10 ms·
AIUI your blog post was nonetheless wrong. As the OP explains, there are multiple layers of encryption. The first is at the hardware level, performed by the SS
by TazeTSchnitzel 11y ago
AIUI your blog post was nonetheless wrong. As the OP explains, there are multiple layers of encryption.
The first is at the hardware level, performed by the SSD itself.[0] It encrypts all data on it with a key stored in rewriteable memory. By changing the key, you can "erase" the drive. The FBI could backup that key if they wanted to undo the "secure erase" feature.
However, this is not the only layer of encryption. The second is done in software, performed by iOS. It encrypts all user data with a key derived from the user's passcode and a unique key burned into the chip. The FBI cannot get past this layer, and this is what they wanted Apple's help for.
You were right in that the FBI could trivially get past the first layer of encryption, but it's not the one we care about. There's more than one layer.
[0] Or rather, by the flash controller. At least, I assume it is. It might actually be an iOS software feature too, but the OP's description reminds me very much of how some SSDs implement secure erase. Whether it's actually done in hardware or software is immaterial, anyway.
- lisper 11y ago> The FBI cannot get past this layer Yes, it can, and I explained exactly how in the original post. It's true I got some of the technical details wrong, but the substance of the post was and is correct.
- deleted 11y ago[deleted]
- deleted 11y ago[deleted]
- oldmanjay 11y agoThe technical details in this case really are everything, so it would make sense to get flagged out of existence if you got them wrong. To be clear, I'm not one of the flaggers, but I can understand some potential motivation there. There is already a lot of noise on this topic.
- lisper 11y agoOne of the technical details is that disjunctive claims are true if any of their constituent elements are true. My claim was of the form, "The iPhone is vulnerable to attack. Here is one attack. If that doesn't work, here's a second attack." The first attack doesn't work, but the second one does. Hence the overall claim -- that the iPhone is vulnerable -- was (and remains) correct. So should you be flagged to death because you got this wrong?
- TazeTSchnitzel 11y agoThe second attack was added in an update after you were criticised, no? It hardly counts.
- lisper 11y agoNo, it was in the original post. " they could use a copy of the chip to try five different PIN codes, and then replace the chip with a fresh copy of the original and try five more. Lather, rinse, repeat. At worst this would take about a week or so."
- cpleppert 11y ago>> Yes, it can, and I explained exactly how in the original post. It's true I got some of the technical details wrong, but the substance of the post was and is correct No you were wrong. You claimed that if the FBI was competent they could retrieve the key from the flash. There were no technical details discussed at all. (you could trivially google this issue and find out what you suggested doesn't work) The ACLU is describing an attack on the PIN not the key. You acknowledge this in another comment on this thread so I have no idea why you are claiming here that the FBI can get past the encryption in any way; which as others have said doesn't work.
- lisper 11y ago> The ACLU is describing an attack on the PIN not the key Yes. And so did I.
- superuser2 11y agoFBI didn't demand help with that layer, it demanded a way to bypass auto erase. They intended to perform the brute force of the 4 digit PIN themselves. Sure, they wanted to be able to enter PINs electronically, but they could just as easily have an intern sit there and enumerate the 1000 combinations once auto erase was disabled.
- TazeTSchnitzel 11y ago> FBI didn't demand help with that layer, it demanded a way to bypass auto erase. ...so that they could get past that layer of encryption by making lots of password attempts.
- tehwebguy 11y agoSeems like you could stick one of those stylus nubs on a 3d printer head and do the same thing but rapid fire. That would be pretty cool actually.
- superuser2 11y agoI've definitely seen a YouTube video of that.
- cplease 11y agoThat was a timing weakness in an older version of iOS that was patched in software. Previously you could just cut power at a precise monent and get unlimited attempts. It's no longer exploitable.
- qb45 11y agoDoes that mean that now if you cut power at the same moment the fail counter increments even if the entered code was correct? Not that it's particularly useful for hackers, I'm just wondering if this can be done "perfectly" at all.
- 11y ago