4 ms·

No, Facebook's side needs to verify that the image is you, and that you're not just hashing a photo of the McDonald's logo.

the8472 9y ago
they can verify that after they have found a match. if there is no match you gave them no data of interest. if there is a match then they already have that image anyway and you didn't make your privacy situation worse, except maybe telling them that you claim that is you, now allowing them to associate more images was you, but that's probably an acceptable tradeoff if there is actual revenge porn of you out there.
- ibejoeb 9y ago
  It's not a simple hash. From Alex Stamos: “There are algorithms that can be used to create a fingerprint of a photo/video that is resilient to simple transforms like resizing.” That doesn't make it clear that they are making use of the powerful classifiers that Facebook has, but it's clearly not md5, either. Regardless, I think your point stands.
  - the8472 9y ago
    They could also combine locally computed perceptual hashes of the unwanted images with face recognition of already uploaded regular images on the profile. That combination makes it even less necessary to send nudes to facebook.
  - Regic 9y ago
    My guess would be that they trained an autoencoder network for facial recognition and they use the encoder part for fingerprinting and check images by the decoder part. https://en.wikipedia.org/wiki/Autoencoder https://en.wikipedia.org/wiki/Autoencoder
- Dylan16807 9y ago
  If they already have the image, then you don't need this system. If they don't have it, but are doing verify-after, then the image won't actually be blocked right away. The proposed system would be of pretty marginal value. Some value, yes, but low enough that facebook decided it wasn't worth building that system. You can't avoid having a tradeoff somewhere.
drb91 9y ago
Presumably it’s both; hashing like this is fairly trivial to break if you can access the code.
- Regic 9y ago
  If the recognition is done by autoencoder network as I suspect, then generative adversarial network could break it easily.

the8472 9y ago

they can verify that after they have found a match. if there is no match you gave them no data of interest. if there is a match then they already have that image anyway and you didn't make your privacy situation worse, except maybe telling them that you claim that is you, now allowing them to associate more images was you, but that's probably an acceptable tradeoff if there is actual revenge porn of you out there.

ibejoeb 9y ago
It's not a simple hash. From Alex Stamos: “There are algorithms that can be used to create a fingerprint of a photo/video that is resilient to simple transforms like resizing.” That doesn't make it clear that they are making use of the powerful classifiers that Facebook has, but it's clearly not md5, either. Regardless, I think your point stands.
- the8472 9y ago
  They could also combine locally computed perceptual hashes of the unwanted images with face recognition of already uploaded regular images on the profile. That combination makes it even less necessary to send nudes to facebook.
- Regic 9y ago
  My guess would be that they trained an autoencoder network for facial recognition and they use the encoder part for fingerprinting and check images by the decoder part. https://en.wikipedia.org/wiki/Autoencoder https://en.wikipedia.org/wiki/Autoencoder
Dylan16807 9y ago
If they already have the image, then you don't need this system. If they don't have it, but are doing verify-after, then the image won't actually be blocked right away. The proposed system would be of pretty marginal value. Some value, yes, but low enough that facebook decided it wasn't worth building that system. You can't avoid having a tradeoff somewhere.

drb91 9y ago

Presumably it’s both; hashing like this is fairly trivial to break if you can access the code.

Regic 9y ago
If the recognition is done by autoencoder network as I suspect, then generative adversarial network could break it easily.