Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: sci.crypt
Subject: Re: how do you tell encrytped data from
Message-ID: <7107@brl-smoke.ARPA>
Date: 15 Jan 88 15:10:57 GMT
References: <660@bucket.UUCP> <3600002@osiris.cso.uiuc.edu> <2415@cup.portal.com>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 19

In article <2415@cup.portal.com> truett@cup.portal.com writes:
>In a binary stream, a one time pad will convert "random" streams to "nonrandom"
>ones just as often as it converts "nonrandom" (presumably plaintext) streams to
>apparently "random" ones.  The only way to camouflage this effect ...

This is quite misleading.  There is no effect to "camouflage", since
the so-called effect being described is the purely theoretical one
where the entire space of possible messages is considered.  Useful
messages are a tiny fraction of this space.  In practice, the cipher
stream does not really exhibit "nonrandomness" (on the average) when
the one-time pad is applied to random plaintext.

>Actually, good random number generators make quite good encryptors.

Actually, assuming you're still talking about such pseudo-random
sequences as are produced by linear congruential feedback shift
registers or other such simple schemes, they make TERRIBLE encryptors.
They have far too much structure with far too small a key.  Therefore
they're quite easy to break, using the proper tools.