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I don't see how this "reassuring"; to me it's rather very confusing (as mentioned in many other comments). If Apple could in fact write a software backdoor, do
by bambax 11y ago
I don't see how this "reassuring"; to me it's rather very confusing (as mentioned in many other comments).
If Apple could in fact write a software backdoor, doesn't it mean that the backdoor exists, at least potentially?
And how can one be sure that Apple is the only company able to build that door? At the very least, couldn't the right Apple engineer be either bribed or forced (by terrorists or the government) to build it?
"Impossible" should mean "impossible", not "not yet done, but possible".
- elmigranto 11y agoNot possible without backing it into iOS with some update that FBI is claiming will be used on one particular phone in this particular case. Apple reasons that there is no way to guarantee no one will take the same update and apply it to other iOS devices. Or government taking this a step further by making Apple to build that into future update for the whole user base.
- epaga 11y agoWhat it means is that the best the FBI can come up with is "Make a way for us to brute force attack the passphrase." And brute force attack is worthless for a strong enough passphrase. That's what is reassuring. Not to mention that this is for the iPhone 5c. As other comments have mentioned, newer iPhones have the hardware-based Secure Enclave which add to the difficulty of breaking into the phone. https://www.apple.com/business/docs/iOS_Security_Guide.pdf https://www.apple.com/business/docs/iOS_Security_Guide.pdf
- fnordfnordfnord 11y agoIt could also be that the FBI has already obtained the info, or can obtain the info through illegal means and simply want to use the issue to force legislative and policy changes or public opinion changes in their favor, and or just want to legitimize their having the information.
- andreyvit 11y agoMy reading of that PDF is that Secure Enclave software can be updated too, it simply does an independent verification of the Apple's digital signature. So while the Secure Enclave enforces the delay between brute force attempts, Apple could still release an update that removes that delay.
- tobylane 11y agoIt's not a backdoor to the phone only being unlocked by the passphrase, but a backdoor to the number of attempts limitation.
- vbezhenar 11y agoThis limitation must be built into security hardware used by iPhone so software couldn't do anything about it. I was under impression that it's how iOS security model works. If it's not and in fact this check implemented in iOS itself, it's much weaker protection and it's really looks like an intended backdoor from Apple.
- schrodinger 11y agoIt sounds like it is built into hardware with newer iPhones containing the secure enclave, but not for an older phone like the iPhone 5C.
- thesmok 11y agoI'm really interested to know more about this. Does TouchId secure enclave really enforce the password attempt limits?
- andreyvit 11y agoIt's not really built into ‘hardware’, it's enforced by the Secure Enclave, which is software-based and accepts software updates signed by Apple. It's secure against kernel exploits and third-parties, but not against Apple.
- mjibson 11y agoI agree. I was under the impression that Apple's security was such that even they didn't have the power to decrypt a device because the crypto made it impossible without the password/pin/key. I'm interested to understand the reasons that it was not done this way.
- ithkuil 11y agoThe current implementation is done this way indeed: even Apple cannot decrypt without using the right password. The right password can be obtained by either knowing it, or by guessing it. As an additional security measure, the software shipped with the phone prevents brute force attacks by wiping the device after a given number of failed attempts. Apple has been asked to modify the software so that it won't wipe the phone, thus allowing the authorities to try many passwords. If anybody could circumvent this additional security measure, actual security would be lower. The authorities are not asking Apple to ship this change to all users: they only want to install it on the device in their possession. However, Apple is concerned that once they provide the authorities such a modified software, it could be leaked and thus be used by third parties to breach the security of any Apple device. It should be noted that currently all data encrypted for example on your laptop's hard drive is already subject to this kind of brute force attacks. It's a well known fact that authorities or malicious users can already attempt brute force attacks on encrypted data if they can access the data on a passive device such as a hard-drive. It's important to understand that Apple (at least not in this case) is not being asked to implement a backdoor in the encryption software. It's also important to understand that even if Apple was forced to install a backdoor, it would affect only the ability to access future data and not help the investigation of the San Bernardino case. This very request by the Authorities suggests that Apple does not currently install any backdoor on stock phones. However there is a logical possibility that the Authorities are either not aware of any such backdoor or in the worst case they are publicly requesting this feature just to hide the real reason of a possible future success at decrypting the phone: they can claim that Apple didn't have any backdoor, and they were just lucky at bruteforcing the device; in fact Apple wasn't even cooperating with them at relaxing the brute force prevention limit, so they could claim they did it in house. (I'm personally not inclined to believe in such improbably well coordinated smoke and mirrors strategies, but they are a logical possibility nevertheless).
- freshyill 11y agoI think they're being asked for a few things—private keys and the ability to automate and not limit passcode entry attempts.
