From: Pavel Machek Subject: Re: random(4) changes Date: Tue, 26 Apr 2016 20:44:39 +0200 Message-ID: <20160426184439.GA8162@amd> References: <20160424020323.GD20980@thunk.org> <5435493.2Hi9JfvD3o@positron.chronox.de> <20160426030735.GD28496@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Theodore Ts'o , Stephan Mueller , Sandy Harris , LKML , linux-crypto@vger.kernel.org, Jason Cooper , John Denker , "H. Peter Anvin" , Andi Kleen Return-path: Content-Disposition: inline In-Reply-To: <20160426030735.GD28496@thunk.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org Hi1 > > When dropping the add_disk_randomness function in the legacy /dev/random, I > > would assume that without changes to add_input_randomness and > > add_interrupt_randomness, we become even more entropy-starved. > > Sure, but your system isn't doing anything magical here. The main > difference is that you assume you can get almost a full bit of entropy > out of each interrupt timing, where I'm much more conservative and > assume we can only get 1/64th of a bit out of each interrupt timing. Maybe 1/64th of a bit is a bit too conservative? I guess we really have more than one bit of entropy on any system with timestamp counter.... Making it 1/2 of bit (or something) should be very easy way to improve entropy early during boot... Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html