From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 66855208AD; Wed, 17 Dec 2025 04:06:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765944386; cv=none; b=qev33vj2ISXO9aeuQTKhWGL2DRO37OFAoRP7KUHXXVTavpur48qtsU4sGAE005DY0g6NNxGc8ykP4JfXl7ZKgHXr2HYLStiaGbakwREdxwrKe69QQ3CI4DjvEetOPlzpkvSeqd57FG/rOw4XP9X3WqogpO2aDMzWyOp6H2ikNTw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765944386; c=relaxed/simple; bh=svnVq++62g6Y0qGIL55PBs0FZANDiwaNI4K1ooLLj8A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cZ3ynmRtWhRjtpcg95hxPkFqODDHd83witHalr56EMebgXM3TB6xiB/vlD//jCCntf0SnNGy0H511lYztSVUrJfJxJ9vSIISkvrZF2BQhV1qIqxtSjs+4IfcHQ0DslMZ5I8TIniswnnblL3DipmrvYbXIne1AXu9V0shlN8S0sQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cVuWqMZB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cVuWqMZB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AD129C4CEFB; Wed, 17 Dec 2025 04:06:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765944385; bh=svnVq++62g6Y0qGIL55PBs0FZANDiwaNI4K1ooLLj8A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cVuWqMZBXI7iNA1mYolP0sdAehNt6bsAtT61YlPFK4aj6ab4MI/+x+a/uOgf+ZvkC pc4mJXEzYAqOkyoucUjIC1+0p0sm0V0zgPMooH51ZWmcRcvQiUo43sbwxSTDyPIOnd z6p9DoeHF2vdiR5N9efBZxFmtzHwFuAp2AVap0Du2qwq1vINql1Hcq/qVfuO/8tzKw y7EDMBVOVLXhmxfwcUPy32nixETQMNjzVft7zstyVjVYPoYgIW/1XV4b9Ng7vYM1Fi R3uPME5C7AWJxbdo9hnHb93NVbFUQgJI6mb/lrpxbVPx0WCVRZkDuqSYr1fq9GKTPs Qsl2/2yQzzprQ== Date: Tue, 16 Dec 2025 20:06:17 -0800 From: Eric Biggers To: "Rusydi H. Makarim" Cc: Herbert Xu , "David S. Miller" , "Jason A. Donenfeld" , Ard Biesheuvel , linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org Subject: Re: [PATCH 0/3] Implementation of Ascon-Hash256 Message-ID: <20251217040617.GA3424@sol> References: <20251215-ascon_hash256-v1-0-24ae735e571e@kriptograf.id> <20251215201932.GC10539@google.com> <7920c742b3be0723119e19e323dc92bc@kriptograf.id> <20251216180245.GD10539@google.com> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Dec 17, 2025 at 10:33:22AM +0700, Rusydi H. Makarim wrote: > On 2025-12-17 01:02, Eric Biggers wrote: > > On Tue, Dec 16, 2025 at 01:27:17PM +0700, Rusydi H. Makarim wrote: > > > While no direct in-kernel use as of now > > > > Thanks for confirming. We only add algorithms when there is a real > > user, so it's best to hold off on this for now. > > > > - Eric > > Rather than leaving this work idle, would it be better to move the > implementation entirely into the Crypto API ? No, that's actually the most problematic part because it would put it in the name-based registry and become impossible to change later. There's a large maintenance cost to supporting algorithms. We've learned this the hard way. In the past the requirements to add new algorithms to the kernel were much more relaxed, and as a result, the Linux kernel community has ended up wasting lots of time maintaining unused, unnecessary, or insecure code. Just recently I removed a couple algorithms (keywrap and vmac). Looking back in more detail, there was actually never any use case presented for their inclusion, and they were never used. So all the effort spent reviewing and maintaining that code was just wasted. We could have just never added them in the first place and saved tons of time. So this is nothing about Ascon not being a good algorithm, but rather we're just careful about adding unused code, as we don't want to repeat past mistakes. And as you've made clear, currently you'd like to add the algorithm just for its own sake and there is no planned user -- which is concerning. I'm not sure if this is a school project or what not, but we don't really do that, sorry. There has to be a clear technical justification with an in-kernel use case. - Eric