If you want it private, you probably shouldn’t have it on a computer period. It’s way too easy to duplicate and manipulate electronic files.

Every letter you type online gets passed through multiple sites before it gets to the server. There really is no such thing as online security without a lot of hassle. (You can investigate a site with Secure Socket Layers like online merchants use, but that seems like a lot of extra work for little payoff.)

I guarantee anything you have on the web will be seen by others, no matter how much you try to secure it.

Go with the old standby notebook with a lock.