void invShiftRows(byte [][] inv_state)
{
///no inverse shift row is to be applied on row 0/
///inverse shift row operation on row 1/
for (ushort i = 3; i > 0; i--)
{
AES_CxDecipher.swap(ref inv_state [1] [i], ref inv_state [1] [i - 1]);
}
///inverse shift row operation on row 2/
for (ushort i = 0; i < 2; i++)
{
for (ushort j = 3; j > 0; j--)
{
AES_CxDecipher.swap(ref inv_state [2] [j], ref inv_state [2] [j - 1]);
}
}
///inverse shift row operation on row 3/
for (ushort i = 0; i < 3; i++)
{
for (ushort j = 3; j > 0; j--)
{
AES_CxDecipher.swap(ref inv_state [3] [j], ref inv_state [3] [j - 1]);
}
}
}
void shiftRows(byte [][] state)
{
///no shift row is to be applied on row 0/
///shift row operation on row 1/
for (ushort i = 0; i < 3; i++)
{
AES_CxDecipher.swap(ref state[1][i], ref state[1][i + 1]);
}
///shift row operation on row 2/
for (ushort i = 0; i < 2; i++)
{
for (ushort j = 0; j < 3; j++)
{
AES_CxDecipher.swap(ref state [2] [j], ref state [2] [j + 1]);
}
}
///shift row operation on row 3/
for (ushort i = 0; i < 3; i++)
{
for (ushort j = 0; j < 3; j++)
{
AES_CxDecipher.swap(ref state [3] [j], ref state [3] [j + 1]);
}
}
}
void invSubBytes(byte [][] inv_state)
{
for (ushort i = 0; i < 4; i++)
{
for (ushort j = 0; j < 4; j++)
{
inv_state [i] [j] = AES_CxDecipher.get_invSBOX_value(inv_state [i] [j]);
}
}
}
void subBytes(byte [][] state)
{
for (ushort i = 0; i < 4; i++)
{
for (ushort j = 0; j < 4; j++)
{
state[i][j] = AES_CxDecipher.get_SBOX_value(state [i][j]);
}
}
}
void keyExpansion(byte[] key, byte[] keySchedule)
{
byte[] temp = new byte[4];
ushort i = 0;
for (; i < this.Nk; i++)
{
for (ushort j = 0; j < 4; j++)
{
keySchedule [4 * i + j] = key [4 * i + j];
}
}
i = (ushort)this.Nk;
while (i < (4 * (this.Nr + 1)))
{
for (ushort j = 0; j < 4; j++)
{
temp[j] = keySchedule[4 * (i - 1) + j];
}
if (i % this.Nk == 0)
{
for (ushort j = 0; j < 3; j++) ///RotWord SubRoutine/
{
AES_CxDecipher.swap(ref temp [j], ref temp [j + 1]);
}
for (ushort j = 0; j < 4; j++) ///SubWord SubRoutine/
{
temp[j] = get_SBOX_value(temp[j]);
}
for (ushort j = 0; j < 4; j++)
{
if (j == 0)
{
temp[j] ^= R_CON[(i / this.Nk) - 1];
}
else
{
temp[j] ^= 0x00;
}
}
}
else if ((this.Nk > 6) && (i % this.Nk == 4))
{
for (ushort j = 0; j < 4; j++) ///SubWord SubRoutine/
{
temp[j] = get_SBOX_value(temp[j]);
}
}
for (ushort j = 0; j < 4; j++)
{
keySchedule [(4 * i) + j] = (byte)(keySchedule [(4 * (i - this.Nk)) + j] ^ temp [j]);
}
i += 1;
}
}