- Some e-mail clients support the sending of e-mails which have been digitally "signed" using the PGP (Pretty Good Privacy) or GnuPG encryption algorithm, to prove the identity of the sender. Information on PGP can be found at http://www.pgp.com/, and information on GnuPG can be found at http://www.gnupg.org/.
Providing your e-mail client has been configured to support digitally-signed e-mail (please see your client's documentation for more details), you can use your "public key" as an alternative means of identification, and you will not need to disclose your chosen PIN. You can paste your public key into the field provided on http://www.livejournal.com/manage/pubkey.bml; once you have clicked the "Save Settings" button, this key can be accessed via the yellow key icon on your User Information Page (http://www.livejournal.com/userinfo.bml).
Instructions on how to post by e-mail using PGP/GPG message signing can be found on http://www.livejournal.com/manage/emailpost.bml?mode=help#pgp.