monster_prom_save_editor.py

#!/usr/bin/env python3
# Monster Prom Save Editor
# Usage: python3 monster_prom_save_editor.py decrypt 76561198083837418_GameProgress.xml 76561198083837418_GameProgress_decrypted.xml
# Usage: python3 monster_prom_save_editor.py encrypt 76561198083837418_GameProgress_decrypted.xml 76561198083837418_GameProgress.xml
# See https://www.pcgamingwiki.com/wiki/Monster_Prom for save file locations
# Backup your save file before using this script

import argparse
import base64
import xml.etree.ElementTree as ET
from Crypto.Cipher import AES
from Crypto.Util.Padding import unpad, pad

MONSTER_PROM_KEY = b"07372495761297179318254963745127"
MONSTER_PROM_RIJNDAEL = AES.new(MONSTER_PROM_KEY, AES.MODE_ECB)
MONSTER_PROM_ENCODING = "us-ascii"


def decrypt(args):
    encrypted_file = args.encrypted_file
    decrypted_file = args.decrypted_file
    tree = ET.parse(encrypted_file)
    root = tree.getroot()
    ciphertext = base64.b64decode(root.text)
    plaintext = unpad(
        MONSTER_PROM_RIJNDAEL.decrypt(ciphertext), AES.block_size, style="pkcs7"
    )
    inner_tree = ET.fromstringlist(["<root>", plaintext, "</root>"])
    root.clear()
    root.extend(inner_tree)
    new_tree = ET.ElementTree(root)
    ET.indent(new_tree)
    with open(encrypted_file, "wb") as f:
        # Use double quotes and \r\n in the declaration
        f.write(
            f'<?xml version="1.0" encoding="{MONSTER_PROM_ENCODING}"?>\r\n'.encode(
                "ascii"
            )
        )
        new_tree.write(f, encoding=MONSTER_PROM_ENCODING, xml_declaration=False)


def strip_whitespace(elem):
    if elem.text:
        elem.text = elem.text.strip()
    if elem.tail:
        elem.tail = elem.tail.strip()
    for child in elem:
        strip_whitespace(child)


def encrypt(args):
    decrypted_file = args.decrypted_file
    encrypted_file = args.encrypted_file
    tree = ET.parse(decrypted_file)
    root = tree.getroot()
    strip_whitespace(root)
    plaintext = b"".join(
        ET.tostring(child, encoding=MONSTER_PROM_ENCODING) for child in root
    )
    ciphertext = MONSTER_PROM_RIJNDAEL.encrypt(
        pad(plaintext, AES.block_size, style="pkcs7")
    )
    root.clear()
    root.text = base64.b64encode(ciphertext).decode("ascii")
    new_tree = ET.ElementTree(root)
    with open(encrypted_file, "wb") as f:
        # Use double quotes and \r\n in the declaration
        f.write(
            f'<?xml version="1.0" encoding="{MONSTER_PROM_ENCODING}"?>\r\n'.encode(
                "ascii"
            )
        )
        new_tree.write(f, encoding=MONSTER_PROM_ENCODING, xml_declaration=False)


def main():
    parser = argparse.ArgumentParser(description="Monster Prom save editor")
    subparsers = parser.add_subparsers(dest="command", required=True)

    parser_decrypt = subparsers.add_parser("decrypt")
    parser_decrypt.add_argument("encrypted_file", type=str)
    parser_decrypt.add_argument("decrypted_file", type=str)
    parser_decrypt.set_defaults(func=decrypt)

    parser_encrypt = subparsers.add_parser("encrypt")
    parser_encrypt.add_argument("decrypted_file", type=str)
    parser_encrypt.add_argument("encrypted_file", type=str)
    parser_encrypt.set_defaults(func=encrypt)

    args = parser.parse_args()
    args.func(args)


if __name__ == "__main__":
    main()

requirements.txt

pycryptodome==3.23.0