From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEF69C433E1 for ; Fri, 15 May 2020 09:11:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 954862065C for ; Fri, 15 May 2020 09:11:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="ZmqiM4bI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727869AbgEOJLB (ORCPT ); Fri, 15 May 2020 05:11:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726922AbgEOJLA (ORCPT ); Fri, 15 May 2020 05:11:00 -0400 Received: from mo6-p02-ob.smtp.rzone.de (mo6-p02-ob.smtp.rzone.de [IPv6:2a01:238:20a:202:5302::11]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E181EC061A0C; Fri, 15 May 2020 02:10:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1589533857; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=5rOBFNRSIm8wOG/3ZTXTdyUjSY/V30dWRh3affiRjZo=; b=ZmqiM4bIncVzBB4IViZsPHc+iMbDAkEidtyCdmA6xmPNkxaCstxJne/PRDsvlrelaK dSLwRZwWfuEXE9pM+TKQjOrvt7g+N5d27qPVoPPRgOuptx7puheA/AH2J3AcWGvQkD0M CTzA6r6WvRTG0BUUfeTE+/BBGoV4UUl/UPMb/SDcGbziVT/HuLgTCWZdbwVmJ1S5SqMC FfW+cIoCZASVKDiAECFS2FfCAmpToN4G16Es16X4ZSLMPUPicgeRqcd29cZg3f2X+KZX dSSu0Pl48AfAj8ipZHIUbgSclgGO3XKdRnDysGHDieJ668xJVo6MHIwIifnnjusiDMWJ xnGA== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzGHXPaJfSc9C1S" X-RZG-CLASS-ID: mo00 Received: from tauon.chronox.de by smtp.strato.de (RZmta 46.6.2 DYNA|AUTH) with ESMTPSA id u08bf3w4F9Aj0s8 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 15 May 2020 11:10:45 +0200 (CEST) From: Stephan Mueller To: Lukasz Stelmach Cc: Matt Mackall , Herbert Xu , Arnd Bergmann , Greg Kroah-Hartman , Ray Jui , Scott Branden , bcm-kernel-feedback-list@broadcom.com, Kukjin Kim , Krzysztof Kozlowski , Florian Fainelli , Markus Elfring , Matthias Brugger , Stefan Wahren , linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org, Bartlomiej Zolnierkiewicz Subject: Re: [PATCH 1/2] hwrng: iproc-rng200 - Set the quality value Date: Fri, 15 May 2020 11:10:45 +0200 Message-ID: <3640422.T8yoyu11Ch@tauon.chronox.de> In-Reply-To: References: <4493123.C11H8YMYNy@tauon.chronox.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Am Freitag, 15. Mai 2020, 11:01:48 CEST schrieb Lukasz Stelmach: Hi Lukasz, As I mentioned, all that is or seems to be analyzed here is the quality of the cryptographic post-processing. Thus none of the data can be used for getting an idea of the entropy content. That said, the ent value indeed looks too low which seems to be an issue in the tool itself. Note, for an entropy assessment commonly at least 1 million traces from the raw noise source are needed. See for examples on how such entropy assessments are conducted in the LRNG documentation [1] or the Linux /dev/random implementation in [2] [1] appendix C of https://www.chronox.de/lrng/doc/lrng.pdf [2] chapter 6 of https://www.bsi.bund.de/SharedDocs/Downloads/EN/BSI/ Publications/Studies/LinuxRNG/LinuxRNG_EN.pdf Ciao Stephan