How to ensure/determine that a post is coming from an specific application running on an iPhone/iTouch?

Question

Building an iPhone OS application that will allow users to anonymously post information to a web application (in my particular case it will be a Rails based site) ... and I

Answer 1

I would suggest the following approach.

Build an ssl enabled access to your rails app. Now create a user account for every plattform you want to use and enable your applications to log in with the correct key. If you use the ssl standard in a correct way there shouldn't be a way to sniff the password and you can use standard components on the rail and the phone side of your app.

You then need to secure the login credentials on your phone with the appropriate technics. Eg. put it in the keychain on the Iphone.