Re: Relative Strength of 40-bit Crypto Implementations

At 01:29 AM 1/7/97 -0500, Vin McLellan wrote:
>	A client asked me today about where he could find evidence of the
>relative strength of different encryption algorithms, when all are
>restricted to 40-bit keys.  He assumed dot-Gov was going to restrict his
>export product to the 40-bit limit, but he wanted to provide the strongest
>security he could within that limitation.

The best answer you can possibly give him is to move production overseas.
Any 40 bit cipher is garbage. Period. It is easy to produce crypto
overseas. Many medium sized companies are doing so today. Insiders claim
that larger companies, such as Netscape, are in the process of setting up
shop abroad as well.

Clearly, one can't produce software containing crypto in the US and stay
competitive at the same time.






-- Lucky Green <mailto:shamrock@netcom.com> PGP encrypted mail preferred
   Make your mark in the history of mathematics. Use the spare cycles of
   your PC/PPC/UNIX box to help find a new prime.
   http://www.mersenne.org/prime.htm

At 01:29 AM 1/7/97 -0500, Vin McLellan wrote:
>	A client asked me today about where he could find evidence of the
>relative strength of different encryption algorithms, when all are
>restricted to 40-bit keys.  He assumed dot-Gov was going to restrict his
>export product to the 40-bit limit, but he wanted to provide the strongest
>security he could within that limitation.

A cypher with a long key setup schedule, such as Blowfish, would be more
resistant to brute force attacks.  (Blowfish requires 500+ encryptions to
set up the key schedule.  This should be similar to adding 9 bits to the
key size.)  While I think Blowfish is good in this respect, one must be
careful to avoid systems, such as DES, which are subject to Peter Trei's
"gray code" techniques.


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