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There is another information leak that I have not seen mentioned in any news report. If an image hash matches the CSAM database, then it is sent to Apple, encr
by occamrazor 5y ago
There is another information leak that I have not seen mentioned in any news report. If an image hash matches the CSAM database, then it is sent to Apple, encrypted and with the “safety voucher”. Apple can decrypt the image only if they receive enough vouchers, and so they claim that they do not have any information about the user in case the number of vouchers is lower than the threshold.
But actually they do have information: they know that a user has a specific number of images which are perceptually similar to known CSAM material. This information is not conclusive, but it’s also not nothing. For example, could a court order Apple to release the unencrypted iCloud backups of all users who had at least one match?
- nicce 5y agoThere is strong evidence, that E2EE backups are coming. How about hold our horses until actual release of iOS 15?
- cageface 5y agoWhat is the evidence for this?
- nicce 5y agoIn iOS 15 beta, there is option to recover backup with some authentication key. There is no use for that without E2EE.
- cageface 5y agoIf that was the plan why wouldn't Apple announce that alongside this to avoid the massive PR hit?
- nicce 5y agoThis whole Child Safety feature was not planned to be announced yet. They tried to fix some missleading leaks. My guess is that they are now preparing well to announce everything in September. I don’t want to be mean, but sometimes leaks do more harm than good, espcially when they don’t match what is actually coming. Many people are angry here, the most of them have not read actual technical details. Respected people should be more responsible about what they spread.
- cageface 5y agoWhat is your source for this information?
- nicce 5y agoI don't want to call names, but here is something: 1. On-device scanning is leaked by some well-known people 2. It gets massive attention 3. Not long after, Apple releases their announcement in very odd time 4. If you read all of their material, there are typos and some are clearly in WIP level 5. It does not make sense to announce, since there is reserved event for all of this in the very close future
- cageface 5y agoInteresting. It does seem hard to explain why Apple would otherwise do this. Thanks for your arguments.
- salawat 5y agoUh, no. Technical docs often live long term with typos. This is a perfectly timed leak to take pressure off regulation pushes by waving one of the biggest honking carrots in front of Western political establishments. This has political quid pro quo written all over it, and anyone who thinks this type of backhanded signalling isn't common isn't paying enough attention.
- nicce 5y agoThis is one point of view. However, there was chance to win over both parties (customers and governments), by announcing everything together. Why do it now, since it is very short time for September, and that time does not really matter anything on regulation level? Or are the scheduled votings coming very very soon? This holds strong arguments against new regulations whether it was leaked or not. Difference being specific attention.
- salawat 5y ago
- villgax 5y agoNot just that, random folks can send you media through multiple ways & you could get embroiled unnecessarily too, innocuous QR code might automatically download an image if your apps are configured that way.
- dogleash 5y ago>innocuous QR code might automatically download an image Just a few days ago at DEF CON some presenter had been going around with the EICAR test string in a QR code and having fun with all the forced AV hits that can cause. https://www.youtube.com/watch?v=cIcbAMO6sxo https://www.youtube.com/watch?v=cIcbAMO6sxo https://en.wikipedia.org/wiki/EICAR_test_file https://en.wikipedia.org/wiki/EICAR_test_file
- GistNoesis 5y agoApple talk about in their technical documentation https://www.apple.com/child-safety/pdf/CSAM_Detection_Technical_Summary.pdf https://www.apple.com/child-safety/pdf/CSAM_Detection_Techni... page 9 : Synthetic Match Vouchers They generate false positives themselves to hide their knowledge of the true number of collisions.
- occamrazor 5y agoThanks, I missed that paragraph.
- merpnderp 5y agoIf they don't keep track of which matches are false positives, wouldn't it be possible to be extremely unlucky and pass the threshold with nothing but false positives generated by Apple? This makes things worse not better.
- occamrazor 5y agoNo, the vouchers attached to the fake positives do not provide information for decrypting the images
- merpnderp 5y agoSo then it is possible to determine which vouchers are real and which are fake, and a court can still order a query for everyone with N-1 hits.
- unicornfinder 5y agoThing is, iCloud Photos are already not E2E encrypted, so it's sort of irrelevant if they're requiring "vouchers" in this case.
- zionic 5y agoThe argument is could this new system result in a court ordering a blanket "send us the backups for anyone who gets a match for any reason" order from some court. This is highly likely in my opinion.
- occamrazor 5y agoThat was in fact my question. Apple thought about tha and the solution looks robust indeed.