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

Header Data

From: David Miller <isdmill@gatekeeper.ddp.state.me.us>
To: Eli Brandt <ebrandt@jarthur.cs.hmc.edu>
Message Hash: 086a9627a540b50ad8c9beb8ff01c00b860c7af094b717e8bf4e5ae07060164a
Message ID: <Pine.3.89.9405271621.A9265-0100000@gatekeeper.ddp.state.me.us>
Reply To: <9405271955.AA21973@toad.com>
UTC Datetime: 1994-05-27 20:10:52 UTC
Raw Date: Fri, 27 May 94 13:10:52 PDT

Raw message

From: David Miller <isdmill@gatekeeper.ddp.state.me.us>
Date: Fri, 27 May 94 13:10:52 PDT
To: Eli Brandt <ebrandt@jarthur.cs.hmc.edu>
Subject: Re: (fwd) Re: NSA Helped Yeltsin Foil 1991 Coup
In-Reply-To: <9405271955.AA21973@toad.com>
Message-ID: <Pine.3.89.9405271621.A9265-0100000@gatekeeper.ddp.state.me.us>
MIME-Version: 1.0
Content-Type: text/plain

On Fri, 27 May 1994, Eli Brandt wrote:

> > 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
I think the second poster assumed what I did - that the message would be 
split into say 5 parts, each to be encrypted differently.  How to X-or 
split the message isn't obvious to me - pnrg? If you use some bytes 
conveniently hanging around you may as well use a OTP, since both ends 
need the same bitstream.  Unless I'm missing something, which is usually 
the case.

	David  isdmill@gatekeeper.ddp.state.me.us