The only change which I did is updating the "dovecot.conf" file. I added below lines.

mail_plugins = $mail_plugins mail_crypt
mail_attribute_dict = file:%h/Maildir/dovecot-attributes

plugin {
  mail_crypt_curve = <some curve you like>
  mail_crypt_save_version = 2
}

I realized that, mails are in plain text format even I added those encryption as dovecot wiki.

On Wed, Nov 7, 2018 at 1:52 PM Anushka Uditha Bandara <anu.udb@gmail.com> wrote:
After I configuring this, I logged in to the server and check the emails. But they are in plain text. I can even read them from backend. 

On Wed, Nov 7, 2018 at 1:49 PM Aki Tuomi <aki.tuomi@open-xchange.com> wrote:

> On 07 November 2018 at 10:10 Anushka Uditha Bandara <anu.udb@gmail.com> wrote:
>
>
> I configured an email solution using dovecot and postfix and it is working
> fine. Now I am working for mail encryption. Is it enough to set below
> configurations on dovecot for mail encryption. Because dovecot wiki is
> little bit confusing to me.
>
> "mail_plugins = $mail_plugins mail_crypt
> mail_attribute_dict = file:%h/Maildir/dovecot-attributes
>
> plugin {
>   mail_crypt_curve = <some curve you like>
>   mail_crypt_save_version = 2
> }"
>
> I am stuck in here.
>
> Thank you in advance,
>
> Anushka Bandara

That should work, why are you stuck?

Aki