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1997-12-23 - Re: hashcash spam prevention & firewalls

Header Data

From: Steve Schear <schear@lvdi.net>
To: Adam Back <bill.stewart@pobox.com
Message Hash: c7f5eaa604924a56c9bf60220d50fa77cd3ce6fbae7be1be502f7c87531b05b7
Message ID: <v03102803b0c4c620c215@[208.129.55.202]>
Reply To: <3.0.3.32.19971218120500.00707254@popd.ix.netcom.com>
UTC Datetime: 1997-12-23 01:48:07 UTC
Raw Date: Tue, 23 Dec 1997 09:48:07 +0800

Raw message

From: Steve Schear <schear@lvdi.net>
Date: Tue, 23 Dec 1997 09:48:07 +0800
To: Adam Back <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: <v03102803b0c4c620c215@[208.129.55.202]>
MIME-Version: 1.0
Content-Type: text/plain



At 5:55 PM +0000 12/22/1997, Adam Back wrote:
>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.

eCache is probably the best solution for remailers (and probably SPAM in general) since real value can pass anonymously from sender to receptient.

>
>> 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.

Yes, especially when the list requires a hashcash 'initiation,' before allowing unlimited postings, to prevent many  common list SPAM abuses.

--Steve

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