From: jim bell <jimbell@pacifier.com>
Date: Fri, 21 Jun 1996 23:21:16 +0800
To: Michael Froomkin <s1113645@tesla.cc.uottawa.ca
Subject: Re: Federal Key Registration Agency
Message-ID: <199606210601.XAA03610@mail.pacifier.com>
MIME-Version: 1.0
Content-Type: text/plain


At 09:20 PM 6/20/96 -0400, Michael Froomkin wrote:
>I have seen the text of the speech.  The wire service accounts wildly,
>wildly exaggerate.  This is a non-story...except for AG Reno's assertion
>that it would take the government a year to break one DES message with a
>"supercomputer".  She presumably believes this.  We know the number for
>known plaintext attacks, but assuming you don't have a known plaintext,
>what's a more reasonable assumption? 

If done in parallel, on a dedicated, 200 MHz custom chip, my WAG says that 
such a chip could try, and statistically analyze the results of 10 million 
DES codes per second.   (it would do the decrypts on a number of parallel 
DES blocks, and look for typical ASCII code pattern probabilities, again all 
in parallel.)  A typical cracking system might have 100 boards of 100 such 
chips, or perhaps a 100 billion such decrypts per second.  Checking the 
keyspace would require 2**19 seconds, or about a half million seconds, or 6 
days.  Average decrypt, of course, in 3 days.


Jim Bell
jimbell@pacifier.com