From: Reiner Steib <reinersteib+gmane@imap.cc>
To: Richard Stallman <rms@gnu.org>
Cc: miles@gnu.org, ding@gnus.org, emacs-devel@gnu.org
Subject: Re: New Emacs facilities from Gnus
Date: Sun, 04 Nov 2007 22:12:34 +0100 [thread overview]
Message-ID: <v9wssxn29p.fsf@marauder.physik.uni-ulm.de> (raw)
In-Reply-To: <E1IolaS-0005XD-0Q@fencepost.gnu.org> (Richard Stallman's message of "Sun, 04 Nov 2007 14:56:48 -0500")
On Sun, Nov 04 2007, Richard Stallman wrote:
> ;;; hashcash.el --- Add hashcash payments to email
> ;; Maintainer: Paul Foley <mycroft@actrix.gen.nz>
>
> What does this do? What are hashcash payments?
I have attached some explanatory text from wikipedia below (*).
In (info "(gnus)Hashcash"), there is also some information.
> Will this work with sendmail.el and rmail.el?
Probably it wouldn't be difficult to add it there (maybe in
`sendmail-send-it').
Bye, Reiner.
(*)
,----[ http://en.wikipedia.org/wiki/Hashcash ]
| Hashcash
| From Wikipedia, the free encyclopedia
|
| Hashcash is a proof-of-work system designed to limit email spam and
| denial of service attacks. It was proposed in March 1997 by Adam
| Back [2].
| [...]
|
| How it works
|
| Hashcash is a method of adding a textual stamp to the header of an
| email to prove the sender has expended a modest amount of CPU time
| calculating the stamp prior to sending the email. In other words, as
| the sender has taken a certain amount of time to generate the stamp
| and send the email, it is unlikely that they are a spammer. The
| receiver can, at negligible computational cost, verify that the stamp
| is valid. However, the only known way to find a header with the
| necessary properties is brute force, trying random values until the
| answer is found; though testing an individual string is easy, if
| satisfactory answers are rare enough it will require a substantial
| number of tries to find the answer.
|
| The theory is that spammers, whose business model relies on their
| ability to send large numbers of emails with very little cost per
| message, cannot afford this investment into each individual piece of
| spam they send. Receivers can verify whether a sender made such an
| investment and use the results to help filter email.
|
| Technical details
|
| The header line looks something like [3]
|
| X-Hashcash: 1:20:060408:adam@cypherspace.org::1QTjaYd7niiQA/sc:ePa
|
| The header contains: the recipients email address, the date, and
| information proving the required computation has been performed. The
| presence of the recipients email address forces a new header be
| computed for each recipient, the date allows the recipient to record
| headers received recently and make sure the header is unique this
| email.
|
| [...]
`----
next prev parent reply other threads:[~2007-11-04 21:12 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-28 9:20 Gnus in Emacs is updated to No Gnus 0.7 Miles Bader
2007-10-28 9:46 ` Leo
2007-10-28 9:58 ` Miles Bader
2007-10-28 14:25 ` Reiner Steib
2007-10-28 14:49 ` Leo
2007-10-28 15:07 ` Miles Bader
2007-10-28 15:57 ` Reiner Steib
2007-10-29 7:50 ` Glenn Morris
2007-10-29 19:26 ` Reiner Steib
2007-10-29 2:56 ` Daiki Ueno
2007-10-29 8:30 ` Michael Albinus
2007-10-30 4:16 ` Daiki Ueno
2007-10-29 7:49 ` New Emacs facilities from Gnus (was: Gnus in Emacs is updated to No Gnus 0.7) Reiner Steib
2007-10-31 18:52 ` encrypt.el in No Gnus 0.7 (was: New Emacs facilities from Gnus) Ted Zlatanov
2007-10-31 20:36 ` encrypt.el in No Gnus 0.7 Reiner Steib
2007-10-31 21:05 ` Ted Zlatanov
2007-11-01 1:30 ` Daiki Ueno
2007-11-01 15:04 ` Ted Zlatanov
2007-11-01 15:24 ` Daiki Ueno
2007-11-01 23:08 ` Richard Stallman
