Question

I am developing a project with Asp.net , and have an encryption method. when i use it to encrypt a string ,it returns a string that contains some chars like ‘+’ and because i use its returned values in my querystring i need to remove these chars

ex :

http://localhost/Cpanel/CompanyInfo/Hotels/EditHotel/VKWbk+G9F6E=

Error : HTTP Error 404.11 – Not Found
The request filtering module is configured to deny a request that contains a double escape sequence.

http://localhost/Cpanel/CompanyInfo/Hotels/EditHotel/bprrmsZ6atI=

It works great

this is my encryption method :

 public static string EncryptString(string Message)
        {
            string Passphrase = System.Configuration.ConfigurationSettings.AppSettings["CryptographyKey"];

            byte[] Results;
            System.Text.UTF8Encoding UTF8 = new System.Text.UTF8Encoding();

            //Hash the passphrase using MD5            
            MD5CryptoServiceProvider HashProvider = new MD5CryptoServiceProvider();
            byte[] TDESKey = HashProvider.ComputeHash(UTF8.GetBytes(Passphrase));

            TripleDESCryptoServiceProvider TDESAlgorithm = new TripleDESCryptoServiceProvider();
            TDESAlgorithm.Key = TDESKey;
            TDESAlgorithm.Mode = CipherMode.ECB;
            TDESAlgorithm.Padding = PaddingMode.PKCS7;

            byte[] DataToEncrypt = UTF8.GetBytes(Message);

            try
            {
                ICryptoTransform Encryptor = TDESAlgorithm.CreateEncryptor();
                Results = Encryptor.TransformFinalBlock(DataToEncrypt, 0, DataToEncrypt.Length);
            }
            finally
            {
                TDESAlgorithm.Clear();
                HashProvider.Clear();
            }

            return HttpUtility.HtmlEncode(Convert.ToBase64String(Results));
        }

how i can do that ?

Answer 1

When you prepare query string value, do as :

Server.UrlEncode(Variable)

and then pass it to query string.

At time of reading query string use method for decode like:

Server.UrlDecode("QuerySting"); 

Let me know for any concerns.