From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <002701c3719f$de0145f0$3129ff87@bl.belllabs.com>
From: "david presotto" <presotto@closedmind.org>
To: <9fans@cse.psu.edu>
References: <200309021608.h82G8Wj21273@augusta.math.psu.edu>
Subject: Re: [9fans] re: spam filtering fs
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Date: Tue,  2 Sep 2003 18:16:31 -0400
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What smime (and pgp) can achieve is digital signing so that spammers can't
masquerade
with From:'s of people in your white list.
----- Original Message -----
From: "Dan Cross" <cross@math.psu.edu>
To: <9fans@cse.psu.edu>
Sent: Tuesday, September 02, 2003 12:08 PM
Subject: Re: [9fans] re: spam filtering fs


> > Another way of achieving authentication for email is to implement and
> > use S/MIME or PGP.  I'm not sure either that or "import ... /mail"
solves
> > the computational cost of spam if the bad guys create invalid
signatures,
> > but it does make a white-list filter more effective.
>
> I see the two as complimentary.  Just because you're securing the contents
> of the wagon by wrapping them in a patrol of the King's men-at-arms
doesn't
> mean you shouldn't also endeavor to clear out the highway robbers.
>
> > Any volunteers to implement S/MIME for Plan 9?   A couple of us here at
> > Bell Labs have worked on it off and on, but there aren't enough free
> > hands here to get it done promptly.  Step one is to implement CMS (also
> > known as PKCS#7 or rfc2315) starting from the ASN.1 goo in
> > /sys/src/libsec/port/x509.c or, if you prefer, by porting an ASN.1
> > compiler.
>
> Help!  I'm melting!
>
> > By the way, I've happily used PGP for many years but decided that S/MIME
> > was more likely to catch on because it is already moderately well
> > supported by default in Outlook and Netscape/Mozilla.
>
> I thought there was an effort to merge OpenPGP and S/MIME in some way?
> S/MIME requires a lot of scaffolding to use effectively; PGP has a much
> lower startup cost.  That said, I'm not a big fan of either.  Most
> people don't need that level of privacy (despite what they may think,
> no one's out to get them and the FBI could care less about their D&D
> campaign plans).  For cutting down on spam, this seems like cutting
> butter with a chainsaw.  A much simpler method would be to just put an
> X- header with some sort of agreed upon token into one's email.  Is it
> secure?  Not really, no, but it'll defeat 99% of the wannabes, and
> that's a lot of bang for the buck.  Of course, either would be nice to
> have for other reasons (everyone knows the government *really is* out
> to get Boyd, for instance...).
>
> A way to exchange tokens: instead of doing it via email, generate an
> image for an unknown user, put it on a public web server somewhere, and
> send them a URL.  Once they get there, have them send back a
> description of the image and then send them a token.  This defeats
> auto-harvesters that are smart enough to send you back a reply to our
> ``send this string back if you're not a spammer'' token.  This will
> work for a while until the spammers start to implement image
> recognition software.
>
> - Dan C.
>
>