/*-------------------------------------------------------------------
* 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 "milenage.h"
#include "rijndael.h"
/*--------------------------- prototypes --------------------------*/
/*-------------------------------------------------------------------
* Algorithm f1
*-------------------------------------------------------------------
*
* Computes network authentication code MAC-A from key K, random
* challenge RAND, sequence number SQN and authentication management
* field AMF.
*
*-----------------------------------------------------------------*/
void f1 ( u8 k[16], u8 rand[16], u8 sqn[6], u8 amf[2],
u8 mac_a[8], u8 op[16] )
{
u8 op_c[16];
u8 temp[16];
u8 in1[16];
u8 out1[16];
u8 rijndaelInput[16];
u8 i;
RijndaelKeySchedule( k );
ComputeOPc( op_c, op );
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;
} /* 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.
*
*-----------------------------------------------------------------*/
void f2345 ( u8 k[16], u8 rand[16],
u8 res[8], u8 ck[16], u8 ik[16], u8 ak[6], u8 op[16] )
{
u8 op_c[16];
u8 temp[16];
u8 out[16];
u8 rijndaelInput[16];
u8 i;
RijndaelKeySchedule( k );
ComputeOPc( op_c, op );
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;
} /* 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.
*
*-----------------------------------------------------------------*/
void f1star( u8 k[16], u8 rand[16], u8 sqn[6], u8 amf[2],
u8 mac_s[8], u8 op[16] )
{
u8 op_c[16];
u8 temp[16];
u8 in1[16];
u8 out1[16];
u8 rijndaelInput[16];
u8 i;
RijndaelKeySchedule( k );
ComputeOPc( op_c, op );
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;
} /* end of function f1star */
/*-------------------------------------------------------------------
* Algorithm f5*
*-------------------------------------------------------------------
*
* Takes key K and random challenge RAND, and returns resynch
* anonymity key AK.
*
*-----------------------------------------------------------------*/
void f5star( u8 k[16], u8 rand[16],
u8 ak[6], u8 op[16] )
{
u8 op_c[16];
u8 temp[16];
u8 out[16];
u8 rijndaelInput[16];
u8 i;
RijndaelKeySchedule( k );
ComputeOPc( op_c, op );
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;
} /* end of function f5star */
/*-------------------------------------------------------------------
* Function to compute OPc from OP and K. Assumes key schedule has
already been performed.
*-----------------------------------------------------------------*/
void ComputeOPc( u8 op_c[16], u8 op[16] )
{
u8 i;
RijndaelEncrypt( op, op_c );
for (i=0; i<16; i++)
op_c[i] ^= op[i];
return;
} /* end of function ComputeOPc */