6 ms·

Not sure how I feel about it still, but this article doesn't really accurately portray the service. From the source linked by the Wired article [1], this is spe

Not sure how I feel about it still, but this article doesn't really accurately portray the service. From the source linked by the Wired article [1], this is specifically intended to prevent a nude photo from being shared maliciously when a user has reason to believe that it will be. They then voluntarily upload the image to Facebook which uses the digital fingerprint to prevent it from being reposted either in its original form or with slight modifications. It's always completely voluntary, Facebook is certainly not requiring or even really encouraging average users to upload their nudes. [1] - https://www.theverge.com/2017/11/9/16630900/facebook-revenge-porn-defense-details https://www.theverge.com/2017/11/9/16630900/facebook-revenge...

cholantesh 9y ago
I don't see how that makes it better.
- cracell 9y ago
  Well in that case it actually makes sense. They can fingerprint the photo and then automatically remove it. Though really would be better to fingerprint all removed photos and automatically prevent any matching photos from being uploaded.
- cbhl 9y ago
  Presumably, you would do this after Facebook already has a copy of the nude -- uploaded by the attacker/malicious ex. If you want Facebook's computers to automatically take down any copies of the photo, yes, you're going to have to trust them with a copy of it. Automated DMCA takedowns of copyrighted music and movies work in very much the same way.
  - the8472 9y ago
    > yes, you're going to have to trust them with a copy of it. No. They could have you compute a fingerprint locally without uploading the image itself, preferably through some audited open source software, without auto-updates. They only don't do that because they want to guard their image hashing as corporate secrets.
    - kemitche 9y ago
      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.
- 1_2__4 9y ago
  Do you have a better idea? I don’t.
  - ProAm 9y ago
    Hash your copy of the nude image client side, and upload the hash only? Seems like a way better idea to me.
    - sliverstorm 9y ago
      A hash would only match an identical file, right? It sounds like image recognition is used here to catch derivatives of the original file, which a hash wouldn't catch.
      - ProAm 9y ago
        I think it would be easy to create multiple hashes (reverse, flipped, etc...) and upload them all and look for matches. Provide the users with image recognition signature creating software (which is exactly what they are going to do) and let the users do it, vs uploading extremely personal and potentially embarrassing images to strangers on the internet.
        sliverstorm 9y ago
        How about recompressed, resized, photoshopped, format-converted... a filter against trivial transformations like transposition is worthless.
        ProAm 9y ago
        tough problem sure, but sending nude photos to a morally questionable company is not remotely close to the best solution to this problem.
        nasredin 9y ago
        If someone has your nudes and intends to share them I think blocking them only on Facebook and not anywhere else is not productive. You should just post the nudes yourself IMHO and be done with it.

cholantesh 9y ago

I don't see how that makes it better.

cracell 9y ago
Well in that case it actually makes sense. They can fingerprint the photo and then automatically remove it. Though really would be better to fingerprint all removed photos and automatically prevent any matching photos from being uploaded.
cbhl 9y ago
Presumably, you would do this after Facebook already has a copy of the nude -- uploaded by the attacker/malicious ex. If you want Facebook's computers to automatically take down any copies of the photo, yes, you're going to have to trust them with a copy of it. Automated DMCA takedowns of copyrighted music and movies work in very much the same way.
- the8472 9y ago
  > yes, you're going to have to trust them with a copy of it. No. They could have you compute a fingerprint locally without uploading the image itself, preferably through some audited open source software, without auto-updates. They only don't do that because they want to guard their image hashing as corporate secrets.
  - kemitche 9y ago
    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.
1_2__4 9y ago
Do you have a better idea? I don’t.
- ProAm 9y ago
  Hash your copy of the nude image client side, and upload the hash only? Seems like a way better idea to me.
  - sliverstorm 9y ago
    A hash would only match an identical file, right? It sounds like image recognition is used here to catch derivatives of the original file, which a hash wouldn't catch.
    - ProAm 9y ago
      I think it would be easy to create multiple hashes (reverse, flipped, etc...) and upload them all and look for matches. Provide the users with image recognition signature creating software (which is exactly what they are going to do) and let the users do it, vs uploading extremely personal and potentially embarrassing images to strangers on the internet.
      - sliverstorm 9y ago
        How about recompressed, resized, photoshopped, format-converted... a filter against trivial transformations like transposition is worthless.
        ProAm 9y ago
        tough problem sure, but sending nude photos to a morally questionable company is not remotely close to the best solution to this problem.
        nasredin 9y ago
        If someone has your nudes and intends to share them I think blocking them only on Facebook and not anywhere else is not productive. You should just post the nudes yourself IMHO and be done with it.