From: Stephan =?ISO-8859-1?Q?M=FCller?= Subject: Re: [PATCH v3 1/3] crypto: hw_random - Add new Exynos RNG driver Date: Tue, 28 Mar 2017 19:41:47 +0200 Message-ID: <93183073.lKE0KLq0vu@tauon.atsec.com> References: <20170325162654.3827-1-krzk@kernel.org> <1564458.pWTRdRYEuG@positron.chronox.de> <20170328164824.3qjaojqzf2riwpqj@kozik-lap> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Cc: PrasannaKumar Muralidharan , Kukjin Kim , Javier Martinez Canillas , Matt Mackall , Herbert Xu , "David S. Miller" , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-crypto@vger.kernel.org, Bartlomiej Zolnierkiewicz , Arnd Bergmann , Olof Johansson To: Krzysztof Kozlowski Return-path: Received: from mail.eperm.de ([89.247.134.16]:58648 "EHLO mail.eperm.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752080AbdC1Rly (ORCPT ); Tue, 28 Mar 2017 13:41:54 -0400 In-Reply-To: <20170328164824.3qjaojqzf2riwpqj@kozik-lap> Sender: linux-crypto-owner@vger.kernel.org List-ID: Am Dienstag, 28. M?rz 2017, 18:48:24 CEST schrieb Krzysztof Kozlowski: Hi Krzysztof, > I tested a little bit and: > 1. Seeding with some value > 2. generating random, > 3. kcapi_rng_destroy+kcrng_init, (I cannot do a hardware reset except > reboot of entire system) > 4. seeding with the same value as in (1) - different random numbers. > > Doing a system reboot and repeating above - different random numbers > (all are different: step (2) and in (4)). > > Your test case also produces different random values every time. Then I would assume that simply adding an outer loop to your for() loop to inject seed larger than the minimum required seed size should be fine. > > Best regards, > Krzysztof Ciao Stephan