public static int[,] Getdecryption(string str, int[,] key)
{
int[] cipherkey = new int[16];
str = str.ToLower();
char[] ch = str.ToCharArray();
int[,] cipher = new int[str.Length / 32, 16];
int[,] plian = new int[str.Length / 32, 16];
int[] plaintext = new int[16];
StringBuilder s = new StringBuilder(100000);
for (int i = 0; i < str.Length; i++)
{
for (int j = 3; j >= 0; j--)
{
s = s.Append(Decryption.GetNum(ch[i]) >> j & 1);
}
}
for (int i = 0; i < cipher.GetLength(0); i++)
{
for (int j = 0; j < 16; j++)
{
cipher[i, j] = Convert.ToInt32(s.ToString(j * 8 + i * 128, 8), 2);
}
}
for (int i = 0; i < cipher.GetLength(0); i++)
{
for (int h = 0; h < 16; h++)
{
cipherkey[h] = key[key.GetLength(0) - 1, h];
plaintext[h] = cipher[i, h];
}
plaintext = AddRoundKey(plaintext, cipherkey);
for (int j = key.GetLength(0) - 2; j > 0; j--)
{
for (int h = 0; h < 16; h++)
{
cipherkey[h] = key[j, h];
}
for (int h = 0; h < plaintext.Length; h++)
{
plaintext[h] = SubBytes.GetByteSub(plaintext[h]);
}
plaintext = InvShiftRows(plaintext);
plaintext = MixColumn.InvMixColumn(plaintext);
plaintext = AddRoundKey(plaintext, cipherkey);
}
for (int h = 0; h < 16; h++)
{
cipherkey[h] = key[0, h];
}
for (int h = 0; h < plaintext.Length; h++)
{
plaintext[h] = SubBytes.GetByteSub(plaintext[h]);
}
plaintext = InvShiftRows(plaintext);
plaintext = AddRoundKey(plaintext, cipherkey);
for (int j = 0; j < 16; j++)
{
plian[i, j] = plaintext[j];
}
}
return(plian);
}
