Windows Phone 8 and Storage - Encrypt Data for Windows Phone

using System.IO;
using System.IO.IsolatedStorage;
using System.Text;
using System.Security.Cryptography;


namespace myPhoneApp
{

    public partial class MainPage : PhoneApplicationPage
    {
        // Constructor
        public MainPage()
        {
            InitializeComponent();
        }

        private string FilePath = "pinfile";

        private void BtnStore_Click(object sender, RoutedEventArgs e)
        {
            // Convert the PIN to a byte[].
            byte[] PinByte = Encoding.UTF8.GetBytes(TBPin.Text);

            // Encrypt the PIN by using the Protect() method.
            byte[] ProtectedPinByte = ProtectedData.Protect(PinByte, null);

            // Store the encrypted PIN in isolated storage.
            this.WritePinToFile(ProtectedPinByte);

            TBPin.Text = "";

        }

        private void WritePinToFile(byte[] pinData)
        {
            // Create a file in the application's isolated storage.
            IsolatedStorageFile file = IsolatedStorageFile.GetUserStoreForApplication();
            IsolatedStorageFileStream writestream = new IsolatedStorageFileStream(FilePath, System.IO.FileMode.Create, System.IO.FileAccess.Write, file);

            // Write pinData to the file.
            Stream writer = new StreamWriter(writestream).BaseStream;
            writer.Write(pinData, 0, pinData.Length);
            writer.Close();
            writestream.Close();
        }

        private void BtnRetrieve_Click(object sender, RoutedEventArgs e)
        {
            // Retrieve the PIN from isolated storage.
            byte[] ProtectedPinByte = this.ReadPinFromFile();

            // Decrypt the PIN by using the Unprotect method.
            byte[] PinByte = ProtectedData.Unprotect(ProtectedPinByte, null);

            // Convert the PIN from byte to string and display it in the text box.
            TBPin.Text = Encoding.UTF8.GetString(PinByte, 0, PinByte.Length);

        }


        private byte[] ReadPinFromFile()
        {
            // Access the file in the application's isolated storage.
            IsolatedStorageFile file = IsolatedStorageFile.GetUserStoreForApplication();
            IsolatedStorageFileStream readstream = new IsolatedStorageFileStream(FilePath, System.IO.FileMode.Open, FileAccess.Read, file);

            // Read the PIN from the file.
            Stream reader = new StreamReader(readstream).BaseStream;
            byte[] pinArray = new byte[reader.Length];

            reader.Read(pinArray, 0, pinArray.Length);
            reader.Close();
            readstream.Close();

            return pinArray;
        }

 
    }
}