I’ve got a native app (it runs on Linux/OSX/Windows) that serves webpages to smartphones on the local network. Users run the app, then point their phone’s browser at the app’s server. For example:
http://192.168.1.10 The phones now interact with the app through the server it’s running.
The web pages served to the phone benefit greatly from fullscreen, device orientation, and device motion features but those features are planned to require HTTPS only.
The app is intended to be installed by average users not technical users (think mom, dad, sister, brother) so installing certificates manually is a non-starter and installing anything whatsoever on the phone is also a non-starter. Asking users to set up custom DNS or configure their routers is also a non-starter.
So, the question is is it possible to enable HTTPS (local server on lan serving to local machines on same lan) in such a scenario and can Let’s Encrypt help with that?
Note: there is an rendezvous server so users don’t have to type ip addresses but that’s mostly irrelevant. Once the rendezvous server has directed the phones to the local server running the app all communication is on the local network between the app and the phones.
If you’re curious the app is here.