One Bad Apple
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One Bad Apple
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Re: One Bad Apple
#2This reads like a failure of the NCMEC, and the legal system surrounding it.
It is insane that using perceptual hashes is likely illegal. As the hashes are actually somewhat reversible and so possession of the hash is a criminal offence. It just shows how twisted up in itself the law is in this area.
One independent image analysis service should not be beating reporting rates of major service providers. And NCMEC should not be acting like detection is a trade secret. Wider detection and reporting is the goal.
And the law as setup prevents developing detection methods. You cannot legally check the results of your detection (which Apple are doing), as that involves transmitting the content to someone other than the NCMEC!
Re: One Bad Apple
#3> To reiterate: scanning your device is not a privacy risk, but copying files from your device without any notice is definitely a privacy issue.
Not a lawyer, but I believe this part about legality is inaccurate, because they aren’t copying your photos without notice. The feature is not harvesting suspect photos from a device, it is attaching data to all photos before they are uploaded to Apple’s servers. If you’re not using iCloud Photos, the feature will not be activated. Furthermore, they’re not knowingly transferring CSAM, because the system is designed only to notify them when a certain “threshold” of suspect images has been crossed.
In this way it’s identical in practice to what Google and Facebook are already doing with photos that end up on their servers, they just run the check before the upload instead of after. I certainly have reservations about their technique here, but this argument doesn’t add up to me.
Re: One Bad Apple
#4> To reiterate: scanning your device is not a privacy risk, but copying files from your device without any notice is definitely a privacy issue. Not a lawyer, but I believe this part about legality is inaccurate, because they aren’t copying your photos without notice. The feature is not harvesting suspect photos from a device, it is attaching data to all photos before they are uploaded to Apple’s servers. If you’re n…
This basic implementation fact has been misrepresented over and over and over again. Does anyone read anymore? I’m starting to get really concerned. The hacker community is where I’ve turned to be more informed, away from the clickbait. But I’m being let down.
Re: One Bad Apple
#5> To reiterate: scanning your device is not a privacy risk, but copying files from your device without any notice is definitely a privacy issue. Not a lawyer, but I believe this part about legality is inaccurate, because they aren’t copying your photos without notice. The feature is not harvesting suspect photos from a device, it is attaching data to all photos before they are uploaded to Apple’s servers. If you’re n…
This basic implementation fact has been misrepresented over and over and over again. Does anyone read anymore? I’m starting to get really concerned. The hacker community is where I’ve turned to be more informed, away from the clickbait. But I’m being let down.
What does "manual review" mean then and how are those images reported?
Re: One Bad Apple
#6Really nice explanation from someone who knows a thing or two about images/photos (Dr. Neal Krawetz is the creator of https://fotoforensics.com and specializes in computer forensics).
Re: One Bad Apple
#7NCMEC has essentially shows that they have zero regard for privacy and called all privacy activists "screeching voices of the minority". At the same time, they're at the center point of a highly opaque, entrenched (often legally mandated) censorhip infrastructure that can and will get accounts shut down irrecoverably and possibly people's homes raided, on questionable data:
In one of the previous discussions, I've seen claims about the NCMEC database containing a lot of harmless pictures misclassified as CSAM. This post confirms this again (ctrl-f "macaque")
It also seems like the PhotoDNA hash algorithm is problematic (to the point where it may be possible to trigger false matches).
Now NCMEC seem to be pushing for the development of a technology that would implant an informant in every single of our devices (mandating the inclusion of this technology is the logical next step that seems inevitable if Apple launches this).
I'm surprised, and honestly disappointed, that the author seems to still play nice, instead of releasing the whitepaper. The NCMEC seems to have decided to position itself directly alongside other Enemies of the Internet, and while I can imagine that they're also doing a lot of important and good work, at this point, I don't think they're salvageable would like to see them disbanded.
Really curious how this will play out. I expect attacks either sabotaging these scanning systems by flooding them with false positives, or exploiting them to get the accounts of your enemies shut down permanently by sending them a picture of a macaque.
Re: One Bad Apple
#8Good article, however-
"Due to how Apple handles cryptography (for your privacy), it is very hard (if not impossible) for them to access content in your iCloud account. Your content is encrypted in their cloud, and they don't have access. If Apple wants to crack down on CSAM, then they have to do it on your Apple device"
I do not believe this is true. Maybe one day it will be true and Apple is planning for it, but right now iCloud service data is encrypted in the sense that they are stored encrypted at rest and in transit, however Apple holds the keys. We know this given that iCloud backups have been surrendered to authorities, and of course you can log into the web variants to view your photos, calendar, etc. Not to mention that Apple has purportedly been doing the same hash checking on their side for a couple of years.
Thus far there has been no compelling answer as to why Apple needs to do this on device.
Re: One Bad Apple
#9Earlier quoted context omitted.
This basic implementation fact has been misrepresented over and over and over again. Does anyone read anymore? I’m starting to get really concerned. The hacker community is where I’ve turned to be more informed, away from the clickbait. But I’m being let down.
What does "manual review" mean then and how are those images reported?
Before: you would upload images to iCloud Photos. Apple can access your images in iCloud Photos, but it does not.
Now: You upload images to iCloud Photos. When doing so, your device also uploads a separate safety voucher for the image. If there are enough vouchers for CSAM matched images in your library, Apple gains the ability to access the data in the vouchers for images matching CSAM. One of the data elements in the voucher is an “image derivative” (probably a thumbnail) which is manually reviewed. If the image derivative also looks like CSAM, Apple files a report with NCMEC’s CyberTip line. Apple can (for now) access the image you stored in iCloud, but it does not. All the data it needs is in the safety voucher.
Lot of words spilled on this topic, yet I’d be surprised if a majority of people are even aware of these basic facts about the system operation.
Re: One Bad Apple
#10Earlier quoted context omitted.
This basic implementation fact has been misrepresented over and over and over again. Does anyone read anymore? I’m starting to get really concerned. The hacker community is where I’ve turned to be more informed, away from the clickbait. But I’m being let down.
What does "manual review" mean then and how are those images reported?
As I understand it:
When you choose to upload your images to iCloud (which currently happens without end-to-end encryption), your phone generates some form of encrypted ticket. In the future, the images will be encrypted, with a backdoor key encoded in the tickets.
If Apple receives enough images that were considered a match, the tickets become decryptable (I think I saw Shamir's Secret Sharing mentioned for this step). Right now, Apple doesn't need that because they have unencrypted images, in a future scheme, decrypting these tickets will allow them to decrypt your images.
(I've simplified a bit, I believe there's a second layer that they claim will only give them access to the offending images. I have not studied their approach deeply.)