random

a.cs

using System;
using System.ComponentModel;
using System.Drawing;
using System.IO;
using System.Security.Cryptography;
using System.Text;

public class HelloWorld
{
    public static void Main(string[] args)
    {
        Console.WriteLine(HelloWorld.Decrypt(Encoding.ASCII.GetString(new byte[]
        {
            65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65,
            80, 103, 117, 72, 103, 90, 90, 122, 54, 112, 69, 43, 116, 69, 116, 55, 77, 99, 69, 77,
            65, 83, 113, 81, 79, 55, 104, 102, 107, 48, 53, 115, 113, 49, 111, 56, 65, 101, 79, 97,
            83, 78, 66, 68, 112, 115, 57, 82, 113, 101, 47, 98, 109, 98, 57, 88, 104, 79, 122, 53,
            76, 104, 72, 99, 74, 74, 110, 115, 116, 121, 121, 53, 113, 79, 52, 83, 87, 88, 78, 107,
            88, 100, 118, 86, 55, 103, 61, 61
        })));
    }
    public static string Decrypt(string cipherText)
    {
    	byte[] salt = Convert.FromBase64String(cipherText.Substring(0, 20));
    	cipherText = cipherText.Substring(20).Replace(" ", "+");
    	byte[] array = Convert.FromBase64String(cipherText);
    	byte[] bytes = new byte[]
    	{
    		116,
    		101,
    		115,
    		116,
    		49,
    		50,
    		51
    	};
    	using (Aes aes = Aes.Create())
    	{
    		Rfc2898DeriveBytes rfc2898DeriveBytes = new Rfc2898DeriveBytes(Encoding.ASCII.GetString(bytes), salt);
    		aes.Key = rfc2898DeriveBytes.GetBytes(32);
    		aes.IV = rfc2898DeriveBytes.GetBytes(16);
    		using (MemoryStream memoryStream = new MemoryStream())
    		{
    			using (CryptoStream cryptoStream = new CryptoStream(memoryStream, aes.CreateDecryptor(), CryptoStreamMode.Write))
    			{
    				cryptoStream.Write(array, 0, array.Length);
    				cryptoStream.Close();
    			}
    			cipherText = Encoding.Unicode.GetString(memoryStream.ToArray());
    		}
    	}
    	return cipherText;
    }
}