From: "Rev. Mark Grant" <mark@unicorn.com>
Date: Tue, 18 Jul 95 18:55:53 PDT
To: Andrew Roos <ANDREWR@real3.realtime.co.za>
Subject: Re: Here it is; bi-directional dining cryptographers
Message-ID: <Pine.3.89.9507171327.A3308-0100000@unicorn.com>
MIME-Version: 1.0
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On Mon, 17 Jul 1995, Andrew Roos wrote:

> If the objective is to keep what Alice and Bob say SECRET then we
> have a problem if the entropy per bit of Alice's data plus the
> entropy per bit of Bob's data is less than one bit, because then
> there is only one likely decryption of the "ciphertext", which will
> reveal what both Alice and Bob are saying.

Yes, but presumably it's expected that they would be using secure
encryption on the messages that they're sending. That might still provide
some information about the message for traffic analysis, e.g. if you send
a PGP message you have your key-id at the beginning, and if you knew the 
keys of all members of the DC-net you could XOR them and see who's 
talking to who.
 
I'd have thought the most significant problem would be reserving the
blocks in an anonymous fashion while not allowing denial-of-service
attacks. 

		Mark