Question

In my game I plan to save the users highest score to then be transferred to my server at a later time, I was planning to do this by saving the score in a .txt file in Isolated Storage.

What precautions should I take to avoid users from editing the file itself or being able to spoof packets to trick the server into saving fake scores?

I’m considering encrypting the data before saving in a way my server can read later on.

So how secure is Isolated Storage?
What encryption should I look at implementing considering my App is .NET(C#) and my server uses PHP.

Answer 1

Use ProtectedData, and store the byte[] to IsolatedStorage.

ProtectedData Class (MSDN)

Edit: If you want this to work serverside, encrypt with, say using AesManaged using a key. use ProtectedData to store the key for your AES encryption. That way, the user cannot find out your key.