3 ms·

This is probably not that a tricky system to implement, from this study. So from description, it seems that they have a 2 layer system, one synchronous one and

This is probably not that a tricky system to implement, from this study. So from description, it seems that they have a 2 layer system, one synchronous one and an asynchronous one. The sync one filters images based on purely the md5 hashes, so basically a lookup-table check. Then the image goes to the async OCR service to have the text extracted, if being decided against the censorship, it will be write back to the front layer hash table. Indeed, this is not very different from Facebook's auto face recognition/tagging features that has been enabled like forever. Just the volume of the system is pretty significant.

ehsankia 7y ago
So all you would need is an app that very slightly modifies one bit in every image you send at random, and it'll never be caught by the synchronous system? Does the async update retroactively delete older posted images? And if so, how long would it take for that to happen?
- xxxpupugo 7y ago
  Probably, an app that applies some random distortion to your source image, just like your own recaptcha. Also Adverisal Patch is a thing, so that could be applied to specifically distorted the system in a human invisible way to misguide the machine learning models. Whether it will be retroactively deleted, it think there is a possibility. If WeChat periodically scan your image and find your image violating the censorship, it will probably delete it and report to the authority. Again, some encryption needs to apply in this case. Just like in the old days.
  - Yetanfou 7y ago
    Technical measures like these don't have to be watertight to be effective with the 'right' laws in place, this has been demonstrated by the restrictions on bypassing 'content protection measures' in the DMCA. Those found out to be using means to bypass image censoring will eventually see their 'social credit score' plummet and be kicked off WeChat and/or the 'net.
- gwern 7y ago
  They say the async is operating on a timescale of seconds (presumably long enough for the batch OCR jobs to get around to it), so you can bypass it, but that won't do you much good.
hhjj 7y ago
Too smart for your own good.

ehsankia 7y ago

So all you would need is an app that very slightly modifies one bit in every image you send at random, and it'll never be caught by the synchronous system? Does the async update retroactively delete older posted images? And if so, how long would it take for that to happen?

xxxpupugo 7y ago
Probably, an app that applies some random distortion to your source image, just like your own recaptcha. Also Adverisal Patch is a thing, so that could be applied to specifically distorted the system in a human invisible way to misguide the machine learning models. Whether it will be retroactively deleted, it think there is a possibility. If WeChat periodically scan your image and find your image violating the censorship, it will probably delete it and report to the authority. Again, some encryption needs to apply in this case. Just like in the old days.
- Yetanfou 7y ago
  Technical measures like these don't have to be watertight to be effective with the 'right' laws in place, this has been demonstrated by the restrictions on bypassing 'content protection measures' in the DMCA. Those found out to be using means to bypass image censoring will eventually see their 'social credit score' plummet and be kicked off WeChat and/or the 'net.
gwern 7y ago
They say the async is operating on a timescale of seconds (presumably long enough for the batch OCR jobs to get around to it), so you can bypass it, but that won't do you much good.

hhjj 7y ago

Too smart for your own good.