From: Tudor Ambarus Subject: Re: [PATCH 0/6] Add support for ECDSA algorithm Date: Wed, 23 Aug 2017 16:40:55 +0300 Message-ID: References: <1484912161-5932-1-git-send-email-nkumbhar@nvidia.com> <20170123142417.GD19957@gondor.apana.org.au> <113d3ef8-ef34-0651-71e7-be09ef55727e@nvidia.com> <20170202135721.GA5289@gondor.apana.org.au> <87fcb3cf-b8ae-47de-550e-c76ae47af431@microchip.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Cc: Herbert Xu , Nitin Kumbhar , "David S. Miller" , Linux Crypto Mailing List To: Sandy Harris Return-path: Received: from esa5.microchip.iphmx.com ([216.71.150.166]:52324 "EHLO esa5.microchip.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754001AbdHWNlm (ORCPT ); Wed, 23 Aug 2017 09:41:42 -0400 In-Reply-To: Content-Language: en-US Sender: linux-crypto-owner@vger.kernel.org List-ID: Hi, Sandy, On 08/22/2017 08:22 PM, Sandy Harris wrote: > On Tue, Aug 22, 2017 at 12:14 PM, Tudor Ambarus > wrote: >> Hi, Herbert, >> >> On 02/02/2017 03:57 PM, Herbert Xu wrote: >>> >>> Yes but RSA had an in-kernel user in the form of module signature >>> verification. We don't add algorithms to the kernel without >>> actual users. So this patch-set needs to come with an actual >>> in-kernel user of ECDSA. >> >> >> ECDSA can be used by the kernel module signing facility too. Is there >> any interest in using ECDSA by the kernel module signing facility? > > I'd say keep it simple wherever possible; adding an algorithm should > need "is required by" not just "can be used by". > > Even then, there is room for questions. In particular, whether such a > fragile algorithm should be trusted at all, let alone for signatures > on infrastructure modules that the whole OS will trust. > https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm#Security > ECDSA is a better alternative to RSA for digital signatures assuming that you don't have implementation bugs. ECDSA requires a much smaller key length in order to provide the same security strength as RSA (see [1]): security strength | RSA key length (bits) | ECDSA key lengths (bits) 112 2048 224-255 128 3072 256-383 When comparing to RSA, ECDSA promises better computational efficiency, signature size and bandwith (see [2]). Cheers, ta [1] NIST.SP.800-57pt1r4, section 5.6.1, table 2 [2] rfc4754, rfc6979