From: nobody@cypherpunks.ca (John Anonymous MacDonald)
Date: Sat, 23 Nov 1996 16:35:16 -0800 (PST)
To: cypherpunks@toad.com
Subject: Re: IPG Algorith Broken!
Message-ID: <199611240021.QAA16004@abraham.cs.berkeley.edu>
MIME-Version: 1.0
Content-Type: text/plain



At 12:33 PM 11/23/1996, Eric Murray wrote:
>John Anonymous MacDonald writes:
>> 
>> 
>> At 8:09 AM 11/23/1996, Eric Murray wrote:
>> >No, you can't.  It's impossible to prove an algorithim unbreakable.
>> 
>> No?  Please prove your assertion.
>
>You can't prove a negative.

If it can't be proven, why do you believe it is true?

The good news is that you can prove a negative.  For example, it has
been proven that there is no algorithm which can tell in all cases
whether an algorithm will stop.

>The best IPG could say is that
>it can't be broken with current technology.
>Next week someone might come up with a new way
>to break ciphers that renders the IPG algorithim breakable.

The best they can say is what they did say: they have a proof that
their system is unbreakable.  What you question, quite reasonably,
is whether they have such a proof.

>You point could have been that the same problem exists
>for proofs- that next week someone could come up
>with a way to prove, for all time, that an algorithim
>really IS unbreakable.  So, to cover that posibility
>I should have said "it's currently impossible to
>prove an algorithim unbreakable". :-)

Or, more accurately, nobody credible has seen such a proof.  But, a
clever person might invent one.

IPG is eager to demonstrate their proof.  They should hire a professional
skilled in the art to evaluate their proof and publicly announce the
results.  This costs less than $5000 and would be, presumably, a small part
of their profits should they have invented such an algorithm.

diGriz