At 09:32 AM 5/20/96 -0700, Ian Goldberg wrote:

I mentioned this to Chaum, and he didn't really seem agree with the need for something lower-level...

Another problem with postage in Mixmaster: the minimum ecash payment is $0.01. Do we want to charge that much for email? Need we consider micropayments?

Absolutely! Given the exponentially increasing rate of data transmission ease, and corresponding cost reduction per bit, any "reasonable" minimum payment today becomes an unreasonable one tomorrow, and a hilariously outrageous one 10 years from now. Suppose the US Government had put a "information storage tax" on hard disks in about 1980, of about $10 per megabyte which would have worked out to be about 1/20 of the retail value at that time. Today, a 1.6 gigabyte hard disk would cost about $1850, which would be $250 for the drive and $1600 for the tax... Any more questions? Many months ago, I suggested using the idea of "probabilistic payments," in which a person could make a very tiny purchase with a large coin, by in effect "gambling" with the payment: You could buy a 0.1-cent email with a 1-cent coin, in which the likelihood of actually paying is 10%. Statistically, both myself and the vendor will be happy in the long run. An advantage of this system is that the payments can be made arbitrarily small and of indefinite granularity: I can pay you 0.3156893 cents with only 1-cent coins. I would be surprised if I was the first to think of such a system, at least in the ecash world, but I never heard anything to the contrary. Jim Bell jimbell@pacifier.com