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Edit: "The main purpose of the hash is to ensure that identical and visually similar images result in the same hash, and images that are different from one anot

Edit: "The main purpose of the hash is to ensure that identical and visually similar images result in the same hash, and images that are different from one another result in different hashes."[1] Apple isn't using a "similar image, similar hash" system. They're using a "similar image, same hash" system. [1]: https://www.apple.com/child-safety/pdf/CSAM_Detection_Technical_Summary.pdf https://www.apple.com/child-safety/pdf/CSAM_Detection_Techni...

heavyset_go 5y ago
> There really is no sound concept of "the more similar the hash." Perceptual hashes are not cryptographic hashes. Perceptual hashing systems do compare hashes using a distance metric like the Hamming distance. If two images have similar hashes, then they look kind of similar to one another. That's the point of perceptual hashing.
- salawat 5y ago
  Except when you're not measuring the similarity you think you are, because NeuralNets are f&#@ing weird. You know, let me put it this way. Yiu know that one really weird family member I'm pretty sure everyone either has or is? Guess what? They're a neural net too. This is what Apple is asking you to trust.
  - heavyset_go 5y ago
    I agree, I'm just talking about the difference between cryptographic hashes and other types of hashes.
- deleted 5y ago
  [deleted]
- andrewmcwatters 5y ago
  This isn’t what Apple is doing, regardless of the fact they are using the same terminology. See my edit above.
function_seven 5y ago
EDIT: Parent edited his comment to clarify. I understand the point now. I'm wrong about similar images needing to have "similar" hashes. Those hashes either need to match exactly, or else not be considered at all. IGNORE THIS: I think that's the parent comment's point. These are definitely not cryptographic hashes, since they—by design and necessity—need to mirror hash similarity to the perceptual similarity of the input images.
- deleted 5y ago
  [deleted]
- whoknowswhat11 5y ago
  They are almost the opposite. The programs create different hashes (though very similar) depending on platform you run on even with SAME input. No crypto hash works even close to this.
- deleted 5y ago
  [deleted]

heavyset_go 5y ago

> There really is no sound concept of "the more similar the hash." Perceptual hashes are not cryptographic hashes. Perceptual hashing systems do compare hashes using a distance metric like the Hamming distance. If two images have similar hashes, then they look kind of similar to one another. That's the point of perceptual hashing.

salawat 5y ago
Except when you're not measuring the similarity you think you are, because NeuralNets are f&#@ing weird. You know, let me put it this way. Yiu know that one really weird family member I'm pretty sure everyone either has or is? Guess what? They're a neural net too. This is what Apple is asking you to trust.
- heavyset_go 5y ago
  I agree, I'm just talking about the difference between cryptographic hashes and other types of hashes.
deleted 5y ago
[deleted]
andrewmcwatters 5y ago
This isn’t what Apple is doing, regardless of the fact they are using the same terminology. See my edit above.

function_seven 5y ago

EDIT: Parent edited his comment to clarify. I understand the point now. I'm wrong about similar images needing to have "similar" hashes. Those hashes either need to match exactly, or else not be considered at all. IGNORE THIS: I think that's the parent comment's point. These are definitely not cryptographic hashes, since they—by design and necessity—need to mirror hash similarity to the perceptual similarity of the input images.

deleted 5y ago
[deleted]
whoknowswhat11 5y ago
They are almost the opposite. The programs create different hashes (though very similar) depending on platform you run on even with SAME input. No crypto hash works even close to this.
deleted 5y ago
[deleted]