61–70 of 86 posts
Pretty soon housing your own infra and not using the mandated govt phone could be made a crime. But think of the children and security of the society. Couple that with constant monitoring of your car and you can be monitored anywhere
(Context: I teach computer security at Princeton and have a paper at this week's Usenix Security Symposium describing and analyzing a protocol that is similar to Apple's: https://www.usenix.org/conference/usenixsecurity21/presentat... .) The proposed attack on Apple's protocol doesn't work. The user's device adds randomness when generating an outer encryption key for the voucher. Even if an adversary obtains both the…
> only able to decrypt if there's a hash match This is one of the concerns in the OP, have an AI generate millions of variations of a certain kind of images and check the hashes. In this case it boils down to how common false positives neural hashes are.
> The proposed attack on Apple's protocol doesn't work.
With all due respect, I think you may have misunderstood the proposed attack @jonathanmayer, as what @jobigoud said is correct.
For some reason, after reading the initial reporting on this system, I thought it was running against any photos on your iPhone, but now I read the actual paper, it seems like it only applies to photos destined to be uploaded to iCloud? So users can opt out by not using iCloud?
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> For CSAM matches, the cryptographic header in the voucher combines with the server-side blinding secret (that was used to blind the known CSAM database at setup time) to successfully decrypt the outer layer of encryption. In the text you referenced, it specifically says that the blinding key would be needed to decrypt vouchers which are CSAM matches. This is because Apple set up their CSAM database in a blinded man…
I’m a little confused. The vouchers you are trying to decrypt have already been generated. How does it matter if the attacker can decrypt vouchers from a database they created but was not used by the vouchers in the breached data?
Apple needs the blinding key, because they encrypt their list of NeuralHashes hashes first, so that others cannot see exactly which CSAM hashes they're testing against. Therefore they first need to decrypt their own database in order to get the corresponding hash value from which to derive the decryption key.
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There may be another attack. Given some CP image, an attacker could perhaps morph it into an innocent looking image while maintaining the hash. Then spread this image on the web, and incriminate everybody.
> Then spread this image on the web, and incriminate everybody. You'd still have to generate several images and persuade people to download multiple of them into their photo roll. And as I understand it there's yet another layer of Apple employees to review the photo metadata before it ever makes its way to law enforcement.
I believe such images are called "Dank Memes" these days.
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No.
What is the difference between CP and CSAM and why is everyone suddenly using the term CSAM instead of CP?
(Context: I teach computer security at Princeton and have a paper at this week's Usenix Security Symposium describing and analyzing a protocol that is similar to Apple's: https://www.usenix.org/conference/usenixsecurity21/presentat... .) The proposed attack on Apple's protocol doesn't work. The user's device adds randomness when generating an outer encryption key for the voucher. Even if an adversary obtains both the…
There may be another attack. Given some CP image, an attacker could perhaps morph it into an innocent looking image while maintaining the hash. Then spread this image on the web, and incriminate everybody.
Earlier quoted context omitted.
There may be another attack. Given some CP image, an attacker could perhaps morph it into an innocent looking image while maintaining the hash. Then spread this image on the web, and incriminate everybody.
Sounds like a fantastic way for law enforcement to get into your phone with probably cause. Random message you a benign picture from some rando account with a matching hash. Immediate capture for CP, data mine the phone, insert rootkit, 'so sorry about the time and money you lost - toodles'.
Like a warrant for CP can’t be used to collect evidence on another cases for say tax fraud.
Earlier quoted context omitted.
Sounds like a fantastic way for law enforcement to get into your phone with probably cause. Random message you a benign picture from some rando account with a matching hash. Immediate capture for CP, data mine the phone, insert rootkit, 'so sorry about the time and money you lost - toodles'.
Don’t warrants have to name why ? Like a warrant for CP can’t be used to collect evidence on another cases for say tax fraud.