How are they going to get that passkey, Okie? Torture of the iPhone's owner? It is not stored on the iPhone. The only thing representing that passcode is a One Way HASH. . . and that is in the Secure Element inside the processor, inaccessible from the outside, and only accessible to the processor for comparison with a newly generated HASH from a newly input passcode entered by the user, which cannot be retained.
Keep in mind, it is a two factor because the passcode is entangled with the iPhone's UUID. So any putative hacker will also require the UUID from the internals of the iPhone. The UUID is NOT on the outside of the iPhone. . . nor is it available from the iPhone without being able to unlock it. OOPS. So the hacker needs both the passcode from the user and the UUID from inside the iPhone. Then to find the real encryption key, our hacker ALSO needs the algorithm which is used to entangle the two to actually generate to encryption key. Good luck with all of that.
Now do you begin to appreciate the mountain that must be climbed???
Cook would be jailed for doing NSA a favor? Hardly.
One thing is certain to me, anything stored electronically is a risk. Saying it’s impossible it foolish. You may not be able to brute force decrypt, but anyone with the tools and access to your laptop for more than a few minutes would have a field day. Remember Stuxnet and its variants? There are even better ones out there now naturally.