added reference on original licence.
* for message hashing and tree construction are now configurable (within limits...) and that the implementation produces
* detached signatures.
* </p>
+ * <p>
+ * The SPHINCS reference implementation is public domain, as per the statement in the second last paragraph of
+ * section 1 in https://eprint.iacr.org/2014/795.pdf
+ * </p>
*/
public class SPHINCS256Signer
implements MessageSigner
