From owner-cvs-all@FreeBSD.ORG  Mon Apr 12 21:50:26 2004
Return-Path: <owner-cvs-all@FreeBSD.ORG>
Delivered-To: cvs-all@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id B1F9D16A50B
	for <cvs-all@FreeBSD.org>; Mon, 12 Apr 2004 21:50:26 -0700 (PDT)
Received: from relay.pair.com (relay.pair.com [209.68.1.20])
	by mx1.FreeBSD.org (Postfix) with SMTP id 2761343D2D
	for <cvs-all@FreeBSD.org>; Mon, 12 Apr 2004 21:50:26 -0700 (PDT)
	(envelope-from silby@silby.com)
Received: (qmail 10651 invoked from network); 13 Apr 2004 04:50:24 -0000
Received: from niwun.pair.com (HELO localhost) (209.68.2.70)
  by relay.pair.com with SMTP; 13 Apr 2004 04:50:24 -0000
X-pair-Authenticated: 209.68.2.70
Date: Tue, 13 Apr 2004 01:07:22 -0500 (CDT)
From: Mike Silbersack <silby@silby.com>
To: Poul-Henning Kamp <phk@phk.freebsd.dk>
In-Reply-To: <5475.1081806410@critter.freebsd.dk>
Message-ID: <20040413010417.U11578@odysseus.silby.com>
References: <5475.1081806410@critter.freebsd.dk>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
cc: src-committers@FreeBSD.org
cc: cvs-src@FreeBSD.org
cc: cvs-all@FreeBSD.org
cc: David Malone <dwmalone@maths.tcd.ie>
cc: richardcoleman@mindspring.com
cc: Mark Murray <mark@grondar.org>
cc: Nate Lawson <nate@root.org>
Subject: Re: cvs commit: src/sys/modules/random Makefile src/sys/dev/random
 randomdev.h randomdev_soft.c randomdev_soft.h yar 
X-BeenThere: cvs-all@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: CVS commit messages for the entire tree <cvs-all.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-all>,
	<mailto:cvs-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/cvs-all>
List-Post: <mailto:cvs-all@freebsd.org>
List-Help: <mailto:cvs-all-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-all>,
	<mailto:cvs-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 13 Apr 2004 04:50:26 -0000


On Mon, 12 Apr 2004, Poul-Henning Kamp wrote:

> I therefore think that we should retain a crypto/yarrow afterburner
> on all random sources, but it may make sense to have offer different
> grades of random bits for performance reasons.
>
> --
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20

One thing that might make sense is to rename + wrap arc4random.  In
the TCP stack, we use arc4random because it's fast and good enough, not
because RC4 has some particular importance.  Therefore, if we instead
called arc4random fast_random, Mark could feed minimally processed
hardware entropy sources to fast_random, bypassing RC4 totally.

However, the question I have is this:  Is the C3's hardware PRNG actually
faster than RC4 by a margin significant enough to make such an
optimization worthwhile?

Mike "Silby" Silbersack