A former student of mine, Kanishka Goel, has pointed out this interesting article:
Last week I wrote about Apple’s new default encryption policy for iOS 8. Since that piece was intended for general audiences, I mostly avoided technical detail. But since some folks (and apparently the Washington Post!) are still wondering about the nitty-gritty details of Apple’s design might work, I thought it might be helpful to sum up what we know and noodle about what we don’t.
To get started, it’s worth pointing out that disk encryption is hardly new with iOS 8. In fact, Apple’s operating system has enabled some form of encryption since before iOS 7. What’s happened in the latest update is that Apple has decided to protect much more of the interesting data on the device under the user’s passcode. This includes photos and text messages — things that were not previously passcode-protected, and which police very much want access to.
via A Few Thoughts on Cryptographic Engineering: Why can’t Apple decrypt your iPhone?.
You can read more about Apple iOS Security here.