From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.emacs.gnus.general/45374 Path: main.gmane.org!not-for-mail From: Simon Josefsson Newsgroups: gmane.emacs.gnus.general Subject: Re: [ANNOUNCE] contrib/hashcash.el spam fighter Date: Mon, 24 Jun 2002 18:41:48 +0200 Sender: owner-ding@hpc.uh.edu Message-ID: References: <02Jun24.115740edt.119250@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 1024936966 22346 127.0.0.1 (24 Jun 2002 16:42:46 GMT) X-Complaints-To: usenet@main.gmane.org NNTP-Posting-Date: Mon, 24 Jun 2002 16:42:46 +0000 (UTC) Cc: "(ding)" 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 17MWvN-0005oI-00 for ; Mon, 24 Jun 2002 18:42:45 +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 17MWuw-00069F-00; Mon, 24 Jun 2002 11:42:18 -0500 Original-Received: by sina.hpc.uh.edu (TLB v0.09a (1.20 tibbs 1996/10/09 22:03:07)); Mon, 24 Jun 2002 11:42:37 -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 LAA21084 for ; Mon, 24 Jun 2002 11:42:13 -0500 (CDT) Original-Received: (qmail 7466 invoked by alias); 24 Jun 2002 16:41:49 -0000 Original-Received: (qmail 7461 invoked from network); 24 Jun 2002 16:41:49 -0000 Original-Received: from 178.230.13.217.in-addr.dgcsystems.net (HELO yxa.extundo.com) (217.13.230.178) by gnus.org with SMTP; 24 Jun 2002 16:41:49 -0000 Original-Received: from latte (yxa.extundo.com [217.13.230.178]) (authenticated bits=0) by yxa.extundo.com (8.12.4/8.12.4) with ESMTP id g5OGfklf031640; Mon, 24 Jun 2002 18:41:47 +0200 Original-To: Stainless Steel Rat Mail-Copies-To: nobody X-Hashcash: 020624:ratinox@peorth.gweep.net:3c603a7f8cd0784a X-Hashcash: 020624:ding@gnus.org:e2dee096e525c2ae In-Reply-To: <02Jun24.115740edt.119250@gateway.intersystems.com> (Stainless Steel Rat's message of "Mon, 24 Jun 2002 12:05:59 -0400") Original-Lines: 24 User-Agent: Gnus/5.090007 (Oort Gnus v0.07) Emacs/21.3.50 (i686-pc-linux-gnu) Precedence: list X-Majordomo: 1.94.jlt7 Xref: main.gmane.org gmane.emacs.gnus.general:45374 X-Report-Spam: http://spam.gmane.org/gmane.emacs.gnus.general:45374 Stainless Steel Rat writes: > | This is not how X-Hashcash works. The sender must generate a X-Hashcash > | specific for each recipient. The recipient keeps a database of received > | coins to prevent double spendings. There are some descriptions and links > | at http://www.cypherspace.org/~adam/hashcash/. > > So, the recipient must keep a list of -all- hashes he has received? And > must search that ever-increasing database for every message he receives? > This puts more work on the recipient than on the sender. No, it does not work like that. Each coin has a limited life length (e.g., 28 days), the receiver only has to keep track of valid ones within the time window. This is explained on the web page... > And what happens when a legitimate sender accidentally generates a > hash that has been used already? If you have good random number generator, this won't happen in practice. > The more I learn about X-Hashcash, the more I see that it is doomed to > fail. Do you have a better idea?