/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.0  (the "License"); you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.openairinterface.org/?page_id=698
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *-------------------------------------------------------------------------------
 * For more information about the OpenAirInterface (OAI) Software Alliance:
 *      contact@openairinterface.org
 */

#include <string.h>
#include "secu_defs.h"

/*!
 * Derive the kNASenc from kasme and perform truncate on the generated key to
 * reduce his size to 128 bits. Definition of the derivation function can
 * be found in 3GPP TS.33401 #A.7
 * @param[in] nas_alg_type NAS algorithm distinguisher
 * @param[in] nas_enc_alg_id NAS encryption/integrity algorithm identifier.
 * Possible values are:
 *      - 0 for EIA0 algorithm (Null Integrity Protection algorithm)
 *      - 1 for 128-EIA1 SNOW 3G
 *      - 2 for 128-EIA2 AES
 * @param[in] kasme Key for MME as provided by AUC
 * @param[out] knas Truncated ouput key as derived by KDF
 */

/*int derive_key_nas(algorithm_type_dist_t nas_alg_type, uint8_t nas_enc_alg_id,
               const uint8_t kasme[32], uint8_t** knas)
{
    uint8_t s[7];
    uint8_t knas_temp[32];

    // FC
    s[0] = 0x15;

    // P0 = algorithm type distinguisher
    s[1] = nas_alg_type & 0xFF;

    // L0 = length(P0) = 1
    s[2] = 0x00;
    s[3] = 0x01;

    // P1
    s[4] = nas_enc_alg_id;

    // L1 = length(P1) = 1
    s[5] = 0x00;
    s[6] = 0x01;

    kdf((uint8_t*)kasme, 32, s, 7, (uint8_t**)&knas_temp, 32);

    // Truncate the generate key to 128 bits
    memcpy(knas, knas_temp, 16);

    return 0;
}
*/