The Secure Enclave in the T1 and all iPhones since the 5s has a unique key in the AES engine's silicon, that cannot be read even from the Secure Enclave's firmw

The Secure Enclave in the T1 and all iPhones since the 5s has a unique key in the AES engine's silicon, that cannot be read even from the Secure Enclave's firmware. This key is "tangled" with user-supplied keys for per-device access to data. I assume the T2 offers this same feature. See UID in the glossary (page 80) or under Hardware security features (page 12) of the iOS 11 Security Guide https://www.apple.com/business/docs/iOS_Security_Guide.pdf https://www.apple.com/business/docs/iOS_Security_Guide.pdf