https://blog.kagi.com/kagi-privacy-pass
https://www.privacyguides.org/articles/2025/04/21/privacy-pass/
Privacy Pass is a protocol that allows people to cryptographically prove they have access to a service without revealing who they are. I think Proton could be able to use this in really cool ways, for example to prevent Proton from correlating Proton VPN activity to users, or to use SimpleLogin aliases without Proton being able to correlate the alias from the original email.