What technique can protect a secret from a fully trusted user?

Question

I am programming a system using C#. My program generates a small message (a hash digest for a file) that I want to store on the hard disk - but I don\'t want the user to be

Answer 1

My program generates a small message (a hash digest for a file) that I want to store on the hard disk - but I don't want the user to be able to read it.

The user has full control over their machine. If your software can read it, so can the user, with a little bit of effort.

Instead of fighting a losing battle against your customers, it's probably better to accept that "It's the users machine, not mine" and don't bother with anything excessive - just Base64 encode it or something.

Why do you need to stop the user reading a hash digest anyway?