3 ms·

I wonder how resistant those are to distortion. The examples on the Insight page are pretty impressive, but fairly naive approaches. I feel like, if you knew th

I wonder how resistant those are to distortion. The examples on the Insight page are pretty impressive, but fairly naive approaches. I feel like, if you knew the algorithm, you could probably manipulate your image data in a way to make it appear almost the same but come up with a very different hash. Similar to adversial images in computer vision. https://spectrum.ieee.org/cars-that-think/transportation/sensors/slight-street-sign-modifications-can-fool-machine-learning-algorithms https://spectrum.ieee.org/cars-that-think/transportation/sen...

Asooka 8y ago
Or put it in an encrypted 7z archive. Or any number of workarounds where you're not sending image data so the filter can't detect you.
- thecatspaw 8y ago
  sure, but I dont think apple expects you to be able to filter this As a platform you cant really filter this, unless you blanket ban all archive files. For tumblr this might be viable, but for a file hoster it wouldnt be
  - swiley 8y ago
    Tumlbr at least used to let you add arbitrary HTML to your blog, I remember putting base64 encoded gifs on mine that the browser would render. Unless they removed that (which IMO, would pretty dramatically change the general feel of the site) there's a real limit to what they can block.
kajecounterhack 8y ago
Perceptual hashing is certainly resistant to some distortions, primarily affine transforms. Unfortunately there's not any easy or sufficiently strong defense against someone gradient descent-ing your algorithm.
woolvalley 8y ago
There is an entire youtube cottage hobby of putting full pirated movies with distortion. The distortion goes beyond simple things like color casts, so I'm guessing they are trying to escape some sort of perceptual hashing. Often the movies don't take the full frame and there are lens flare like overlays put on the images. The audio is also distorted.

Asooka 8y ago

Or put it in an encrypted 7z archive. Or any number of workarounds where you're not sending image data so the filter can't detect you.

thecatspaw 8y ago
sure, but I dont think apple expects you to be able to filter this As a platform you cant really filter this, unless you blanket ban all archive files. For tumblr this might be viable, but for a file hoster it wouldnt be
- swiley 8y ago
  Tumlbr at least used to let you add arbitrary HTML to your blog, I remember putting base64 encoded gifs on mine that the browser would render. Unless they removed that (which IMO, would pretty dramatically change the general feel of the site) there's a real limit to what they can block.

kajecounterhack 8y ago

Perceptual hashing is certainly resistant to some distortions, primarily affine transforms. Unfortunately there's not any easy or sufficiently strong defense against someone gradient descent-ing your algorithm.

woolvalley 8y ago

There is an entire youtube cottage hobby of putting full pirated movies with distortion. The distortion goes beyond simple things like color casts, so I'm guessing they are trying to escape some sort of perceptual hashing. Often the movies don't take the full frame and there are lens flare like overlays put on the images. The audio is also distorted.