4 ms·

How is it any more ‘bit flips’ away from scanning every photo on your device than it was before?

by zepto 5y ago

Wowfunhappy 5y ago
Because if (willBeUploaded) { scanPhoto(); } can become if (true) { scanPhoto(); } Obviously, this is stupidly oversimplified, I have no idea how Apple has structured their code. But the fact of the matter is, if the scanning routine is already on the phone, and the photos are on the phone, all anyone has to do is change which photos get scanned by the routine...
- jkcxn 5y ago
  By the way they already scan photos that aren’t uploaded to iCloud. I’ve never used iCloud and I can go on the photos app and search for food for example
  - ninkendo 5y ago
    Right, the difference is that now, you can be reported to the authorities for a photo that the CSAM algorithm mistook for child pornography, whereas before the image classifying was purely for your own use.
    - zepto 5y ago
      This is simply a complete falsehood, because photos that are not uploaded are not scanned for CSAM. Photos for your own use that you do not upload to Apple’s cloud are completely unaffected.
  - zepto 5y ago
    Exactly. They already analysed photos on your phone for search. They don’t in fact do CSAM detection on the photos on your phone. But why are people only objecting now when they were already doing on-device analysis? CSAM detection is a complete red herring. It is less of a general purpose scanning mechanism than the search function that was already there.
    - Wowfunhappy 5y ago
      They're doing on device analysis, but there isn't any process by which an image of a hotdog will be sent to someone else without my knowledge.
      - zepto 5y ago
        Right, but neither is the CSAM code being used to detect anything but CSAM. If a bit can be flipped to make the CSAM detector go evil, surely it can be flipped to make photo search go evil, or spotlight start reporting files that match keywords for that matter. There is nothing special about this CSAM detector except that it’s narrower and harder to repurpose than most of the rest of the system.
        pritambaral 5y ago
        > ... to make photo search go evil, or spotlight start reporting files that match keywords for that matter. As your immediate parent has already said: there isn't any process by which an image of a hotdog will be sent to someone else without my knowledge. Neither "photo search" nor "spotlight" report anything to third parties currently.
        zepto 5y ago
        No, but a ‘bit flip’ could make them do so just as easily as a ‘bit flip’ could make the CSAM detector do something nefarious.
        pritambaral 5y ago
        How are you still not getting this?: "search" and "spotlight" do not have the code to report anything to anyone.
        zepto 5y ago
        How are you still not getting it? The code to ‘report’ something is barely more than a one liner http request. It could be added at any time. On the other hand, making the CSAM code scan your text documents would be pointlessly difficult given that the other mechanisms exist.
- zepto 5y ago
  Right, but the CSAM scanning routine is absurdly narrow and difficult to use for detecting anything but CSAM, whereas a general purpose hash matching algorithm really is just a few lines of code. This whole ‘now that they have a scanner it’s easier’ reasoning doesn’t make sense. iOS already had numerous better matching algorithms if your goal is to do general spying.
  - Wowfunhappy 5y ago
    Isn't the scanning routine searching for fingerprints? What happens if someone adds a fingerprint to the database, which matches something other than CSAM?
    - zepto 5y ago
      No. It’s way more complex than that, and has been engineered to prevent exactly that scenario. I recommend you actually check out some of Apple’s material on this. The idea that it’s just a list or fingerprints or hashes that can easily be repurposed is simply wrong, but is the root of almost all of the complaints.
      - Wowfunhappy 5y ago
        I've looked through Apple's paper, what are you referring to?
        zepto 5y ago
        So you know it’s not just a fingerprint. Did you notice the parts about the safety vouchers and the visual derivatives?
        dannyw 5y ago
        Yes, I did. You do realise that CSAM is just a policy control, and there is literally nothing technical from Apple adding non-CSAM content to the same policy and systems? I feel like you may not have actually read the paper in depth. The paper clearly shows this is a generalised solution for detecting content that perceptually matches a database. The "what" is CSAM today, but nothing about the technicals require it to be CSAM. To answer your specific response of safety voucher and visual derivative: - The 'safety voucher' is an encrypted packet of information containing a part of the user's decryption keys, as well as a low resolution, grayscale version of the image (visual derivative). It is better described as "backdoor voucher". - The 'visual derivative' is just the image but smaller and grayscale. None of those two technologies have anything to do with CSAM. Apple's statement that they will only add CSAM to the database is a policy statement. Apple can literally change it overnight to detect copyrighted content, or Snowden documents, or whatever.

