---------- From: Trei, Peter Reply To: Trei, Peter Sent: Thursday, September 07, 2000 10:06 AM To: cypherpunks@einstein.ssz.com; 'juzam' Subject: CDR: RE: Re: Permutations in DES

My understanding is that the initial permutation, (which essentially writes the 64 bits of key in a 8 x 8 block by column and row, ^ replace 'key' with 'data'. mea culpa -pt then reads it out by row and column) was included to simplify early DES chip hardware. It has no impact on the security of the algorithm. If you know what you are doing, it does not effect key agility in software implementations.

Peter Trei