CDR: Re: Permutations in DES

At 09:08 PM 9/6/00 -0400, Kevin Elliott wrote:

initial permutations to be in the same category as Blowfish's (and derivative algorithm's) time consuming key expansion phase- a neat "trick" that does not improve theoretical security but significantly increases the difficulty of real world attacks.

They do an *excellent* job of that but hamper key agility, unless you do something like page state.