URL参数加密解密过程

  public static string Encode(string str, string key)
 2         {
 3             DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
 4             provider.Key = Encoding.ASCII.GetBytes(key.Substring(0, 8));
 5             provider.IV = Encoding.ASCII.GetBytes(key.Substring(0, 8));
 6             byte[] bytes = Encoding.UTF8.GetBytes(str);
 7             MemoryStream stream = new MemoryStream();
 8             CryptoStream stream2 = new CryptoStream(stream, provider.CreateEncryptor(), CryptoStreamMode.Write);
 9             stream2.Write(bytes, 0, bytes.Length);
10             stream2.FlushFinalBlock();
11             StringBuilder builder = new StringBuilder();
12             foreach (byte num in stream.ToArray())
13             {
14                 builder.AppendFormat("{0:X2}", num);
15             }
16             stream.Close();
17             return builder.ToString();
18         }

 1  public static string Decode(string str, string key)
 2         {
 3             DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
 4             provider.Key = Encoding.ASCII.GetBytes(key.Substring(0, 8));
 5             provider.IV = Encoding.ASCII.GetBytes(key.Substring(0, 8));
 6             byte[] buffer = new byte[str.Length / 2];
 7             for (int i = 0; i < (str.Length / 2); i++)
 8             {
 9                 int num2 = Convert.ToInt32(str.Substring(i * 2, 2), 0x10);
10                 buffer[i] = (byte)num2;
11             }
12             MemoryStream stream = new MemoryStream();
13             CryptoStream stream2 = new CryptoStream(stream, provider.CreateDecryptor(), CryptoStreamMode.Write);
14             stream2.Write(buffer, 0, buffer.Length);
15             stream2.FlushFinalBlock();
16             stream.Close();
17             return Encoding.GetEncoding("GB2312").GetString(stream.ToArray());
18         } 

<p>
        <asp:TextBox ID="txtbox" runat="server"></asp:TextBox>
        <asp:Button ID="btnok" runat="server" onclick="btnok_Click" Text="加密" />
        <asp:Button ID="btncanel" runat="server" Text="解密" onclick="btncanel_Click" />
    </p>

 1   protected void btnok_Click(object sender, EventArgs e)
 2         {
 3 
 4             txtbox.Text = Helper.Encode(txtbox.Text.Trim(), "Rainight").Trim();
 5 
 6          
 7 
 8            
 9         }
10 
11         protected void btncanel_Click(object sender, EventArgs e)
12         {
13             txtbox.Text = Helper.Decode(txtbox.Text.Trim(), "Rainight").Trim();
14             Response.Write(Helper.Decode(txtbox.Text.Trim(), "Rainight"));
15         }