IETF Logo Mail Archive

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

Russ Housley <housley@vigilsec.com> Tue, 01 November 2022 16:39 UTC

Return-Path: <housley@vigilsec.com>
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 A2798C1524A8 for <cose@ietfa.amsl.com>; Tue, 1 Nov 2022 09:39:18 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.909
X-Spam-Level:
X-Spam-Status: No, score=-1.909 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_BLOCKED=0.001, RCVD_IN_ZEN_BLOCKED_OPENDNS=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 suhJVCNvWPBb for <cose@ietfa.amsl.com>; Tue, 1 Nov 2022 09:39:17 -0700 (PDT)
Received: from mail3.g24.pair.com (mail3.g24.pair.com [66.39.134.11]) (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 C101AC1522CA for <cose@ietf.org>; Tue, 1 Nov 2022 09:39:17 -0700 (PDT)
Received: from mail3.g24.pair.com (localhost [127.0.0.1]) by mail3.g24.pair.com (Postfix) with ESMTP id 9ED6BCAB8D; Tue, 1 Nov 2022 12:39:16 -0400 (EDT)
Received: from [10.0.1.2] (pfs.iad.rg.net [198.180.150.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail3.g24.pair.com (Postfix) with ESMTPSA id 7A696CAB8C; Tue, 1 Nov 2022 12:39:16 -0400 (EDT)
Content-Type: text/plain; charset="utf-8"
Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.21\))
From: Russ Housley <housley@vigilsec.com>
In-Reply-To: <93D7CFD8-8526-4D99-896E-5FECF2ECF1B9@tzi.org>
Date: Tue, 01 Nov 2022 12:39:15 -0400
Cc: Hannes Tschofenig <Hannes.Tschofenig@arm.com>, 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>
Content-Transfer-Encoding: quoted-printable
Message-Id: <62258369-1D53-4996-8868-FA77723E5CE1@vigilsec.com>
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> <93D7CFD8-8526-4D99-896E-5FECF2ECF1B9@tzi.org>
To: Carsten Bormann <cabo@tzi.org>
X-Mailer: Apple Mail (2.3445.104.21)
X-Scanned-By: mailmunge 3.10 on 66.39.134.11
Archived-At: <https://mailarchive.ietf.org/arch/msg/cose/siNlLSw1nTzwi0J11epA2MXI7_g>
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 16:39:18 -0000


> On Nov 1, 2022, at 6:40 AM, Carsten Bormann <cabo@tzi.org> wrote:
> 
> 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.


I'm trying to see how the recipient would find this helpful.  It is just another value that would need to be adjusted by the attacker to mount the attacks that Sophie is sharing.

Russ

v2.23.0 | Report a Bug | By Email