2007-11-02 14:12 ` Ted Zlatanov
2007-11-02 21:36 ` Stefan Monnier
2007-11-04 19:56 ` Richard Stallman
2007-11-05 1:49 ` Ted Zlatanov
2007-11-05 8:47 ` Richard Stallman
2007-11-05 15:13 ` Ted Zlatanov
2007-11-06 2:16 ` Richard Stallman
2007-11-06 17:58 ` Ted Zlatanov
2007-11-07 7:56 ` Richard Stallman
2007-11-07 14:34 ` Ted Zlatanov
2007-11-08 0:58 ` Daiki Ueno
2007-11-08 1:16 ` Daiki Ueno
2007-11-08 14:48 ` Ted Zlatanov
2007-11-08 23:11 ` Daiki Ueno
2007-11-09 0:19 ` Leo
2007-11-09 2:39 ` Ted Zlatanov
2007-11-09 6:39 ` Stephen J. Turnbull
2007-11-10 3:00 ` Richard Stallman
2007-11-09 10:40 ` Sascha Wilde
2007-11-07 7:56 ` Richard Stallman
2007-11-07 14:47 ` Ted Zlatanov
2007-11-06 21:11 ` Reiner Steib
2007-11-07 15:01 ` Ted Zlatanov
2007-11-07 16:12 ` Stefan Monnier
2007-11-07 17:34 ` Ted Zlatanov
2007-11-07 16:47 ` Reiner Steib
2007-11-07 17:25 ` Ted Zlatanov
2007-11-02 14:08 ` Ted Zlatanov
2007-11-03 2:49 ` Daiki Ueno
2007-11-05 1:27 ` Ted Zlatanov
2007-11-05 1:37 ` Daiki Ueno
2007-11-01 7:32 ` encrypt.el in No Gnus 0.7 (was: New Emacs facilities from Gnus) Richard Stallman
2007-11-01 8:15 ` Daiki Ueno
2007-11-01 14:47 ` New Emacs facilities from Gnus Simon Josefsson
2007-11-01 16:16 ` Daiki Ueno
2007-11-01 20:09 ` Reiner Steib
2007-11-02 2:06 ` Richard Stallman
2007-11-04 19:56 ` New Emacs facilities from Gnus (was: Gnus in Emacs is updated to No Gnus 0.7) Richard Stallman
2007-11-14 23:41 ` New Emacs facilities from Gnus Lars Magne Ingebrigtsen
2007-11-04 19:56 ` New Emacs facilities from Gnus (was: Gnus in Emacs is updated to No Gnus 0.7) Richard Stallman
2007-11-14 23:42 ` New Emacs facilities from Gnus Lars Magne Ingebrigtsen
2007-11-15 13:07 ` Richard Stallman
2007-11-15 19:54 ` Lars Magne Ingebrigtsen
2007-11-16 18:32 ` Richard Stallman
2007-11-17 12:29 ` ecomplete.el (was: New Emacs facilities from Gnus) Reiner Steib
2007-11-17 23:31 ` Richard Stallman
[not found] ` <87lk8zr0e4.fsf@mocca.josefsson.org>
2007-11-17 12:28 ` Reiner Steib
2007-11-17 13:23 ` ecomplete.el Tassilo Horn
2007-11-18 2:18 ` ecomplete.el Bastien
2007-11-04 19:56 ` New Emacs facilities from Gnus (was: Gnus in Emacs is updated to No Gnus 0.7) Richard Stallman
2007-11-04 20:36 ` New Emacs facilities from Gnus Manoj Srivastava
2007-11-05 8:47 ` Richard Stallman
2007-11-22 20:50 ` Reiner Steib
2007-11-23 4:35 ` Richard Stallman
2007-11-04 21:12 ` Reiner Steib [this message]
2007-11-04 19:56 ` New Emacs facilities from Gnus (was: Gnus in Emacs is updated to No Gnus 0.7) Richard Stallman
2007-11-05 22:23 ` New Emacs facilities from Gnus Arne Jørgensen
2007-11-06 8:26 ` Stefan Monnier
2007-11-06 8:37 ` Richard Stallman
2007-11-06 22:35 ` Arne Jørgensen
2007-11-07 7:56 ` Richard Stallman
2007-11-07 16:58 ` Reiner Steib
2007-11-07 17:22 ` Stefan Monnier
2007-11-07 18:02 ` Reiner Steib
2007-11-07 18:20 ` Stefan Monnier
2007-11-09 10:45 ` Sascha Wilde
2007-11-09 12:14 ` Reiner Steib
2007-11-22 20:30 ` Reiner Steib
2007-11-06 11:33 ` New Emacs facilities from Gnus (was: Gnus in Emacs is updated to No Gnus 0.7) CHENG Gao
2007-11-06 18:45 ` New Emacs facilities from Gnus Reiner Steib
2007-11-07 3:35 ` CHENG Gao
2007-11-07 7:56 ` New Emacs facilities from Gnus (was: Gnus in Emacs is updated to No Gnus 0.7) Richard Stallman
2007-11-11 23:53 ` Richard Stallman
2007-11-13 1:39 ` New Emacs facilities from Gnus Ted Zlatanov
2007-11-13 20:03 ` Richard Stallman
2007-11-11 23:54 ` New Emacs facilities from Gnus (was: Gnus in Emacs is updated to No Gnus 0.7) Richard Stallman
2007-10-29 19:24 ` Gnus in Emacs is updated to No Gnus 0.7 Reiner Steib
2007-10-29 23:11 ` Miles Bader
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