If you can break AES... then the NSA would love to have a word with you :P The F...

superuser2 · on Feb 17, 2016

The user's password is not used to create the crypto key; it is randomly generated and burned in at the factory.

X-Istence · on Feb 17, 2016

It is used to create the crypto key, using a password based key derivation function, using the user's password fed into the PBKDF the output is the key used for encryption/decryption.

The users device key is mixed into that PBKDF. Without both parts of the equation, you have nothing.

For your reading enjoyment: https://www.apple.com/business/docs/iOS_Security_Guide.pdf

Specifically page 11 the diagram at the bottom.