Re: QUIC-LB update: Eliminate block ciphers?

Martin Duke <martin.h.duke@gmail.com> Wed, 06 October 2021 23:28 UTC

Return-Path: <martin.h.duke@gmail.com>
X-Original-To: quic@ietfa.amsl.com
Delivered-To: quic@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 1DAD73A0A41 for <quic@ietfa.amsl.com>; Wed, 6 Oct 2021 16:28:18 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.097
X-Spam-Level:
X-Spam-Status: No, score=-2.097 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id sceoapQ8SnKp for <quic@ietfa.amsl.com>; Wed, 6 Oct 2021 16:28:12 -0700 (PDT)
Received: from mail-ua1-x933.google.com (mail-ua1-x933.google.com [IPv6:2607:f8b0:4864:20::933]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id BBFE63A0A3D for <quic@ietf.org>; Wed, 6 Oct 2021 16:28:12 -0700 (PDT)
Received: by mail-ua1-x933.google.com with SMTP id e7so2949625ual.11 for <quic@ietf.org>; Wed, 06 Oct 2021 16:28:12 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=XnG2JFwfgT+ZEpE8l7hSQQO+pBWkuNWuuW8BKoUhM8Q=; b=C6ASXuhPfiVPhefwt/eoz/XhySBZeGSgbRGIKvJFlE1NdVEcyPIms+6Py0oak3hMU7 4r6Kj1zlnqYNcYqjcsWYVTccsfmlK4VzEmj9uGrQKRKeTA6bmYbGr2zO9zhPrJXED8wx FHohFkGfKD9aLK1XI8TnOXCrEq4rWm9j6QMii5vfoA+vWbFg77HCucFvROYoY33YADtT esm8f4mPRZ2oZ4GbTLZL+7N03GI1cAx6sBmZCvelXjtd8H+km35dIuj62NBKhXpjsoHu YTmBi+8+iuo2Mvjc3Sxf34KyoLiDHs424LTmhzXNfmAkFONLFT1fna3w50jBNhqSumus oJFQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=XnG2JFwfgT+ZEpE8l7hSQQO+pBWkuNWuuW8BKoUhM8Q=; b=za+VFPbzewdW4phXZDBybvxstKlT0F0vEL+HKlWwMaDdOu9UEhtH1C7culHUTZLB04 SVumVLdEFqZUPPq1LHCpGAkXNGHaJgpN0Psf+igbZ0LfSLCOne2Yw8jYWersBiXmzt7J c2NC9P92nISuWpPNe4Z/cTMBejUAGf+J1T5dvBxxmORt8N8/UtdBvHzqv7VmzhwB6P6g ZhMbJXMv4wLpnXQr3EpCbB+3lpvpE5SFgzP9muRT1z7d8kxK/10Ap7qLB+/jFX+V4FzE 3J/3zPWOXv9m4laGu633nDz8/LzMwMhmY+Th022XELOua7ttRi/0FhfcpYXGFvASHSuK yPBQ==
X-Gm-Message-State: AOAM530wiop+SHousykLg3l9eUNZm8hY77y8OtVInBOL344+0CFjTNhg S3kF/ZD5df1BLftpGurcgPPs8y0u1+APyXpejEZlMncArqU=
X-Google-Smtp-Source: ABdhPJxrkSJCGz1mGWTJdrvDKgzXszzBqdxvSBXwMLX8rNjcsEYAdpinpxgzrZ6y24ZSCGCvTE7EOF+BwwvWc431rn0=
X-Received: by 2002:ab0:2095:: with SMTP id r21mr1418796uak.55.1633562891737; Wed, 06 Oct 2021 16:28:11 -0700 (PDT)
MIME-Version: 1.0
References: <CAM4esxT=QrJBaPsmK-6dXV+WUYn+tiHUEk_PpJu9L_agdU4EtQ@mail.gmail.com> <6f4f125359b247f588c8a74eb7ebfa1a@huawei.com> <CAKcm_gNRmKEDninEbHd6L_Jf7qJRBOvh5q2VyQT4FFabnDKL6g@mail.gmail.com> <CAM4esxQ7oUb2k3HKs21gUy15FxDr3wMDPH4EyR8FkX8q+a9A3Q@mail.gmail.com> <CAMm+Lwg2Ds=MdKXcry-ukRjc3nSjXy4XHXFdBU8eJP9S9xOchg@mail.gmail.com> <4c53f268-3d1b-562c-da5b-9973737464dc@huitema.net> <3ca56d7b-072e-4206-be10-c7732d796d36@www.fastmail.com> <CAMm+LwjazawphkGCAEeWKonfJrWdmc2mNBUPgeCrytzA1GA0Cg@mail.gmail.com>
In-Reply-To: <CAMm+LwjazawphkGCAEeWKonfJrWdmc2mNBUPgeCrytzA1GA0Cg@mail.gmail.com>
From: Martin Duke <martin.h.duke@gmail.com>
Date: Wed, 6 Oct 2021 16:27:59 -0700
Message-ID: <CAM4esxTEHgzbS-6cOW7bh-9WN5LUsBLZqK9Sf1U1kdoMvz9eig@mail.gmail.com>
Subject: Re: QUIC-LB update: Eliminate block ciphers?
To: Phillip Hallam-Baker <phill@hallambaker.com>
Cc: Martin Thomson <mt@lowentropy.net>, IETF QUIC WG <quic@ietf.org>
Content-Type: multipart/alternative; boundary="000000000000e15d5605cdb77f25"
Archived-At: <https://mailarchive.ietf.org/arch/msg/quic/a8hwzGcAlJOT6oftxU6PlcJGEx4>
X-BeenThere: quic@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Main mailing list of the IETF QUIC working group <quic.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/quic>, <mailto:quic-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/quic/>
List-Post: <mailto:quic@ietf.org>
List-Help: <mailto:quic-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/quic>, <mailto:quic-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 06 Oct 2021 23:28:18 -0000

