But Apple is refusing to help the FBI break into the phone. CEO Tim Cook argued in an open letter that "it would be the equivalent of a master key, capable of opening hundreds of millions of locks - from restaurants and banks to stores and homes. No reasonable person would find that acceptable."
However, we can tell from the FBI's court order and Apple's own security documentation what it would like if Apple decided to play ball and let the FBI hack the phone.
Here's the first thing you need to know: Apple doesn't just have a magic key it could hand the FBI that would unlock an iPhone. Instead, the FBI is asking Apple to remove limitations that make it impossible for the FBI to guess the iPhone password without wiping the device.
Here, via security firm Trail of Bits, is what the FBI is asking Apple to do:
[Apple] will bypass or disable the auto-erase function whether or not it has been enabled;
[Apple] will enable the FBI to submit passcodes to the SUBJECT DEVICE for testing electronically via the physical device port, Bluetooth, Wi-Fi, or other protocol available on the SUBJECT DEVICE; and
[Apple] will ensure that when the FBI submits passcodes to the SUBJECT DEVICE, software running on the device will not purposefully introduce any additional delay between passcode attempts beyond what is incurred by Apple hardware.
Essentially the FBI wants Apple's help in hacking the iPhone. It wants to be able to directly enter passcodes into the iPhone, without risking the data being wiped. All Apple needs to do is modify the software to remove the auto-erase function and then the FBI would be free to try as many passwords as it likes.
Devices like IP-boxes have been used in the past to brute-force iPhone passwords. They connected directly to the iPhone and ran through a series of passwords until they guessed the right one:
But the FBI realises that there is one thing Apple can't fix: the hardware delay built into the iPhone. Apple can, in theory, modify its mobile operating system to let the FBI guess the password, but it can't touch a piece of hardware called the secure enclave.
Apple's iOS security guide document explains that the secure enclave is a separate processor inside an iPhone. It handles all of the secure stuff like checking whether a fingerprint or password is correct. The problem for the FBI is that the secure enclave introduces a delay between password attempts, which would mean that it would take much more time to open up an iPhone.
Apple can't just "fix" the secure enclave, either. We don't know exactly what would happen if it was tamped with, but Trail of Bits suggests that it could wipe any saved passwords, effectively erasing the device.
