Implement OpenPGP (GnuPG) signatures

It would be very useful for users with an OpenPGP (GnuPG) key to be able to sign and encrypt with an OpenPGP key, since other standards such as S/MIME are paid for and many people prefer decentralised options. If you look at LibreOffice, you will see that it implements OpenPGP signing.
Thanks

Hello @eliotttak

I assume you are referring to document encryption. Can you share a link to an article that describes the workflow in named processor?

Sorry, I have a very little level in English… What do you mean by named processor ?

I am referring to this statement. Can you share a link to the documentation that describes usage of this type of signatures in the app?