From owner-freebsd-current Fri Jul 21 9:51:57 2000 Delivered-To: freebsd-current@freebsd.org Received: from cypherpunks.ai (cypherpunks.ai [209.88.68.47]) by hub.freebsd.org (Postfix) with ESMTP id 8371737BBBA; Fri, 21 Jul 2000 09:51:50 -0700 (PDT) (envelope-from jeroen@vangelderen.org) Received: from vangelderen.org (grolsch.ai [209.88.68.214]) by cypherpunks.ai (Postfix) with ESMTP id A158152; Fri, 21 Jul 2000 12:51:48 -0400 (AST) Message-ID: <39787FA4.A79BAE0B@vangelderen.org> Date: Fri, 21 Jul 2000 12:51:48 -0400 From: "Jeroen C. van Gelderen" X-Mailer: Mozilla 4.73 [en] (X11; I; Linux 2.2.12 i386) X-Accept-Language: en MIME-Version: 1.0 To: Mark Murray Cc: Kris Kennaway , current@FreeBSD.ORG Subject: Re: randomdev entropy gathering is really weak References: <200007211253.OAA00377@grimreaper.grondar.za> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Mark Murray wrote: > > > > What about saving the state of the RNG and re-reading it on bootup? That > > > will allow Yarrow to continue right where it left off. :-) > > > > That's a bad thing. You don't want someone to be able to examine the exact > > PRNG state at next boot by looking at your hard disk after the machine has > > shut down. > > It is a Yarrow-mandated procedure. Please read the Yarrow paper. Actually, it's not. You don not want to save the exact PRNG state to disk, ever. It's not Yarrow mandated procedure but a big security hole. That said, you do not write out the state of the PRNG, you write out a couple of blocks of output from which the state cannot be derived. That *is* okay and that's what you are doing. And just for completeness: it's not mandatory to do so. I don't know where you read that in the paper. > If they can do that, they have either the console (==root) or they have > root. Either way, who cares what they know about your machine, they have > the whole darn thing :-O. Someone may well compromise your randomness source without you noticing. And read your PGP mail for the coming couple of years because your PGP key was compromised without you noticing. Perfect Trojan horse to write for the FBI, IRS, anyone who doesn't like you. Oops. Cheers, Jeroen -- Jeroen C. van Gelderen o _ _ _ jeroen@vangelderen.org _o /\_ _ \\o (_)\__/o (_) _< \_ _>(_) (_)/<_ \_| \ _|/' \/ (_)>(_) (_) (_) (_) (_)' _\o_ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message