using System;

using System.Security.Cryptography;

using System.Text;

public class Program

{

    static string key = "KEY_HERE";

    public static void Main()

    {

        string encrypted = "Encrypted_String";

        Console.WriteLine("Decrypted: " + Decrypt(encrypted, key));

    }

    public static string Decrypt(string value, string key)

    {

        byte[] buffer = Convert.FromBase64String(value.Replace(" ", "+"));

​

        using (DESCryptoServiceProvider des = new DESCryptoServiceProvider())

        {

            des.BlockSize = 64;

            des.KeySize = 64;

            des.Mode = CipherMode.ECB;

            des.Padding = PaddingMode.PKCS7;

            des.Key = Encoding.UTF8.GetBytes(key);

            using (ICryptoTransform transform = des.CreateDecryptor())

                buffer = transform.TransformFinalBlock(buffer, 0, buffer.Length);

            des.Clear();

        }

​

        return Encoding.UTF8.GetString(buffer);

    }   

}