eddsa_get_digest_from_priv_key
ret = eddsa_get_digest_from_priv_key(hash, &hash_size, priv_key); EG(ret, err);
ret = eddsa_get_digest_from_priv_key(hash, &hsize, priv_key); EG(ret, err);
ret = eddsa_get_digest_from_priv_key(hash, &hash_size, &(key_pair->priv_key)); EG(ret, err);
ret = eddsa_get_digest_from_priv_key(hash, &hsize, priv_key); EG(ret, err);
ret = eddsa_get_digest_from_priv_key(digest, &digest_size, in_priv); EG(ret, err);