From: Ben Laurie <ben@gonzo.ben.algroup.co.uk>
Date: Sun, 24 Nov 1996 13:40:23 -0800 (PST)
To: The Deviant <deviant@pooh-corner.com>
Subject: Re: IPG Algorith Broken!
In-Reply-To: <Pine.LNX.3.94.961124150747.15531B-100000@random.sp.org>
Message-ID: <9611242036.aa13728@gonzo.ben.algroup.co.uk>
MIME-Version: 1.0
Content-Type: text/plain


The Deviant wrote:
> 
> -----BEGIN PGP SIGNED MESSAGE-----
> 
> On Sun, 24 Nov 1996, John Anonymous MacDonald wrote:
> 
> > 
> > At 6:56 PM 11/23/1996, The Deviant wrote:
> > >On Sat, 23 Nov 1996, John Anonymous MacDonald wrote:
> > >> 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.
> > 
> > Please prove your assertion.
> > 
> > If you can't prove this, and you can't find anybody else who has, why
> > should we believe it?
> 
> Prove it?  Thats like saying "prove that the sun is bright on a sunny
> day".  Its completely obvious.  If somebody has a new idea on how to
> attack their algorithm, it might work.  Then the system will have been
> broken.  You never know when somebody will come up with a new idea, so the
> best you can truthfully say is "it hasn't been broken *YET*".  As I
> remember, this was mentioned in more than one respected crypto book,
> including "Applied Cryptography" (Schneier).

It seems appropriate to quote Schneier on the subject:

"Those who claim to have an unbreakable cipher simply because they can't break
it are either geniuses or fools. Unfortunately, there are more of the latter in
the world."

And...

"Believe it or not, there is a perfect encryption system. It's called a
one-time pad..."

Cheers,

Ben.

-- 
Ben Laurie                Phone: +44 (181) 994 6435  Email: ben@algroup.co.uk
Freelance Consultant and  Fax:   +44 (181) 994 6472
Technical Director        URL: http://www.algroup.co.uk/Apache-SSL
A.L. Digital Ltd,         Apache Group member (http://www.apache.org)
London, England.          Apache-SSL author