IETF Logo Mail Archive

Re: [COSE] COSE Support for AES-CTR and AES-CBC

Carsten Bormann <cabo@tzi.org> Tue, 01 November 2022 10:40 UTC

Return-Path: <cabo@tzi.org>
X-Original-To: cose@ietfa.amsl.com
Delivered-To: cose@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id C60FBC14CE32 for <cose@ietfa.amsl.com>; Tue, 1 Nov 2022 03:40:39 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.209
X-Spam-Level:
X-Spam-Status: No, score=-4.209 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_ZEN_BLOCKED_OPENDNS=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([50.223.129.194]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id salQR0F7Sz7u for <cose@ietfa.amsl.com>; Tue, 1 Nov 2022 03:40:37 -0700 (PDT)
Received: from smtp.zfn.uni-bremen.de (smtp.zfn.uni-bremen.de [134.102.50.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 78E54C14F73E for <cose@ietf.org>; Tue, 1 Nov 2022 03:40:36 -0700 (PDT)
Received: from client-0198.vpn.uni-bremen.de (client-0198.vpn.uni-bremen.de [134.102.107.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.zfn.uni-bremen.de (Postfix) with ESMTPSA id 4N1mkn1nqYzDCct; Tue, 1 Nov 2022 11:40:33 +0100 (CET)
Content-Type: text/plain; charset="utf-8"
Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.120.23.2.7\))
From: Carsten Bormann <cabo@tzi.org>
In-Reply-To: <DBBPR08MB591506256FED669E6FC23ED5FA369@DBBPR08MB5915.eurprd08.prod.outlook.com>
Date: Tue, 01 Nov 2022 11:40:32 +0100
Cc: Sophie Schmieg <sschmieg=40google.com@dmarc.ietf.org>, "Arciszewski, Scott" <scottarc@amazon.com>, "Zundel, Brent" <brent.zundel@avast.com>, "cose@ietf.org" <cose@ietf.org>
X-Mao-Original-Outgoing-Id: 688992032.796303-43c55f4260b395d3d32c668514eefad9
Content-Transfer-Encoding: quoted-printable
Message-Id: <93D7CFD8-8526-4D99-896E-5FECF2ECF1B9@tzi.org>
References: <CAGi82uNOmJJdO2HKcE8M491Vv_PLgk8J8vvfsEE88CMZkmALmw@mail.gmail.com> <a69db82e96374a36b1f7164da3c5556e@amazon.com> <CAEEbLAZXLmvQbXkdqJcO2erQLVBic3gfuGPv8XRTSxZRiAaAvQ@mail.gmail.com> <6791A073-9A6D-4B9F-BE35-6C577C3D5CCC@tzi.org> <CAEEbLAab3jckpU1+9_tOZFsnPKt7G=cCpbLGK=QKHejem2VzGQ@mail.gmail.com> <DBBPR08MB591506256FED669E6FC23ED5FA369@DBBPR08MB5915.eurprd08.prod.outlook.com>
To: Hannes Tschofenig <Hannes.Tschofenig@arm.com>
X-Mailer: Apple Mail (2.3608.120.23.2.7)
Archived-At: <https://mailarchive.ietf.org/arch/msg/cose/fxazSkTWOF1qqIVrlgYzcC8p544>
Subject: Re: [COSE] COSE Support for AES-CTR and AES-CBC
X-BeenThere: cose@ietf.org
X-Mailman-Version: 2.1.39
Precedence: list
List-Id: CBOR Object Signing and Encryption <cose.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/cose>, <mailto:cose-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/cose/>
List-Post: <mailto:cose@ietf.org>
List-Help: <mailto:cose-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/cose>, <mailto:cose-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 01 Nov 2022 10:40:39 -0000

On 2022-11-01, at 11:29, Hannes Tschofenig <Hannes.Tschofenig@arm.com> wrote:
> 
> when you say “separating AEAD from unauthenticated encryption” are you referring to separating the storage of the tag from the encrypted ciphertext?

I actually meant separating it in the way COSE_Mac and COSE_Sign are separated in COSE, based on Sophie’s observation that separating Macs and Signatures provides some protection for these.  I was not sure, however, that this new separation would actually be useful.
Just an idea.

Grüße, Carsten

v2.23.0 | Report a Bug | By Email