How is it any more ‘bit flips’ away from scanning every photo on your device than it was before?

by zepto 5y ago

How is it any more ‘bit flips’ away from scanning every photo on your device than it was before?

Because if (willBeUploaded) { scanPhoto(); } can become if (true) { scanPhoto(); } Obviously, this is stupidly oversimplified, I have no idea how Apple has structured their code. But the fact of the matter is, if the scanning routine is already on the phone, and the photos are on the phone, all anyone has to do is change which photos get scanned by the routine...

jkcxn 5y ago
By the way they already scan photos that aren’t uploaded to iCloud. I’ve never used iCloud and I can go on the photos app and search for food for example
- ninkendo 5y ago
  Right, the difference is that now, you can be reported to the authorities for a photo that the CSAM algorithm mistook for child pornography, whereas before the image classifying was purely for your own use.
  - zepto 5y ago
    This is simply a complete falsehood, because photos that are not uploaded are not scanned for CSAM. Photos for your own use that you do not upload to Apple’s cloud are completely unaffected.
- zepto 5y ago
  Exactly. They already analysed photos on your phone for search. They don’t in fact do CSAM detection on the photos on your phone. But why are people only objecting now when they were already doing on-device analysis? CSAM detection is a complete red herring. It is less of a general purpose scanning mechanism than the search function that was already there.
  - Wowfunhappy 5y ago
    They're doing on device analysis, but there isn't any process by which an image of a hotdog will be sent to someone else without my knowledge.
    - zepto 5y ago
      Right, but neither is the CSAM code being used to detect anything but CSAM. If a bit can be flipped to make the CSAM detector go evil, surely it can be flipped to make photo search go evil, or spotlight start reporting files that match keywords for that matter. There is nothing special about this CSAM detector except that it’s narrower and harder to repurpose than most of the rest of the system.
      - pritambaral 5y ago
        > ... to make photo search go evil, or spotlight start reporting files that match keywords for that matter. As your immediate parent has already said: there isn't any process by which an image of a hotdog will be sent to someone else without my knowledge. Neither "photo search" nor "spotlight" report anything to third parties currently.
        zepto 5y ago
        No, but a ‘bit flip’ could make them do so just as easily as a ‘bit flip’ could make the CSAM detector do something nefarious.
        pritambaral 5y ago
        How are you still not getting this?: "search" and "spotlight" do not have the code to report anything to anyone.
        zepto 5y ago
        How are you still not getting it? The code to ‘report’ something is barely more than a one liner http request. It could be added at any time. On the other hand, making the CSAM code scan your text documents would be pointlessly difficult given that the other mechanisms exist.
zepto 5y ago
Right, but the CSAM scanning routine is absurdly narrow and difficult to use for detecting anything but CSAM, whereas a general purpose hash matching algorithm really is just a few lines of code. This whole ‘now that they have a scanner it’s easier’ reasoning doesn’t make sense. iOS already had numerous better matching algorithms if your goal is to do general spying.
- Wowfunhappy 5y ago
  Isn't the scanning routine searching for fingerprints? What happens if someone adds a fingerprint to the database, which matches something other than CSAM?
  - zepto 5y ago
    No. It’s way more complex than that, and has been engineered to prevent exactly that scenario. I recommend you actually check out some of Apple’s material on this. The idea that it’s just a list or fingerprints or hashes that can easily be repurposed is simply wrong, but is the root of almost all of the complaints.
    - Wowfunhappy 5y ago
      I've looked through Apple's paper, what are you referring to?
      - zepto 5y ago
        So you know it’s not just a fingerprint. Did you notice the parts about the safety vouchers and the visual derivatives?
        dannyw 5y ago
        Yes, I did. You do realise that CSAM is just a policy control, and there is literally nothing technical from Apple adding non-CSAM content to the same policy and systems? I feel like you may not have actually read the paper in depth. The paper clearly shows this is a generalised solution for detecting content that perceptually matches a database. The "what" is CSAM today, but nothing about the technicals require it to be CSAM. To answer your specific response of safety voucher and visual derivative: - The 'safety voucher' is an encrypted packet of information containing a part of the user's decryption keys, as well as a low resolution, grayscale version of the image (visual derivative). It is better described as "backdoor voucher". - The 'visual derivative' is just the image but smaller and grayscale. None of those two technologies have anything to do with CSAM. Apple's statement that they will only add CSAM to the database is a policy statement. Apple can literally change it overnight to detect copyrighted content, or Snowden documents, or whatever.