def _initialize_encryption(self, options):
        # type: (Descriptor, blobxfer.models.options.Upload) -> None
        """Download is resume capable
        :param Descriptor self: this
        :param blobxfer.models.options.Upload options: upload options
        """
        if (options.rsa_public_key is not None and self.local_path.size > 0 and
                (self._ase.mode == blobxfer.models.azure.StorageModes.Block or
                 self._ase.mode == blobxfer.models.azure.StorageModes.File)):
            em = blobxfer.models.crypto.EncryptionMetadata()
            em.create_new_metadata(options.rsa_public_key)
            self.current_iv = em.content_encryption_iv
            self._ase.encryption_metadata = em
Download is resume capable
        :param Descriptor self: this
        :param blobxfer.models.options.Upload options: upload options