Tainting the CSAM client-side scanning database
I am against the idea of scanning for the reason that the author pointed out: It&#x27;s trivial to repurpose the technology to use it in dystopian ways.<p>I however have precisely zero concerns about impersonating hashes:<p>1. It&#x27;s trivial to deal with tainting the database: both secondary hashing and more invasive hashes deal with that problem.<p>2. It&#x27;s trivial to deal with impersonated hashes, all positives can be scanned on device in a second round with a different hash method. Those which are still positive can have be checked off device in an automated, yet privacy preserving, way such as by sending a low resolution crop with faces blurred to a system that does a likeness check against the matched CSA image: only the real image will bear likeness.<p>3. These systems have undisclosed minimums. A person sharing CSAM will be generating positive results at a significant rate. Receiving a few images with faked hashes won&#x27;t set off alarms, and if a victim is suddenly receiving hundreds of images, that would already be obvious.<p>4. These articles over sensationalise what occurs when a positive match is found. They vaguely gesture to serious consequences from a single match. In reality even without secondary automated checks, the false positive will be noticed by a human and then discarded. If a person is receiving a lot of false positives that may lead to the individual being informed that they are begin targeted.<p>Overall the idea of scanning chat content seems ineffective, for much of the same reasons why it&#x27;s ineffective to ban end-to-end encrypted chat: those with criminal intent will just use something else or roll their own.