The temporary mailbox enables secure communication with everyone who has an e-mail address, world-wide. This mechanism has been designed to promote the sending of encrypted e-mails over the Internet, and avoid the interception of messages by third parties.
If you send an encrypted message to someone without a known public PGP key, this person (the external user) will receive two emails. At first an e-mail containing a link to a login form for their temporary Guard mailbox.
A second email will contain the password for their temporary Guard mailbox and an additional message added by the sender:
They can open the link in a web browser and log in to mailbox.org using the password sent to them in a second, separate e-mail and, if enabled, the additional PIN transmitted by you, the sender.
Once the external user has logged in, they can read and reply to any encrypted e-mail they may have received. The connection to the temporary mailbox is secured via https and any e-mails sent from there will be encrypted automatically.
If the external user happens to actually use PGP and you just didn’t know their key when sending them an e-mail, they have the option to download the generated keys after login and import it in theire email client. mailbox.org Guard will then send any future communication directly and securely encrypted to their e-mail address, without any further need for a temporary mailbox.