I always see this document linked to on HN even though it's a (relatively) high level description of what is happening on the device.
Besides, there is absolutely no guarantee that Apple isn't just being "semi-open" with their security mechanisms. In other words, who is to say that there are no redundant, undocumented mechanisms in place?
But I will concede that Apple is ahead of everyone else in this regard. It's just that I think Apple being ahead doesn't mean that the information they're providing is enough.
You're right that a whitepaper isn't enough to be really sure. That takes disassembly of binaries and then you are still stuck with judging the trustworthiness of the hardware and I'm not sure how you solve that problem.
Besides, there is absolutely no guarantee that Apple isn't just being "semi-open" with their security mechanisms. In other words, who is to say that there are no redundant, undocumented mechanisms in place?
But I will concede that Apple is ahead of everyone else in this regard. It's just that I think Apple being ahead doesn't mean that the information they're providing is enough.