codec_value_to_string
retval = codec_value_to_string(obj, "vendor", &ti->vendor);
retval = codec_value_to_string(obj, "challenge", &ti->challenge);
retval = codec_value_to_string(obj, "tokenID", &ti->token_id);
retval = codec_value_to_string(obj, "algID", &ti->alg_id);
retval = codec_value_to_string(obj, "service", &chl->service);
retval = codec_value_to_string(obj, key, &tmp);