From: hallam@w3.org
Date: Mon, 23 Oct 95 15:07:40 PDT
To: Doug Hughes <Doug.Hughes@eng.auburn.edu>
Subject: Re: "power one time pad"
In-Reply-To: <doug-9509231532.AA014714381@netman.eng.auburn.edu>
Message-ID: <9510232207.AA15919@zorch.w3.org>
MIME-Version: 1.0
Content-Type: text/plain



>This is the most confusing part of the whole thing.. How does it get started.
>unfortunately, as this is embroiled in non-disclosure and patent-pending,
>we're not going to know, but are forced to take the word of experts such
>as David Kahn that it works as advertised.

Has David Kahn made such a statement? Where can I read the context in which it 
was made? Kahn is a historian of cryptography, not a cryptographer. 

On the basis of the documents made avaliable to me it looks like the standard 
linear feedback sequence generator hack. It does not appear to be a one time pad 
system in anything but name.


>Yes, I and a friend of mine were the only two people in the audience
>that were not Journalists.  It does look rather intruguing, but so much
>negativism is flying about, that most people have dismissed it out of hand.

Often the best thing to do. I don't know who designed POTP nor what they created 
but if I use it and it fails I take the risk. Note that in the Mondex case if it 
fails Mondex take the hit.


As a final point one the security of one time pads is only guaranteed as long as 
the pads are never reused in any sense whatsoever. The system is exceptionaly 
fragile, the slightest breach of secuirty can destroy it, consider the Venona 
decrypts for example.

I'm thinking of writing a paper "How One Time Pads Fail" to discuss failures of 
"unbreakable systems". I have some new material on how to copy the Venona 
cracking method and also plan to analyse POTP and a few other alledged one time 
pad systems. If anyone knows of other alledged one time pad systems that weren't 
please email me and I'll include them.

	Phill