Better: get your own computer, and be the only one who knows how to use it.
I could have research all on my desktop, if I change the extension so it's an unreadable file, not only would it never be touched, but just in case some one got on my computer, they'd have no idea what I did to the file in order to play it.
Hell, I probably wouldn't even have to change the extension, this is mine, I bought it, mine.