From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from resdmta-h1p-028597.sys.comcast.net (resdmta-h1p-028597.sys.comcast.net [IPv6:2001:558:fd02:2446::d]) by sourceware.org (Postfix) with ESMTPS id CC8713858D33 for ; Wed, 15 Feb 2023 22:12:01 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org CC8713858D33 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=comcast.net Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=comcast.net Received: from resomta-h1p-028515.sys.comcast.net ([96.102.179.209]) by resdmta-h1p-028597.sys.comcast.net with ESMTP id SGKMp1Lxqe8GwSQ0MpvcjU; Wed, 15 Feb 2023 22:11:58 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=20190202a; t=1676499118; bh=BEWybV+7K1rknYR8IzFJxKhzj6tmYykB5uEVVDhA8JA=; h=Received:Received:Content-Type:Mime-Version:Subject:From:Date: Message-Id:To:Xfinity-Spam-Result; b=nssk9MGGWWHVDuR8cjJtpDtfLHEWhavD2aynqhSlgtBdrWe1VkdKlP+nQfY/rgYzK 538r59wsJBYqDCBXARb36YO8GM3jUu50Vx7cSiPBMwfdcJCUaDrayGMQ+czW0SS/b1 aR+QSjLOHq1/QyUewUGini7zzHoU3PG5Mq2nQw2qF/9nKKYKw07DMW2ZSwhywggduI WlB49WDluFHOLIktvvcVuYR+EhJq/NUN2IZChRquASTawrW+3FiVb9njkO4qWZTV7h 2Q783a9rgMoGifqS9D7ZFflz3e2pEBH4BZ2Kv+3A/8xLy5u4JWqJ6UDbe3ANUReiqU UqfFxBwgO5mtQ== Received: from smtpclient.apple ([73.60.223.101]) by resomta-h1p-028515.sys.comcast.net with ESMTPSA id SQ0IpHCZ9loZnSQ0JprFhK; Wed, 15 Feb 2023 22:11:58 +0000 X-Xfinity-VAAS: gggruggvucftvghtrhhoucdtuddrgedvhedrudeihedgudehudcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucevohhmtggrshhtqdftvghsihdpqfgfvfdppffquffrtefokffrnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpegtggfuhfgjffevgffkfhfvofesthhqmhdthhdtvdenucfhrhhomheprfgruhhlucfmohhnihhnghcuoehprghulhhkohhnihhnghestghomhgtrghsthdrnhgvtheqnecuggftrfgrthhtvghrnhepveekveelffeliefgiedufeehgeejtdfhgedujeehueekiedtgfetffevgffggfdvnecukfhppeejfedriedtrddvvdefrddutddunecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehhvghlohepshhmthhptghlihgvnhhtrdgrphhplhgvpdhinhgvthepjeefrdeitddrvddvfedruddtuddpmhgrihhlfhhrohhmpehprghulhhkohhnihhnghestghomhgtrghsthdrnhgvthdpnhgspghrtghpthhtohepfedprhgtphhtthhopegsihhnuhhtihhlshesvghmrghgihhirdgtohhmpdhrtghpthhtohepnhhitghktgesrhgvughhrghtrdgtohhmpdhrtghpthhtohepsghinhhuthhilhhssehsohhurhgtvgifrghrvgdrohhrgh X-Xfinity-VMeta: sc=-100.00;st=legit Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.2\)) Subject: Re: RFC: generating a header using the linker (CRC calculation) From: Paul Koning In-Reply-To: <3D8C014D-966D-4129-82AC-AA04593A1F6B@emagii.com> Date: Wed, 15 Feb 2023 17:11:54 -0500 Cc: Nick Clifton , binutils@sourceware.org Content-Transfer-Encoding: quoted-printable Message-Id: <0BDE213A-C146-4BC7-92B7-064D32F9CBB2@comcast.net> References: <8511B960-E529-47FB-9B17-55F666B58EE7@comcast.net> <3D8C014D-966D-4129-82AC-AA04593A1F6B@emagii.com> To: Ulf Samuelsson X-Mailer: Apple Mail (2.3696.120.41.1.2) X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,SPF_HELO_PASS,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: > On Feb 15, 2023, at 5:08 PM, Ulf Samuelsson = wrote: >=20 > The AUTOSARS says CRC-64 ECMA. > It is also popular in Linux. > I have not seen anyone using SHA algorithms or MD5 in any embedded = project I have worked with to verify the flash contents. I'm not sure I have on anything I worked on, but it's how one would do = cryptographic integrity (for example, signed code) when = tamper-resistance is required. It's more likely to show up as a = signature on an update kit, which would prevent the installation of = false updates. > My proposed implementation would make it easy to use the ISO or ECMA = variants, but also allow a user defined polynom. That's certainly useful, so long as it is understood that CRC provides = no protection whatsoever against deliberate tampering. paul