2 ms·

So we know they are using perceptual hashing and what kind?

• pseudalopex 5y ago
  "Hashes using a new and proprietary neural hashing algorithm Apple has developed, and gotten NCMEC to agree to use."
  • zepto 5y ago
    That sounds like we know it’s perceptual but not what kind, and therefore we don’t know the collision characteristics.
    • pseudalopex 5y ago
      We know perceptual hashing and cryptography have incompatible requirements. Think of an image, the same image with 1 pixel changed, and a very different image. A perceptual hash should say 1 and 2 were related and not 3. Cryptographers call that failing a chosen plaintext attack.
      • zepto 5y ago
        Agreed, but we don’t know the collision characteristics of this algorithm so knowing this difference is moot in this context.