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Re: Mailing lists and unsolicited/malicious spam
From: Valdis.Kletnieks () vt edu
Date: Fri, 26 Nov 2004 18:21:49 -0500

On Fri, 26 Nov 2004 16:51:27 GMT, n3td3v said:

I was thinking, why are all e-mail addresses not encrypted as soon as
they leave the authors mail client, surely this would stop anyone
seeing the address, apart from the mail client at the other end the
message was intended for. And when a user mails a mailing list the
e-mail address could be read by the mailing list software, but stays
encrypted for the broadcast out to the subscribers of the list.

The biggest problem here is that "reply" breaks.

The less obvious problem is that you are implying a way for the mailing
list software to decrypt the address, but *not* allow a spammer to decrypt
the address.  The only obvious solution for *that* is to encrypt to the
public key of the mailing list (forget a "shared secret" scheme, that won't
scale at all).  This however implies that your MUA knows about the public
keys for all lists you post to (which also means that you can't send e-mail
from a internet cafe or any machine that doesn't know what lists you are on).

An even less obvious problem is that you lose all cross-list identity - perhaps
'n3d3v' only posts to F-D, but I post to a number of lists, and a large number
of people read my postings on multiple lists.  As such, things like "Oh, he's
the guy who posts clued stuff on NANOG" or "Oh, that's Harlan Carvey, he has a
clue over on that other list" are difficult to correlate across lists....

(It cuts both ways - it also means that you have to re-learn that a given user
is a total idiot over and over, once for each list, rendering kill files much
less useful...)

I'm sure if I think some more, I'll spot some more problems.. :)

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