Re: [auth48] AUTH48: RFC-to-be 9334 <draft-ietf-rats-architecture-22> for your review

[[e-mail]]

Authors,

While reviewing this document during AUTH48, please resolve (as necessary) the following questions, which are also in the XML file.

1) <!-- [rfced] We had the following questions related to the
     abbreviation RATS.  JAR - This document expands it as "Remote
     Attestation Procedures (RATS)" on first use:

a) The working group uses didactic caps for this abbreviation (i.e.,
Remote ATtestation ProcedureS Working Group).  We assume that this
document does not purposefully.  Please let us know if updates are
necessary.

b) We see RFC 6813 expanded RATS as "remote attestation protocols".
We see this term used in this document as well.  Might this cause
confusion for readers?  Please let us know if any updates are
necessary.

c) We see one use of "Remote attestation defined by RATS".  Is this
redundant?

d) Was the repetition of RATS in this sentence necessary/desirable?
Please review our update for accuracy.

Original:
Additionally, the concepts of freshness and trust relationships with
respect to RATS are elaborated on to enable implementers to choose
appropriate solutions to compose their Remote Attestation Procedures.

Current:
Additionally, the concepts of freshness and trust relationships are
specified to enable implementers to choose appropriate solutions to
compose their Remote Attestation Procedures.


e) Would it be helpful to add the abbreviation RATS to the document
title?

Original:
Remote Attestation Procedures Architecture

Perhaps:
Remote Attestation Procedures (RATS) Architecture


-->


2) <!-- [rfced] Please insert any keywords (beyond those that appear in the
     title) for use on https://www.rfc-editor.org/search. -->


3) <!-- [rfced] Is "provide for a model" intentional in this sentence?  If so, what is being provided?  If neither of our suggestions fit, please let us know how to rephrase.

Original:
An attempt is made to provide for a model that is neutral toward
processor architectures, the content of claims, and protocols.

Perhaps A:
An attempt is made to provide a model that is neutral toward
processor architectures, the content of Claims, and protocols.

Perhaps B:
An attempt is made to provide context for a model that is neutral
toward processor architectures, the content of Claims, and protocols. -->


4) <!-- [rfced] The Web Portion of the Style Guide
     (https://www.rfc-editor.org/styleguide/part2/) recommends using
     the abbreviated form of an abbreviation after it has been
     introduced.  We will implement this style for each of the
     following abbreviations unless we hear objection.

Remote Attestation Procedures (RATS) (please see related query above)
machine learning (ML)
Trusted Application Manager (TAM)
Fast Identity Online (FIDO)
CBOR Web Token (CWT)
embedded Secure Elements (eSEs)
Trusted Execution Environment (TEE)
Trusted Platform Module (TPM)
Personally Identifiable Information (PII)
JSON Web Token (JWT)
Network Endpoint Assessment (NEA) -->


5) <!-- [rfced] Regarding the SVG in this document, please see the warning below when generating HTML output. This warning occurs with each artwork  element throughout the document (14 total). May the attributes be updated
so that the figures can scale?

Warning: Found SVG with width or height specified, which will make the artwork not scale.  Specify a viewBox only to let the artwork scale.-->


6) <!-- [rfced] We note that the Terminology section appears later in the
     document (Section 4) than some of the terms it describes.  Might
     it be helpful to the reader to move this section to follow the
     Introduction? -->


7) <!-- [rfced] Should the title of Figure 2 be updated to accurately reflect the information provided in Section 3.1?

Original: 
Figure 2: Two Types of Environments

Perhaps:
Figure 2: Two Types of Environments of an Attester -->


8) <!-- [rfced] (A), (B), and (C) do not appear in Figure 3. Should they
     be added to the figure or removed from the text below?

Original:
The example device illustrated in Figure 3 includes (A) a BIOS stored
in read-only memory, (B) a bootloader, and (C) an operating system
kernel.

Perhaps: 
The example device illustrated in Figure 3 includes a BIOS stored in
read-only memory, a bootloader, and an operating system kernel. -->


9) <!-- [rfced] Please review our rewording of this text to ensure that
     we have maintained your intended meaning.

Original: 
The final Evidence thus contains two sets of Claims: one set about the
bootloader as measured and signed by the BIOS, plus a set of Claims
about the kernel as measured and signed by the bootloader.

Perhaps:
The final Evidence thus contains two sets of Claims: one set about the
bootloader as measured and signed by the BIOS and another set of
Claims about the kernel as measured and signed by the bootloader
-->


10) <!-- [rfced] Should the title of Figure 4 be updated to accurately reflect the information provided in Section 3.3?

Original: 
Figure 4: Composite Device

Perhaps: 
Figure 4: Conceptual Data Flow for a Composite Device -->


11) <!--[rfced] We see the use of "Compare:" throughout the Terminology
     section has special meaning.  As the text that follows isn't
     really a sentence, and the slashes may be confusing/distracting,
     we will update as follows for each of these similar instances
     unless we hear objection.

Original:
Compare: /relying party/ in [RFC4949].

