Apple's New CSAM Protections May Make iCloud Photos Bruteforceable • Hacker News Board

Re: Apple's New CSAM Protections May Make iCloud Photos Bruteforceable

#11

Post by Teever » Sun, Aug 08, 2021, 4:59 AM UTC

function_seven wrote: post #9

Teever wrote: post #7

Earlier quoted context omitted.

What is the difference between CP and CSAM and why is everyone suddenly using the term CSAM instead of CP?

Good link to explain why "CSAM" is being used in lieu of "CP" https://www.adfsolutions.com/news/what-is-csam > However, the phrase “child pornography” is almost too sterile and generic to properly exemplify the horrors of what is being created. That is why many advocates, including the National Center for Missing and Exploited Children (NCMEC), believe this phrase to be outdated. > NCMEC refers to these kinds of mate…

What terrible reasoning.

'Child pornography' is already too long to say repeatedly in a sentence so it is often shortened to "child porn." CSAM has far too many syllables so it too is shortened to two syllables in the form of the spoken acronym "CSAM" and so we're back to square one.

With that said this is a fascinating display someone pressing the reverse button on the euphemism treadmill. I don't think I've ever seen that before.

Re: Apple's New CSAM Protections May Make iCloud Photos Bruteforceable

#12

Post by function_seven » Sun, Aug 08, 2021, 5:09 AM UTC

Teever wrote: post #11

function_seven wrote: post #9

Earlier quoted context omitted.

Good link to explain why "CSAM" is being used in lieu of "CP" https://www.adfsolutions.com/news/what-is-csam > However, the phrase “child pornography” is almost too sterile and generic to properly exemplify the horrors of what is being created. That is why many advocates, including the National Center for Missing and Exploited Children (NCMEC), believe this phrase to be outdated. > NCMEC refers to these kinds of mate…

What terrible reasoning. 'Child pornography' is already too long to say repeatedly in a sentence so it is often shortened to "child porn." CSAM has far too many syllables so it too is shortened to two syllables in the form of the spoken acronym "CSAM" and so we're back to square one. With that said this is a fascinating display someone pressing the reverse button on the euphemism treadmill. I don't think I've ever se…

I don't think the number of syllables is the important thing here. Rather that the term "porn" doesn't—by itself!—impute any moral judgement. It's just a thing. Some people think it's all bad, others think some is okay while some isn't, and some think anything with consenting performers is fair game.

But children are incapable of being consenting performers. That's what separates abuse material from porn. So to make damn sure there isn't any overlap in the Venn diagram of media that depicts sexual acts, they'd rather not associate "child porn" with anything else that exists in the universe of "porn".

It's a completely separate category, not some "bad" end of a spectrum.

That's the reasoning I've heard before, anyway.

And I agree with you on the reverse treadmill thing. It's interesting. On a related tangent: I've always hated how journalists use the term "sexual assault" to refer to a wide range of offenses, from forcible rape to a passing grope. Although those are both bad things, it's clear that one is tremendously more harmful than the other. We should use language to clarify that.

Re: Apple's New CSAM Protections May Make iCloud Photos Bruteforceable

#13

Post by NTroy » Sun, Aug 08, 2021, 5:10 AM UTC

shuckles wrote: post #8

NTroy wrote: post #5

Earlier quoted context omitted.

The question doesn't presume that, as the the secret for blinding the CSAM database would only be helpful if a third party were also looking to see which accounts contained CSAM. In this case, the question assumes that an attacker would more or less be creating their own database of hashes and derived keys (to search for and decrypt known photos and associate them with user accounts, or to bruteforce unknown photos),…

> What's to stop an attacker from generating a NeuralHash of popular memes, deriving a key, then bruteforcing the leaked data until it successfully decrypts an entry, thus verifying the contents within a specific user's cloud photo library, and degrading their level of privacy? Decrypting vouchers requires the server blinding key and the NeuralHash derived metadata of the input image (technical summary page 10, Bella…

> 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 manner. Therefore to access a hash from the database from which to derive a decryption key, Apple would need the blinding key to first decrypt that hash value.

However, and attacker would be generating their own (presumably unblinded) database, and therefore wouldn't need to access Apple's blinding key.

Re: Apple's New CSAM Protections May Make iCloud Photos Bruteforceable

#14

Post by norov » Sun, Aug 08, 2021, 5:16 AM UTC

function_seven wrote: post #9

Teever wrote: post #7

Earlier quoted context omitted.

What is the difference between CP and CSAM and why is everyone suddenly using the term CSAM instead of CP?

Good link to explain why "CSAM" is being used in lieu of "CP" https://www.adfsolutions.com/news/what-is-csam > However, the phrase “child pornography” is almost too sterile and generic to properly exemplify the horrors of what is being created. That is why many advocates, including the National Center for Missing and Exploited Children (NCMEC), believe this phrase to be outdated. > NCMEC refers to these kinds of mate…

I realized child beauty pagents and other sexual exploitation of children would be considered Child Sexual Abuse Material in some cases. People, even those with good intentions, are not going to like where this is going.

Re: Apple's New CSAM Protections May Make iCloud Photos Bruteforceable

#15

Post by Teever » Sun, Aug 08, 2021, 5:17 AM UTC

function_seven wrote: post #12

Teever wrote: post #11

Earlier quoted context omitted.

