From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.emacs.gnus.general/45437 Path: main.gmane.org!not-for-mail From: "Patrick J. LoPresti" Newsgroups: gmane.emacs.gnus.general Subject: Re: [ANNOUNCE] contrib/hashcash.el spam fighter Date: 29 Jun 2002 20:20:16 -0400 Sender: owner-ding@hpc.uh.edu Message-ID: References: <02Jun24.115740edt.119250@gateway.intersystems.com> <02Jun24.151839edt.119751@gateway.intersystems.com> <02Jun25.104630edt.119271@gateway.intersystems.com> <02Jun28.122222edt.119118@gateway.intersystems.com> <02Jun28.172137edt.119392@gateway.intersystems.com> NNTP-Posting-Host: localhost.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: main.gmane.org 1025396473 19176 127.0.0.1 (30 Jun 2002 00:21:13 GMT) X-Complaints-To: usenet@main.gmane.org NNTP-Posting-Date: Sun, 30 Jun 2002 00:21:13 +0000 (UTC) Return-path: Original-Received: from malifon.math.uh.edu ([129.7.128.13]) by main.gmane.org with esmtp (Exim 3.33 #1 (Debian)) id 17OSSn-0004zB-00 for ; Sun, 30 Jun 2002 02:21:13 +0200 Original-Received: from sina.hpc.uh.edu ([129.7.128.10] ident=lists) by malifon.math.uh.edu with esmtp (Exim 3.20 #1) id 17OSSY-0002A8-00; Sat, 29 Jun 2002 19:20:58 -0500 Original-Received: by sina.hpc.uh.edu (TLB v0.09a (1.20 tibbs 1996/10/09 22:03:07)); Sat, 29 Jun 2002 19:21:19 -0500 (CDT) Original-Received: from sclp3.sclp.com (qmailr@sclp3.sclp.com [209.196.61.66]) by sina.hpc.uh.edu (8.9.3/8.9.3) with SMTP id TAA01877 for ; Sat, 29 Jun 2002 19:21:09 -0500 (CDT) Original-Received: (qmail 27659 invoked by alias); 30 Jun 2002 00:20:43 -0000 Original-Received: (qmail 27654 invoked from network); 30 Jun 2002 00:20:42 -0000 Original-Received: from lockupnat.curl.com (HELO egghead.curl.com) (216.230.83.254) by gnus.org with SMTP; 30 Jun 2002 00:20:42 -0000 Original-Received: (qmail 29298 invoked by uid 10171); 29 Jun 2002 20:20:16 -0400 Original-To: ding@gnus.org In-Reply-To: Original-Lines: 27 User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/20.7 Precedence: list X-Majordomo: 1.94.jlt7 Xref: main.gmane.org gmane.emacs.gnus.general:45437 X-Report-Spam: http://spam.gmane.org/gmane.emacs.gnus.general:45437 Stainless Steel Rat writes: > Real hashcash -- NOT X-Hashcash!!!! They are not the same thing! -- > does not force senders to spend hours and hours calculating a single > hash collision. The idea is to make him spend 5 or 6 seconds > calculating a single collision. That is negligible for most > legitimate uses, but for spammers sending out bulk, that 5 seconds > times 5 million is thousands of hours of CPU time. That is where > hashcash works... and X-Hashcash does not, so PLEASE! do not confuse > the two or treat them as the same thing. If those 5 million recipients all use X-Hashcash, the spammer has to compute a distinct hash for each of them. Sounds like it works to me. X-Hashcash is just hashcash implemented by the end user. You seem to think that this is somehow fundamentally different than having the MTA do it, but you have yet to give a very good argument why. (Other than failing to work with BCC, but I suspect many people would consider that fairly minor.) Having to keep a database of spent coins is the only extra cost of a non-challenge-response implementation, but that database is cheap. Ever use nnmail-treat-duplicates? If all you want to do is cost the sender 5 or 6 seconds at the MTA level, why not just stall the TCP connection for 5 seconds per envelope recipient? It would be much simpler than hashcash :-). - Pat