using System;

using System.IO;

using System.Text;

using System.Security.Cryptography;

​

public class Program

{       

    public static void Main()

    {

        var hash="SQn/6RXfyvX/Tog9Pm429SAchHcLAQKwLbnb7NRAiwI=";

        Console.WriteLine("Decrypted Text : " + Decrypt(hash));

    }

        public static string Decrypt(string cipherText)

        {

            var salt="0812bf590a1b04eda67b90c613dd1b3a";

            string EncryptionKey = salt;

            byte[] cipherBytes = Convert.FromBase64String(cipherText);

            using (Aes encryptor = Aes.Create())

            {

                Rfc2898DeriveBytes pdb = new

                    Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });

                encryptor.Key = pdb.GetBytes(32);

                encryptor.IV = pdb.GetBytes(16);

                using (MemoryStream ms = new MemoryStream())

                {

                    using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateDecryptor(), CryptoStreamMode.Write))

                    {

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

                        cs.Close();

                    }

                    cipherText = Encoding.Unicode.GetString(ms.ToArray());

                }

            }

            return cipherText;

        }

​

}