C＃DES算法解密

Question

这个问题是关于加密/解密算法的大学项目。

加密效果很好，我需要做的就是解密。目标是将ASCII代码解密为纯文本。但在我的情况下，它用另一个ASCII码解密它。这是解密代码：

public static string BinaryToString(string data) 
{ 
     List byteList = new List();

     for (int i = 0; i < data.Length; i += 8)
     {
        byteList.Add(Convert.ToByte(data.Substring(i, 8), 2));
     }
     return Encoding.ASCII.GetString(byteList.ToArray());

}

private void BTN_Decrypt_Click(object sender, EventArgs e) { 
    lis.Clear();      
    lisToBeDone.Clear(); 
    lb_output.Items.Clear();

    bkey = ""; btext = "";
    if (tb_key.Text.Length <= 1)
        MessageBox.Show("Enter a valid key.");

    else
    {

        skey = tb_key.Text;
        stext = tb_input.Text;
        int strlength = stext.Length;
        if (stext.Length % 2 != 0)
        {

            stext += '/';
            strlength++;
        }
        char[,] twoDarray = new char[strlength / 2, 16];
        int rowcount = 0;

        //converts the key to binary 2 by 2 chars
        foreach (char ch in skey)
        {
            string bit = Convert.ToString(ch, 2);
            if (bit.Length != 
                bit = bit.PadLeft(8, '0');
            bkey += bit;
        }

        lb_output.Items.Add("Key in Binary:" + bkey);
        lb_output.Update();
        //converts the text to binary 2 by 2 chars
       char[] temparray = new char[2];
            for (int i = 0; i < strlength; i++)

                if (i % 2 == 0)
                {
                    temparray[0] = stext.ElementAt(i);
                    temparray[1] = stext.ElementAt(i + 1);
                    foreach (char ch in temparray)
                    {
                        string bit = Convert.ToString(ch, 2);
                        if (bit.Length != 
                            bit = bit.PadLeft(8, '0');
                        btext += bit;
                    }
                        for (int y = 0; y < 16; y++)
                        {
                            twoDarray[rowcount, y] = btext.ElementAt(y);
                        }
                    btext = "";
                    rowcount++;
                }
            lb_output.Items.Add("Text in binary form: ");
            lb_output.Items.Add(btext);
            lb_output.Update();
            //here we Decrypt our text
            string s;
            int z = rowcount;
            int x = 0;
            lb_output.Items.Add("Decrypted text:");
            for (int i = 0; i < z; i++)
            {
                s = "";
                x = 0;
                while(x <=15)
                {
                    s += twoDarray[i, x].ToString();
                    x++;
                }
                lisToBeDone.Add(s);
            }
            for (int k = 0; k < lisToBeDone.Count; k++)
            {
                cipherText = "";
                mydes.Decrypt(bkey, lisToBeDone[k]);
                cipherText = mydes.CipherText;
                lis.Add(cipherText);
            }
            string tmptext = "";
            for (int l = 0; l < lis.Count; l++)
            {
                tmptext +=BinaryToString( lis[l]);
            }

            lb_output.Items.Add(tmptext);
    }