1994-05-27 - Re: (fwd) Re: NSA Helped Yeltsin Foil 1991 Coup

Header Data

From: Eli Brandt <ebrandt@jarthur.cs.hmc.edu>
To: cypherpunks list <cypherpunks@toad.com>
Message Hash: c57da418e7db2065ebf99ed64ace5bde0cc0058cc838662e26e3921e5bde6848
Message ID: <9405271955.AA21973@toad.com>
Reply To: <9405271908.AA09401@snark.imsi.com>
UTC Datetime: 1994-05-27 19:55:51 UTC
Raw Date: Fri, 27 May 94 12:55:51 PDT

Raw message

From: Eli Brandt <ebrandt@jarthur.cs.hmc.edu>
Date: Fri, 27 May 94 12:55:51 PDT
To: cypherpunks list <cypherpunks@toad.com>
Subject: Re: (fwd) Re: NSA Helped Yeltsin Foil 1991 Coup
In-Reply-To: <9405271908.AA09401@snark.imsi.com>
Message-ID: <9405271955.AA21973@toad.com>
MIME-Version: 1.0
Content-Type: text/plain

> From: "Perry E. Metzger" <perry@imsi.com>
> > If you suspect that some of the non DOD/NSA cyphers might be broken,
> > but you are not ready to employ one-time-pads, then you should
> > threshold you mesages into N parts so that all N are needed to recover
> > the original.  Then encrypt each part under a different cypher.
> Its far simpler to encrypt your message with multiple systems, one
> after another, than to break it up in the manner you suggest, and the
> security is in fact better that way than in the manner you suggest.

Why?  If you XOR-split the message and encrypt each mask differently,
you are /guaranteed/ that all of the encryption methods must be
broken to retrieve the original.  If you use repeated encryption,
this is much harder to prove, and not always true.  There's a result
that if you choose the first cipher unwisely, you're hosed no matter
what you do on top of it.

   Eli   ebrandt@hmc.edu