A convenience method which pads and encrypts at once.

def Encrypt(self, data):
    """A convenience method which pads and encrypts at once."""
    encryptor = self.GetEncryptor()
    padded_data = self.Pad(data)

    try:
      return encryptor.update(padded_data) + encryptor.finalize()
    except ValueError as e:
      raise CipherError(e)