From: "Thomas S." <ths@rz.tu-ilmenau.de>
Date: Sun, 16 Feb 1997 07:26:15 -0800 (PST)
To: "Timothy C. May" <tcmay@got.net>
Subject: Re: (fwd) DES challenge organisation
Message-ID: <199702161526.HAA18395@toad.com>
MIME-Version: 1.0
Content-Type: text/plain


Hi!

(wow, what a distribution. I should mention that des-challenge is down
this weekend, so the response may not be as expected.)

>>>>> "Timothy" == Timothy C May <tcmay@got.net> writes:

    Timothy> At 11:02 PM +0000 2/15/97, Adam Back wrote:

    >> Thomas S <ths@fh28.fa.umist.ac.uk> writes:
    >>> [...]
    >>> 
    >>> 5. The prize money will be split equally between Gutenberg and
    >>> EFF. There is a possibility of using part of it for stickers
    >>> or something similar, but don't count on it.
    >>  Not a good idea.
    >> 
    >> How can this be enforced? The RSADSI DES challenge is open to
    >> all comers, and how do you prove that someone who finds the key
    >> found it through this group effort?

The client reports the key to the server, not to the user (very
simple, and very simple ways to get around of course). In a nutshell:
we can't enforce it, at least I can't see a way to do so. We certainly
can't keep people from doing their own "treasure hunt".

...
    Timothy> A 2-4x factor is significant, and may warrant a
    Timothy> coordinated search. However, the various problems
    Timothy> implicit in coordinated searches are factors, too.

    Timothy> Also, an uncoordinated search solves the "prize" problem,
    Timothy> as whomever finds the key makes the contact with RSADSI.

Indeed--that's what we try to avoid. Our project is not a race for
money, it is a demonstration with a political impact.

The main point in favour of a coordinated search is the availability
of progress reports. Nobody can argue that the key was found by
chance--as there is exact data about performance and the expected
maximum duration for the search.

    Timothy> One of the problems with a coordinated search, if the
    Timothy> remaining keyspace to be doled out is publically
    Timothy> announced, is that as the keyspace is searched and a key
    Timothy> _not_ found, the remaining keyspace is increasingly more
    Timothy> tempting for "independent searchers" to search. Sort of
    Timothy> the way the odds on some lotteries actually become
    Timothy> "acceptable" as the lottery pot grows. The organizer of
    Timothy> the coordinated search must then, I surmise, keep the
    Timothy> assignments secret and dole out keyspace securely.

This is a technical problem which is discussed at the moment. The
keyspace will not be publically announced (and it wasn't during the
last project).

			Thomas
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