The GPG plugins (PGP/Core, PGP/Mime and PGP/Inline) provide digital signature and encryption features: - Checking signatures of received emails - Decrypting received emails - Sending signed and/or encrypted emails - Creating new key pairs easily - Optionally, caching your passphrase or using gpg-agent. S/MIME plugin handles S/MIME signed and/or encrypted mails. WWW: http://claws-mail.org/plugin.php?plugin=gpg