Martien van Steenbergen wrote:
> Very interesting. Is this akin to David Chaum's anonymous digital money?
> His concept makes sure money is anonymous unless it is compromised, i.e.
> the same money spent more than once. As soon as it's compromised, the
> ‘counterfeiter’ is immediately publicly exposed.

It's similar in that it uses digital signatures for coins, but different
in the approach to privacy and preventing double-spending.  The
recipient of a Bitcoin payment is able to check whether it is the first
spend or not, and second-spends are not accepted.  There isn't an
off-line mode where double-spenders are caught and shamed after the
fact, because that would require participants to have identities.

To protect privacy, key pairs are used only once, with a new one for
every transaction.  The owner of a coin is just whoever has its private key.

Of course, the biggest difference is the lack of a central server.  That
was the Achilles heel of Chaumian systems; when the central company shut
down, so did the currency.

> Also, in bitcoin, is there a limited supply of money (that must be
> managed)? Or is money created exaclty at the moment of transaction?

There is a limited supply of money.  Circulation will be 21,000,000
coins.  Transactions only transfer ownership.

Thank you for your questions,

Satoshi

<a href="http://www.bitcoin.org/">http://www.bitcoin.org</a>