objectEncryptionKey, err := decryptObjectMeta(ssecClientKey, bucket, object, oi.UserDefined)
	if err != nil {
		return nil, err
	}
	w.objectEncryptionKey = objectEncryptionKey

	if err := w.buildDecrypter(w.parts[w.partIndex].Number); err != nil {
		return nil, err
	}
	return w, nil
}

// DecryptBlocksReader - decrypts multipart parts, while implementing
// a io.Reader compatible interface.