import struct import sys out = open(sys.argv[2], 'w') sum = 0x1121 len = 0 with open(sys.argv[1], 'rb') as f: while True: byte = f.read(1) if not byte: break sum ^= ord(byte) for i in range(8): if(sum & 1): sum = (sum >> 1) ^ 0x8408 else: sum >>= 1 len += 1 sum = ~sum & 0xFFFF f.closed out.write(struct.pack('