From: ph@netcom.com (Peter Hendrickson)
Date: Sun, 17 Nov 1996 11:43:50 -0800 (PST)
To: Simon Spero <ses@tipper.oit.unc.edu>
Subject: Re: Members of Parliament Problem
Message-ID: <v02140b05aeb518d83c92@[192.0.2.1]>
MIME-Version: 1.0
Content-Type: text/plain


At 1:39 PM 11/17/1996, Simon Spero wrote:
>On Fri, 15 Nov 1996, Rich Graves wrote:
>>Peter Hendrickson wrote:
>>> There are times when one wishes to speak anonymously, yet speak
>>> as a member of a group.

>> You either need to trust a shared server to know and then blind your
>> identity, or trust the people with whom you share a secret key not to
>> give that key to non-group members.

> Why not use  blinding for obtaining the certificate?

> Create a number up public/private key pairs, blind them, then do the
> cut-and-choose thing with the security officer. He signs the blinded key,
> then returns it. Unblind the remaining pubic key, and you've got a public
> key with the appropriate signature on it.

Okay, this would work.  But, it requires that all (or at least many) of the
Members of Parliament cooperate.  If not, then the security officer will
be able to make very good guesses about who is speaking.

Parliamentarians may not cooperate for a variety of reasons.  They may
not wish to be attacked by terrorists for the words of others.  They
may believe that cowardice is not to be encouraged.  They may not believe
in anonymity.  It might be too hard for them.

What I would like to see is a method which relies only on published
public keys and no other cooperation from the people who are (more
or less) being used as shields.  This may be impossible.

(A number of people have posted references to other ways of doing
this.  I have yet to track down the references they gave so I don't
know if any of them fit the bill.)

Peter