[vngzs]

In the bloom filter example, what device calculates the hash inputs for the bloom filters? If it's the server, then the server needs a copy of the image to check. So is it the client? If so, how can you prevent a malicious client from forging their hashes to be those of known-safe images?

Not saying it's not possible to build an E2E image storage service that also has the protections society tends to demand. Just saying that I haven't seen anyone do it yet, because these problems are subtle.

[dannyw]

Apple has direct-from-bootloader control over all of their hardware, unless you boot Linux on a Mac (in which case you don't get iCloud).

So a 'malicious client' doesn't need to be part of the threat model here. And also, if you really stretch your argument, that's like saying we need to outlaw Linux and open source software because malicious actors can modify the code.

The whole idea that society demands content providers compromise ETE just because of child pornography isn't something I've heard of being 'accepted as common truth' outside of this post.

Some politicians demand it, but I thought at least amongst tech, there's the recognization that strong, *unbreakable* encryption is important.

There's an implicit obligation to build services and technology that is resistant to abuse, but that isn't an argument to not implement ETE.

[vngzs]

Thanks for the "how" - I guess if you fully control the client and server, there's some extra checks you could implement client-side based on the cryptographic root of trust.

FWIW, I wasn't really trying to make a prescriptive statement about how the world ought to be, I was more trying to describe what (I think) the perspective of these corporations has been on the matter.

In the past, I've been an encryption advocate with the knowledge that we (tech) must sacrifice some ability to appease politicians in implementing it. What you're describing sounds like an innovative way to preserve privacy and provide security for at-risk people, which is a perspective I haven't heard before.