Some software lets you save files with a password. The more furtive you get though, the more chance you'll forget how to access the files. At least that's what I do. If I want to lose something forever, I put it in a Safe Place.

You can e-mail your writing to an address, as e-mail programs require passwords. Google lets you take out more than one account. You could also start a blog that only you have access to, although you may end up wanting to share your writing with people who have similar interests. There might not be anyone local, but I bet there are loads of people on the internet.