Add Support for WKD Protocol for Automatic GPG Public Key Discovery in eM Client

Hi eM Client Team,

First, thank you for your continued development of eM Client—it’s an outstanding application for email and calendar management!

I would like to request a feature that would greatly enhance the usability and security of encrypted email workflows: support for the WKD (Web Key Directory) protocol to automatically discover and retrieve GPG/OpenPGP public keys.

Currently, securely exchanging encrypted emails requires users to manually obtain their correspondents’ public keys, which can be cumbersome and error-prone. The WKD protocol provides a standardized and privacy-respecting way for email clients to automatically fetch a recipient’s public key directly from their domain, greatly simplifying the key discovery process.

Benefits

  • Seamless Encryption: Makes it much easier for users to send encrypted emails without needing to manually search for and import public keys.
  • Improved Security: Reduces the risk of man-in-the-middle attacks or key confusion by fetching keys directly from the sender’s domain.
  • Interoperability: Many modern email providers (e.g., ProtonMail, Mailbox.org, Posteo) already support WKD, and several email clients (like Thunderbird, K-9 Mail, and GpgOL) have implemented it.
  • User Experience: Streamlines the process for both new and experienced users, encouraging wider adoption of secure email practices.

Proposed Functionality

  • When composing an encrypted email, eM Client should attempt to discover the recipient’s public key using WKD if it is not already in the user’s local keyring.
  • If a key is found via WKD, prompt the user to trust and import it, or (optionally) allow automatic import.
  • Provide clear feedback in the UI when retrieving keys via WKD.

References