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/*-------------------------------------------------------------------
 * Example algorithms f1, f1*, f2, f3, f4, f5, f5*
 *-------------------------------------------------------------------
 *
 * A sample implementation of the example 3GPP authentication and
 * key agreement functions f1, f1*, f2, f3, f4, f5 and f5*. This is
 * a byte-oriented implementation of the functions, and of the block
 * cipher kernel function Rijndael.
 *
 * This has been coded for clarity, not necessarily for efficiency.
 *
 * The functions f2, f3, f4 and f5 share the same inputs and have
 * been coded together as a single function. f1, f1* and f5* are
 * all coded separately.
 *
 *-----------------------------------------------------------------*/

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "auc.h"

/*--------- Operator Variant Algorithm Configuration Field --------*/
/*------- Insert your value of OP here -------*/
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u8 OP[16]= {
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  0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
  0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11
};
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/*--------------------------- prototypes --------------------------*/
void ComputeOPc( u8 op_c[16] );

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void SetOPc(const u8 const op_c[16])
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{
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  memcpy(OP, op_c, 16);
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  printf("SetOPc: OP : %02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X ",
         OP[0],OP[1],OP[2],OP[3],OP[4],OP[5],OP[6],OP[7],
         OP[8],OP[9],OP[10],OP[11],OP[12],OP[13],OP[14],OP[15]);
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}

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void generate_autn(const u8 const sqn[6], const u8 const ak[6], const u8 const amf[2], const u8 const mac_a[8], u8 autn[16])
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{
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  int i;

  for (i = 0; i < 6; i++) {
    autn[i] = sqn[i] ^ ak[i];
  }

  memcpy(&autn[6], amf, 2);
  memcpy(&autn[8], mac_a, 8);
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}

/*-------------------------------------------------------------------
 * Algorithm f1
 *-------------------------------------------------------------------
 *
 * Computes network authentication code MAC-A from key K, random
 * challenge RAND, sequence number SQN and authentication management
 * field AMF.
 *
 *-----------------------------------------------------------------*/
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void f1 ( const u8 const k[16], const u8 const _rand[16], const u8 const sqn[6], const u8 const amf[2],
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          u8 mac_a[8] )
{
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  u8 op_c[16];
  u8 temp[16];
  u8 in1[16];
  u8 out1[16];
  u8 rijndaelInput[16];
  u8 i;
  RijndaelKeySchedule( k );
  ComputeOPc( op_c );

  for (i=0; i<16; i++)
    rijndaelInput[i] = _rand[i] ^ op_c[i];

  RijndaelEncrypt( rijndaelInput, temp );

  for (i=0; i<6; i++) {
    in1[i] = sqn[i];
    in1[i+8] = sqn[i];
  }

  for (i=0; i<2; i++) {
    in1[i+6] = amf[i];
    in1[i+14] = amf[i];
  }

  /* XOR op_c and in1, rotate by r1=64, and XOR *
   * on the constant c1 (which is all zeroes) */
  for (i=0; i<16; i++)
    rijndaelInput[(i+8) % 16] = in1[i] ^ op_c[i];

  /* XOR on the value temp computed before */
  for (i=0; i<16; i++)
    rijndaelInput[i] ^= temp[i];

  RijndaelEncrypt( rijndaelInput, out1 );

  for (i=0; i<16; i++)
    out1[i] ^= op_c[i];

  for (i=0; i<8; i++)
    mac_a[i] = out1[i];

  return;
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} /* end of function f1 */

/*-------------------------------------------------------------------
 * Algorithms f2-f5
 *-------------------------------------------------------------------
 *
 * Takes key K and random challenge RAND, and returns response RES,
 * confidentiality key CK, integrity key IK and anonymity key AK.
 *
 *-----------------------------------------------------------------*/
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void f2345 ( const u8 const k[16], const u8 const _rand[16],
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             u8 res[8], u8 ck[16], u8 ik[16], u8 ak[6] )
{
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  u8 op_c[16];
  u8 temp[16];
  u8 out[16];
  u8 rijndaelInput[16];
  u8 i;
  RijndaelKeySchedule( k );
  ComputeOPc( op_c );

  for (i=0; i<16; i++)
    rijndaelInput[i] = _rand[i] ^ op_c[i];

  RijndaelEncrypt( rijndaelInput, temp );

  /* To obtain output block OUT2: XOR OPc and TEMP, *
   * rotate by r2=0, and XOR on the constant c2 (which *
   * is all zeroes except that the last bit is 1). */
  for (i=0; i<16; i++)
    rijndaelInput[i] = temp[i] ^ op_c[i];

  rijndaelInput[15] ^= 1;
  RijndaelEncrypt( rijndaelInput, out );

  for (i=0; i<16; i++)
    out[i] ^= op_c[i];

  for (i=0; i<8; i++)
    res[i] = out[i+8];

  for (i=0; i<6; i++)
    ak[i] = out[i];

