1993-09-28 - Re: Phil Zimmerman on ‘The Death of DES’

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From: cme@ellisun.sw.stratus.com (Carl Ellison)
To: cypherpunks@toad.com
Message Hash: 8deebbf672c3c383161d1325fde50426e336780ef48ebf9af723a6f554a7b5cc
Message ID: <9309282044.AA26047@ellisun.sw.stratus.com>
Reply To: N/A
UTC Datetime: 1993-09-28 20:46:22 UTC
Raw Date: Tue, 28 Sep 93 13:46:22 PDT

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From: cme@ellisun.sw.stratus.com (Carl Ellison)
Date: Tue, 28 Sep 93 13:46:22 PDT
To: cypherpunks@toad.com
Subject: Re:  Phil Zimmerman on 'The Death of DES'
Message-ID: <9309282044.AA26047@ellisun.sw.stratus.com>
MIME-Version: 1.0
Content-Type: text/plain


Single DES is weak, for a known plaintext attack.  I think we knew that.
We didn't know how weak.

We can extrapolate to an NSA machine with 1 second scan of all keys,
perhaps.

So -- 

1.	use triple DES

2.	before using DES, XOR with a stream from a decent PRNG (destroying
	the known plaintext)

3.	in between DES operations, mix bytes up as with	tran (posted on
	sci.crypt occasionally, avbl from me by mail or on ripem.msu.edu)
	-- spreading bytes out within a huge block, further hiding any
	known text

 - Carl





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