Actually, the problem of centralized login services tracking users across the net was considered and partially solved in 2010 by a team from Google and MIT. Th

Actually, the problem of centralized login services tracking users across the net was considered and partially solved in 2010 by a team from Google and MIT. This was at a time when OpenID was the most popular federated login system, so the proposal was called PseudoID. Unfortunately this idea didn't gain more traction, and there are only a few references to it online now, such as this research paper and a YouTube video by one of the authors: https://ai.google/research/pubs/pub36553 https://ai.google/research/pubs/pub36553 https://www.youtube.com/watch?v=fCBPuGsO_I4 https://www.youtube.com/watch?v=fCBPuGsO_I4 Also, it didn't address all the methods by which a malicious identity provider could track the user, so it would probably have to be extended by having support added in the browser.