  /* To obtain output block OUT3: XOR OPc and TEMP, *
   * rotate by r3=32, and XOR on the constant c3 (which *
   * is all zeroes except that the next to last bit is 1). */

  for (i=0; i<16; i++)
    rijndaelInput[(i+12) % 16] = temp[i] ^ op_c[i];

  rijndaelInput[15] ^= 2;
  RijndaelEncrypt( rijndaelInput, out );

  for (i=0; i<16; i++)
    out[i] ^= op_c[i];

  for (i=0; i<16; i++)
    ck[i] = out[i];

  /* To obtain output block OUT4: XOR OPc and TEMP, *
   * rotate by r4=64, and XOR on the constant c4 (which *
   * is all zeroes except that the 2nd from last bit is 1). */
  for (i=0; i<16; i++)
    rijndaelInput[(i+8) % 16] = temp[i] ^ op_c[i];

  rijndaelInput[15] ^= 4;
  RijndaelEncrypt( rijndaelInput, out );

  for (i=0; i<16; i++)
    out[i] ^= op_c[i];

  for (i=0; i<16; i++)
    ik[i] = out[i];

  return;
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} /* end of function f2345 */

/*-------------------------------------------------------------------
 * Algorithm f1*
 *-------------------------------------------------------------------
 *
 * Computes resynch authentication code MAC-S from key K, random
 * challenge RAND, sequence number SQN and authentication management
 * field AMF.
 *
 *-----------------------------------------------------------------*/
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void f1star( const u8 const k[16], const u8 const _rand[16], const u8 const sqn[6], const u8 const amf[2],
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             u8 mac_s[8] )
{
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  u8 op_c[16];
  u8 temp[16];
  u8 in1[16];
  u8 out1[16];
  u8 rijndaelInput[16];
  u8 i;
  RijndaelKeySchedule( k );
  ComputeOPc( op_c );

  for (i=0; i<16; i++)
    rijndaelInput[i] = _rand[i] ^ op_c[i];

  RijndaelEncrypt( rijndaelInput, temp );

  for (i=0; i<6; i++) {
    in1[i] = sqn[i];
    in1[i+8] = sqn[i];
  }

  for (i=0; i<2; i++) {
    in1[i+6] = amf[i];
    in1[i+14] = amf[i];
  }

  /* XOR op_c and in1, rotate by r1=64, and XOR *
   * on the constant c1 (which is all zeroes) */
  for (i=0; i<16; i++)
    rijndaelInput[(i+8) % 16] = in1[i] ^ op_c[i];

  /* XOR on the value temp computed before */
  for (i=0; i<16; i++)
    rijndaelInput[i] ^= temp[i];

  RijndaelEncrypt( rijndaelInput, out1 );

  for (i=0; i<16; i++)
    out1[i] ^= op_c[i];

  for (i=0; i<8; i++)
    mac_s[i] = out1[i+8];

  return;
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} /* end of function f1star */

/*-------------------------------------------------------------------
 * Algorithm f5*
 *-------------------------------------------------------------------
 *
 * Takes key K and random challenge RAND, and returns resynch
 * anonymity key AK.
 *
 *-----------------------------------------------------------------*/
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void f5star( const u8 const k[16], const u8 const _rand[16],
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             u8 ak[6] )
{
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  u8 op_c[16];
  u8 temp[16];
  u8 out[16];
  u8 rijndaelInput[16];
  u8 i;
  RijndaelKeySchedule( k );
  ComputeOPc( op_c );

  for (i=0; i<16; i++)
    rijndaelInput[i] = _rand[i] ^ op_c[i];

  RijndaelEncrypt( rijndaelInput, temp );

  /* To obtain output block OUT5: XOR OPc and TEMP, *
   * rotate by r5=96, and XOR on the constant c5 (which *
   * is all zeroes except that the 3rd from last bit is 1). */
  for (i=0; i<16; i++)
    rijndaelInput[(i+4) % 16] = temp[i] ^ op_c[i];

  rijndaelInput[15] ^= 8;
  RijndaelEncrypt( rijndaelInput, out );

  for (i=0; i<16; i++)
    out[i] ^= op_c[i];

  for (i=0; i<6; i++)
    ak[i] = out[i];

  return;
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} /* end of function f5star */

/*-------------------------------------------------------------------
 * Function to compute OPc from OP and K. Assumes key schedule has
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 * already been performed.
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 *-----------------------------------------------------------------*/
void ComputeOPc( u8 op_c[16] )
{
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  u8 i;
  printf("ComputeOPc: OP : %02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X ",
         OP[0],OP[1],OP[2],OP[3],OP[4],OP[5],OP[6],OP[7],
         OP[8],OP[9],OP[10],OP[11],OP[12],OP[13],OP[14],OP[15]);

  RijndaelEncrypt( OP, op_c );

  for (i=0; i<16; i++)
    op_c[i] ^= OP[i];

  return;
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} /* end of function ComputeOPc */