decrypts SWZ files

reverse.py

import struct
import zlib
import argparse
import sys

def rotate_left(value, shift, bit_size=32):
    """Rotate left a 32-bit integer."""
    return ((value << shift) & (2**bit_size - 1)) | (value >> (bit_size - shift))

def decrypt_and_decompress(file_path):
    """Decrypts and decompresses binary data from a given file."""
    try:
        with open(file_path, "rb") as f:
            data = f.read()
    except FileNotFoundError:
        print(f"Error: File '{file_path}' not found.")
        sys.exit(1)

    offset = 0
    
    # Read the encryption key
    if len(data) < 8:
        print("Error: File is too small to contain required header data.")
        sys.exit(1)

    decryption_key, = struct.unpack(">I", data[offset:offset+4])  # Read 4 bytes as uint32
    offset += 4

    # Read number of XML blocks
    num_blocks, = struct.unpack(">I", data[offset:offset+4])  # Read another 4 bytes
    offset += 4

    xml_list = []

    for _ in range(num_blocks):
        if offset + 4 > len(data):
            print("Error: Unexpected end of file while reading chunk size.")
            break

        # Read chunk size
        chunk_size, = struct.unpack(">I", data[offset:offset+4])
        offset += 4

        if offset + chunk_size > len(data):
            print("Error: Unexpected end of file while reading chunk data.")
            break

        encrypted_chunk = bytearray(data[offset:offset+chunk_size])
        offset += chunk_size

        # Decrypt the chunk
        for i in range(chunk_size):
            shift_amount = i & 7
            encrypted_chunk[i] ^= (decryption_key & 0xFF)
            decryption_key = rotate_left(decryption_key, 32 - shift_amount)

        # Decompress the chunk
        try:
            decompressed_data = zlib.decompress(encrypted_chunk)
        except zlib.error:
            print("Decompression failed! The data might be corrupt or incorrectly decrypted.")
            continue

        # Convert bytes to string (XML)
        xml_string = decompressed_data.decode("utf-8")
        xml_list.append(xml_string)

    return xml_list

def main():
    parser = argparse.ArgumentParser(description="Decrypt and decompress an AS3 encrypted binary file containing XML data.")
    parser.add_argument("input_file", help="Path to the encrypted binary file.")
    args = parser.parse_args()

    xml_contents = decrypt_and_decompress(args.input_file)

    for idx, xml in enumerate(xml_contents):
        print(f"Extracted XML {idx + 1}:\n{xml}\n")

if __name__ == "__main__":
    main()