From: wichita@cyberstation.net
Date: Sat, 30 Nov 1996 00:21:22 -0800 (PST)
To: The Deviant <deviant@pooh-corner.com>
Subject: Re: IPG Algorith Broken!
In-Reply-To: <Pine.LNX.3.94.961124024959.14102A-100000@random.sp.org>
Message-ID: <Pine.BSI.3.95.961130021602.19278D-100000@citrine.cyberstation.net>
MIME-Version: 1.0
Content-Type: text/plain




On Sun, 24 Nov 1996, The Deviant wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> 
> On Sat, 23 Nov 1996, John Anonymous MacDonald wrote:
> 
> > 
> > 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.
> 
> No, he was right.  They can't prove that their system is unbreakable.
> They _might_ be able to prove that their system hasn't been broken, and
> they _might_ be able to prove that it is _unlikely_ that it will be, but
> they *CAN NOT* prove that it is unbreakable.  This is the nature of
> cryptosystems.
> 
> > >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.
> 
> It is impossible to prove such a thing.  It's like saying you have proof
> that you have the last car of a certain model ever to be built.  Anybody
> could come along and build another, and then you don't have the last one.
> 
> > 
> > >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.
> 
> There *IS NO SUCH PROOF*.  Just like you can't prove that god created the
> universe, or that Oswald shot Kennedy, and so on and so forth.  It can't
> be proven.  It never has been proven, and it never will be proven.  People
> have new ideas, new algorithms are invented.  Someday, somebody will crack
> _all_ the cryptosystems that have now been invented.
> 

To repeat Frantz', I thought Shannon proved OTPs were unbreakable. I can
also assure you that they are unbreakable, because you cannot solve a
three variable equation where only one variable is known, ie. the
ciphertext. That is a fact, not an opinion like God, or Oswald, there are
facts and opinions. It is a fact that OTPs are unbreakable and it is a
fact that our system is unbreakable. Q.E.D. for the very same reasons
except that we must use exclusionary proof instead of inclusionary proof
like Shannon. 

With Kindest Regards,

Don Wood