All this does is munge the filename/directoryname so it doesn't show up in Finder. You can still see everything with an ls -la from a shell prompt and you can even see all the content. There is no encryption or anything useful here. You are much better off using the built-in OSX FileVault (System Preferences - Security) if you want to make sure bad guys can't get at your files if they get a hold of your computer.
This thing is basically equivalent to "mv foo .foo" when you make foo secret and "mv .foo foo" to bring it back out of hiding. I don't think this qualifies as a useful application.