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1997-12-22 - Re: hashcash spam prevention & firewalls

Header Data

From: Adam Back <aba@dcs.ex.ac.uk>
To: bill.stewart@pobox.com
Message Hash: b4f803fb73c2f788c5d19695cc2b8d1e30f71554cd01be0b2ae54f6530103e7e
Message ID: <199712221755.RAA00355@server.eternity.org>
Reply To: <3.0.3.32.19971218120500.00707254@popd.ix.netcom.com>
UTC Datetime: 1997-12-22 18:19:09 UTC
Raw Date: Tue, 23 Dec 1997 02:19:09 +0800

Raw message

From: Adam Back <aba@dcs.ex.ac.uk>
Date: Tue, 23 Dec 1997 02:19:09 +0800
To: bill.stewart@pobox.com
Subject: Re: hashcash spam prevention & firewalls
In-Reply-To: <3.0.3.32.19971218120500.00707254@popd.ix.netcom.com>
Message-ID: <199712221755.RAA00355@server.eternity.org>
MIME-Version: 1.0
Content-Type: text/plain




Bill Stewart <bill.stewart@pobox.com> writes:
> >This is exactly what I was addressing: remailers only have to get
> >themselves certified as remailers and then prove their certification
> >to the destination
> 
> You're both taking the wrong approach - make the originator of the
> message generate the hashcash, and make sure the remailer syntax
> lets them paste it in as needed.  For chained remailers, generate
> multiple layers of hashcash.  Maintaining whitelists is a losing
> game, but unnecessary here.

This works well enough.

The more thorny problem to solve is that posed by Robert Costner: what
do you do about nyms.  You (the sender) can't include postage for nym
reply blocks because you don't know (and mustn't know) the remailer
chain pointed to by the reply block.

> Mailing lists are still hard, and perhaps best handled by the user's
> software (or some fancy variant like user-selectable filters at the
> ISP mailbox.)

I think it's simplest to have the user explicitly allow the mailing
list.

You could possibly auto detect the pattern of a user subscribing to a
mailing list at the mail filter level also.

Adam
-- 
Now officially an EAR violation...
Have *you* exported RSA today? --> http://www.dcs.ex.ac.uk/~aba/rsa/

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)]}\EsMsKsN0[lN*1lK[d2%Sa2/d0<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<J]dsJxp"|dc`

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