From owner-freebsd-current Sat Jul 22 23:54:20 2000 Delivered-To: freebsd-current@freebsd.org Received: from shell.webmaster.com (ftp.webmaster.com [209.10.218.74]) by hub.freebsd.org (Postfix) with ESMTP id 62DD137B5BD for ; Sat, 22 Jul 2000 23:54:14 -0700 (PDT) (envelope-from davids@webmaster.com) Received: from whenever ([216.152.68.2]) by shell.webmaster.com (Post.Office MTA v3.5.3 release 223 ID# 0-12345L500S10000V35) with SMTP id com; Sat, 22 Jul 2000 23:53:15 -0700 From: "David Schwartz" To: "Mark Murray" Cc: Subject: RE: randomdev entropy gathering is really weak Date: Sat, 22 Jul 2000 23:53:48 -0700 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2911.0) In-Reply-To: <200007221939.VAA37028@grimreaper.grondar.za> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6700 Importance: Normal Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > > /dev/random should block if the system does not contain as much > real entropy > > as the reader desires. Otherwise, the PRNG implementation will be the > > weakest link for people who have deliberately selected higher levels of > > protection from cryptographic attack. > I don't want to rehash this thread from the beginning. Please go > back, read the Yarrow paper, and recognise that Yarrow is not an > entropy-counter, it is a cryptographically secure PRNG. The "count > random bits and block" model does not apply. Then the current implementation cannot provide the usual semantics for /dev/random, while it can provide the semantics for /dev/urandom. As I understand it, /dev/random is supposed to provide true randomness suitable for generating keys of unlimited length, whereas /dev/urandom is supposed to provide cryptographically-strong randomness for general applications. If people want /dev/random to seed 1024-bit keys, /dev/random must be stronger than a 1024-bit key. DS To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message