CNSA-216-FP/FWA_MAIN/Crypt.cs

using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Web.UI.WebControls;
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using System.Web;

namespace FWA_MAIN
{
    public class Crypt
    {
        static private string encryptKey =
            "CXvA@xsFmBik#E4#7tf4zY7JK^qaTUwFYw^QuC7sipSyBPfkS$qFFU%ZQmRb5GY85unfCmEw@dK7Bhiyt%3asL62yygk6x6D@@D8CUnJfF8@F$C9vtJgGwNhmSxvo#Lh";

        static private string encryptSalt =
            "gab-purgatory-studio-atlantic-ladle-challenge-slaw-unshaken-eastward-caring-deftly-devious-crudeness-walrus-glorifier-unsteady-sauciness-feminist-jailbreak-upside";

        static public string Encrypt(string cleartext)
        {
            byte[] plainText = Encoding.UTF8.GetBytes(cleartext);

            using (RijndaelManaged rijndaelCipher = new RijndaelManaged())
            {
                PasswordDeriveBytes secretKey = new PasswordDeriveBytes(Encoding.ASCII.GetBytes(encryptKey),
                    Encoding.ASCII.GetBytes(encryptSalt));
                using (ICryptoTransform encryptor =
                       rijndaelCipher.CreateEncryptor(secretKey.GetBytes(32), secretKey.GetBytes(16)))
                {
                    using (MemoryStream memoryStream = new MemoryStream())
                    {
                        using (CryptoStream cryptoStream =
                               new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
                        {
                            cryptoStream.Write(plainText, 0, plainText.Length);
                            cryptoStream.FlushFinalBlock();
                            string base64 = Convert.ToBase64String(memoryStream.ToArray());

                            // Generate a string that won't get screwed up when passed as a query string.
                            string urlEncoded = HttpUtility.UrlEncode(base64);
                            return urlEncoded;
                        }
                    }
                }
            }
        }

        static public string Decrypt(string cleartext)
        {
            byte[] encryptedData = Convert.FromBase64String(cleartext);
            PasswordDeriveBytes secretKey = new PasswordDeriveBytes(Encoding.ASCII.GetBytes(encryptKey),
                Encoding.ASCII.GetBytes(encryptSalt));

            using (RijndaelManaged rijndaelCipher = new RijndaelManaged())
            {
                using (ICryptoTransform decryptor =
                       rijndaelCipher.CreateDecryptor(secretKey.GetBytes(32), secretKey.GetBytes(16)))
                {
                    using (MemoryStream memoryStream = new MemoryStream(encryptedData))
                    {
                        using (CryptoStream cryptoStream =
                               new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
                        {
                            byte[] plainText = new byte[encryptedData.Length];
                            cryptoStream.Read(plainText, 0, plainText.Length);
                            string utf8 = Encoding.UTF8.GetString(plainText);
                            return utf8.Trim('\0');
                        }
                    }
                }
            }
        }
    }
}