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=-5.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 AE334C433DF for ; Thu, 14 May 2020 20:20:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8469720675 for ; Thu, 14 May 2020 20:20:49 +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="RqNivGnk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726073AbgENUUt (ORCPT ); Thu, 14 May 2020 16:20:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726035AbgENUUs (ORCPT ); Thu, 14 May 2020 16:20:48 -0400 Received: from mo6-p01-ob.smtp.rzone.de (mo6-p01-ob.smtp.rzone.de [IPv6:2a01:238:20a:202:5301::6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DFBCBC061A0C; Thu, 14 May 2020 13:20:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1589487643; 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=5qEHN9Aos9wJSmrSmHepYAI40f0iVUfr9ovzdP/JcuY=; b=RqNivGnkFF0hqbR9whm7bRNPlxdKtUaxIvYKZ922smuep0hBkRRh1znY6a6BeKDVKO pxWhYVd+Z2A8uvNKlN+c/1yB9Z+82trSIdPNex8c4DKZS8D2mV9RoTWMfXU7mJxvzumN XO2fGM1kJwzCoogMEFHPeHCuVTZAJAqY7tZttrWudM8xedjWPS6hdXPeTZvP4jy/V/9v 7TLRYqBHhDP1P5ZT1Bb2TYllsR+PJbpVjnj3fwd/EkTSKRq9ial+NPwHAaYKRxM1p/2R wQcCBe8byuh61fbbcwyqvkJMZuDMeze7+9Pte+h8YshZEcnyR1ZCMzpFqTo1G2NscyCf X6BQ== 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 u08bf3w4EKKQxtG (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Thu, 14 May 2020 22:20:26 +0200 (CEST) From: Stephan Mueller To: =?utf-8?B?xYF1a2Fzeg==?= 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: Thu, 14 May 2020 22:20:26 +0200 Message-ID: <4493123.C11H8YMYNy@tauon.chronox.de> In-Reply-To: <20200514190734.32746-2-l.stelmach@samsung.com> References: <20200514190734.32746-1-l.stelmach@samsung.com> <20200514190734.32746-2-l.stelmach@samsung.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="UTF-8" Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Am Donnerstag, 14. Mai 2020, 21:07:33 CEST schrieb =C5=81ukasz Stelmach: Hi =C5=81ukasz, > The value has been estimaded by obtainig 1024 chunks of data 128 bytes > (1024 bits) each from the generator and finding chunk with minimal > entropy using the ent(1) tool. The value was 6.327820 bits of entropy > in each 8 bits of data. I am not sure we should use the ent tool to define the entropy level. Ent=20 seems to use a very coarse entropy estimation. I would feel more comfortable when using other measures like SP800-90B whic= h=20 even provides a tool for the analysis. I understand that entropy estimates, well, are estimates. But the ent data = is=20 commonly not very conservative. [1] https://github.com/usnistgov/SP800-90B_EntropyAssessment Ciao Stephan