So far I have read how you can Access external (o)data sources from a SharePoint 2013 App (using External ContentTypes). However, I haven't come across a solution for accessing a non-public data source. Using a farm solution I can store credentials in a Secure Store Application. However, I don't think an App can be granted Access to it. I tried to deploy my App both at Tenant and App Scope with the same result (error: not authenticated). If I Import the BCD Model into the central BCS Service Application it works like charm. Am I right in assuming that it's not possible to Access non-public data sources from an App using ETCs?
Thanks for some pointers, Marco