With version 1.14 you can now encrypt outline files you edit with Fargo.
I recommend starting with one file, to keep life simple, and put all the stuff in there that you'd like to keep away from prying eyes.
You can't encrypt files you want to publish.
Pick a good password. Don't store your password in your Dropbox folder. That would negate all the value to using encryption.
Please report any problems. Provide screen shots and details sufficient that we can reproduce the problem. If we can't reproduce it, there's no way to find or fix it.
If all goes well, I'll announce this feature on Scripting News tomorrow morning.