Declan misses the mark on ecash

[Adam Back]

A little behind on mail, but I figure some of this is sufficiently
misleading to dig up again: 

On Thu, Jun 14, 2001 at 03:33:03PM -0400, Declan McCullagh wrote:
> 
> On Thu, Jun 14, 2001 at 07:00:21PM -0000, lcs Mixmaster Remailer wrote:
> > It is a botched attempt to describe the "cut and choose" mechanism.
> 
> Right, it was an attempt to describe "cut and choose" in three
> sentences or so. It's a news article, not a technical paper. Deal.

The point is Chaums ecash never did deploy cut and choose.  So whether the
description of cut and choose was unclear or not it was irrelevant, and
confused to describe it at all.

> > The article also contains a recap of the Chaum/Brands patent wars.
> > It would have been more interesting if there were some reference
> > to new approaches to ecash that avoid the patents, such as the
> > Lucre software by Ben Laurie, based on David Wagner's blinding
> > (http://anoncvs.aldigital.co.uk/lucre/
> 
> The point of that section of the article was to talk about available
> patents. Wagner's scheme appears to reply on Chaum's (original)
> patents, so it wasn't relevant.

According to who?  You?  Care to elaborate on your thinking?

So far your analysis of the patent discussion around Wagner's scheme
looks like just spurious uninformed dismisive comments.

The point of Wagner's scheme is that it is not a blind signature but a MAC
coupled with a zero-knowledge proof of non-coin marking.

I'd say it's more accurate to say it's not clear whether it is covered
by something in the patent minefield or not.  There was a comment on
dbs list that a lawyer at berkeley had offered the opinion that it was
not.  Chaum offers the opinion that it is covered by his blind signature
patents.  I find that unlikely as it is not a signature as it fails one
of the main aspects of a signature -- that there is something that is
verifiable by the holder and usually others relating to some message.

There are of course other opinions also, but I find your dismissive
comments misleading.

Also this comment :

> appears to be unpatented." Right. Whatever. 
> You can take that anonymous claim to the bank.

I don't think anyone was claiming you would proceed in any patented
area without legal advise.  I don't think anonymous comments should
hold less weight.  Yet you were presuming to dismiss Wagner's approach
as clearly covered by patents which appears to be an uninformed and
probably incorrect opinion.

Adam