[3372] in cryptography@c2.net mail archive
Re: Fwd: Re: r.e. quality of IDEA...
daemon@ATHENA.MIT.EDU (Bill Sommerfeld)
Thu Sep 24 18:51:09 1998
To: Steve Bellovin <smb@research.att.com>
cc: perry@piermont.com, Rodney Thayer <rodney@tillerman.nu>,
cryptography@c2.net
In-reply-to: Your message of "Thu, 24 Sep 1998 16:16:02 -0400 ."
<199809242016.QAA01230@postal.research.att.com>
Date: Thu, 24 Sep 1998 17:00:52 -0400
From: Bill Sommerfeld <sommerfeld@orchard.arlington.ma.us>
While we're picking nits, I think the issue of key setup for DES (and
3DES) *hardware* is a red herring. As I recall, the per-round key
setup for DES is just a permutation & selection which, in hardware,
for the most part will only cost area, not time..
Presuming non-brain-dead hardware design, you still need to load the
56-bit key into the device every time you change keys, but that's
presumably not going to be too much more expensive than pushing packet
data into the device..
Your milage will vary for other ciphers.
- Bill
