From: bryce@digicash.com
Date: Wed, 22 May 1996 03:24:31 +0800
To: Matts Kallioniemi <matts@pi.se>
Subject: Re: The Crisis with Remailers
In-Reply-To: <2.2.32.19960521121126.00371160@mail.pi.se>
Message-ID: <199605211334.PAA25526@digicash.com>
MIME-Version: 1.0
Content-Type: text/plain



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 Matts Kallionieme <matts@pi.se> wrote:
>
> At 10:08 1996-05-21 +0200, bryce@digicash.com wrote:
> >The "minimum ecash payment" is not known at this time,
> >although we think it might be greater than 2^-32 US Dollars
> 
> How do you create such tiny payments? When I try (2.1.5a MT)
> to pay $.001 I receive the warning "Too many digits after '.'!" and
> even though it's just a warning I can't do the payment.


The Ecash(tm) coins minted by the Mark Twain Bank have a base
value of 0.01 U.S. Dollar.  So in using those coins, you can't
spend less than 0.01 U.S. Dollar unless you adopt some protocol
like only pay every tenth time, or only pay on a 1-in-10 random
chance every time, or something.


But _Ecash(tm)_ itself does not have that restriction.
Different coinages of Ecash(tm), issued by different banks, may
have different base values.


> Assuming that you had a client that allows tiny amounts, how would
> you represent a tenth of a cent in binary? To to it exactly would
> require an infinite number of coins...


Well how do we represent 0.01 U.S. Dollars in Mark Twain 
Ecash(tm)?  Easy-- we take a few bits of data, interpret it as 
an unsigned binary number, and then say "this number is how many
U.S. pennies this coin is worth."


Actually it can sometimes get more complicated than that, and 
there are some details about how the forthcoming ecashlib 
handles this to be found at "http://www.digicash.com/api".


Regards,

Bryce




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