Import and use OpenPGP keys of other parties
It will be very nice to have chiose import and use OpenPGP keys of other parties for messaging. Keys could be imported via link to keyserver with hash at protonmail user contact database.
We are building a key management system to allow sending to other PGP keys.
The modern way of associating public keys with email addresses is to use RFC 7929:
As ProtonMail already supports DNSSEC, this should be a relatively simple but extremely helpful addition, in terms of both usability and security.
This will include integrating an efficient key-store within the user account, so that (s)he can perform all the key management operations.
To this date, the only solution that does this is 'Mailfence.com' - which surely is one of the purest end-to-end encryption solution out there.
Protonmail needs to adapt this (or atleast put it on their roadmap) - as its the foremost thing that PGP enthusiast always look for in PGP centric solutions.