From owner-freebsd-current@FreeBSD.ORG Thu Aug 5 07:36:01 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id EBFFD16A4CE; Thu, 5 Aug 2004 07:36:01 +0000 (GMT) Received: from storm.FreeBSD.org.uk (storm.FreeBSD.org.uk [194.242.157.42]) by mx1.FreeBSD.org (Postfix) with ESMTP id 66F5843D2F; Thu, 5 Aug 2004 07:36:01 +0000 (GMT) (envelope-from mark@grondar.org) Received: from storm.FreeBSD.org.uk (Ugrondar@localhost [127.0.0.1]) i757ZRVH000749; Thu, 5 Aug 2004 08:35:27 +0100 (BST) (envelope-from mark@grondar.org) Received: (from Ugrondar@localhost)i757ZRxe000748; Thu, 5 Aug 2004 08:35:27 +0100 (BST) (envelope-from mark@grondar.org) X-Authentication-Warning: storm.FreeBSD.org.uk: Ugrondar set sender to mark@grondar.org using -f Received: from grondar.org (localhost [127.0.0.1])i757XiGC053052; Thu, 5 Aug 2004 08:33:44 +0100 (BST) (envelope-from mark@grondar.org) From: Mark Murray Message-Id: <200408050733.i757XiGC053052@grimreaper.grondar.org> To: Sam Leffler In-Reply-To: Your message of "Wed, 04 Aug 2004 21:39:52 PDT." <200408042139.52577.sam@errno.com> Date: Thu, 05 Aug 2004 08:33:44 +0100 Sender: mark@grondar.org X-Mailman-Approved-At: Thu, 05 Aug 2004 13:47:15 +0000 cc: markm@FreeBSD.ORG cc: freebsd-current@FreeBSD.ORG cc: Robert Watson Subject: Re: So much entropy it's coming out of our ears? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 05 Aug 2004 07:36:02 -0000 Sam Leffler writes: > Virtually all performance-sensitive installations will disable entropy > gathering through fast paths. I've suggested for a long time that this sort > of collection should be enabled only under dire circumstances and never by > default. Regardless the last time I looked at the entropy harvesting it used > a model where entropy was unilateraly sent for harvest and discarded when too > plentiful. I term this the "push model". I've advocated a "pull model" > where the PRNG requests entropy when a low water mark is hit and/or a hybrid > scheme where producers have some sort of flow control or feedback mechanism. Yarrow is not conducive to "water-mark" type flow-control, but I'm looking at replacing Yarrow with Fortuna (code at an advanced stage). This should improve things all-round. > Everything that goes on inside the PRNG is a separate issue. *nod* M -- Mark Murray iumop ap!sdn w,I idlaH