A shopping cart application I'm working on jumps domain when it goes from the normal page into the submit-your-details page.
Long story short there are two copies of the application deployed: one server for the 'main' site and one server with an ev certificate running on https for the customer details (including payment; this is a PCI compliance issue).
My question is this:
When jumping from http://shop.domain -> https://secure.domain (and back, if the user browses back), how can I preserve the session?
Its trivial to pass cookies cross domain using JSONP, but I have no idea what to do with them on the remote side to 'reconnect' to the session.
I have read various things about rolling your own custom session provider, etc. etc. but I haven't found one that is more than just generic advice; certainly no examples of how this might be used to rejoin a session.
This is a for an MVC3 c# web app.