While the precedent this sets is indeed concerning, the specific hypotheticals this article give are nonsensical.
> an adversary could trick Apple’s algorithm into erroneously matching an existing image
In which case the malicious, adversary-controlled images are sent to Apple. After which—the implication is—they can be re-obtained by... the adversary that created them. So what?
An adversary could conceivably lower the reporting threshold by getting the victim to save a bunch of false-positive images. Again, so what? Surely if the adversary has reason to believe there are some number of CSAM images on a user's phone, there are more direct ways of going after them.
> These kinds of false positives could happen if the matching database has been tampered with or expanded to include images that do not depict child abuse
An adversary would either have to:
A) carry out a supply-chain attack on Apple,
B) ship different iOS images in different countries, or
C) insert entries into the database on a specific users phone.
Options A and C are irrelevant: if the phone is compromised, the CSAM database being modified is the least of your concerns. And option B is independently verifiable (granted, Apple does not do enough to make third-party auditing of iOS easy, but it is possible).
> an adversary could trick Apple’s algorithm into erroneously matching an existing image
In which case the malicious, adversary-controlled images are sent to Apple. After which—the implication is—they can be re-obtained by... the adversary that created them. So what?
An adversary could conceivably lower the reporting threshold by getting the victim to save a bunch of false-positive images. Again, so what? Surely if the adversary has reason to believe there are some number of CSAM images on a user's phone, there are more direct ways of going after them.
> These kinds of false positives could happen if the matching database has been tampered with or expanded to include images that do not depict child abuse
An adversary would either have to:
A) carry out a supply-chain attack on Apple, B) ship different iOS images in different countries, or C) insert entries into the database on a specific users phone.
Options A and C are irrelevant: if the phone is compromised, the CSAM database being modified is the least of your concerns. And option B is independently verifiable (granted, Apple does not do enough to make third-party auditing of iOS easy, but it is possible).