Because the app is implemented with JavaScript and the PhoneGap framework I need PHP proxy scripts (same origin policy).
Of course the data is sent encrypted. I don't understand why you think they are unencrypted.
Even the sessionIDs are encrypted.
The server scripts are just forwarding the data to the agencies and will bring back the statistics.
I'm not storing any user data on my servers.
Of course the users have to trust my app, because it could be used to theft user data, but this is possible with every app that requiers user data.
I'm showing my full name and email address in the app description and on the info page inside the app.
It's not my intention to steal any data.