Subject: RE: namedroppers, continued

From: Dean Anderson <[email-masked]>
Date: Sat, 7 Dec 2002 12:18:27 -0500 (EST)

This seems clever, however, it will also take significant computational
effort to verify the computational effort was actually done. Even if a
class of functions are found that are "easier" to verify than to compute,
they will no doubt still take up a significant fraction of time.

Also, all outgoing messages would need this computation, since a
mailserver does not know who it has sent mail to in the past, and whether
they are still in receipt of the verification.  So then you would only be
able to send 8000 messages a day, too.

Clearly, that doesn't scale very well.

It seems unlikely that this would change the percentage of spam, since it
would merely reduce the total amount of mail sent.

I haven't observed a recent proliferation of spam, however. Spam seems to
be level.

		--Dean

On Fri, 6 Dec 2002, Ayyasamy, Senthilkumar  (UMKC-Student) wrote:
> this is the work all about (yesterday's seminar in a MIT group)
>
> " If I don't know you, and you want your e-mail to appear in my
>   inbox, then you must attach to your message an easily verified
>  "proof of computational effort", just for me and just for this
>  message.
>
> If the proof of effort requires, say, 10 seconds to compute, then the
> economics of sending spam are radically altered, as a single machine
> can send only 8,000 messages per day.
>
> The recent proliferation of spam has lead to a renewed interest in
> these ideas.  This  work is about both the choice of
> functions that can be used to yield easily verifiable proofs of
> computational effort, and architectures for implementing the proof of
> effort approach.  Filtering and/or forcing senders to pay in other
> currencies, such as human attention and money, will be covered as time
> permits"
>
>
> for more details http://research.microsoft.com/research/sv/PennyBlack
>
>
>
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---

From: Ketil Froyn <[email-masked]>
Date: Sun, 8 Dec 2002 18:13:43 +0100 (CET)

[ post by non-subscriber.  with the massive amount of spam, it is easy to miss
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> can send only 8,000 messages per day.

Wouldn't something like this cause problems for (large/free) email
providers?  They would probably need a lot of extra hardware to do all
this computation. And until something like this is included in the
standard, the receiver must accept mail from senders that don't implement
this yet.

I personally like the idea behind qconfirm (http://smarden.org/qconfirm/)
and TMDA (http://tmda.net/). If I receive an email that I do not recognize
or otherwise find to be authentic, a mail is sent back to the sender,
requesting that they send a verification mail to a unique secret address.
When a mail is received at this secret address, the original mail is
delivered to me, and the secret address is removed. For a spammer, it is
too expensive to receive and reply to all these mails.

Ketil