> Mail is stored e2ee on server

Exclusively, or do they keep caches around? I am asking since everything is clear text in the webmail. I wonder if they handle the rare case of proton to proton (encrypted) mail differently from regular unencrypted mail. I assume they have to decrypt a master key stored on the server with your password, and then decrypt every encrypted email on the fly on the server, or they have to send the master key to the client side.

Now think that through when you have thousands of searchable e-mails, sorted arbitrarily. I won't say it is impossible, but I think that maintaining plain text indexes rather than encrypted ones are really tempting.

You’re post is full of misconceptions and mistakes.

Mail is stored e2ee exculsively. The’ve been summoned to hand over mail many times, which they weren’t able to do. Quick search on Ecosia and find the articles.

They don’t have a master key or else the whole e2ee story is a fad, which it isn’t. The Proton code is in Github so you can check how it works yourself. Part of the password is used to decrypt the data.

Search is done client side. You have to download a big search index in order to have proper search. The iOS app doesn’t support downloading the index so search is limited there.

Please think and do some work before you reply.