@xnull: interesting, my download of that file has slightly different text:

    The device’s unique ID (UID) and a device group ID (GID) are AES 256-bit keys *fused* into the application processor during manufacturing. No software or firmware can read them directly; they can see only the results of encryption or decryption operations performed using them. The UID is unique to each device and is not recorded by Apple or any of its suppliers.

(emphasis added)

That language, along with this gem later:

    The passcode is “tangled” with the device’s UID, so brute-force attempts must be performed on the device under attack

lead me to believe they're describing a PUF. By the way, can you save a local copy of that file? My SHA256 is b9d1f5290ebe56780af692e2b12037d6b7e085ef1f6050c1e27ea8426f94bfcc, what's yours?

>The threat model here is not Apple, but the manufacturer. In this case the options I mentioned earlier would allow very fast attacks that could be launched selectively at target devices later on.

Right, I understand. No matter what Apple says, you can't verify, so you can't trust.

>Definitely not verifiable of falsifiable by you or by me. I would suggest however that the claims and reputation of the Secure Enclave is not deserved. Finally, in crypto, skepticism is a feature.

Well, who am I to say whether Secure Enclave lives up to its hype? But definitely agreed about skepticism...