9 ms·
The problem of hash or NN based matching is, the authority can avoid explaining the mismatch. Suppose the authority want to false-arrest you. They prepare a ha
by ezoe 5y ago
The problem of hash or NN based matching is, the authority can avoid explaining the mismatch.
Suppose the authority want to false-arrest you. They prepare a hash that matches to an innocent image they knew the target has in his Apple product. They hand that hash to the Apple, claiming it's a hash from a child abuse image and demand privacy-invasive searching for the greater good.
Then, Apple report you have a file that match the hash to the authority. The authority use that report for a convenient reason to false-arrest you.
Now what happens if you sue the authority for the intentional false-arrest? Demand the original intended file for the hash? "No. We won't reveal the original file because it's child abusing image, also we don't keep the original file for moral reason"
But come to think of it, we already have tons of such bogus pseudo-science technology like the dogs which conveniently bark at police's secret hand sign, polygraph, and the drug test kit which detect illegal drugs from thin air.
- thaumasiotes 5y ago> 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.
- exporectomy 5y agoAirport 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 5y ago[deleted]
- thaumasiotes 5y agohttps://reason.com/2021/05/13/the-police-dog-who-cried-drugs-at-every-traffic-stop/ https://reason.com/2021/05/13/the-police-dog-who-cried-drugs... > Similar patterns abound nationwide, suggesting that Karma's career was not unusual. Lex, a drug detection dog in Illinois, alerted for narcotics 93 percent of the time during roadside sniffs, but was wrong in more than 40 percent of cases. Sella, a drug detection dog in Florida, gave false alerts 53 percent of the time. Bono, a drug detection dog in Virginia, incorrectly indicated the presence of drugs 74 percent of the time.
- imwillofficial 5y agoOut of how many dogs? We’re these outliers or the regular thing?
- stickfigure 5y agoWhat feedback loop is built into the system to discourage this from being the regular thing?
- dagw 5y agoI've had my bag sniffed at airports at least 50 times, and they've never stopped me. So there must be something else going on as well
- pixl97 5y agoThe handler didn't think you looked untrustworthy and didn't hint for the dog to bark.
- fortran77 5y agoDrug detection dogs sit down near the bag. They don't bark.
- emodendroket 5y agoThe police only call in the dogs when they wish to search and the driver does not agree. The airport doesn't do things this way so the same strategy wouldn't work.
- jsjohnst 5y agoAirport dogs (at least in the baggage claim area) are not sniffing for drugs. They alert on food products that aren’t allowed.
- heavyset_go 5y agoAnd explosives.
- intricatedetail 5y agoDogs are used to protect police from accusations of racism and profiling.
- pixl97 5y agoWhich is odd as dogs can be just as racist as their handlers want.
- jbuhbjlnjbn 5y agoTo be more precise, if the dog always barks and only missing positives are counted, it is inevitable to never miss. An obvious number cheat.
- fogof 5y agoWell, presumably at that point, someone in that position would just reveal their own files with the hash an prove to the public that they weren't illegal. Sure, it would be shitty to be forced to reveal your private information that way, but you would expose a government agency as fabricating evidence and lying about the contents of the picture in question to falsely accuse someone. It seems like that would be a scandal of Snowden-level proportions.
- gpm 5y agoIt wouldn't prove anything, because hash functions are many-to-one. It's entirely possible that it was just a coincidence.
- deleted 5y ago[deleted]
- dannyw 5y agoThere are literally hundreds of cases of police fabricating evidence and getting caught in court, or on bodycam. This happens today. We must not build technology that makes it even more devastating.
- visarga 5y agoYou can reveal your files and people can accuse you you deleted the incriminating ones.
- kelnos 5y agoNot if you show the file that matches the perceptual hash that "caught" you.
- deanclatworthy 5y agoWould a court be compelled to provide that hash to your defence? Arguable as it could be used by criminals to clean their collection. And by that time your life is ruined anyway.
- 5y ago
- jokoon 5y ago> Suppose the authority want to false-arrest you. Why would they want that?
