Thanks. I knew you knew your stuff. . . I posted the details for the benefit of everyone on here. The Secure Enclave is much more hardened than the Encryption Engine and I sincerely doubt that it will be as easy to get at without destroying/damaging what they are after.
It is difficult being attacked by the know-nothings who are convinced that Apple is doing this purely for PR purposes. . . these short-sighted people cannot see the very serious philosophical underpinnings of what Apple is doing or the long-term consequences of what a loss means for them personally.
and follow the links even deeper if you like. Numerous people have spent a great deal of time in prison for violating these copyright/patent/import and export laws.
All of your numbers of possible combinations and permutations for the AES-256 bit encryption assume a brute force attack. This paper published 22 years ago was "authorized" (ie allowd to be published from worked researched years earlier) and presents mathematical attacks on block ( and stream ) cyphers which significantly reduce the complexity in both time and space of a brute force attack. I am sure that world class mathematicians employeed by numerous .govs around the world have even more tricks up their sleeves. US laws regarding encryption do not protect you from those people who have the brains and resources to attack these cyphers with better methods than brute force only from those who don't have the requisite resources.
This paper is from Canada. I assume the pdf is free of adobe "back doors". (LOL)
Linear differential cryptanalysis
The first casualty of war is truth! Loose lips sink ships! Believe half of what you see and none of what you hear! etc.