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0 pointsteekert4y ago0 comments

1 in a trillion with a billion devices with 10k pics is not a small chance. But what do we know? It's not like Apple is communicating any numbers anywhere so we can make a reasonable guess as to the number of false positives, and as to whether we may think it is actually worth it.

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Grustaf4y ago

It’s not per photo, it’s per photo library. But it’s per year, so on average once every 1000 years there will be a false positive for someone.

They are communicating numbers. For example, they tested with 100 million photos and got 3 false positives. They also tested with 100 k normal porn photos and got 0 false positives.

kbelder4y ago

I think their numbers are completely irrelevant, now that we know the visual hash can be gamed. Since it can be, it will be.

Basically, that 1 in a trillion number has an implicit "assuming people aren't cheating", as most mathematical models do. But it's already evident people can cheat this system.

I don't know what the odds will end up being, 1 in a trillion or 1 in 100, but they will not be based on statistical analysis. The odds will be based on cultural and social factors... how quickly do Apple reviewers get overwhelmed? How easily can script kiddies use the tools to fake hashes? Are there consequences for false reports? How many people want to get you in trouble?

Grustaf4y ago

All the other big players have been using similar algorithms for years, in the cloud. Why haven’t they been overwhelmed by false positive attacks?

j / k navigate · click thread line to collapse

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Grustaf4y ago

It’s not per photo, it’s per photo library. But it’s per year, so on average once every 1000 years there will be a false positive for someone.

They are communicating numbers. For example, they tested with 100 million photos and got 3 false positives. They also tested with 100 k normal porn photos and got 0 false positives.

kbelder4y ago

I think their numbers are completely irrelevant, now that we know the visual hash can be gamed. Since it can be, it will be.

Basically, that 1 in a trillion number has an implicit "assuming people aren't cheating", as most mathematical models do. But it's already evident people can cheat this system.

Grustaf4y ago

All the other big players have been using similar algorithms for years, in the cloud. Why haven’t they been overwhelmed by false positive attacks?

j / k navigate · click thread line to collapse