Lots of people use Yahoo Groups, so I made a group there, sent some mail
to it. Here's the before and after versions of a typical HTML message.
I realize that some people are not fans of HTML mail, but we're stuck with
HTML whether we like it or not because that's the kind of mail that most
mail users send these days.
Yahoo reordered some of the headers, added a bunch of new headers, and
changed the From: and Subject: lines.
Then it went into the message body and inserted an ad and message tag into
the HTML. Yahoo picks the ad, the list manager picks the tag. This
message has the default tag but I can set it to anything I want. Note
that the inserted HTML is inserted into the body, not after the end.
Yahoogroups runs more lists than anyone else in the world, and probably
more than all mailman and majordomo lists put together. If a scheme is to
work in the world at large, it's much more important that it work with
Yahoo Groups than that it work with mailman.
So as I've been asking, pretty please, show me a signature validation
algorithm that will determine that the after version of this message
matches the signature of the before version, and that won't leave giant
loopholes that spammers will drive through to make hostile changes to your
mail. While you're at it, please don't break the message by doing
something like removing the subject tag that people use to sort mail in
their MUAs. Good luck.
Regards,
John Levine, johnl(_at_)iecc(_dot_)com, Primary Perpetrator of "The Internet
for Dummies",
Information Superhighwayman wanna-be, http://iecc.com/johnl, Mayor
"I dropped the toothpaste", said Tom, crestfallenly.
----- what I sent to Yahoogroups -----
Message-ID: <41B49A12(_dot_)8040504(_at_)johnlevine(_dot_)com>
Date: Mon, 06 Dec 2004 12:42:42 -0500
From: Buster the Cephalopod <buster(_at_)johnlevine(_dot_)com>
User-Agent: Mozilla Thunderbird 0.9 (Windows/20041103)
X-Accept-Language: en-us, en
MIME-Version: 1.0
To: glreorg(_at_)yahoogroups(_dot_)com
Subject: Recount shows that Ohio voted to join Canada
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
<h2><b>Lake Erie Forever!</b></h2>
<b><br>
</b>But I can't say I'm very surprised.<br>
<br>
</body>
</html>
----- what Yahoogroups sent to the subscribers -----
Return-Path:
<sentto-14121546-2-1102354962-buster=johnlevine(_dot_)com(_at_)returns(_dot_)groups(_dot_)yahoo(_dot_)com>
Delivered-To: johnl-jl-buster(_at_)johnlevine(_dot_)com
Received: (qmail 15316 invoked from network); 6 Dec 2004 17:42:44 -0000
Received: from n7a.bulk.scd.yahoo.com (66.94.237.41)
by mail.iecc.com with SMTP; 6 Dec 2004 17:42:44 -0000
Received: from [66.218.66.58] by n7.bulk.scd.yahoo.com with NNFMP; 06 Dec 2004
17:42:42 -0000
Received: from [66.218.67.192] by mailer7.bulk.scd.yahoo.com with NNFMP; 06 Dec
2004 17:42:42 -0000
X-Yahoo-Newman-Property: groups-email
X-Sender: prvs=buster/07580683ee(_at_)johnlevine(_dot_)com
X-Apparently-To: glreorg(_at_)yahoogroups(_dot_)com
Received: (qmail 25202 invoked from network); 6 Dec 2004 17:42:41 -0000
Received: from unknown (66.218.66.167)
by m10.grp.scd.yahoo.com with QMQP; 6 Dec 2004 17:42:41 -0000
Received: from unknown (HELO tom.iecc.com) (208.31.42.38)
by mta6.grp.scd.yahoo.com with SMTP; 6 Dec 2004 17:42:40 -0000
Received: (qmail 15310 invoked from network); 6 Dec 2004 17:42:40 -0000
Received: (ofmipd johnl(_at_)208(_dot_)31(_dot_)42(_dot_)39); 6 Dec 2004
17:42:18 -0000
Message-ID: <41B49A12(_dot_)8040504(_at_)johnlevine(_dot_)com>
To: glreorg(_at_)yahoogroups(_dot_)com
User-Agent: Mozilla Thunderbird 0.9 (Windows/20041103)
X-Accept-Language: en-us, en
X-eGroups-Remote-IP: 208.31.42.38
From: "Buster the Cephalopod" <buster(_at_)johnlevine(_dot_)com>
MIME-Version: 1.0
Mailing-List: list glreorg(_at_)yahoogroups(_dot_)com; contact
glreorg-owner(_at_)yahoogroups(_dot_)com
Delivered-To: mailing list glreorg(_at_)yahoogroups(_dot_)com
Precedence: bulk
List-Unsubscribe: <mailto:glreorg-unsubscribe(_at_)yahoogroups(_dot_)com>
Date: 6 Dec 2004 12:42:42 -0500
Subject: [glreorg] Recount shows that Ohio voted to join Canada
Reply-To: glreorg(_at_)yahoogroups(_dot_)com
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
<h2><b>Lake Erie Forever!</b></h2>
<b><br>
</b>But I can't say I'm very surprised.<br>
<br>
<br>
<!-- |**|begin egp html banner|**| -->
<table border=0 cellspacing=0 cellpadding=2>
<tr bgcolor=#FFFFCC>
<td align=center><font size="-1" color=#003399><b>Yahoo! Groups
Sponsor</b></font></td>
</tr>
<tr bgcolor=#FFFFFF>
<td align=center width=470><table border=0 cellpadding=0 cellspacing=0> <tr>
<td align=center><font face=arial size=-2>ADVERTISEMENT</font><br><a
href="http://us.ard.yahoo.com/SIG=129mu9quv/M=298184.5639630.6699735.3001176/D=groups/S=1705408780:HM/EXP=1102441362/A=2434971/R=0/SIG=11eeoolb0/*http://www.netflix.com/Default?mqso=60185400";
alt=""><img
src="http://us.a1.yimg.com/us.yimg.com/a/ne/netflix/111704_1104_g_300250a.gif";
alt="click here" width="300" height="250" border="0"></a></td></tr></table>
</td>
</tr>
<tr><td><img alt="" width=1 height=1
src="http://us.adserver.yahoo.com/l?M=298184.5639630.6699735.3001176/D=groups/S=:HM/A=2434971/rand=912936284";></td></tr>
</table>
<!-- |**|end egp html banner|**| -->
<!-- |**|begin egp html banner|**| -->
<br>
<tt><hr width="500">
<b>Yahoo! Groups Links</b><br>
<ul>
<li>To visit your group on the web, go to:<br><a
href="http://groups.yahoo.com/group/glreorg/";>http://groups.yahoo.com/group/glreorg/</a><br>
<li>To unsubscribe from this group, send an email to:<br><a
href="mailto:glreorg-unsubscribe(_at_)yahoogroups(_dot_)com?subject=Unsubscribe">glreorg-unsubscribe(_at_)yahoogroups(_dot_)com</a><br>
<li>Your use of Yahoo! Groups is subject to the <a
href="http://docs.yahoo.com/info/terms/";>Yahoo! Terms of Service</a>.
</ul>
</tt>
</br>
<!-- |**|end egp html banner|**| -->
</body>
</html>
![http://us.a1.yimg.com/us.yimg.com/a/ne/netflix/111704_1104_g_300250a.gif"](http://us.a1.yimg.com/us.yimg.com/a/ne/netflix/111704_1104_g_300250a.gif"){kind=link}