At 2:37 PM +0200 2005-05-16, Christophe Meessen wrote: >> If the signature is automatically generated by the MUA, then the >> trojans/spybots can make use of this and still get through. The only >> way you can make this work is if you require actual human intervention >> on the part of the sender, > > That's true and is also the normal working model for signed messages.
Not with the plug-ins I've seen. They work to make cryptographic signatures as simple and easy to use as possible, which means that there must be absolutely no additional user involvement required. >> and that would probably also require human intervention on the part >> of the mailing list administrator -- for each and every message. > > That's not true. A mail signature is basically a hash value encrypted > with a secret key. I am quite well acquainted with the nature of public key encryption. I've been using PGP since before the 2.6 days, I donated money to Phil for his defense, and I personally know Mike Elkins (the guy who wrote the PGP/MIME RFC, as well as the principal author of mutt, the premier PGP/MIME MUA). I don't use PGP today because it's too much of a pain to integrate with my MUA of choice on my platform of choice, although I am always close to being pushed over the edge to moving all ten-plus GB of my mail archives over to mutt, because I've been forced to futz around with this damn program one too many times. The problem is that if the crypto signature on the client side does not forcibly require the user to manually intervene and sign each and every message, then in order to achieve the result you're looking for you will instead force the list moderator to manually intervene and personally check and approve each and every message. > Whenever this user sends a signed mail to the list you use his public > key to decode the hash value and check the mail integrity. If it's > valid you may forward it to the list. The signature can be removed if > desired. This would protect the list from forged mails. But it wouldn't protect us at all against Sober.Q or whatever the latest variant is, since they already have complete control over the users MUA and they can send out millions of messages as being "from" that user, including all necessary cryptographic signatures. > For lists that don't require subscription, there is no way to make > a difference with spammers and normal users. The problem is far more complex (and worse) than that. Even for lists that do require subscriptions, there is no way you can reliably tell the difference between a legitimate mail message and spam, regardless of whether or not it was spoofed. -- Brad Knowles, <[EMAIL PROTECTED]> "Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety." -- Benjamin Franklin (1706-1790), reply of the Pennsylvania Assembly to the Governor, November 11, 1755 SAGE member since 1995. See <http://www.sage.org/> for more info. ------------------------------------------------------ Mailman-Users mailing list Mailman-Users@python.org http://mail.python.org/mailman/listinfo/mailman-users Mailman FAQ: http://www.python.org/cgi-bin/faqw-mm.py Searchable Archives: http://www.mail-archive.com/mailman-users%40python.org/ Unsubscribe: http://mail.python.org/mailman/options/mailman-users/archive%40jab.org Security Policy: http://www.python.org/cgi-bin/faqw-mm.py?req=show&file=faq01.027.htp