4 ms·

This isn’t true. The db is blinded. We have no way of knowing what’s in it. It would be trivial to have the same payload on each device, and extract different

This isn’t true. The db is blinded. We have no way of knowing what’s in it. It would be trivial to have the same payload on each device, and extract different answers using the matching server side db which varies by country. Perhaps not trivial, but just short.

breuleux 5y ago
I feel that it's the kind of scheme that requires too much cooperation from too many people and organizations with conflicting incentives. It's possible some countries would not want the hashes from certain other governments in the db at all. And then what? I may be wrong, but I also believe we can know how many hashes are in the db, which means that if it contains extra hashes from dozens of governments, it would become suspiciously large relative to how many CSAM images we know exist. Furthermore, in this scenario the db cannot be auditable, so the scheme falls apart as soon as some rogue judge decides to order an audit. I honestly don't think Apple wants to deal with any of that crap and that they would rather silently can the system and do exactly what everybody else does than place themselves in the line of fire when their own unique trademark system is being abused.
- sillysaurusx 5y ago
  Would they rather deal with the CCP shutting off iPhone sales in China? History has shown that the CCP is willing to do that if it comes down to it. (I remind you that at one time, Google was a primary search engine in China.)
azinman2 5y ago
What do you mean blinded? It’s already been promised there will be a way to verify the hash db on your own device.
- sillysaurusx 5y ago
  It’s blinded in the cryptographic sense. It’s a specific term. I would go into detail, but <reasons>. Suffice to say, unless you provide proof, I am reasonably confident there’s no way to verify the hash db doesn’t contain extra hashes other than the CSAM hashes provided by the US government. But I’ve been wrong many times before.
  - azinman2 5y ago
    Well first of all, it's not provided by the US government. It's a non-profit, and Apple has already said they're going to look for another db from another nation and only included hashes that are the union of the two to prevent exactly this kind of attack. If what you mean by blinded is that you don't know what the source image is for the hash, that's true. Otherwise Apple would just be putting a database of child porn on everyone's phones. You gotta find some kind of balance here. What do you mean you can't verify it doesn't contain extra hashes? Meaning that Apple will say here are the hashes in your phone, but secretly will have extra hashes they're not telling you about? Not only is this the kind of thing that security researchers will quickly find, you're assuming a very sinister set of features from Apple that they'll only tell you half the story. If that were the case, then why offer the hashes at all? It's an extremely cynical take. The reality is all of the complaints about this system went from this specific implementation, and then as details get revealed, it's now all about the future hypothetical situations. I'm personally concerned about future regulations, but those regulations could/would exist independently of this specific system. Further, Dropbox, Facebook, Microsoft, Google, etc all have user data unencrypted on their servers and are also just as vulnerable to said legislation. If the argument is this is searching your device, well the current implementation is its only searching what would be uploaded to a server instead. If you suggest that could change to anything on your device due to legislation, wouldn't that happen anyway? And then what is Google going to do... not follow the same laws? Both companies would have to implement new architectures and systems for complying. I'm generally concerned about the future of privacy, but I think people (including myself initially) have gone too far in losing their minds.
    - conradev 5y ago
      I would just read the document explaining how this works (see "Matching-Database Setup"): https://www.apple.com/child-safety/pdf/CSAM_Detection_Technical_Summary.pdf https://www.apple.com/child-safety/pdf/CSAM_Detection_Techni... At no point is anyone besides Apple able to view any NeuralHash hashes from the CSAM database. You can verify the database is the same on all iPhones, but you are not able to look at any of the hashes.
- IncRnd 5y ago
  There are many functions to which cryptographic blinding is applied, but they each rely upon multiple parties to compute the function in question. In that way, the input and output are blinded to a single party.

breuleux 5y ago

I feel that it's the kind of scheme that requires too much cooperation from too many people and organizations with conflicting incentives. It's possible some countries would not want the hashes from certain other governments in the db at all. And then what? I may be wrong, but I also believe we can know how many hashes are in the db, which means that if it contains extra hashes from dozens of governments, it would become suspiciously large relative to how many CSAM images we know exist. Furthermore, in this scenario the db cannot be auditable, so the scheme falls apart as soon as some rogue judge decides to order an audit. I honestly don't think Apple wants to deal with any of that crap and that they would rather silently can the system and do exactly what everybody else does than place themselves in the line of fire when their own unique trademark system is being abused.

sillysaurusx 5y ago
Would they rather deal with the CCP shutting off iPhone sales in China? History has shown that the CCP is willing to do that if it comes down to it. (I remind you that at one time, Google was a primary search engine in China.)

azinman2 5y ago

What do you mean blinded? It’s already been promised there will be a way to verify the hash db on your own device.

sillysaurusx 5y ago
It’s blinded in the cryptographic sense. It’s a specific term. I would go into detail, but <reasons>. Suffice to say, unless you provide proof, I am reasonably confident there’s no way to verify the hash db doesn’t contain extra hashes other than the CSAM hashes provided by the US government. But I’ve been wrong many times before.
- azinman2 5y ago
  Well first of all, it's not provided by the US government. It's a non-profit, and Apple has already said they're going to look for another db from another nation and only included hashes that are the union of the two to prevent exactly this kind of attack. If what you mean by blinded is that you don't know what the source image is for the hash, that's true. Otherwise Apple would just be putting a database of child porn on everyone's phones. You gotta find some kind of balance here. What do you mean you can't verify it doesn't contain extra hashes? Meaning that Apple will say here are the hashes in your phone, but secretly will have extra hashes they're not telling you about? Not only is this the kind of thing that security researchers will quickly find, you're assuming a very sinister set of features from Apple that they'll only tell you half the story. If that were the case, then why offer the hashes at all? It's an extremely cynical take. The reality is all of the complaints about this system went from this specific implementation, and then as details get revealed, it's now all about the future hypothetical situations. I'm personally concerned about future regulations, but those regulations could/would exist independently of this specific system. Further, Dropbox, Facebook, Microsoft, Google, etc all have user data unencrypted on their servers and are also just as vulnerable to said legislation. If the argument is this is searching your device, well the current implementation is its only searching what would be uploaded to a server instead. If you suggest that could change to anything on your device due to legislation, wouldn't that happen anyway? And then what is Google going to do... not follow the same laws? Both companies would have to implement new architectures and systems for complying. I'm generally concerned about the future of privacy, but I think people (including myself initially) have gone too far in losing their minds.
  - conradev 5y ago
    I would just read the document explaining how this works (see "Matching-Database Setup"): https://www.apple.com/child-safety/pdf/CSAM_Detection_Technical_Summary.pdf https://www.apple.com/child-safety/pdf/CSAM_Detection_Techni... At no point is anyone besides Apple able to view any NeuralHash hashes from the CSAM database. You can verify the database is the same on all iPhones, but you are not able to look at any of the hashes.
IncRnd 5y ago
There are many functions to which cryptographic blinding is applied, but they each rely upon multiple parties to compute the function in question. In that way, the input and output are blinded to a single party.