Path: utzoo!attcan!uunet!mcvax!ukc!etive!hwcs!zen!jules
From: jules@zen.co.uk (Julian Perry)
Newsgroups: comp.mail.elm
Subject: Re: Mail Encypherment
Message-ID: <1333@zen.co.uk>
Date: 18 Jul 88 08:26:20 GMT
References: <2085@hplabsz.HPL.HP.COM>
Reply-To: jules@zen.UUCP (Julian Perry)
Organization: Zengrange Limited, Leeds, England
Lines: 38

In article <2085@hplabsz.HPL.HP.COM> taylor@hpdstma.hp.com (Dave Taylor) writes:
>.....
>That is, if someone *really* wants to read your email, either
>along the way or once it's arrived, then they *can* do so.  The
>`cryptbreakers workbench' package is widely available, for
>example, and it is reputed to be able to break the crypt(1)
>function that is shipped with Unix (crypt is a partial implementation
>of the DES encryption algorithm, using a shorted [simpler] 52 bit
>key rather than the original [as designed at IBM] 64 bit key.  BTW:
>I once talked to Dennis Ritchie about whether the simpler 
>implementation was a `plot by the NSA' as widely believed and 
>he laughed...)

About the crypt-breakers workbench ...... I played with this little tool
for a few days and had some fun with it.  It seems to work  fairly  well
but it relies on some  knowledge of what is in the text being  decrypted
at least  that's as far as I got with it.  The user  supplies  a list of
words  and it tries to find them and you  slowly  build up the  complete
text.

This method of  decryption  can easily be foiled by  compressing  (using
compress,  pack, compact or any other  similar  routine) the text before
encrypting it.  I'm sure this does not make it impossible to decrypt but
it makes it one hell of a lot  harder  and as far as I know well  beyond
the  bounds  of  the  casual  hacker  -  even  if  s/he  does  have  the
crypt-breakers workbench.

Why not send encrypted mail as:    compress - crypt - uuencode

>Dave Taylor

Jules

-- 
IN-REAL-LIFE:  Julian Perry           
E-MAIL:        jules@zen.co.uk || ...!uunet!mcvax!ukc!zen.co.uk!jules
PHONE:         +44 532 489048 ext 217
ADDRESS:       Zengrange Limited, Greenfield Road, Leeds, England, LS9 8DB