unlock_score.py

#!/usr/bin/env python3
import hashlib
import binascii
import zlib
import zipfile
import sys
import os
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.backends import default_backend

STATIC_SALT_HEX = "da40cc64900b617a0f72ad4e6ef42f9c"

def decrypt_gpif(encrypted_data, password):
    # Fixed salt from binary
    salt = binascii.unhexlify(STATIC_SALT_HEX)
    iterations = 4096
    key_length = 32
    
    # Derive key
    key = hashlib.pbkdf2_hmac("sha1", password.encode(), salt, iterations, key_length)
    
    if len(encrypted_data) < 16:
        return None
        
    iv = encrypted_data[:16]
    ciphertext = encrypted_data[16:]
    
    backend = default_backend()
    cipher = Cipher(algorithms.AES(key), modes.CBC(iv), backend=backend)
    decryptor = cipher.decryptor()
    
    decrypted = decryptor.update(ciphertext) + decryptor.finalize()
    
    # Files are zlib compressed after encryption
    if decrypted.startswith(b'\x78'):
        try:
            return zlib.decompress(decrypted)
        except zlib.error:
            pass
            
    return decrypted

def unlock_file(zip_path):
    print(f"Processing: {zip_path}")
    
    edit_locked_content = None
    encrypted_score = None
    
    # 1. Read necessary data
    try:
        with zipfile.ZipFile(zip_path, 'r') as z:
            if 'editLocked' in z.namelist():
                edit_locked_content = z.read('editLocked').decode('utf-8')
                print(f"[+] Found editLocked: {edit_locked_content}")
            else:
                print("[-] No editLocked file found. Is it locked?")
                return False
                
            if 'Content/score.gpif' in z.namelist():
                encrypted_score = z.read('Content/score.gpif')
            else:
                print("[-] No score.gpif found.")
                return False
    except Exception as e:
        print(f"[-] Error reading zip: {e}")
        return False

    # 2. Decrypt
    print("[*] Decrypting score...")
    # The "password" is the editLocked content string
    decrypted_score = decrypt_gpif(encrypted_score, edit_locked_content)
    
    if not decrypted_score or (b"<GPIF" not in decrypted_score[:200] and b"<?xml" not in decrypted_score[:200]):
        print("[-] Decryption failed. Key or logic incorrect.")
        return False
        
    print("[+] Decryption SUCCESS! Valid XML header found.")
    
    # 3. Create unlocked file
    output_path = os.path.splitext(zip_path)[0] + "_unlocked.gp"
    print(f"[*] Creating unlocked file: {output_path}")
    
    try:
        with zipfile.ZipFile(zip_path, 'r') as zin:
            with zipfile.ZipFile(output_path, 'w', zipfile.ZIP_DEFLATED) as zout:
                for item in zin.infolist():
                    # Skip lock file
                    if item.filename == 'editLocked':
                        continue
                        
                    # Replace score
                    if item.filename == 'Content/score.gpif':
                        zout.writestr('Content/score.gpif', decrypted_score)
                    else:
                        zout.writestr(item, zin.read(item.filename))
        print(f"[+] Done! Unlocked file saved to: {output_path}")
        return True
    except Exception as e:
        print(f"[-] Error creating output zip: {e}")
        return False

if __name__ == "__main__":
    if len(sys.argv) < 2:
        print("Usage: python3 unlock_score.py <file.gp>")
        sys.exit(1)
        
    unlock_file(sys.argv[1])

A possible error that someone may be seeing, ModuleNotFoundError: No module named 'cryptography', means that Python cannot find the specific library required to handle the AES decryption used in the script.

While Python comes with many built-in tools, the cryptography library is a third-party package that must be installed separately.

How to Fix It:
You need to use pip (Python's package installer) to download the missing module. Open your Command Prompt (CMD) or PowerShell and run the following command: pip install cryptography