Quote from: gavinandresen on November 29, 2010, 09:28:56 PM

Quote from: farmer_boy on November 29, 2010, 08:54:02 PM

What are your thoughts on digital coin?

I grabbed the "Digital Coin Technology" pdf file.

It looks to me like it fails in the second paragraph:

Quote

This  Digital Coin  serial  number  can  be  up  to  512  numbers  long.   The  Digital Coin  software   alone  can  find,  read  and  alter  this serial  number. 

If the DigitalCoin software can read the serial number, then so can other software. It is simply not true that "The DigitalCoin software alone can ..."

Either you have a central server running the DigitalCoin software and you have to trust that the people running that server won't double-spend DigitalCoins.

Or... you have Bitcoin, where the "serial numbers" are the public keys of coin generation transactions.

Let me put it differently: I think the _ideas_ with respect to associating to every product its own self-issued currency have some value. The double spending problem has to be addressed, yes, and that's why I would prefer that people that bring these systems into the world would first take the time to show why they would be secure in the first place. Today it is even possible to show these properties in a way that it is verifiable by software that this holds.

Claims and proofs of the form: P=/NP -> description_of_payment_system -> NoDoubleSpendingPossible description_of_payment_system /\ NoForgeryPossible description_of_payment_system are possible to express in systems like this.