Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265523AbTF2CWA (ORCPT ); Sat, 28 Jun 2003 22:22:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265524AbTF2CWA (ORCPT ); Sat, 28 Jun 2003 22:22:00 -0400 Received: from h80ad25cd.async.vt.edu ([128.173.37.205]:17025 "EHLO turing-police.cc.vt.edu") by vger.kernel.org with ESMTP id S265523AbTF2CV7 (ORCPT ); Sat, 28 Jun 2003 22:21:59 -0400 Message-Id: <200306290236.h5T2a5Gk004076@turing-police.cc.vt.edu> X-Mailer: exmh version 2.6.3 04/04/2003 with nmh-1.0.4+dev To: Justin Pryzby Cc: "Luca T." , linux-kernel@vger.kernel.org Subject: Re: /dev/random broken? In-Reply-To: Your message of "Sat, 28 Jun 2003 19:10:18 PDT." <20030629021018.GA26162@andromeda> From: Valdis.Kletnieks@vt.edu References: <20030629021018.GA26162@andromeda> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1681803940P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Sat, 28 Jun 2003 22:36:04 -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1448 Lines: 36 --==_Exmh_1681803940P Content-Type: text/plain; charset=us-ascii On Sat, 28 Jun 2003 19:10:18 PDT, Justin Pryzby said: > /dev/urandom is what you want; it makes up its own entropy. /dev/random > uses entropy from user input (low order bits I imagine). Strictly speaking, urandom doesn't "make up" any entropy - it generates a pseudorandom stream of bits of arbitrary length using a small chunk of entropy from the entropy pool. That's why it's able to generate multi-megabyte streams of bits even when the entropy pool is empty - it is generating a fixed but unpredictable stream based on the initial entropy. The distinction is important mostly to cryptographers - for almost all practical uses, the pseudorandom stream of bits produced by urandom is quite sufficient, much faster, and leaves the entropy pool untouched for those applications that *do* care about the difference.... --==_Exmh_1681803940P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iD8DBQE+/lCUcC3lWbTT17ARAq9pAJ91EWCX4Qs6tL0ISLBd3BSUM2XGrQCg7+I/ +6OnTN6xUMzeYBLuqT+uSsM= =e6ko -----END PGP SIGNATURE----- --==_Exmh_1681803940P-- - 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/