I have read all this discussion, but with my bad english, it is difficult.
I have not found the solution of my question:
I ahve built an appli in wich the users must save the an array in webstorage, in the cache of the computer (ipad).
And i want create a external save to dropbox with your plugin.
But my users have usually no experience to use API key.
Is it possible for theim to connect with their Username and Password (of their personal DropBox)? It would be nice and simple !