Why we still don't use digital cash

[georgemw at speakeasy.net]

On 14 Jun 2001, at 14:52, Declan McCullagh wrote:


> [Digital cash inventor David Chaum filed for his first patent in this
> area on June 25, 1982. The suite begins to expire in 2002, with an
> important patent expiring in 2005. Seems as though we'll have to wait
> 'til then to see truly anonymous digital cash. For now, we're stuck
> with PayPal and credit cards. Sigh. --Declan]
> 

You think so?  Chaum's proposals always seemed a little
weird to me,  I'd be amazed if there wasn't a perfectly
good way to implement dc without stepping on his patents.

If you look at the process of obtaining digital cash abstractly,
I give you a bag of money,  you give me a bag of tokens I can
use to spend in shops,  it seems to me that there are in principle
two general sorts of ways that I can maintain my anonymity.

1) Make it so somehow you don't recognize the tokens when they
get back to you.

This is the Chaumian approach,  which seems very counterintuitive 
to me.  I believe his aproach was motivated by a desire to ensure 
that there are circumstances by which you could lose your 
anonymity, for example if you attempt to double-spend

2) Just make it so you don't see my face when I get the bag of
tokens.

This seems a lot more straightforward and natural to me.

George