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Apple enabling client-side CSAM scanning on iPhone tomorrow

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Re: Apple enabling client-side CSAM scanning on iPhone tomorrow

#581

Earlier quoted context omitted.

Great, so what's the solution? What are you doing to fix it? Do you roll your own silicon? Do you grow your own food (we have no idea what someone could be putting in it)? Are you completely off-grid? Or are you as completely dependent on society writ large as everyone else? Making holier than thou comments about everyone else being sheep isn't helpful or thought provoking. Offer an alternative if it is a bad one (lo…

Dumping Facebook and its products as I and others have done is one strong step forward but people can't even manage this. It's deeply disappointing. Techno bears its seeds in rebellion but everybody throwing techno parties is coordinating on what is essentially an Orwellian state. Punks too, they're cozied up to this framework of oppression and can't see it for what it is. I think people have a hard time seeing the e…

> Dumping Facebook and its products as I and others have done is one strong step forward

A strong step forward that gets nullified when Facebook buys the alternative app you're using, or when the app you're using does things as Facebook does.

You can propose all individual options you want, this is a collective issue that won't get fixed just by calls to individual action.

Re: Apple enabling client-side CSAM scanning on iPhone tomorrow

#582
post #58

I'm really conflicted about this. For context, I deeply hate the abuse of children and I've worked on a contract before that landed 12 human traffickers in custody that were smuggling sex slaves across boarders. I didn't need to know details about the victims in question, but it's understood that they're often teenagers or children. So my initial reaction when reading this Twitter thread was "let's get these bastards…

The NCMEC database that Apple is likely using to match hashes, contains countless non-CSAM pictures that are entirely legal not only in the U.S. but globally. This should be reason enough for you to not support the idea. From day 1, it's matching legal images and phoning home about them. Increasing the scope of scanning is barely a slippery slope, they're already beyond the stated scope of the database.

[deleted]

Re: Apple enabling client-side CSAM scanning on iPhone tomorrow

#583

Earlier quoted context omitted.

I'm OK with software generating signatures from cloud drive images to eliminate child porn pictures and catch pedophiles.

You should read the rest of the linked Twitter thread, because the issue is that if the hash algorithm has a collision vulnerability, any image could be manipulated to show up as "child porn" to the scanner.

Microsoft created and hosts the PhotoDNA service which all providers use, and PhotoDNA has false positives. All reports are supposed to be manually reviewed before being sent to Cyber Tip.

Re: Apple enabling client-side CSAM scanning on iPhone tomorrow

#584
post #62

I was under the impression that one of the reasons why these tools aren’t available for public download is because the hashes and system can be used to design defeat mechanisms? Doesn’t this mean that someone who has an image and a jail broken device can just watch the system, identify how the photo is detected, and modify it so that it doesn’t trip the filter? PhotoDNA and systems like it are really interesting, but…

I see it as a huge risk too.

If the algorithm and the blocklists leaked, then not only it would be possible to develop tools that reliably modify CSAM to avoid detection, but also generate new innocent-looking images that are caught by the filter. That could be used to overwhelm law enforcement with false positives and also weaponized for SWAT-ing.

Re: Apple enabling client-side CSAM scanning on iPhone tomorrow

#585
post #27

So if I understand correctly, they want to scan all your photos, stored on your private phone, that you paid for, and they want to check if any of the hashes are the same as hashes of child porn? So... all your hashes will be uploaded to the cloud? How do you prevent them from scanning other stuff (memes, leaked documents, trump-fights-cnn-gif,... to profile the users)? Or will a huge hash database of child porn hash…

> and they want to check if any of the hashes are the same as hashes of child porn? ... without any technical guarantee or auditability that any of the hashes they're alerting on are actually of child porn. How much would you bet against law enforcement to abuse their ability to use this, and add hashes to find out who's got anti government memes or police committing murder images on their phones? And that's just in…

I remember the story where some large gaming company permanently banned someone because they had a file with a hash that matched a "hacking tool". Turns out the hash was for an empty file.

This will end badly for humanity.

Re: Apple enabling client-side CSAM scanning on iPhone tomorrow

#586
post #22

Earlier quoted context omitted.

What are the implications?

A country can collect a list of people sharing any content they put on a hash list. Like gay porn, 'save Khashoggi' meme, or a photo from documentary about missing Uighurs. It's hard to imagine how this could be misused, right?

That seems like a real problem, and of course it could be misused, however nothing so far revealed actually tells us whether it is possible.

E.g. how the hashes are computed, where they come from, and what happens when a positive match is detected.

Until we have a clear understanding of these things, the rest is just speculation.

Re: Apple enabling client-side CSAM scanning on iPhone tomorrow

#587
post #275

Earlier quoted context omitted.

If the details of the "hashing" scheme used is publicized, I imagine it will be near trivial. It's a long-standing problem in computer vision, to find a digital description of an image such that two similar images compare equal or at least similar. State-of-the-art for this field is deep learning, and a /huge/ problem with the DL approach is that you can generate adversarial examples. So for example, a picture of a t…

Since this algorithm presumably runs on-device, I am sure it won’t be long before someone has reverse engineered it…

Indeed, at which point we’ll know if Apple has implemented an obviously broken solution which opens us up to egregious government surveillance, or whether that is all just speculation without a factual basis.

Re: Apple enabling client-side CSAM scanning on iPhone tomorrow

#588

So if I understand correctly, they want to scan all your photos, stored on your private phone, that you paid for, and they want to check if any of the hashes are the same as hashes of child porn? So... all your hashes will be uploaded to the cloud? How do you prevent them from scanning other stuff (memes, leaked documents, trump-fights-cnn-gif,... to profile the users)? Or will a huge hash database of child porn hash…

This is the big one right here. A malware will definitely be created, almost immediately, that will download files that are intentionally made to match CP - either for the purposes of extortion or just watching the world burn. I'm usually sticking my neck out in defence of more government access to private media than most on HN because of the need to stop CP, but this plan is so naive, and so incredibly irresponsible…

If this was easy to do, it’d already be a problem because Apple is already scanning some iCloud services for CSAM per their terms of service.

Re: Apple enabling client-side CSAM scanning on iPhone tomorrow

#589

Earlier quoted context omitted.

I agree, I would add that people have generated legal images that match the hashes. So I want to ask what happens if you have a photo that is falsely identified as one in question and then an automated mechanism flags you and reports you to the FBI without you even knowing. Can they access your phone at that point to investigate? Would they come to your office and ask about it? Would that be enough evidence to reques…

>I would add that people have generated legal images that match the hashes. That seems like a realistic attack. Since the hash list is public (has to be for client side scanning), you could likely set your computer to grind out a matching image hash but of some meme which you then distribute.

The NCMEC hash list is private, and adversarial attacks require running gradient descent and being able to generate a hash value for arbitrary input.
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