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ImageNet contains naturally occurring Apple NeuralHash collisions

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Re: ImageNet contains naturally occurring Apple NeuralHash collisions

#2
There's been a lot of focus on the likelihood of collisions and whether someone could upload eg; an image with a matching hash to your device to "set you up", etc. But what's still extremely concerning is that there is still no guarantee that the hash list used can't be coopted for another purpose (eg; politically insensitive content).

Re: ImageNet contains naturally occurring Apple NeuralHash collisions

#3
> In order to test things, I decided to search the publicly available ImageNet dataset for collisions between semantically different images. I generated NeuralHashes for all 1.43 million images and searched for organic collisions. By taking advantage of the birthday paradox, and a collision search algorithm that let me search in n(log n) time instead of the naive n^2, I was able to compare the NeuralHashes of over 2 trillion image pairs in just a few hours.

> This is a false-positive rate of 2 in 2 trillion image pairs (1,431,168^2). Assuming the NCMEC database has more than 20,000 images, this represents a slightly higher rate than Apple had previously reported. But, assuming there are less than a million images in the dataset, it's probably in the right ballpark.

It's great to see the ingenuity and attention this whole debacle is receiving from the community. Maybe it will lead to advances in perceptual hashing (and also advances in consumer awareness of tech related privacy issues).

Re: ImageNet contains naturally occurring Apple NeuralHash collisions

#4

There's been a lot of focus on the likelihood of collisions and whether someone could upload eg; an image with a matching hash to your device to "set you up", etc. But what's still extremely concerning is that there is still no guarantee that the hash list used can't be coopted for another purpose (eg; politically insensitive content).

The OP mentions that two countries have to agree to add a file to the list, but your concern is definitely valid:

> Perhaps the most concerning part of the whole scheme is the database itself. Since the original images are (understandably) not available for inspection, it's not obvious how we can trust that a rogue actor (like a foreign government) couldn't add non-CSAM hashes to the list to root out human rights advocates or political rivals. Apple has tried to mitigate this by requiring two countries to agree to add a file to the list, but the process for this seems opaque and ripe for abuse.

Re: ImageNet contains naturally occurring Apple NeuralHash collisions

#7

There's been a lot of focus on the likelihood of collisions and whether someone could upload eg; an image with a matching hash to your device to "set you up", etc. But what's still extremely concerning is that there is still no guarantee that the hash list used can't be coopted for another purpose (eg; politically insensitive content).

this also punts the debate to the checking process instead of the fact that there even is a process to start with..

Re: ImageNet contains naturally occurring Apple NeuralHash collisions

#8
It doesn’t matter if there are collisions if the two images don’t actually look the same. Do people honestly believe a single CSAM flag from an “innocent” image is going to result in someone going to prison in America?

PhotoDNA has existed for over a decade doing the same thing with no instances that I have heard of.

If some corrupt government wants to get you they don’t need this. They can just unilaterally say you’ve done something bad without evidence and imprison you. It happens all the time. It’s even happened in America. Just look up DNA exonerations - people have had DNA on the scene that literally proves their innocence and they’re still locked up.

People should care about their governments being corrupt, not necessarily about this.

Re: ImageNet contains naturally occurring Apple NeuralHash collisions

#9

> In order to test things, I decided to search the publicly available ImageNet dataset for collisions between semantically different images. I generated NeuralHashes for all 1.43 million images and searched for organic collisions. By taking advantage of the birthday paradox, and a collision search algorithm that let me search in n(log n) time instead of the naive n^2, I was able to compare the NeuralHashes of over 2…

ImageNet is a very well-known data set. Are we sure apple didn't test on it when designing this algorithm?
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