dep wrote:

> it's not either/or. protonmail is a secure mail service, not a mail
> client. you can learn about it if you like at protonmail.com. thing is,
> access to protonmail in linux is currently via a secure web interface (or
> an unofficial desktop app that is really a secure browser dedicated to
> protonmail). for windows and mac there is a thing called protonmail
> bridge. it encrypts the mail on the local machine before sending it, and
> decrypts it upon receipt, allowing more traditional mail clients to send
> and receive mail through protonmail. there is currently a beta, available
> only from protonmail, of the bridge for linux. that is what i am trying to
> install, so i can continue to use kmail, as i have for nearly two decades.
> 
> part of the reason for this is a change of the terms of use by my isp a
> week ago, wherein they announced that they would be combing through my
> email, pictures, and everything else in search of things useful to them.
> as a reporter and photographer for a living, i found this unacceptable.
> hence protonmail and hence my desire to make it work with kmail.

In my opinion the PGPG support in KMail is pretty sufficient to enable
secure communication with any recipient.
Why would you bother paying for something you already have? 

I ask myself if you clearly understand the concept of encrypted mails?

regards