Example: Game uses www/data/System.json and encrypted graphics in www/img/.
Step 1 – Locate encryption key
Step 2 – Write a decryptor in Python (using Crypto.Cipher.AES)
from Crypto.Cipher import AES import zlib
def decrypt_file(in_path, out_path, key): with open(in_path, 'rb') as f: data = f.read() cipher = AES.new(key.encode(), AES.MODE_ECB) decrypted = cipher.decrypt(data) # Remove PKCS7 padding decrypted = decrypted[:-decrypted[-1]] # Decompress if needed decompressed = zlib.decompress(decrypted) with open(out_path, 'wb') as f: f.write(decompressed)rpg maker decompiler
Step 3 – Iterate archive index
Parse www/data/System.json to map files → decrypt each.
The decompilation process encountered the following issues: Example : Game uses www/data/System
Understanding the target format is essential.
| RPG Maker Version | Archive Extension | Encryption | Script System |
|------------------|------------------|------------|----------------|
| XP / VX / VX Ace | .rgss2a, .rgss3a | Optional XOR + Zlib | RGSS (Ruby) |
| MV / MZ | .ww2a, .rpgproject | Optional AES-256 | JavaScript (NW.js) |
The decompiler’s job: reverse the archive format and decryption routine without the original key (if possible) or by extracting keys from the game’s executable. Step 2 – Write a decryptor in Python (using Crypto
An RPG Maker decompiler is a software tool designed to reverse the packaging process of games made with specific RPG Maker engines.
Unlike reversing a AAA game made in Unreal or Unity (which compiles to machine code), RPG Maker games are closer to interpreted scripts. When you play an RPG Maker game, the engine’s runtime reads data files (maps, events, database entries) and script files (Ruby or JavaScript) to reconstruct the game logic on the fly.
A decompiler does not “crack” the game in the traditional sense. Instead, it:
Most MV/MZ games use a file called www/data/ with files like Map001.json (maps) and Actors.json (database). To “protect” these, developers run them through an encryption tool (often the built-in Encryption via Key or a third-party plugin like Greenworks or Sister’s Plugin).