encryptedKey bytes.Buffer
	)
	mac := hmac.New(sha256.New, extKey)
	mac.Write(iv[:])
	mac.Write([]byte(domain))
	mac.Write([]byte(SealAlgorithm))
	mac.Write([]byte(path.Join(bucket, object))) // use path.Join for canonical 'bucket/object'
	mac.Sum(sealingKey[:0])
	if n, err := sio.Encrypt(&encryptedKey, bytes.NewReader(key[:]), sio.Config{Key: sealingKey[:], CipherSuites: fips.DARECiphers()}); n != 64 || err != nil {