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

>>>Verification of a stamp wouldn't have to be much different from a DNS
>>>query. "Is the following n-tuple (perhaps source plus stamp) valid?",
>>>or likely valid would be far better than what we have now.
>>
>> Oh, OK.  So you give me one stamp, and I use it on 100,000,000 million
>> pieces of mail, each of which verifies.  Seems reasonable.
>
>It's a distributed system with less-than-perfect real-time replication.
>So maybe 8 or 10 of them verify before every server knows the stamp is
>used.

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.

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.