4 ms·

> It only weakens privacy for iCloud photos if you have CP or photos in a CP database Or people who have photos that hash the same as CP.

smoldesu 5y ago
Or possess tampered photos that were engineered to be a hash collision.
- azinman2 5y ago
  You’d have to not only have over 30 hash collisions, but also have it collide with another secret hash function, and then also have a human look at it and agree it’s CP. So what’s the actual realistic issue here? This keeps getting thrown around as if it’s likely, yet not only are there numerous steps against this in the Apple chain, this would already be a huge issue with Dropbox, Facebook, Microsoft, Google, etc who do CP scanning according to all of the comments on HN.
  - nullc 5y ago
    > You’d have to not only have over 30 hash collisions That's trivial. If the attacker can get one image onto your device they can get several. It's very easy to construct preimages for Apple's neural hash function, including fairly good looking ones (e.g. https://github.com/AsuharietYgvar/AppleNeuralHash2ONNX/issues/1#issuecomment-902977931 https://github.com/AsuharietYgvar/AppleNeuralHash2ONNX/issue... ) > collide with another secret hash function The supposed other 'secret' hash function cannot be secret from the state actors generating the databases. Also, if it has a similar structure/training, it's not that unlikely that the same images would collide by chance. > also have a human look at it and agree it’s CP That's straight-forward: simply use nude or pornographic images which looks like they could be children or ones where without context you can't tell. It's a felony for them to fail to report child porn if they see it in review, and the NCMEC guidance tells people when in doubt to report. Besides, once someone else has looked at your pictures your privacy has been violated.
    - azinman2 5y ago
      If this really was such a problem, then as I said, we’d have been getting reports of this over the past 10+ years it’s already been in place at big cloud providers. So where is all of this ruining of peoples lives by uploading CP on their devices? Also if you’re a gov actor trying to frame someone, why bother with a pre-image when you could put the real images on it? None of that is new today — all that’s new is Apple is joining the effort to scan for CSAM, and instead of doing it on server they’re doing it on device right before you upload in a way that attempts to be more secure and private than other efforts.
      - feanaro 5y ago
        > So where is all of this ruining of peoples lives by uploading CP on their devices? Once the capability is in place on everyone's devices, how are we supposed to guarantee it will never be used maliciously? Just say no to the capability. > Also if you’re a gov actor trying to frame someone, why bother with a pre-image when you could put the real images on it? Because the capability for this is now built-in in everyone's phones.
      - jliptzin 5y ago
        What do you mean? People are arrested all the time for having CP on their machines, I see it in the news frequently. Impossible to know how many of them could have just been framed, no one is giving the benefit of the doubt to an accused pedo. And it never goes to trial due to the possibility of enormous prison sentences. If you’re innocent would you risk 100 years in federal prison going to trial or plead guilty and only face a few years?
        nullc 5y ago
        Many people seem to miss that the automated scanning makes framing much more effective. Say I sneak (psedo-)child porn onto your device. How do I get authorities to search you without potentially implicating myself? An anonymous tipline call is not likely to actually trigger a search. With automated mass scanning that problem is solved: All users will be searched.

smoldesu 5y ago

Or possess tampered photos that were engineered to be a hash collision.

azinman2 5y ago
You’d have to not only have over 30 hash collisions, but also have it collide with another secret hash function, and then also have a human look at it and agree it’s CP. So what’s the actual realistic issue here? This keeps getting thrown around as if it’s likely, yet not only are there numerous steps against this in the Apple chain, this would already be a huge issue with Dropbox, Facebook, Microsoft, Google, etc who do CP scanning according to all of the comments on HN.
- nullc 5y ago
  > You’d have to not only have over 30 hash collisions That's trivial. If the attacker can get one image onto your device they can get several. It's very easy to construct preimages for Apple's neural hash function, including fairly good looking ones (e.g. https://github.com/AsuharietYgvar/AppleNeuralHash2ONNX/issues/1#issuecomment-902977931 https://github.com/AsuharietYgvar/AppleNeuralHash2ONNX/issue... ) > collide with another secret hash function The supposed other 'secret' hash function cannot be secret from the state actors generating the databases. Also, if it has a similar structure/training, it's not that unlikely that the same images would collide by chance. > also have a human look at it and agree it’s CP That's straight-forward: simply use nude or pornographic images which looks like they could be children or ones where without context you can't tell. It's a felony for them to fail to report child porn if they see it in review, and the NCMEC guidance tells people when in doubt to report. Besides, once someone else has looked at your pictures your privacy has been violated.
  - azinman2 5y ago
    If this really was such a problem, then as I said, we’d have been getting reports of this over the past 10+ years it’s already been in place at big cloud providers. So where is all of this ruining of peoples lives by uploading CP on their devices? Also if you’re a gov actor trying to frame someone, why bother with a pre-image when you could put the real images on it? None of that is new today — all that’s new is Apple is joining the effort to scan for CSAM, and instead of doing it on server they’re doing it on device right before you upload in a way that attempts to be more secure and private than other efforts.
    - feanaro 5y ago
      > So where is all of this ruining of peoples lives by uploading CP on their devices? Once the capability is in place on everyone's devices, how are we supposed to guarantee it will never be used maliciously? Just say no to the capability. > Also if you’re a gov actor trying to frame someone, why bother with a pre-image when you could put the real images on it? Because the capability for this is now built-in in everyone's phones.
    - jliptzin 5y ago
      What do you mean? People are arrested all the time for having CP on their machines, I see it in the news frequently. Impossible to know how many of them could have just been framed, no one is giving the benefit of the doubt to an accused pedo. And it never goes to trial due to the possibility of enormous prison sentences. If you’re innocent would you risk 100 years in federal prison going to trial or plead guilty and only face a few years?
      - nullc 5y ago
        Many people seem to miss that the automated scanning makes framing much more effective. Say I sneak (psedo-)child porn onto your device. How do I get authorities to search you without potentially implicating myself? An anonymous tipline call is not likely to actually trigger a search. With automated mass scanning that problem is solved: All users will be searched.