Re: Voice/Fax Checks

> I had the impression from that paper that with transferred ecash, a person
> earlier on the trail could always recognize the cash even at a later point.
> This followed, Chaum claimed, from the need to detect double-spending.
 
That makes sense, and I don't see it as being too much of a problem either. 
Physical cash works that way too; if I write down the serial numbers of all
money that goes through my hands, then if it ever comes back into my hands
I'm going to recognize it. It would be nice if ecash could not have this
"flaw", but it doesn't seem vital, or even particularly important, to me.

Jonathan Rochkind <jrochkin@cs.oberlin.edu> writes:

>Physical cash works that way too; if I write down the serial numbers of all
>money that goes through my hands, then if it ever comes back into my hands
>I'm going to recognize it. It would be nice if ecash could not have this
>"flaw", but it doesn't seem vital, or even particularly important, to me.

OK, but one of the main characteristics of electronic cash is its anonymity.
If we don't care about serial numbers we can just use an RSA-signed message
from the bank saying "I'm worth $1.00" as the cash (at least in an on-line
system).  The whole reason we go through the blinding rigamorole is to make
it so that the cash is unrecognizable after transfer.  That is why I keep
raising the issue about recognizability.  You are probably right that most
people wouldn't care, though.

Hal