return key, ErrCustomerKeyMD5Mismatch
	}
	copy(key[:], clientKey)
	return key, nil
}

// UnsealObjectKey extracts and decrypts the sealed object key
// from the metadata using the SSE-C client key of the HTTP headers
// and returns the decrypted object key.
func (s3 ssec) UnsealObjectKey(h http.Header, metadata map[string]string, bucket, object string) (key ObjectKey, err error) {
	clientKey, err := s3.ParseHTTP(h)