/*******************************************************************************
    OpenAirInterface
    Copyright(c) 1999 - 2014 Eurecom

    OpenAirInterface is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.


    OpenAirInterface is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with OpenAirInterface.The full GNU General Public License is
   included in this distribution in the file called "COPYING". If not,
   see <http://www.gnu.org/licenses/>.

  Contact Information
  OpenAirInterface Admin: openair_admin@eurecom.fr
  OpenAirInterface Tech : openair_tech@eurecom.fr
  OpenAirInterface Dev  : openair4g-devel@lists.eurecom.fr

  Address      : Eurecom, Compus SophiaTech 450, route des chappes, 06451 Biot, France.

 *******************************************************************************/
#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;
}
*/