I recently learned about Microsoft PhotoDNA[1]. Very interesting (and cool) technology. My understanding is that a decade or so ago a Microsoft engineer stumble

I recently learned about Microsoft PhotoDNA[1]. Very interesting (and cool) technology. My understanding is that a decade or so ago a Microsoft engineer stumbled upon a law enforcement guy giving a talk about the challenges of combating child pornography with the rise of the internet, etc. The Microsoft engineer and the LEO started talking and came up with a concept of a platform where known abuse material is hashed, and automated scanning tools can be deployed in the field when suspects are detained. The net result was it saved law enforcement officers from having to view the same material again and again, and instead could determine with the certainty of a SHA1/2 hash that it is indeed abuse-related material, justifying further review/inspection. That said, I'm not sure from a privacy perspective that I like communication apps playing the referee. Sure, its terrorism or child porno now. What about when it is political content regarding 'X' that is prohibited? [1] https://www.microsoft.com/en-us/photodna https://www.microsoft.com/en-us/photodna