Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The Problem with Perceptual Hashes

rentafounder.com

Post reply on HN
Print view View original

181–190 of 440 posts

Re: The Problem with Perceptual Hashes

#181

Post by MinusGix »

emodendroket wrote: post #43
toxik wrote: post #33

Earlier quoted context omitted.

This is really a difficult problem to solve I think. However, I think most people who are prosecuted for CP distribution are hoarding it by the terabyte. It’s hard to claim that you were unaware of that. A couple of gigabytes though? Plausible. And that’s what this CSAM scanner thing is going to find on phones.

A couple gigabytes is a lot of photos... and they'd all be showing up in your camera roll. Maybe possible but stretching the bounds of plausibility.

As others have said, people have a lot of photos. It wouldn't be too hard to hide them a bit from obvious view. As well, I rarely look at my gallery unless I need to. I just add a few photos occasionally. So maybe once every two weeks I look at my gallery, plenty of time to initiate that.

Re: The Problem with Perceptual Hashes

#182

Post by matheusmoreira »

Klonoar wrote: post #114
mrtksn wrote: post #72

The technical challenges aside, I’m very disturbed that my device will be reporting me to the authorities. That’s very different from authorities taking a sneak peek into my stuff. That’s like the theological concept of always being watched. It starts with child pornography but the technology is indifferent towards it, it can be anything. It’s always about the children because we all want to save the children. Soon t…

I would really like people to start answering this: what exactly do you think has changed? e.g, >That’s very different from authorities taking a sneak peek into my stuff. To be very blunt: - The opt out of this is to not use iCloud Photos. - If you _currently_ use iCloud Photos, your photos are _already_ hash compared. - Thus the existing opt out is to... not use iCloud Photos. The exact same outcome can happen regar…

What changed is we are not the masters of our technology anymore. If I tell my computer to do something, it should do it without question. It doesn't matter if it's a crime. The computer is supposed to be my tool and obey my commands.

Now what's going to happen instead is the computer will report me to its real masters: corporations, governments. How is this acceptable in any way?

Re: The Problem with Perceptual Hashes

#183

Post by bigyikes »

esyir wrote: post #167
gpm wrote: post #156

Earlier quoted context omitted.

With you up to here, but this is jumping the shark > I bet you, after the next election in the US your device will be reporting you for spreading far right or deep state lies, depending on who wins. The US is becoming less stable, sure [1], but there is still a very strong culture of free speech, particularly political speech. I put the odds that your device will be reporting on that within 4 years as approximately 0…

>but there is still a very strong culture of free speech In my opinion, that culture has been rapidly dying, chipped away by a very sizable and growing chunk that doesn't value it at all, seeing it only as a legal technicality to be sidestepped.

I find this varies greatly depending on location. Living in California, I was convinced of the same. Living in Texas now, I’m more optimistic.

Re: The Problem with Perceptual Hashes

#184

Post by [deleted] »

starkd wrote: post #59

The method Apple is using looks more like a cryptographic hash. That's entirely different (and more secure) than a perceptual hash. From https://www.apple.com/child-safety/ "Before an image is stored in iCloud Photos, an on-device matching process is performed for that image against the known CSAM hashes. This matching process is powered by a cryptographic technology called private set intersection, which determines…

[deleted]

Re: The Problem with Perceptual Hashes

#185

Post by [deleted] »

exporectomy wrote: post #152
thaumasiotes wrote: post #148

Earlier quoted context omitted.

> like the dogs which conveniently bark at police's secret hand sign This isn't necessary; the state of the art is for drug dogs to alert 100% of the time. They're graded on whether they ever miss drugs. It's easy to never miss.

Airport baggage drug dogs must obviously have far fewer false positives than that. So alerting on everything can't be the state of the art.

[deleted]

Re: The Problem with Perceptual Hashes

#186

Post by dylan604 »

ssklash wrote: post #177
dylan604 wrote: post #138

Earlier quoted context omitted.

>but I’m not going to carry a snitch in my pocket. I wonder how this will hold up against 5th ammendment (in the US) covering self-incrimination?

I assume the third party doctrine makes it so that the 5th amendment doesn't apply here.

