[47609] in Cypherpunks
Re: DES in real life
daemon@ATHENA.MIT.EDU (Perry E. Metzger)
Sat Jan 20 19:16:13 1996
To: Michael Froomkin <froomkin@law.miami.edu>
Cc: cypherpunks <cypherpunks@toad.com>
In-Reply-To: Your message of "Sat, 20 Jan 1996 11:26:47 EST."
<Pine.SUN.3.91.960120111743.16171F-100000@viper.law.miami.edu>
Reply-To: perry@piermont.com
Date: Sat, 20 Jan 1996 19:01:09 -0500
From: "Perry E. Metzger" <perry@piermont.com>
Michael Froomkin writes:
> Recognizing that DES is not the best thing out there, but that it is
> better than RC40 and life is a series of cost/benefit tradeoffs and that
Thats RC4, and it isn't neccessarily better than RC4, especially if
the RC4 key length is reasonable. No one really knows the strength of RC4.
> 1) Suppose you are approached by a corporate client who believes that they
> can get export permission for DES (but nothing stronger, i.e. no 3DES).
> What kind of real-world, non-banking, applications is DES just too weak
> for today?
I'd guess that anyone who consideres their messages to be worth more
than a few hundred bucks a pop has cause to worry, because thats the
upper limit on the cost of cracking DES keys these days.
> 2) How long before DES becomes generally unsuitable for (A) corporate
> (B) personal use [please keep the threat model on which this question is
> based in mind -- threats *other than* the US government wiretapping you]?
I'd say it is unsuitable for anything approaching a valued corporate
secret today. Personal use? Well, the threat model there is all
important. Certainly your cousin can't crack DES keys -- yet.
> 3) Do you have a view as to whether DES (A) will and (B) should be
> recertified next time the issue arises?
DES should not be recertified. I have no opinions on what the
government will do.
Perry
