From: Adam Back <aba@dcs.ex.ac.uk>
Date: Wed, 25 Jun 1997 02:10:00 +0800
To: davidlu@sco.COM
Subject: Wiener paper (was Re: Comparing Cryptographic Key Sizes)
In-Reply-To: <3.0.2.32.19970624162104.007bb990@middx.x.co.uk>
Message-ID: <199706241754.SAA00563@server.test.net>
MIME-Version: 1.0
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Re comments that I should re-read the paper, here is what Wiener's
paper says about estimated costs of a specialized DES key breaker:

 $100,000 for a machine to break DES in an average of  35 hrs
 $1 mil   for a machine to break DES in an average of 3.5 hrs
 $10 mil  for a machine to break DES in an average of  21 mins

It was as Peter says published in 1993.

Wiener also budgets for $500,000 in design costs (wages, parts, fab
etc).

Another interesting part of the design is that it is based on a
pipelined chip, clocked at 50Mhz which can try 50 Million keys/sec.

35 hours sounds a reasonable amount of time to break a Swift banking
transfer key protecting trillions of dollars of funds.

Perhaps $10,000 isn't too far off the current day costs of breaking
DES after all.  (500Mhz chips?  You can get dec alphas at that speed,
and thats a general purpose CPU)

(If anybody is short of a copy, I've put the one up I've got (no idea
where I got it from) here:

	http://www.dcs.ex.ac.uk/~aba/crypto-papers/des_key_search.ps
)

Adam
-- 
Have *you* exported RSA today? --> http://www.dcs.ex.ac.uk/~aba/rsa/

print pack"C*",split/\D+/,`echo "16iII*o\U@{$/=$z;[(pop,pop,unpack"H*",<>
)]}\EsMsKsN0[lN*1lK[d2%Sa2/d0<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<J]dsJxp"|dc`