> After you've given me that, I'll be happy to rip it to shreds for you.

Rip this to shreds: if at least one victim of a crime can be prevented by catching a witless criminal then it is worth it. Also this: Homomorphic encryption and differential privacy are a thing, if certificate transparency logs can prove no certs are issued maliciously then similar logs can be published publicly to prove that the scanning list (similar to a CRL) does not contain hashes/patterns that haven't gone through appropriate legal/regulatory checks and balances. E2EE can also be used to secure the message between the gov agency and the device. Certificate authorities already have similar exposure that can compromise all your traffic (including the signal app download/install), "shred" this and show me why a similar risk model is inapplicable to gov scan lists.

> Nobody, not me, not Meredith Whittaker, not anybody, has claimed that client side scanning is impossible, or that you can't turn around and encrypt a copy of a message after you've spied on it. That is a straw man. It is entirely your fantasy.
> What they've said is that it's stupid and contrary to the whole point of having the encryption in the first place. It leaks information that's supposed to be private, including false positives, and paints a target on the most sensitive stuff. It creates infrastructure for abuse. Those are the "security properties" being "communicated". And that is 100 percent true.

No, the message you have been spreadning is that it is impossible to secure a message and spy in it which you just admitted there. That is false, that is not a strawman on my end, you just admitted it! The infrastructure can be abused? So can signal's source code repo infrastructure. Your lie is that of omission and context framing while fully knowing how non-technical policymakers will interpret what you are saying. It is absolutley possible to implement a scanning infrastructure that has the same security properties as the app's code or app store download/signature security. If you are claiming the gov end can be abused by malicious humans then that is beyond your exertise to police humans breaking laws, so long as transparency logs can be produced to criminally punish violators.

> Anybody with a remotely clear-headed view of the situation understands that sending off plaintext copies of the stuff you then turn around and encrypt is in tension with the purpose of doing the encryption.

That is not what was suggeste and I am sure you are aware that it is possible to scan for messages without sending off a copy of the message off device and also without informing anyone of false positive hits. Or even contents of true positive hits (requiring them to get a proper warrant and target the device for intrusive collection).

> That's another fantasy of yours. She's been very clear that if the UK does this, Signal will exit the UK market.

It's not a fantasy, it is possibility and I am glad signal will exit the UK if this happens. I support this kind of boycotting.

> It is sometimes right and maybe even morally required to directly break the law.

Maybe, but not everytime you don't like a law, that undermimes the rule of law. Only active and imminent harm to humans is a reason for civil disobedience not mere speculation and disagreement. You spoke of burden of proof, the other side has proof of harm to humans you are on the opposite side of civil disobedience here. You are on the side of the oblivious technocrats profiting from harming people.

> Personally, I'm looking forward to the widespread use of P2P tools that will make Signal look like an open book... whether they're legal or not. At this point, laws even in the "free world" are descending into insanity.

Me too, but for opposite reasons: so that you people finally get that technocrats and civil disobedience is not a thing. You cannot solve politics with technical rebellion. You have to actually convince your peers. Here I am as your peer engaging with you while being aware of most of the technical facts and you are not convincing me. Your strategy of using technical expertise to deceive people will backfire too and so will downvoting people like me attempting to engage in civil discourse with you in good faith. I think you will just end up facilitating the building of "GFW" level national firewalls in the west with your techniques. They are not going to stop trying to find a solution to reduce CSAM and other illicit crimes, a privacy preserving solution is possible and fighting it is a lose-lose scenario.