From: Anonymous

Subject: Re: Ladder DES
Date: 23 Feb 1994 03:52:08 GMT
Organization: Michigan State University
Lines: 18
X-Newsreader: TIN [version 1.2 PL1]

Terry Ritter ( wrote:
:  To maintain earlier levels of security, DES must be replaced with
:  a stronger cipher.  The one obvious alternative to DES is a simple
:  construct built from DES called triple-DES.  Triple-DES, while
:  generally being thought of as "strong enough," also carries the
:  baggage of requiring three times the processing of normal DES.

Another, already somewhat widely used alternative is 
RSA Data Security's "DESX", as implemented in their commercial
products MailSafe and BSAFE since 1986/87.  DESX is ordinary
DES with pre- and post-processing to expand keysize and
security.  Like Ladder DES, it is faster than triple-DES.

I have some reason to believe that RSA may be willing to
allow use of DESX free of licensing fees.  Perhaps someone
from RSA would comment?

Mark R