What terrible reasoning. 'Child pornography' is already too long to say repeatedly in a sentence so it is often shortened to "child porn." CSAM has far too many syllables so it too is shortened to two syllables in the form of the spoken acronym "CSAM" and so we're back to square one. With that said this is a fascinating display someone pressing the reverse button on the euphemism treadmill. I don't think I've ever se…

I don't think the number of syllables is the important thing here. Rather that the term "porn" doesn't—by itself!—impute any moral judgement. It's just a thing. Some people think it's all bad, others think some is okay while some isn't, and some think anything with consenting performers is fair game. But children are incapable of being consenting performers. That's what separates abuse material from porn. So to make…

The number of syllables matter if the goal is to prevent a term from feeling too sterile. If a term is too long and unwieldy then people will naturally shorten it to an acronym. And once they're using an acronym then we're back to square one because acronyms are devoid of the meaning that words have.

I've wondered if there is an intent to distinguish between child pornography that teenagers are producing on their own to share with each other and the kind child pornography that pedophiles and child rapists create forcibly against the will of the children in the content.

Maybe that's the actual difference between CP and CSAM. Maybe both are a subset of CP.

Re: Apple's New CSAM Protections May Make iCloud Photos Bruteforceable

#16

Post by function_seven » Sun, Aug 08, 2021, 5:21 AM UTC

Teever wrote: post #15

function_seven wrote: post #12

Earlier quoted context omitted.

I don't think the number of syllables is the important thing here. Rather that the term "porn" doesn't—by itself!—impute any moral judgement. It's just a thing. Some people think it's all bad, others think some is okay while some isn't, and some think anything with consenting performers is fair game. But children are incapable of being consenting performers. That's what separates abuse material from porn. So to make…

The number of syllables matter if the goal is to prevent a term from feeling too sterile. If a term is too long and unwieldy then people will naturally shorten it to an acronym. And once they're using an acronym then we're back to square one because acronyms are devoid of the meaning that words have. I've wondered if there is an intent to distinguish between child pornography that teenagers are producing on their own…

Oh, that’s a good point about the syllables. I agree. “Cee-Sam” is a technical jargon-y sounding term. No visceral feeling behind it.

Re: Apple's New CSAM Protections May Make iCloud Photos Bruteforceable

#17

Post by shuckles » Sun, Aug 08, 2021, 5:23 AM UTC

NTroy wrote: post #13

shuckles wrote: post #8

Earlier quoted context omitted.

> What's to stop an attacker from generating a NeuralHash of popular memes, deriving a key, then bruteforcing the leaked data until it successfully decrypts an entry, thus verifying the contents within a specific user's cloud photo library, and degrading their level of privacy? Decrypting vouchers requires the server blinding key and the NeuralHash derived metadata of the input image (technical summary page 10, Bella…

> 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?

Re: Apple's New CSAM Protections May Make iCloud Photos Bruteforceable

#18

Post by 015a » Sun, Aug 08, 2021, 5:26 AM UTC

Teever wrote: post #11

function_seven wrote: post #9

Earlier quoted context omitted.

Good link to explain why "CSAM" is being used in lieu of "CP" https://www.adfsolutions.com/news/what-is-csam > However, the phrase “child pornography” is almost too sterile and generic to properly exemplify the horrors of what is being created. That is why many advocates, including the National Center for Missing and Exploited Children (NCMEC), believe this phrase to be outdated. > NCMEC refers to these kinds of mate…

What terrible reasoning. 'Child pornography' is already too long to say repeatedly in a sentence so it is often shortened to "child porn." CSAM has far too many syllables so it too is shortened to two syllables in the form of the spoken acronym "CSAM" and so we're back to square one. With that said this is a fascinating display someone pressing the reverse button on the euphemism treadmill. I don't think I've ever se…

Well, it is from an organization named "NCMEC". Not exactly pros at inventing marketable acronyms.

Re: Apple's New CSAM Protections May Make iCloud Photos Bruteforceable

#19

Post by starwatch » Sun, Aug 08, 2021, 5:46 AM UTC

Teever wrote: post #7

floatingatoll wrote: post #4

Earlier quoted context omitted.

No.

What is the difference between CP and CSAM and why is everyone suddenly using the term CSAM instead of CP?

Last year Sam Harris interviewed Gabriel J.X. Dance, the deputy investigations editor at The New York Times [0]. They speak to this. It's a tough episode to listen to - they cover many uncomfortable topics along this theme.

From what I recall of the episode, porn (rightly or wrongly) is seen as opt-in for the participants. But if children are involved it cannot be opt-in and is more appropriately described as rape or sexual abuse. Thus CSAM is the preferred term.

[0]: https://samharris.org/podcasts/213-worst-epidemic/

Re: Apple's New CSAM Protections May Make iCloud Photos Bruteforceable

#20

Post by dannyw » Sun, Aug 08, 2021, 6:02 AM UTC

starwatch wrote: post #19

Teever wrote: post #7

Earlier quoted context omitted.

What is the difference between CP and CSAM and why is everyone suddenly using the term CSAM instead of CP?

Last year Sam Harris interviewed Gabriel J.X. Dance, the deputy investigations editor at The New York Times [0]. They speak to this. It's a tough episode to listen to - they cover many uncomfortable topics along this theme. From what I recall of the episode, porn (rightly or wrongly) is seen as opt-in for the participants. But if children are involved it cannot be opt-in and is more appropriately described as rape or…

Depends on age and context doesn't it? Is a 17 year old snapchatting their private parts to her 17 year old boyfriend CSAM?

Should both parties be imprisoned and go on sex offenders registries for life?