Keep on using Dropbox. If you use all that proprietary, anti-privacy rubbish then you can assume they can access to all your information anyway.

On the bright side, I wouldn't worry too much about the NSA browsing through your cat pics.

Or if you're willing to put in some work you can try something like this https://fak3r.com/2009/09/14/howto-build-your-own-open-sourc...