Re: e-postage stamps, was Welcome to the new(ish) ASRG list

>> I don't think the scale works.  Most payment systems are designed with
>> the assumption that most transactions will succeed, with failed ones
>> relatively uncommon.  In the e-postage world where 90% of the mail is
>> spam, I'd expect 90% of the stamps to be double spent.
>
>If the spammers get hold of every legitimate stamp and re-use it, 8/9 of
>spam is still stopped.  If they double-use their own stamps, their costs
>for stamps are halved; the business still doesn't work.

I'm not explaining this very well.  Look at my paper, it explains why it
is extremely unlikely that one could build a stamp system that could cover
its costs for anything that people are likely to pay, particularly if
the majority of the transactions are rejected so there's no revenue.

>> This also has the adverse selection problem, it encourages phishing,
>> fake drugs, and other high value spammers who figure that it's just
>> a cost of doing business.  Or they set up the First Very Authentic
>> E-Postage Bank of Nigeria, and debase the currency.
>
>Why would any ISP consider that bank valid?

Unless you expect the world of e-mail to break up into regional walled
gardens, there'd need to be clearinghouses to connect the ISPs to the
issuers, analogous to what Master Card and Visa do for credit cards,
or SWIFT and the domestic ACH system do for bank transfers.  The
FVAE-PBN doesn't have to persuade ISPs that it's valid, it has to
persuade a clearinghouse, and the track record of clearinghouses
ejecting dodgy members is not encouraging.

Do read the whitepaper, it's remarkably un-stale considering that I
wrote it ten years ago.