Simplest possible ecash mint

[Tim May]

On Monday, December 24, 2001, at 12:40 AM, Nomen Nescio wrote:

> How simple can an ecash mint be?
>
> For the simplest case there should be no accounts.  All the mint does is
> exchange coins for other coins.  There are no customer lists, no records
> of transactions (except as needed for double-spending detection).
>
> The very simplest mint is a pure ecoin changer.  You give it a coin and
> it gives you a new one in return.  It checks that the coin you gave it 
> is
> valid and has not been spent before.  You also supplied blinding factors
> so that the new coin you get is blinded and will not be recognized by
> the mint when spent later.

This is a terribly important point. Implementing this "atomic 
transaction" would be a major step. Having a Web site that does this 
EVEN WITH PLAY TOKENS would be a useful step. (Many dislike toy 
applications, but a site which did this would be a way to play with the 
software, test the reliability, and get ideas for further developments. 
The "Play Tokens" would be of literally no value, ostensibly.)

>
> By itself, this trivial mint can support a transaction system, and in
> principle a whole economy.  For Alice to pay Bob, she gives him coins.
> Bob exchanges them at the mint for new coins, thereby checking that they
> are good.  End of transaction.  Bob can spend his new coins elsewhere,
> unlinkable to the exchange.

Like a cellular automata, the basic rules dramatically affect future 
evolutionary paths.

With the proper atomic transaction protocols, the rest unfolds naturally.

Money changers can profit by returning some fraction (e.g., 0.99) of 
what they are given.

>
> The mint does not even have to be involved in transfers between ecash
> and other forms of payment.  This is one of the things the e-gold people
> got right.  They outsourced in- and out-transactions.  You go to any of
> dozens of coin dealers, currency services, shady operators of all 
> stripes,
> to get money into or out of your e-gold account.  The same thing would
> work here.  Third parties would offer to buy or sell ecash for dollars,
> grams of gold, hi grade cocaine, etc.
>
> As described, this mint has a constant money supply.  There is neither
> creation nor destruction of coins.  In practice there would be slow
> destruction due to occasional losses of data.  This could lead to very
> slow deflation, or the mint could be adjusted to slightly inflate the
> currency in order to compensate for this effect.


--Tim May


"That the said Constitution shall never be construed to authorize 
Congress to infringe the just liberty of the press or the rights of 
conscience; or to prevent the people of the United States who are 
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