| Jeff Abrahamson on 12 Mar 2004 14:51:02 -0000 |
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On Thu, Mar 11, 2004 at 03:01:14PM -0500, George Gallen wrote:
> [71 lines, 415 words, 2721 characters] Top characters: etosianl
>
> I'd like to know who is going to keep track of the stamps?
> And how will this stop a spammer from using an ISP outside
> the country that doesn't impose email sending fees?
I read a paper that proposed an interesting infrastructure that could
do this. (Sorry, I don't remember the reference.)
It basically goes like this. I have my email address
(jeff@purple.com), but I can also assign cryptographically secure
variants (jeff-55ca6286e3e4f4fba5d0448333fa99fc5a404a73@purple.com).
No one wants to type that, but, like PGP keys, our mail clients
largely could take care of it for us. By secure here all I mean is
that you can't forge a special address to me and if I get mail with
such an address I know who you are.
Now I tell the world that my email address is jeff@purple.com. When
you send me mail, my mail client picks everything addressed to the
unsecured version and looks for an attached micropayment. If it finds
one, it lets the mail through. I can then do one of two things.
1. I can return the micropayment (because I want to receive mail
from you) and optionally issue you a unique secure email address
for me so we don't have to go through this each time.
2. I can accept the payment and ignore you. If you send me spam, I
have been compensated. There's some price where it's worthwhile
for me to receive spam.
If mail is sent to my general address and either doesn't have a
micropayment or has too low a payment (since I set the threshold), it
responds to the sender that a micropayment of X is required for
receipt of the mail, but that the payment will be returned if the
sender is not a spammer. The sender then resends with the
micropayment or doesn't.
If mail arrives with a valid secure address, it is accepted. If I
start seeing that mail to a secure address is spam, I can revoke that
address.
This is relatively complicated, but the complexity is largely handled
by software. It has the nice features that it specifies a protocol
but not an implementation or a vendor. It allows any MTA, MUA, MDA,
and micropayment entity of the users' choices.
The disadvantage is that it does require mail clients to support it,
and it does require a micropayment infrastructure.
BTW, for those who haven't seen it, a very promising and
algorithmically interesting micropayment scheme is peppercoin,
developed (on the math side) by an old professor of mine, Silvio
Micali:
http://www.peppercoin.com/General/FAQAnswerPage.ppp?keyID=helpfaq/faqs/AboutPeppercoin
Their FAQ is hard to read, unfortunately.
--
Jeff
Jeff Abrahamson <http://www.purple.com/jeff/>
GPG fingerprint: 1A1A BA95 D082 A558 A276 63C6 16BF 8C4C 0D1D AE4B
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