From owner-freebsd-hackers Sun Oct 1 10:58:05 1995 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.6.12/8.6.6) id KAA20832 for hackers-outgoing; Sun, 1 Oct 1995 10:58:05 -0700 Received: from kryten.atinc.com (kryten.Atinc.COM [198.138.38.7]) by freefall.freebsd.org (8.6.12/8.6.6) with ESMTP id KAA20824 for ; Sun, 1 Oct 1995 10:57:55 -0700 Received: (jmb@localhost) by kryten.atinc.com (8.6.9/8.3) id NAA18370; Sun, 1 Oct 1995 13:50:24 -0400 Date: Sun, 1 Oct 1995 13:50:21 -0400 (EDT) From: "Jonathan M. Bresler" Subject: Re: How to get to the hardware? To: Mark Murray cc: Bruce Evans , hackers@freebsd.org, mark@grondar.za In-Reply-To: <199510011230.OAA04285@grumble.grondar.za> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-hackers@freebsd.org Precedence: bulk On Sun, 1 Oct 1995, Mark Murray wrote: > * The second function uses the inter-interrupt timing as random > * inputs to the entropy pool. Note that not all interrupts are good > * sources of randomness! For example, the timer interrupts is not a the interrupt from a network card, provided one is available and connected to an active segment, may be a very good choice of inter-interrupt time period randomness. if a net device is not available, the time between key strokes is another source. this time period is used as a source of random bits by pgp when generating key pairs. > * good choice, because the periodicity of the interrupts is to > * regular, and hence predictable to an attacker. Disk interrupts are > * a better measure, since the timing of the disk interrupts are more > * unpredictable. The routines try to estimate how many bits of > * randomness a particular interrupt channel offers, by keeping track > * of the first and second order deltas in the interrupt timings. > > BTW - would you be prepared to review this code before committal? i would like to see a copy ;) Jonathan M. Bresler jmb@kryten.atinc.com | Analysis & Technology, Inc. FreeBSD Postmaster jmb@FreeBSD.Org | 2341 Jeff Davis Hwy play go. | Arlington, VA 22202 ride bike. hack FreeBSD.--ah the good life | 703-418-2800 x346