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> That is not exactly true. They wrote the OS, they designed the phone, they know where the JTAG connectors are. Cracking the phone apart and putting is logic board up on a debugger would likely enable them to bypass security.

No, they can't. A quick update to recent hardware practices: modern SoCs like Apple's have something called "Secure Enclave Processor" that's on-die. This is the first thing to start when the chip is powered up, the thing that loads a cryptographically-signed bootloader, and the thing that gates a lot of IO with the outside world (like the NAND).

Hardware encryption on consumer hardware has existed for over a decade (look up Intel's TPM), and while it hasn't obviously taken hold on the more open Intel world, locked-down hardware platforms like Apple's top-to-bottom design has had much more liberty in implementing secure computing.

Furthermore, all debug/probing features can be disabled by fuses at the factory. The manufacturer can test the chip with those features on, and once verified, blow those fuses. No-one's JTAG-debugging that chip, not even Apple.

That said, Apple's focus on security and privacy ramped up in recent years. You want more secure, get more recent hardware. The downside, of course, is that if even Apple can't hack the software... neither can you.



"Computationally-signed bootloader" - but does Apple have the private key? If so, why can't they create another bootloader?


As I understand it, if the code running in the "secure enclave" (containing the private keys) is ever upgraded, the hardware side intentionally deletes the private keys as part of the upgrade, whether the upgraded code would want it to or not.



The reasoning there is far from conclusive. The argument is that the secure enclave has been updated in the past (to lengthen enforced delays) without wiping user keys.

However, without more information, this does not tell us whether it is possible in this case. The obvious implementation for a secure enclave resisting this sort of attack is to only allow key-preserving updates when already in unlocked state (which would be the case for any normal user update). All other cases should destroy the user keymat, even if the update is validly signed by Apple. This would be done by the hardware and/or previous firmware before it loaded the new firmware so you can't create an update that bypasses this step.

If this isn't how the secure enclave works now, I'll bet it will be in the next version (or update if possible).


You can't update the firmware on the SE without unlocking the device first.


We assume.

I'm also confused by a lot of this since don't you need the password anyway to upgrade?


> We assume.

I bet if Apple is forced to comply with this order they will make sure that they will find a way to design the iPhone such that they physically can't comply with similar requests in the future.


> No, they can't. A quick update to recent hardware practices: modern SoCs like Apple's have something called "Secure Enclave Processor" that's on-die.

Yes, they can. The particular phone in question is from before the Secure Enclave Processor


To play devil's advocate: If they can be compelled to produce de-novo firmware for the purpose of data extraction they could also be compelled to design the means necessary to extract the data from the secure enclave, e.g. by prying the chips open and putting it under a scanning tunneling microscope.


The packages on those chips are usually designed to be melded to the underlying structures enough that opening them destroys the keys they're attempting to hide.


I think you're missing my point here.

Some people trot the argument that it's OK for the government to compel apple to deliver the backdoored firmware because the measures it would circumvent are not of cryptographic/information-theoretical nature.

Then one could expand that argument by saying that compelling physical reverse-engineering is also OK because the devices are not built to be physically impossible (read: laws of nature) to pry open.


The devices ARE built to be physically impossible to open without destroying their contents.


In security, impossible usually means "there is no documented method yet".




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