From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.emacs.gnus.general/45364 Path: main.gmane.org!not-for-mail From: David Masterson Newsgroups: gmane.emacs.gnus.general Subject: Re: [ANNOUNCE] contrib/hashcash.el spam fighter Date: 23 Jun 2002 22:41:05 -0700 Organization: Programmer At Large Sender: owner-ding@hpc.uh.edu Message-ID: References: NNTP-Posting-Host: localhost.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: main.gmane.org 1024897212 14624 127.0.0.1 (24 Jun 2002 05:40:12 GMT) X-Complaints-To: usenet@main.gmane.org NNTP-Posting-Date: Mon, 24 Jun 2002 05:40:12 +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 17MMaB-0003nk-00 for ; Mon, 24 Jun 2002 07:40:11 +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 17MMYs-0003cE-00; Mon, 24 Jun 2002 00:38:50 -0500 Original-Received: by sina.hpc.uh.edu (TLB v0.09a (1.20 tibbs 1996/10/09 22:03:07)); Mon, 24 Jun 2002 00:39:11 -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 AAA19626 for ; Mon, 24 Jun 2002 00:38:59 -0500 (CDT) Original-Received: (qmail 5649 invoked by alias); 24 Jun 2002 05:38:33 -0000 Original-Received: (qmail 5644 invoked from network); 24 Jun 2002 05:38:33 -0000 Original-Received: from main.gmane.org (80.91.224.249) by gnus.org with SMTP; 24 Jun 2002 05:38:33 -0000 Original-Received: from list by main.gmane.org with local (Exim 3.33 #1 (Debian)) id 17MMYH-0003lV-00 for ; Mon, 24 Jun 2002 07:38:13 +0200 Original-To: ding@gnus.org X-Injected-Via-Gmane: http://gmane.org/ Original-Received: from news by main.gmane.org with local (Exim 3.33 #1 (Debian)) id 17MMYG-0003lN-00 for ; Mon, 24 Jun 2002 07:38:12 +0200 Original-Path: not-for-mail Original-Newsgroups: gmane.emacs.ding Original-Lines: 29 Original-NNTP-Posting-Host: m198-149.dsl.rawbw.com Original-X-Trace: main.gmane.org 1024897092 14212 198.144.198.149 (24 Jun 2002 05:38:12 GMT) Original-X-Complaints-To: usenet@main.gmane.org Original-NNTP-Posting-Date: Mon, 24 Jun 2002 05:38:12 +0000 (UTC) User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 Precedence: list X-Majordomo: 1.94.jlt7 Xref: main.gmane.org gmane.emacs.gnus.general:45364 X-Report-Spam: http://spam.gmane.org/gmane.emacs.gnus.general:45364 >>>>> Stainless Steel Rat writes: > * Simon Josefsson on Sun, 23 Jun 2002 > | Pregenerated or not, the computation of the field requires someone > | to burn CPU time, if the limit is set sufficiently high spammers > | will find it costs too much to send spam, which is the point. > For the sake of argument, say that hashcash.el users want a 128 bit > hash. Today I calculate a 128 bit hash and send out a million > messages using that hash in the X-Hashcash header. Tomorow I > generate a new 128 bit hash so that the old one is no longer useful > as filter bait, and send out another million messages. I repeat > this cycle indefinitely. > Please explain to me where in this scheme I am burning any > significant CPU time generating hashes, or how it forces the spammer > to do more work than the recipients, because I cannot see it. Is that the method of using hashcash? It would seem for it to be used as postage, the hash would have to be calculated for each person you (the spammer) want to send email to (assuming everyone was requiring postage). Therefore, it's not compute 1 128-bit hash and send out a million messages, but rather compute a million 128-bit hashes to apply to each message. -- David Masterson dsm@rawbw.com