Re: [Rats] Composite Evidence

Michael Richardson <mcr+ietf@sandelman.ca> Fri, 24 January 2020 18:19 UTC

Return-Path: <mcr+ietf@sandelman.ca>
X-Original-To: rats@ietfa.amsl.com
Delivered-To: rats@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 2E7301200F5 for <rats@ietfa.amsl.com>; Fri, 24 Jan 2020 10:19:42 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.2
X-Spam-Level:
X-Spam-Status: No, score=-4.2 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
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 3P0w6JX3g62w for <rats@ietfa.amsl.com>; Fri, 24 Jan 2020 10:19:38 -0800 (PST)
Received: from tuna.sandelman.ca (tuna.sandelman.ca [IPv6:2607:f0b0:f:3:216:3eff:fe7c:d1f3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 41AC3120044 for <rats@ietf.org>; Fri, 24 Jan 2020 10:19:37 -0800 (PST)
Received: from sandelman.ca (obiwan.sandelman.ca [IPv6:2607:f0b0:f:2::247]) by tuna.sandelman.ca (Postfix) with ESMTP id 38D683897F; Fri, 24 Jan 2020 13:19:02 -0500 (EST)
Received: from localhost (localhost [IPv6:::1]) by sandelman.ca (Postfix) with ESMTP id 586BB60A; Fri, 24 Jan 2020 13:19:36 -0500 (EST)
From: Michael Richardson <mcr+ietf@sandelman.ca>
To: "Smith, Ned" <ned.smith@intel.com>
cc: "rats@ietf.org" <rats@ietf.org>
In-Reply-To: <B7A7F7E5-EC09-44C4-AE02-C480E6D7F8D9@intel.com>
References: <BYAPR11MB2536867559E1A20682A1FC2BA10F0@BYAPR11MB2536.namprd11.prod.outlook.com> <25403.1579747229@localhost> <BYAPR11MB2536EEF62BD7B1C53EC59659A10F0@BYAPR11MB2536.namprd11.prod.outlook.com> <85492C6F-E854-448F-9507-BBAC25455392@intel.com> <14896.1579811757@localhost> <B7A7F7E5-EC09-44C4-AE02-C480E6D7F8D9@intel.com>
X-Mailer: MH-E 8.6; nmh 1.7+dev; GNU Emacs 25.1.1
X-Face: $\n1pF)h^`}$H>Hk{L"x@)JS7<%Az}5RyS@k9X%29-lHB$Ti.V>2bi.~ehC0; <'$9xN5Ub# z!G,p`nR&p7Fz@^UXIn156S8.~^@MJ*mMsD7=QFeq%AL4m<nPbLgmtKK-5dC@#:k
MIME-Version: 1.0
Content-Type: multipart/signed; boundary="=-=-="; micalg="pgp-sha256"; protocol="application/pgp-signature"
Date: Fri, 24 Jan 2020 13:19:36 -0500
Message-ID: <14740.1579889976@localhost>
Archived-At: <https://mailarchive.ietf.org/arch/msg/rats/nR9gX8Fv6l-oqR3M3nXxvSzIk7Y>
Subject: Re: [Rats] Composite Evidence
X-BeenThere: rats@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Remote Attestation Procedures <rats.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rats>, <mailto:rats-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/rats/>
List-Post: <mailto:rats@ietf.org>
List-Help: <mailto:rats-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rats>, <mailto:rats-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 24 Jan 2020 18:19:42 -0000

Smith, Ned <ned.smith@intel.com> wrote:
    mcr> [%] I think you are saying that rather than documenting that we
    mcr> forward a union of evidence and attestation results, that we
    mcr> document that will create a kind of evidence, which includes attestation results?

    Ned> Maybe. It really is a case of multiplexing several conversations
    Ned> over the same conveyance mechanism, but otherwise conversations
    Ned> could be de-multiplexed (without creating unnecessary
    Ned> cross-dependencies). For example in both Passport and BK-Check
    Ned> topology models, a message is simply relayed. The endpoints are
    Ned> still the way they're defined in the Roles Arch diagram.

yes, I agree, we could send a list of evidence and a list of attestion
results from components.  I don't really know what the list of potential
*verification* protocols is.
(I know that I want to include it in RFC8366/BRSKI voucher-requests, once
that is an RFC)

I don't think this communication can ever be via certificate, while the final
attestation results could be placed inside a certificate.

    Ned> Email may not be the best way to try to illustrate but here goes. I
    Ned> assert that Eric's diagram can be recast into two graphs where graph
    Ned> (a) is the sub-component attester (A1), the local verifier (V1) and
    Ned> a relying party (RP). The second graph (b) consists of the top level
    Ned> Attester (A2), a remote verifier (V2) and the same relying party
    Ned> (RP).

    Ned> Looks something like:
    Ned> (a) A1 --- E1 ---> V1 --- AR1 ---> RP;
    Ned> (b) A2 --- E2 ---> V2 --- AR2 ---> RP.

I agree this is a reasonable diagram.

    Ned> If it makes sense to define "routing claims" that assert that A2
    Ned> intended to piggy back AR1 with E2 then that should imply that if E2
    Ned> = (c1) and c2 = routing claim then E2' = (c1, c2). The conveyance
    Ned> still carries (AR1, E2') , but possibly the c2 claim names AR1 as
    Ned> the piggy i.e. c2.name = "AR1".

Are you saying that the fact that (b) is relayed via E1 is important, and
should be communicated by having E1 sign the transaction as well?

    Mcr> It could be that there are competitive or regulatory reasons why the Lead
    Mcr> Attester does not wish to reveal the types of the line cards attached.
    Mcr> Consider an automobile (or passenger rail car, or human-rated Rocket) that
    Mcr> needs to attest that it has four good tires (which passed their 20,000km
    Mcr> inspection), but which does not wish to reveal which manufacturer provided
    Mcr> those tires.  Passing on evidence directly would be a problem.

    Ned> [nms] Privacy is an important consideration. If Evidence is privacy
    Ned> sensitive, then it can be encrypted. The routing claims don't
    Ned> require transparent Evidence to name them. Could compute a hash of E
    Ned> or AR or if endpoints have security associations, then E and AR can
    Ned> be encrypted and a digest of ciphertext becomes its name for the
    Ned> purpose of routing claims (see my response above).

Agreed.

--
]               Never tell me the odds!                 | ipv6 mesh networks [
]   Michael Richardson, Sandelman Software Works        |    IoT architect   [
]     mcr@sandelman.ca  http://www.sandelman.ca/        |   ruby on rails    [


--
Michael Richardson <mcr+IETF@sandelman.ca>, Sandelman Software Works
 -= IPv6 IoT consulting =-