Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755421AbXLKTqt (ORCPT ); Tue, 11 Dec 2007 14:46:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753019AbXLKTqm (ORCPT ); Tue, 11 Dec 2007 14:46:42 -0500 Received: from iriserv.iradimed.com ([72.242.190.170]:4309 "EHLO iradimed.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752113AbXLKTql (ORCPT ); Tue, 11 Dec 2007 14:46:41 -0500 Message-ID: <475EE920.7000108@cfl.rr.com> Date: Tue, 11 Dec 2007 14:46:40 -0500 From: Phillip Susi User-Agent: Thunderbird 2.0.0.9 (Windows/20071031) MIME-Version: 1.0 To: Theodore Tso , Matt Mackall , Marc Haber , Eric Dumazet , Alan Cox , Adrian Bunk , linux-kernel@vger.kernel.org, David.S.Mille@vax.1wt.eu Illegal-Object: Syntax error in To: address found on vger.kernel.org: To: David S.Mille ^ ^-missing end of address \-extraneous tokens in address Illegal-Object: Syntax error in To: address found on vger.kernel.org: To: David S.Mille ^ ^-missing end of address \-extraneous tokens in address Subject: Re: Why does reading from /dev/urandom deplete entropy so much? References: <20071204114125.GA17310@torres.zugschlus.de> <20071204161811.GB15974@stusta.de> <20071204164720.6e4dc2c4@the-village.bc.nu> <475599D6.4030008@cosmosbay.com> <20071205212646.GP17536@waste.org> <20071209124200.GA31147@torres.zugschlus.de> <20071209161605.G <20071211013414.GS17037@thunk.org> In-Reply-To: <20071211013414.GS17037@thunk.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 11 Dec 2007 19:46:53.0085 (UTC) FILETIME=[94186CD0:01C83C2E] X-TM-AS-Product-Ver: SMEX-7.5.0.1243-5.0.1023-15600.000 X-TM-AS-Result: No--13.737600-5.000000-2 X-TM-AS-User-Approved-Sender: No X-TM-AS-User-Blocked-Sender: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 852 Lines: 18 Theodore Tso wrote: > Note that even paranoid applicatons should not be using /dev/random > for session keys; again, /dev/random isn't magic, and entropy isn't > unlimited. Instead, such an application should pull 16 bytes or so, > and then use it to seed a cryptographic random number generator. What good does using multiple levels of RNG do? Why seed one RNG from another? Wouldn't it be better to have just one RNG that everybody uses? Doesn't the act of reading from the RNG add entropy to it, since no one reader has any idea how often and at what times other readers are stirring the pool? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/