From: bryce@digicash.com
Date: Tue, 16 Jul 1996 02:19:51 +0800
To: "David G.W. Birch" <daveb@hyperion.co.uk>
Subject: Re: #E-CASH: PRODUCT OR SERVICE?
In-Reply-To: <1374700491-41210125@mail.hyperion.co.uk>
Message-ID: <199607151336.PAA27295@digicash.com>
MIME-Version: 1.0
Content-Type: text/plain



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David G.W. Birch <daveb@hyperion.co.uk> wrote:
>
> Johan,
> 
> >Careful there. At least ecash is a registered trademark. And as far as I know
> 
> It is alleged that a trademark has been applied for on the term "ecash" 
> in some countries: that's why Robert was careful (as we always are) to 
> use the term "e-cash" instead.


"Ecash" is a registered trademark of DigiCash.  It is registered
with the Benelux trademark office and the United States
trademark office.  I believe that it is considered unwise to use
minor variations on trademarked names, but I'm not an
intellectual property rights lawyer.


> >Mondex isn't one of the true electronic cash systems. Please correct me if
> >I'm wrong, but isn't mondex an electronic debit card system?
> 
> Mondex is _the only_ true electronic cash system in the world that I know 
> of, precisely because it isn't an electronic debit card system (like 
> Avant) or digital travellers' cheques (like Digicash).


I think it would behoove us all to clarify our terms.  I call
Ecash(tm) coins "electronic cash" for several reasons.  Ecash(tm)
has all of the following characteristics in common with
conventional cash, in descending order of importance:


1.  Unforgeability.  Ecash(tm) coins have intrinsic value 
because they are cryptographically impossible to forge.



2.  Finality.  Payments are cleared on the spot.  No outstanding
payment obligations remain after a purchase.

3.  Bi-directionality.  Payers and recipients use the same 
software and the same protocol.  It is not necessary for
recipients to be specially trusted by the bank or by the payers.

4.  Privacy.  The privacy of Ecash(tm) payers is mathematically
unconditional.

5.  Composability.  You can make large Ecash(tm) payments out of
a collection of smaller Ecash(tm) coins.  This is in contrast to
a check-based system where you typically draw a check for the
exact amount and transfer only a single check.

6.  Small payments.  Ecash(tm) coins are cheap enough to use 
that they are practical for small payments.

(As a note, I do not use the word "micropayments" here, because
I am beginning to think that a good technical definition of
"micropayments" is "payments whose value is less than the cost
of using current electronic coins".  This qualifies schemes like
Shamir's and disqualifies, well...  current electronic coins.)


There might be other angles we should talk about here.


I think that the first quality is the defining one, technically.


So, could a knowledgeable person e.g. Mr. Birch tell us why
Mondex should be considered to be "electronic cash"?  


And similarly I would like to hear an informed opinion about 
why Ecash(tm) should not be considered "electronic cash".  
I tend to agree that Ecash(tm) would be even _more_ cashlike 
if it were cleared off-line, but I don't consider that 
difference very fundamental.  (_Any_ digital money based on 
our current understandings will have to be cleared at a 
central clearer eventually, since digital information is 
perfectly copyable.)


Thank you for your correspondance.


Regards,

Bryce

Ecash 2.x Team




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