Encrypted MLs

Fred Lindberg lindberg at id.wustl.edu
Tue Apr 28 11:29:35 CEST 1998

On Tue, 28 Apr 1998 09:55:27 -0500, Fred Lindberg wrote:

>It assumes that the private key and pass phrase is secret. The list
>could have a mechanism that generates a new /dev/urandom-based pass
>phrase for the key at random intervals (not while gpg is running). This
>way, deletion of the passphrase file would make all communication to
>the list unreadable.

Forget the pass phrase refresh. I was thinking of guarding against
copying files/backup. However, anyone having a copy of key + passphrase
will have the key even if pass phrases are changed, so the above
complicates without any gain :-( The key itself could be changed, but
this requires notifying all subscribers of the new public key (can be
done as a regular list message) and invalidates messages en route to
the list. The list could of course have some key expiration system with
partial overlap, but again this type of complication seems better for

I realize that we never introduced this discussion, although it can be
gleaned from the subject:

We (Sen Nagata and I) would like to add support for encryption and
authentication to ezmlm.

ezmlm is a fast mailing list manager based on qmail
(http://www.qmail.org/). Both were written by Dan J. Bernstein
(http://www.pobox.com/~djb). ezmlm uses "cryptographic cookies" to
authenticate subscribe/unsubscribe requests. ezmlm-idx is an add-on to
ezmlm (http://www.ezmlm.org/; written by me with Fred Ringel) that
allows "cookie-protected" message moderation, subscription moderation,
remote administration, digests, archive retrieval, MIME support and
customization (all lists set up with a single command and customized
for language, etc, with a ezmlmrc file).

ezmlm at the moment requires qmail as the MTA (sendmail-replacement).
qmail was designed for security and reliability
(http://www.pobox.com/~djb/qmail.html). ezmlm fully exploits qmail's
features. qmail is "free" but you may only distribute Dan's source
package as is (he's worried about less secure modified versions). Thus,
there are patches, but no official binary distributions. ezmlm is
publically available from Dan's ftp server and has no stated
distribution restrictions. ezmlm-idx, of couse, is GPL (if Dan grants
you other less restrictive rights to ezmlm, you automatically get them
to ezmlm-idx).

-Sincerely, Fred

(Frederik Lindberg, Infectious Diseases, WashU, St. Louis, MO, USA)

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