"The third-party doctrine is a United States legal doctrine that holds that people who voluntarily give information to third parties—such as banks, phone companies, internet service providers, and e-mail servers—have "no reasonable expectation of privacy." A lack of privacy protection allows the United States government to obtain information from third parties without a legal warrant and without otherwise complying with the Fourth Amendment prohibition against search and seizure without probable cause and a judicial search warrant." --wiki

Okay, but the users of said 3rd party are doing it under the assumption that it is encrypted on the 3rd party's system in a way that they cannot gain access to it. The unencrypted data is not what the user is giving to iCloud. So technically, the data this scan is providing to the authorities is not the same data that the user is giving to the 3rd parties.

Definitely some wiggle room on both sides for some well versed lawyers to chew up some billing hours.

Re: The Problem with Perceptual Hashes

#187

Post by bigiain »

Klonoar wrote: post #114
mrtksn wrote: post #72

The technical challenges aside, I’m very disturbed that my device will be reporting me to the authorities. That’s very different from authorities taking a sneak peek into my stuff. That’s like the theological concept of always being watched. It starts with child pornography but the technology is indifferent towards it, it can be anything. It’s always about the children because we all want to save the children. Soon t…

I would really like people to start answering this: what exactly do you think has changed? e.g, >That’s very different from authorities taking a sneak peek into my stuff. To be very blunt: - The opt out of this is to not use iCloud Photos. - If you _currently_ use iCloud Photos, your photos are _already_ hash compared. - Thus the existing opt out is to... not use iCloud Photos. The exact same outcome can happen regar…

> The opt out of this is to not use iCloud Photos.

Wasn’t yesterday’s version of this sorry about how Apple is implementing this as a client side service on iPhones?

https://news.ycombinator.com/item?id=28068741

I don’t know if the implication there is “don’t use the stock Apple camera app and photo albums”, or “don’t store any images on yours Phone any more” if they are scanning files from other apps for perceptual hash matches as well…

Re: The Problem with Perceptual Hashes

#188

Post by dwaltrip »

jjtheblunt wrote: post #50
stickfigure wrote: post #10

I've also implemented perceptual hashing algorithms for use in the real world. Article is correct, there really is no way to eliminate false positives while still catching minor changes (say, resizing, cropping, or watermarking). I'm sure I'm not the only person with naked pictures of my wife. Do you really want a false positive to result in your intimate moments getting shared around some outsourced boiler room for…

Why would other people have a naked picture of your wife?

Others have pictures of their wife, not GP's wife.

Re: The Problem with Perceptual Hashes

#189

Post by dwaltrip »

mjlee wrote: post #18
stickfigure wrote: post #10

I've also implemented perceptual hashing algorithms for use in the real world. Article is correct, there really is no way to eliminate false positives while still catching minor changes (say, resizing, cropping, or watermarking). I'm sure I'm not the only person with naked pictures of my wife. Do you really want a false positive to result in your intimate moments getting shared around some outsourced boiler room for…

> I'm sure I'm not the only person with naked pictures of my wife. I'm not completely convinced that says what you want it to.

The reasonable interpretation is that GP is saying many people may have private pictures of their partner.

Re: The Problem with Perceptual Hashes

#190

Post by macintux »

dannyw wrote: post #172
gpm wrote: post #156

Earlier quoted context omitted.

With you up to here, but this is jumping the shark > I bet you, after the next election in the US your device will be reporting you for spreading far right or deep state lies, depending on who wins. The US is becoming less stable, sure [1], but there is still a very strong culture of free speech, particularly political speech. I put the odds that your device will be reporting on that within 4 years as approximately 0…

Did you literally not see a former president effectively get silenced in the public sphere by 3 corporations? How can you seriously believe that these corporations (who are not subject to the first amendment, and cannot be challenged in court) won't extend and abuse this technology to tackle "domestic extremism" but broadly covering political views?

> a former president effectively get silenced in the public sphere

It's laughable that a man who can call a press conference at a moment's notice and get news coverage for anything he says can be "silenced" because private companies no longer choose to promote his garbage.

Post reply on HN