If the Block Cipher goes away, this will simply be the "encrypted" method.
No need to bikeshed the name for now.

On Wed, Oct 6, 2021 at 4:21 PM Phillip Hallam-Baker <phill@hallambaker.com>
wrote:

> I think this is a different cryptographic construct and we should create a
> name for the generic. Something like Keyed Permutation.
>
> Rather than bikeshed the name here, I propose taking it to either CFRG or
> the Cryptography list (or both) to socialize the concept. It is quite
> possible that there is a prior nomenclature we should follow.
>
>
> It is not clear to me what the precise security properties required here
> are. For my particular application, they are fairly weak because I am only
> providing some traffic analysis resistance. I am not interested in
> plaintext recovery attack, but I do care about the attacker being able to
> discover that E(n), E(N+1) are a sequence.
>
> None of my systems are going to collapse if this primitive is broken but
> it might afford a foothold.
>
>
> On Wed, Oct 6, 2021 at 6:13 PM Martin Thomson <mt@lowentropy.net> wrote:
>
>> On Thu, Oct 7, 2021, at 07:02, Christian Huitema wrote:
>> > Phil,
>> >
>> > What we have in the current LB spec is called a "stream cipher", but
>> > that's a misnomer. What we have in the spec is actually a variable size
>> > block cipher, derived from AES-ECB using a construct similar to FFX.
>> > Your review of that algorithm would be appreciated.
>>
>> Christian,
>>
>> I would call this a Feistel network, but avoid talking about FFX.  FFX
>> has a bunch of guidance about the number of iterations of the network that
>> this ignores; to call this FFX or even imply that it is FFX isn't really
>> fair.  When you get right down to it, the real contribution in FFX is the
>> analysis that produces guidance on the number of iterations and the
>> inclusion of tweaks; if you use neither, then it's not really FFX.  As
>> additional iterations are necessary to maintain a security level, we need
>> to be careful about the claims we make in relation to security.
>>
>>