Hacker News Reader

Comment by function_seven | Hacker News Reader

It all depends on how you define a backdoor. The 5c doesn't have the secure enclave†, so all of it's encryption routines are done in the CPU, as software/firmware.

That software doesn't contain a backdoor, but the fact that a new software load could be created and installed could be viewed as the backdoor itself. But if that software doesn't currently exist, is the mere potential of it a backdoor? Somewhat of a philosophical question.

If Apple prevails and doesn't write the software the FBI is demanding, then the backdoor is not there.

The later iPhones with the Secure Enclave may truly be unbreakable if they protect their secrets with hardware in the chip.

But my understanding of it is that Apple is NOT capable of unlocking the phone right now. The FBI is demanding that they develop that capability. So I guess they're capable of being capable...

† At the risk of being an armchair SE expert...

View on HN

How would a backdoor look? Some secret additional encryption key capable of unlocking the encrypted data?

Such a key exists, and it is whatever key Apple uses to sign the iOS updates. Only Apple can sign a new iOS release, so only Apple can update the code to remove all security features. This looks a lot like a backdoor to me, just that the implementation hasn't been written. But all you really would need, in theory, is the signing key.

From the Judge's request and Tim Cook's response, it looks like the updated OS with the backdoor would no longer wait after each passcode try, and would allow inputting a passcode through WiFi. That allows remotely bruteforcing the passcode.

I would guess that that passcode encrypts the phone, which is why they can't decrypt it.

There's probably more to it (otherwise, they could copy the encrypted data elsewhere to bruteforce it, in which case it would all be a show from the FBI and their real target is other phones).

I'll agree that the ability to update the firmware without the phone being unlocked is poor design on Apple's part. Given the security flaws they've had in the past, this one seems genuine.

You make a very good point: why do they even need to update the firmware? Surely, just cloning the phone's encrypted memory should be possible? (I have no knowledge of hardware at all, but I would have thought that the data is stored on a memory chip somewhere in a phone, and it should(?) be possible to copy the data from that chip to process it offline?)

In some of the other threads on this topic there were very many explanations why that is not possible.

At root of it is that even with a flash memory image, brute-forcing AES-256 is impossible. And the key is key fused into the processor and no software or firmware can read it directly.

A Schrödingers Backdoor? lol.. Err, anyway. Carry on.

They are capable of unlocking the phone. There is no philosophical question about this, as they have the knowledge and the ability and the authority.

That it might take some expertise and effort is not really relevant - some is required in any case even if the firmware already existed, so its just a matter of scale. For example I know several people who could not update a phone firmware without supervision, and probably some who could at a stretch (given massive time and resources) reverse engineer it. Apple firmly occupy the sweet spot in this range, they have the secret knowledge that would otherwise have to be reproduced and it would be a bit of effort to build on this but not huge. Changing a bit of code [to remove the delay] and rebuilding a binary image is not a complicated task for their engineers, it is likely something they do all the time.

Personally, I think they should just do it if they are legally compelled to do so. They have done in the past and this is an older device and in 5 years the issue will be moot, as any firmware they create now would be useless.

>Personally, I think they should just do it if they are legally compelled to do so. They have done in the past and this is an older device and in 5 years the issue will be moot, as any firmware they create now would be useless.

If they do it now, they the point will indeed be moot in 5 years, not because of technology, but because it will be required of them to make sure they can do this to ALL iPhones.

> Personally, I think they should just do it if they are

> legally compelled to do so. They have done in the past and

> this is an older device and in 5 years the issue will be

> moot, as any firmware they create now would be useless.

If they lose this lawsuit they will be forced again and again to build backdoors into their own systems. It's a very unreasonable request that does not find the right balance and the reasons are laid out eloquently in Apple's letter.

Reply on news.ycombinator.com