don’t have extensions, but we may identify their file types by inspecting their headers using Hex editor tools like HexFiend for MacOS (there are a lot of Windows alternatives available).
You will end up with files with extensions like AWB/ACB (encrypted audio files), some PNG images, and some files without extensions.
Inspect files without extensions with HexFiend
The file headers decoded by HexFiend will tell you whether they are UnityFS, JFIF, PNG (encoded) or some other formats.
Unpack AWB (into HCA then) into WAV audio files
Use QuickBMS with the AWB quickbms script
The unpacked files have .dat extensions and inspecting their headers with HexFiend doesn’t reveal what files they are. However, game rippers know from experience that they are HCA files, which can be unpacked into WAV files using a decrypt key unique to every game application.
Unpack UnityFS using UnityPy
Follow the README instructions in the UnityPy GitHub repo to install UnityPy and unpack the texture and sprites. I found all of the sprite atlas but also encountered some limitations: I wasn’t able to unpack the game text scripts as they are likely wrapped in Unity MonoBehaviour binaries. I also wasn’t able to locate the BG and CG files. These will be next steps to tackle if I were to pick up game ripping again.
Video Walkthrough
It’s my first time recording a video tutorial so bear with me XD
