/*
* The MixColumns transformation of AES
*/
void MixColumns( unsigned char state[4][4] )
{
int col,row,k;
unsigned char tmp[4][4];
memset ( tmp, 0, 4*4 );
for(col=0; col<4; col++){
for(row=0; row<4; row++){
for(k=0; k<4; k++)
tmp[row][col] ^= FieldMult( MC[row][k], state[k][col] );
}
}
memcpy( state, tmp, 4*4 );
}
void MixColumn(unsigned char state[4][4])
{
int i, j, k;
unsigned char tmp[4];
for(j = 0; j < 4; j++){
for(i = 0; i < 4; i++) {
unsigned char sum = 0;
for(k = 0; k < 4; k++)
sum ^= FieldMult(MixColMatrix[i][k], state[k][j]);
tmp[i] = sum;
}
for(i = 0; i < 4; i++)
state[i][j] = tmp[i];
}
}