> Then you need the social media sites to agree on a common auth mechanism that uses the zero-knowledge proof, and if the same proof gets used on multiple devices, you log out the previously used device.
> So even if a parent lets their kid use the parent's passport to generate the proof on the kids phone, every time the kid uses this proof, the parent gets logged out of Facebook and all other social media apps.
Doesn't this automatically give the "common auth mechanism" perfect knowledge of all the parent's social media accounts, whether under a real name or a pseudonym? That sounds like an additional means of tracking.
Also, what if the parent legitimately has multiple devices that they use for social media (e.g., a phone and a laptop)? You might say, "log them out if it's used simultaneously from multiple devices", but then you're tracking all social-media usage everywhere in realtime.
> So even if a parent lets their kid use the parent's passport to generate the proof on the kids phone, every time the kid uses this proof, the parent gets logged out of Facebook and all other social media apps.
Doesn't this automatically give the "common auth mechanism" perfect knowledge of all the parent's social media accounts, whether under a real name or a pseudonym? That sounds like an additional means of tracking.
Also, what if the parent legitimately has multiple devices that they use for social media (e.g., a phone and a laptop)? You might say, "log them out if it's used simultaneously from multiple devices", but then you're tracking all social-media usage everywhere in realtime.