void InvMixColumns(BYTE State[4][4])
{
BYTE temp[4*4];
DWORD i,j;
for (i = 0; i < 4; i++) // copy State DWORDo temp[]
{
for (j = 0; j < 4; j++) //0e 0b 0d 09 Page108
{ //09 0e 0b 0d
temp[4*i+j] = State[i][j]; //0d 09 0e 0b
} //0b 0d 09 0e
}
for (j = 0; j < 4; j++)
{
State[0][j] = (BYTE) ( (DWORD)gfmultby0e(temp[j]) ^ (DWORD)gfmultby0b(temp[4+j]) ^
(DWORD)gfmultby0d(temp[4*2+j]) ^ (DWORD)gfmultby09(temp[4*3+j]) );
State[1][j] = (BYTE) ( (DWORD)gfmultby09(temp[j]) ^ (DWORD)gfmultby0e(temp[4+j]) ^
(DWORD)gfmultby0b(temp[4*2+j]) ^ (DWORD)gfmultby0d(temp[4*3+j]) );
State[2][j] = (BYTE) ( (DWORD)gfmultby0d(temp[j]) ^ (DWORD)gfmultby09(temp[4+j]) ^
(DWORD)gfmultby0e(temp[4*2+j]) ^ (DWORD)gfmultby0b(temp[4*3+j]) );
State[3][j] = (BYTE) ( (DWORD)gfmultby0b(temp[j]) ^ (DWORD)gfmultby0d(temp[4+j]) ^
(DWORD)gfmultby09(temp[4*2+j]) ^ (DWORD)gfmultby0e(temp[4*3+j]) );
}
}
void InvMixColumns(ctx_aes* aes)
{
unsigned char temp[4*4];
int r,c;
for (r = 0; r < 4; r++) // copy State into temp[]
{
for (c = 0; c < 4; c++)
{
temp[4*r+c] = aes->State[r][c];
}
}
for (c = 0; c < 4; c++)
{
aes->State[0][c] = (unsigned char) ( (int)gfmultby0e(temp[c]) ^ (int)gfmultby0b(temp[4+c]) ^
(int)gfmultby0d(temp[4*2+c]) ^ (int)gfmultby09(temp[4*3+c]) );
aes->State[1][c] = (unsigned char) ( (int)gfmultby09(temp[c]) ^ (int)gfmultby0e(temp[4+c]) ^
(int)gfmultby0b(temp[4*2+c]) ^ (int)gfmultby0d(temp[4*3+c]) );
aes->State[2][c] = (unsigned char) ( (int)gfmultby0d(temp[c]) ^ (int)gfmultby09(temp[4+c]) ^
(int)gfmultby0e(temp[4*2+c]) ^ (int)gfmultby0b(temp[4*3+c]) );
aes->State[3][c] = (unsigned char) ( (int)gfmultby0b(temp[c]) ^ (int)gfmultby0d(temp[4+c]) ^
(int)gfmultby09(temp[4*2+c]) ^ (int)gfmultby0e(temp[4*3+c]) );
}
} // InvMixColumns