- awestroke 5y agoOh, sweet, naive child.
- jokoon 5y agoI'm not american, I'm just asking a simple question.
- awestroke 5y agoCorrupt governments and police forces are not unique to the US (although it seems like the police in the US has become corrupt through and through).
- deleted 5y ago[deleted]
- kleene_op 5y agoThis has nothing to do with America.
- deleted 5y ago[deleted]
- l33t2328 5y agoAre you from a country where the government has never abused its power?
- latexr 5y agoBe kind[1]. Not everyone will have a life experience or knowledge similar to yours. Someone looking to fill the gaps in their knowledge in good faith should be encouraged, not ridiculed. [1]: https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
- delusional 5y agoWhat about trolling. Assume 4chan figures out apples algorithm. What now happens when they start generating memes that happen to match known child pornography? Will anyone who saves those memes (or repost them to reddit/facebook) be flagged? What will apple do once flagged false positive photos go viral?
- deleted 5y ago[deleted]
- sunshinerag 5y ago>> Will anyone who saves those memes (or repost them to reddit/facebook) be flagged? Shouldn't they be?
- paulryanrogers 5y agoUmm, no? If someone happens upon some funny cat meme that 4chan users made with an intentional hash collision then they're not guilty of anything. A poor analogy could be trolls convincing a flash mob to dress like a suspect's description which they overheard with a police scanner. No one in the mob is guilty of anything more than poor fashion choice.
- Frost1x 5y agoThe point made was that there are always flaws in these sorts of approaches that lead to false positives. If you can discover the flawed pattern(s) that leads to false positives and engineer them into seemingly harmless images, you can quite literally do what OP I'd suggesting. It's a big IFF but it's not theoretically impossible. The difference between this and hashes that require image data to be almost identical is that someone who accidently sees it can avoid and report it. If I can make cat photos that set off Apple's false positives, then there's a lot of people who will be falsely accused of propagating child abuse photos when they're really just sending cat memes.
- mirkules 5y agoOne way this hair-brained Apple program could end is to constantly generate an abundance of false positives, and try to render it useless. For those old enough to remember “Jam Echelon Day”, maybe it won’t have any effect. But what other recourse do we have other than to maliciously and intentionally subvert and break it?
- emodendroket 5y agoParallel construction is another way this is often pursued.
- deleted 5y ago[deleted]
- ATsch 5y agoThe way I see it, this is the only possible purpose this system could have. With the press after this announcement, almost every single person in posession of those materials knows it's not safe to store them on an iPhone. By it's construction, this system can only be effective against things that the owner is not aware their phones are being searched for.
- nullc 5y ago> Demand the original intended file for the hash? Even if they'd provide it-- the attacker need only perturb an image from an existing child abuse image database until it matches the target images. Step 1. Find images associated with the race or political ideology that you would like to genocide and compute their perceptual hashes. Step 2. Obtain a database of old widely circulated child porn. (Easy if you're a state actor, you already have it, otherwise presumably it's obtainable since if it wasn't none of this scanning would be needed). Step 3. Scan for the nearest perceptual matches for the target images in the CP database. Then perturb the child porn images until they match (e.g. using adversarial noise). Step 4. Put the modified child porn images into circulation. Step 5. When these in-circulation images are added to the database the addition is entirely plausibly denyable. Step 6. After rounding up the targets, even if they're allowed any due process at all you disallow them access to the images. If that dis-allowance fails, you can still cover by the images existing and their addition having been performed by someone totally ignorant of the scheme.
- some_random 5y agoThe police can arrest you for laws that don't exist but they think exist. They don't need to any of this stuff.
- jMyles 5y agoI know this is a tough thing to consider, but: Isn't this a problem generally with laws against entire classes of media? Planting a child abuse image (or even simply claiming to have found one) is trivial. Even robust security measures like FDE don't prevent a criminal thumb-drive from appearing. I think we probably need to envision a future in which there is simply no such concept under law as an illegal number.