From: bryce@digicash.com
Date: Sun, 12 May 1996 20:03:57 +0800
To: perry@piermont.com
Subject: Re: found nym-differentiation! Still need perpetual motion, FTL travel, cold fusion
In-Reply-To: <199605112302.TAA07610@jekyll.piermont.com>
Message-ID: <199605120836.KAA15055@digicash.com>
MIME-Version: 1.0
Content-Type: text/plain



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 The entity calling itself "Perry Metzger" <perry@piermont.com> is alleged to
 have written:
(> Bryce wrote:)

> > Simple as pie, because of some of the properties of DC-Nets.
> > If someone sends out the wrong number of pubkeys, then
> > everyone will know, right?  So when that happens everyone
> > just reveals their shared-secret data from the DC-Net
> > session.
> 
> And if several people lie about their shared secrets?


If some of your N participants are going to collude to share
their nyms then it is manifestly impossible to stop them.
But that doesn't bother me.  The purpose of this scheme is
to create N nyms for N people and be sure that each of then 
N people who wanted a nym got one.  If you are sure that 
each of the N people wanted a nym, then you can be sure you 
have a one-to-one mapping between people and nyms, but
unconditional untraceability from nyms to people.


But perhaps what you were talking about was a
denial-of-service attack on the DC-Net's network layer.
That has been addressed extensively in Chaum's original
"Dining Cryptographers" paper.  Chaum's method for dealing
with denial-of-service attacks is typically brilliant, but
even so it is an unwieldly and expensive (in terms of
computation and bandwidth) proposition.  I recommend "Dining
Cryptographers" to everyone, and I hope that someone who
reads it will come up with a better solution.


Regards,

Bryce




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