C# - Encryption Decryption for URL Query String

Encryption for URL Querystring parameter.

Normal encryption will not restrict URL Reserved character, but here you can update your reserve characters.

public static class EncryptDecryptQueryString

    {

        private static byte[] key = { };

        private static string sEncryptionKey = "B@|@j!";

        private static byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xab, 0xcd, 0xef };

        public static string Decrypt(string stringToDecrypt)

        {

            //URL Decrytion Avoid Reserved Characters

            stringToDecrypt = stringToDecrypt.Replace("-2F-", "/");

            stringToDecrypt = stringToDecrypt.Replace("-21-", "!");

            stringToDecrypt = stringToDecrypt.Replace("-23-", "#");

            stringToDecrypt = stringToDecrypt.Replace("-24-", "$");

            stringToDecrypt = stringToDecrypt.Replace("-26-", "&");

            stringToDecrypt = stringToDecrypt.Replace("-27-", "'");

            stringToDecrypt = stringToDecrypt.Replace("-28-", "(");

            stringToDecrypt = stringToDecrypt.Replace("-29-", ")");

            stringToDecrypt = stringToDecrypt.Replace("-2A-", "*");

            stringToDecrypt = stringToDecrypt.Replace("-2B-", "+");

            stringToDecrypt = stringToDecrypt.Replace("-2C-", ",");

            stringToDecrypt = stringToDecrypt.Replace("-3A-", ":");

            stringToDecrypt = stringToDecrypt.Replace("-3B-", ";");

            stringToDecrypt = stringToDecrypt.Replace("-3D-", "=");

            stringToDecrypt = stringToDecrypt.Replace("-3F-", "?");

            stringToDecrypt = stringToDecrypt.Replace("-40-", "@");

            stringToDecrypt = stringToDecrypt.Replace("-5B-", "[");

            stringToDecrypt = stringToDecrypt.Replace("-5D-", "]");

            byte[] inputByteArray = new byte[stringToDecrypt.Length + 1];

            try

            {

                key = System.Text.Encoding.UTF8.GetBytes(sEncryptionKey);

                DESCryptoServiceProvider des = new DESCryptoServiceProvider();

                inputByteArray = Convert.FromBase64String(stringToDecrypt);

                System.IO.MemoryStream ms = new System.IO.MemoryStream();

                CryptoStream cs = new CryptoStream(ms,

                  des.CreateDecryptor(key, IV), CryptoStreamMode.Write);

                cs.Write(inputByteArray, 0, inputByteArray.Length);

                cs.FlushFinalBlock();

                System.Text.Encoding encoding = System.Text.Encoding.UTF8;

                return encoding.GetString(ms.ToArray());

            }

            catch (Exception e)

            {

                return e.Message;

            }

        }

        public static string Encrypt(string stringToEncrypt)

        {

            string returnstring = "";

            try

            {

               

                key = System.Text.Encoding.UTF8.GetBytes(sEncryptionKey);

                DESCryptoServiceProvider des = new DESCryptoServiceProvider();

                byte[] inputByteArray = Encoding.UTF8.GetBytes(stringToEncrypt);

                System.IO.MemoryStream ms = new System.IO.MemoryStream();

                CryptoStream cs = new CryptoStream(ms,

                  des.CreateEncryptor(key, IV), CryptoStreamMode.Write);

                cs.Write(inputByteArray, 0, inputByteArray.Length);

                cs.FlushFinalBlock();

                returnstring = Convert.ToBase64String(ms.ToArray());

                

                //URL Encryption Avoid Reserved Characters

                returnstring = returnstring.Replace("/", "-2F-");

                returnstring = returnstring.Replace("!", "-21-");

                returnstring = returnstring.Replace("#", "-23-");

                returnstring = returnstring.Replace("$", "-24-");

                returnstring = returnstring.Replace("&", "-26-");

                returnstring = returnstring.Replace("'", "-27-");

                returnstring = returnstring.Replace("(", "-28-");

                returnstring = returnstring.Replace(")", "-29-");

                returnstring = returnstring.Replace("*", "-2A-");

                returnstring = returnstring.Replace("+", "-2B-");

                returnstring = returnstring.Replace(",", "-2C-");

                returnstring = returnstring.Replace(":", "-3A-");

                returnstring = returnstring.Replace(";", "-3B-");

                returnstring = returnstring.Replace("=", "-3D-");

                returnstring = returnstring.Replace("?", "-3F-");

                returnstring = returnstring.Replace("@", "-40-");

                returnstring = returnstring.Replace("[", "-5B-");

                returnstring = returnstring.Replace("]", "-5D-");

                return returnstring;

            }

            catch (Exception e)

            {

                return e.Message;

            }

        }

    }