There are two main problems with this approach. The first is that you won't remember the password. History has shown us that unless people regularly use a password, they'll forget it. If you do choose an easy to remember password - the chances are that it will be easy to guess. The second problem is that you're relying on a weak second factor - that the file is "hard" to find. If you have created a bitly link, the chances are that a search engine has already picked up the file.