// compile in https://dotnetfiddle.net/

​

using System;

using System.IO;

using System.Security.Cryptography;

using System.Text;

​

public class CR

{   

    private const string K = "667912";

​

    private const string I = "1L1SA61493DRV53Z";

​

    private const string SA = "1313Rf99";

    public static void Main()

    {

        Console.WriteLine("Will it decrypt?");

        string code = DS("yyEq0Uvvhq2uQOcWG8peLoeRQehqip/fKdeG/kjEVb4=");

        Console.WriteLine(code);

        return;

    }

​

    public static string DS(string EncryptedString)

    {

        if (string.IsNullOrEmpty(EncryptedString))

        {

            return string.Empty;

        }

        return RD(EncryptedString, "667912", "1313Rf99", 3, "1L1SA61493DRV53Z", 256);

    }

​

    public static string ES(string PlainString)

    {

        if (string.IsNullOrEmpty(PlainString))

        {

            return string.Empty;

        }

        return RE(PlainString, "667912", "1313Rf99", 3, "1L1SA61493DRV53Z", 256);

    }

​

    private static string RE(string plainText, string passPhrase, string saltValue, int passwordIterations, string initVector, int keySize)

    {

        //Discarded unreachable code: IL_00b9

        byte[] bytes = Encoding.ASCII.GetBytes(initVector);

        byte[] bytes2 = Encoding.ASCII.GetBytes(saltValue);

        byte[] bytes3 = Encoding.ASCII.GetBytes(plainText);

        Rfc2898DeriveBytes rfc2898DeriveBytes = new Rfc2898DeriveBytes(passPhrase, bytes2, passwordIterations);

        byte[] bytes4 = rfc2898DeriveBytes.GetBytes(checked((int)Math.Round((double)keySize / 8.0)));

        AesCryptoServiceProvider aesCryptoServiceProvider = new AesCryptoServiceProvider();

        aesCryptoServiceProvider.Mode = CipherMode.CBC;

        ICryptoTransform transform = aesCryptoServiceProvider.CreateEncryptor(bytes4, bytes);

        using (MemoryStream memoryStream = new MemoryStream())

        {

            using (CryptoStream cryptoStream = new CryptoStream(memoryStream, transform, CryptoStreamMode.Write))

            {

                cryptoStream.Write(bytes3, 0, bytes3.Length);

                cryptoStream.FlushFinalBlock();

                byte[] inArray = memoryStream.ToArray();

                memoryStream.Close();

                cryptoStream.Close();

                return Convert.ToBase64String(inArray);

            }

        }

    }

​

    private static string RD(string cipherText, string passPhrase, string saltValue, int passwordIterations, string initVector, int keySize)

    {

        byte[] bytes = Encoding.ASCII.GetBytes(initVector);

        byte[] bytes2 = Encoding.ASCII.GetBytes(saltValue);

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

        Rfc2898DeriveBytes rfc2898DeriveBytes = new Rfc2898DeriveBytes(passPhrase, bytes2, passwordIterations);

        checked

        {

            byte[] bytes3 = rfc2898DeriveBytes.GetBytes((int)Math.Round((double)keySize / 8.0));

            AesCryptoServiceProvider aesCryptoServiceProvider = new AesCryptoServiceProvider();

            aesCryptoServiceProvider.Mode = CipherMode.CBC;

            ICryptoTransform transform = aesCryptoServiceProvider.CreateDecryptor(bytes3, bytes);

            MemoryStream memoryStream = new MemoryStream(array);

            CryptoStream cryptoStream = new CryptoStream(memoryStream, transform, CryptoStreamMode.Read);

            byte[] array2 = new byte[array.Length + 1];

            int count = cryptoStream.Read(array2, 0, array2.Length);

            memoryStream.Close();

            cryptoStream.Close();

            return Encoding.ASCII.GetString(array2, 0, count);

        }

    }

}

​