Where would the content for in-app purchases come from?

I've been reading up on in-app purchases and I have been able to figure out that th开发者_开发问答ere are two options to provide purchased content to the user:

1: On a successful transaction, unlock content that was already part of the app

2: On a successful transaction, download content from my own CMS

Are these the only ways to provide in-app purchase content? Which one is preferable?

I would think that #2 would be preferable because:

If you unlock already downloaded content, you will need to save this information somehow. Most apps that I have seen use NSUserDefaults which is really easy to hack into.

If you are going to choose #1, however, I would strongly suggest an encrypted plist (based off of the device UDID / Serial) for saving the unlocked content.