I understand what you are saying about 256-bit AES encryption.
Is that the level of encryption protecting a user's data on a newer iphone?
My wife's iphone requires her to enter a 4 digit PIN number to start. That is certainly not 256 bits. How would she make use of this very strong encryption as described in this article?
The data on iPhones and other iOS 8 and iOS 9 devices have been encrypted to AES 256 bit encryption since Apple started using those versions. It doesn't matter what level of passcode you are using to unlock your iPhone or iPad. Whether you use 4 or 6 numbers, or choose to use a more complex passcode of alphanumeric characters with other symbols, the passcode you use will be entangled with a 128 character UUID that is imbedded inside the A8 or A9 processor of the device. That passcode and UUID are used to construct the 256 bit AES key to encrypt the data.
If she wants a more complex passcode, go into settings, TouchID and Passcode, you'll be required to enter your current passcode, then select passcode options, again you'll have to enter your current passcode, you can then select from four digit, six digit, or complex pass code options. You can then change your wife's passcode, after selecting your option.