From the latest Apple vs FBI story it's known that Apple is technically capable of changing the boot-loader of the iPhone to provide interface for brute-force finding of 4-digit password.
I'm wondering, is it theoretically possible for Apple or any other software any hardware company to create a fully-encrypted smartphone. By fully-encrypted smartphone I mean that it would have the next properties:
- The device is encrypted via some key (possible implementations, but a requirement: 4-digit, x-length alphanumerical, TouchID, retinal scan, etc.
- Neither manufacturer nor FBI can decrypt data is a timely manner (100+ years with currently available hardware).
- It's not possible to change a part of it's software or hardware without data being lost.
- The chances to recover data after data wipe are negligible.
Please think of physical access to the RAM and Flash memory. No one should be able to "connect" to RAM memory while device is working and read unencrypted user data.
Also, the smartphone itself should behave just like any other modern smartphone - it should have apps downloadable from the store, software updates, etc.
Update: Let's ignore software or hardware exploits, worms, vulnerability, etc.