using System;

using System.IO;

using System.Text;

​

namespace ConsoleApp1

{

    class Program

    {

        static void Main(string[] args)

        {

            string data = "WUFCQUsLGRhWXFhbUEcYRlFFXlBfXFBVVBtVXlUeCVJZVwpKYV9adRgZY1lFQFJdGA==";

            string secret1 = "15618670379";

            string secret2 = "156181670379";

​

            byte[] bytes = Convert.FromBase64String(data);

​

            var s = TextDecrypt(bytes, secret2);

​

            Console.WriteLine(s);

        }

​

        public static string TextDecrypt(byte[] data, string secretKey)

        {

            byte[] key = Encoding.UTF8.GetBytes(secretKey);

​

            for (int i = 0; i < data.Length; i++)

            {

                data[i] ^= key[i % key.Length];

            }

​

            return Encoding.UTF8.GetString(data, 0, data.Length);

        }

    }

}

​