--
In a strictly anonymous transactions one cannot prove that there
was any agreement to pay, or any payment, to anyone in particular.
For many purposes, what one wants is transactions with controlled
nymity, where Alice can prove she paid Bob such and such an
amount, in accordance with such and such an agreement, but does
not need to reveal every payment to the bank in order to prove
this for the on payment that goes wrong.
Strictly anonymous transactions work well for small payments that
are frequently repeated. Because the payments are small, tracking
identity is a burdensome overhead, and if the payer does not get
what he wants, he merely wanders off elsewhere.
Pornography, on the model of those machines where one keeps
inserting quarters to keep the video rolling, or interactive
pornography, where one makes ad hoc payments to the performers,
are good applications for strictly anonymous payments.
However there are many applications, some of them more respectable
and perhaps larger volume, where controlled nymity is appropriate.
One important such application is the gray market. Usually the
payer wishes to conceal his real identity from the recipient, and
also does not wish anyone to know that there has been a
transaction between payer and supplier.
Goods on the gray market are gray for a variety of reasons.
Sometimes, like straying wives or husbands, businesses are making
deals they do not wish major customers or suppliers to find out
about.
The gray market softly shades into the black market. There are
deals that are not exactly illegal, but which the parties would
prefer the government not to find out about. For example the
government often restrains businesses from cutting prices, or
forcefully encourages them to maintain prices at an artificially
high level. Undue price cuts might be penalized as dumping, as
unfair competition, and so on and so forth. For example exporters
are generally required to participate in export cartels, which
they tend to ignore. A german company selling goods in the US too
cheaply is likely to be punished by German authorities for
unfairly competing with other german firms, and by US authorities
as "dumping". A US firm selling goods too cheaply in the US might
be harassed by the justice department for "predation".
To perform a transaction with controlled nymity, as is required to
support gray market transactions, I propose the following
mechanism.
Buyer and seller make a deal, perhaps on a website like EBay where
they are identified by handles. They agree to a delivery contact.
The payee registers the transaction with the money issuer, the
registration consisting of a hash code of the contract the amount
to be paid, and a transient public key. The payer deposits
Chaumian coins to the required amount to the transaction record,
creating a public record that the contract has been paid, though
by whom and to whom does not become known unless the contract
corresponding to the hash code is made public, and not necessarily
even then, since the parties to the contract are identified by
handles, with reputations associated with the handles, as at Ebay.
The payee then withdraws the coins, encrypted using the public key
associated with the contract, a process that creates no traceable
connection between the handle and supplier and beneficiary.
--digsig
James A. Donald
6YeGpsZR+nOTh/cGwvITnSR3TdzclVpR0+pr3YYQdkG
iuj6pa04sjBj2fp2icqR6W+6S28KntHqmFQRF5C3
47uanT19FGKI5xy+444UTEU6MHx2MA1RyK62LpuyT
