code: def cbc_mac(key, data):
      
      engine = AES.new(key, AES.MODE_CBC, get_zero_vector(16))
      return engine.encrypt(data)[-16:]
docs: AES-265-CBC-MAC on the data used in ProcessData.
      Does not use padding (data has to be already padded).
  
      :param key:
      :param data:
      :return: