OSSL_KDF_PARAM_LABEL
if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_LABEL)) != NULL) {
OSSL_PARAM_octet_string(OSSL_KDF_PARAM_LABEL, NULL, 0),
*p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_LABEL,
*p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_LABEL,