You can also send encrypted E-Mails to external recipients who are no groupware users. When adding an external recipient, Guard checks whether a public key is available for this recipient. Depending on the result, Guard uses different procedures for sending the encrypted E-Mail.
If there is a public key for the recipient:
The message is sent encrypted with this key. The recipient can read the message with his/her private key.
To enable the recipient to send an encrypted reply, your public key is sent as attachment. The attachment is called public.asc. The recipient can import this key to his/her E-Mail client.
If there is no public key for the recipient:
If the external user already has a guest account, he/she receives an E-Mail with the link to the login page of his/her guest account. When having logged in, he/she can read the encrypted E-Mail on the guest page. He/she can send an encrypted reply from this page.
If there is no guest account, a guest account will be created. The external recipient receives an E-Mail with some guidelines and an automatically created password. He/she receives a further E-Mail with the link to the guest page. On the guest page, he/she logs in with the automatically created password. Then he/she can create an own password.
Depending on the groupware configuration, guest account E-Mails are deleted after a specific number of days. To still make those E-Mails available, the E-Mail with the link to the guest page contains an attachment with the encrypted E-Mail. The attachment is called encrypted.asc. This attachment can be uploaded and read on the guest page.