I want to learn about PGP and how to encrypt email. Someone sells that service, great. And it is not like I cannot send normal emails to anyone else.
I don’t disagree with you, I believe it as well. PGP is it stands is cumbersome.
The thing is that could’ve still implemented a easy-to-use, “just login and send email” type of web client and abstracted the user from the PGP complexities while still delivering everything over IMAP/SMTP.
They are using the same standard, not some made up version of SMTP (when sending to other servers, I assume any email from client A to client B both being Proton customer never leave their server, so no need for a new protocol).
You assume correctly, but when your mail client is trying to send an email instead of using SMTP to submit to their server, you’re using a proprietary API in a proprietary format and the same goes for receiving email.
This is well documented and to prove it further if you want to configure Proton in a generic mail client like Thunderbird then you’re required to install a “birdge”, a piece of software that essentially simulates a local IMAP and SMPT server (that Thunderbird communicates with) and then will convert those requests into requests their proprietary API understands. There are various issues with this approach the most obvious one is that it is an extra step, there’s also the issue that in iOS for eg. you’re forced to use their mail app because you can’t run the bridge there.
The bridge is an afterthought to support generic email clients and generic protocols, only works how and where they say it should work and may be taken away at any point.
while being fully open source using open standards
Delivering your data over proprietary APIs doesn’t count as “open standards” - sorry.
Yes, that’s precisely the problem there. You can use PGP with any generic IMAP provider and that will work just fine with handheld devices. There are multiple mail clientes capable of doing and all your mail is still encrypted on the server. Proton just made an alternative implementation that forces you into proprietary systems because it’s more convenient for them.
Those kinds of setups with servers encrypting your mail and still delivering over IMAP are fairly easy to implement, here’s an example. They simply decided to go all proprietary.
On a generic mail system SMTP is used in two places: 1) from your mail client to your provider and 2) between your provider and other providers. Proton is NOT using SMPT for the first step, making it non-standard and much more closed.