I've been searching and searching for what seems days and have not come up with any definitive answer on a solution to my problem.
To explain without going into terrible detail I am building a store, this store does NOT have a cart system, so the user will purchase one item at a time, possibly with a quantity system but that's beside the point, it will also NOT have a login or registration system for users.
In the accepting payments department we are relying on Stripe with some PHP and ajax so handle that end, we have used the before over SSL with great success and I am confident in it's security abilities.
I haven't done a terrible amount of research in how secure Parse's backend is but it seems seemingly simple to grab those keys and use them like I mentioned above.
For reference here is the Adapter that I am using that will maybe give you a better idea of how it's working.
I'm really hoping someone can shed some light on this subject because I am at the end of my rope it seems here, I just can't seem to wrap my head around this.