Open up isolated storage based on identity of user + assembly evidence : IsolatedStorage « File Directory Stream « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. File Directory Stream
3. IsolatedStorage

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

using System.IO;
using System.IO.IsolatedStorage;
using System.Security.Permissions;

[assembly: IsolatedStorageFilePermission(SecurityAction.RequestMinimum, UsageAllowed = IsolatedStorageContainment.AssemblyIsolationByUser)]
public class MainClass{
    public static void Main()
    {
      using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForAssembly())
      {
        using (IsolatedStorageFileStream isStream = new IsolatedStorageFileStream("MyData.txt",FileMode.OpenOrCreate, store))
        {
          using (StreamWriter sw = new StreamWriter(isStream))
          {
            sw.WriteLine("This is my data.");
            sw.WriteLine("Cool, huh?");
          }
        }
      }
    }
}