- Loic 11y agoIn the world of cryptography, it is always possible, because you can always be lucky and guess the right "unlock" code. In fact, social engineering is normally used to find the right "unlock" code[0]. The FBI can also unsolder the components in the phone, make a full image of the content, find the encrypted section and then brute-force. This is what is done for SSD. They do not power up the drive, unsolder, put the memory modules in a special reader and copy the data before the controller of the SSD automatically wipe out data because of automatic optimization after a delete/trim. [0]: https://xkcd.com/538/ https://xkcd.com/538/
- jupp0r 11y agoIt's kind of hard to social engineer dead people, though.
- Loic 11y agoThis is why the "normally" in my sentence. But the point I really wanted to make is that you have no "impossible" with encryption.
- datashaman 11y agodead people were once alive. go through their pockets or their apartment.
- Majestic121 11y agoYou can go through each and every physical object I own or even was in contact with, but you won't find any of my passwords
- joonoro 11y agoThey didn't make any mention of how feasible it would be, just that they wouldn't even try because it would threaten the security of their users.
- dba7dba 11y agoLet me correct it for you. "Perceived security of their users". A lot of it about PR.
- taneq 11y agoIt sounds like it'd be trivial to nop out the timer on repeated passcode attempts. Which makes sense... Leaving any short passcode trivially crackable.
- curryhowardiso 11y agoYes but like where would you nop? You can't statically analyse the code because the image is encrypted at rest (and potentially partially in ram also?)
- thefreeman 11y agoThe code which decrypts the system (and is responsible for wiping the drive on repeated failures) is definitely not encrypted. How would it be able to take the input in order to decrypt the drive.
- curryhowardiso 11y agoYes but that code is all running in ram, precluding static analysis. You can still dynamically analyse it, but that is much harder. The way I understand it (and, correct me if I'm wrong) is that the code flows from disk through the aes engine where it is decrypted and then placed in a presumably interesting/hard to reverse place in ram at which point it is executed. I imagine even more interesting things are done to higher value data in ram, but that's not code - because as you said, code has to be decrypted (at the latest) by the time it reaches the registers.
- andreyvit 11y agoTheir security PDF says that the system has a chain of trust established, anchored at an immutable loader residing inside the chip, and each step verifies the digital signature of the next step against the hardcoded Apple CA certificate.
- curryhowardiso 11y agoSo to clarify you're saying that you can't just nop instructions, or it's not as simple as that, right?
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- ry_ry 11y ago> If Apple could in fact write a software backdoor, doesn't it mean that the backdoor exists Schroedinger's Backdoor? ;)
- ikeboy 11y agoOnly Apple has the ability to sign updates to software (barring jailbreak).
- 0942v8653 11y agoIt's not a backdoor, it's a frontdoor. In cryptography, there's no way to make repeated attempts more computationally expensive. The lockout just an extra feature Apple put on, that Apple could easily remove. If we're going to have 4- and 6- digit PINs, there is no way to stop a dedicated attacker frome brute-forcing it. None.
- OJFord 11y ago> no way to stop a dedicated attacker from brute-forcing it Wipe after x incorrect? Can't stop the attacker, but you can make it futile, surely.
- 0942v8653 11y agoNope. If the attacker (Apple in this case) can replace the OS, they will just do so before the phone gets wiped—replacing the OS will remove that wipe feature.
- germanier 11y agoNot if the check and wiping is done in hardware as claimed by Apple for newer devices than the one in question here.
- 0942v8653 11y agoMeh. Then the attacker can simply replace the hardware. Remember, our attacker model is Apple; non-cryptographic security measures mean very little to a company with such complete knowledge of the hardware and software involved.
- germanier 11y agoThe point is that the key is stored there too (part of it burned during production in silicone) and can't be read or changed. Sure, if they wanted to they could implement a backdoor. But assuming they correctly created and shipped the secure enclave it shouldn't be possible to circumvent it even for Apple.
- sametmax 11y agoBut why would you even think apple, google or facebook would be a good bet to defend your privacy in the first place ? They got the most terrible track record of not caring about. If you have things that you need to be private, don't put it on a smartphone.
- macintux 11y agoI wish people would stop lumping Apple with Google/Facebook with regards to privacy. Apple has implicitly for a long time, and lately much more vocally, cared about privacy. They don't have the same data-driven business model that Google and FB do.
- CaptSpify 11y ago> Apple has implicitly for a long time, and lately much more vocally, cared about privacy. They say that. But with closed source software we can't verify that it's true. I'm not saying they don't care about privacy, only that we don't really know if they do or not.
- zimpenfish 11y agoWith open source software, it doesn't appear that people can verify things are safe either given the long-term security issues with things like OpenSSL et al.
- CaptSpify 11y agoI never said they could. There is a better chance that they can, but that line of thinking ends up trying to prove a negative.
- sametmax 11y agoWe found the bug in OpenSSL BECAUSE it was opensource. If it weren't, nobody would have seen it. Plus, with open source you can verify intent, which you can't with apple. Which provide a device getting your finger prints, all your phone numbers, internet search, bank details, some paiements, network communication, voice communications, text communications, localisation using GPS and wifi + hotspot + phone towers and soon ihealth device collection body metrics. And they are profit oriented, not people oriented.