Perhaps:
Compare: relying party [RFC4949]


-->


12) <!--[rfced] "informs" seems like it should take an object.  Might a
     rewording be acceptable here?

Original:
   Appraisal Policy for Evidence: A set of rules that informs how a
   Verifier evaluates the validity of information about an Attester.
   Compare: /security policy/ in [RFC4949].
      
Perhaps:      
   Appraisal Policy for Evidence: A set of rules that provides
   information about how a Verifier evaluates the validity of
   information about an Attester.  Compare: /security policy/ in
   [RFC4949].
-->


13) <!--[rfced] The use of "pass the policy" seems somewhat unusual.
     Please let us know how we may rephrase.

Original:
   *  The second way in which the process may fail is when the
      Attestation Result is examined by the Relying Party, and based
      upon the Appraisal Policy for Attestation Results, the result does
      not pass the policy.
      
 
-->


14) <!-- [rfced] We had the following questions related to the use of <tt>
     and <em> in the document.

a) Please confirm that <tt> and <em> provide output that is expected
after reading the points below.  Let us know if any changes are
necessary.

-In the html and pdf outputs, the text enclosed in <tt> is output in
fixed-width font. In the txt output, there are no changes to the font.

-In the html and pdf outputs, the text enclosed in <em> is output in
italics. In the txt output, the text enclosed in <em> appears with an
underscore before and after.

b)   FYI: We removed 'in' from the emphasized string of text below to
     provide more emphasis to the word "encapsulated". Please let us know
     any objections.

Original XML: 
The only requirement is that the Evidence can be <em>encapsulated in</em> the format required by the resource access protocol between the Attester and Relying Party.

Current XML: 
The only requirement is that the Evidence can be <em>encapsulated</em> in the format required by the resource access protocol between the Attester and Relying Party.
-->


15) <!-- [rfced] Will readers be able to easily identify the expansion of
     GPIO?  We recommend expanding abbreviations on first use (see RFC
     7322).

Original: 
Alternative channels to convey conceptual messages include function
calls, sockets, GPIO interfaces, local busses, or hypervisor calls. -->


16) <!--[rfced] In the following text, is it the other authorized parties
     that address the handling of sensitive information?  Or should it
     be "a governing policy that addresses" for subject/verb
     agreement?

Original:
 The Verifier might share this information with other
   authorized parties, according to a governing policy that address the
   handling of sensitive information (potentially included in Appraisal
   Policies for Evidence).

Perhaps:
 The Verifier might share this information with other
   authorized parties according to a governing policy that addresses the
   handling of sensitive information (potentially included in Appraisal
   Policies for Evidence).
-->


17) <!-- [rfced] We suggest rewording this sentence to avoid repetition of the phrases "in such a case/in which case". This change will make the text
more concise and easier to read. Does the following suggestion change the
original meaning of the text?

Original:
In such a case, authentication or attestation in both directions might
be needed, in which case typically one side's Evidence must be
considered safe to share with an untrusted entity, in order to
bootstrap the sequence.

Perhaps: 
In such a case, authentication or attestation in both directions might
be needed. Typically, one side's Evidence must be considered safe to
share with an untrusted entity in order to bootstrap the sequence.
-->


18) <!--[rfced] Please review the use of COAP in the following text.
     Should this be made "CoAP" (Constrained Application Protocol)?

Original:
   In this diagram, the protocol between Attester and a Relying Party
   can be any new or existing protocol (e.g., HTTP(S), COAP(S), ROLIE
   [RFC8322], 802.1x, OPC UA [OPCUA], etc.), depending on the use case.
-->


19) <!--[rfced] Please review the use of "non-predictable" as opposed to
     "unpredictable".

Original:
In this approach, a non-predictable nonce is sent by the appraising
entity and the nonce is then signed and included along with the Claims
in the Evidence or Attestation Result.
-->


20) <!-- [rfced] Please confirm our edits to this text have not altered
     the intended meaning.

Original:
For public-key cryptography, it is, by definition, not necessary to
maintain confidentiality of the public key: however integrity of the
chain of custody of the public key is necessary in order to avoid
attacks where an attacker is able to get a key they control endorsed.

Current:
By definition, it is not necessary to maintain confidentiality of the
public key for public-key cryptography; however, integrity of the
chain of custody of the public key is necessary in order to avoid
attacks where an attacker is able to get a key that the attacker
controls endorsed.
-->


21) <!-- [rfced] The titles listed for the following reference entries do
     not match the titles that appear at the links provided.  For each
     reference below, we have updated to match the URL.  Please let us
     know any objections.

Original (1): 
[WebAuthN] W3C, "Web Authentication: An API for accessing Public Key
              Credentials", n.d., <https://www.w3.org/TR/webauthn-1/>.

Current (1): 
[WebAuthN] W3C, "Web Authentication: An API for accessing Public Key
              Credentials Level 1", 4 March 2019,
              <https://www.w3.org/TR/webauthn-1/>. 

Original (2): 
[CTAP]     FIDO Alliance, "Client to Authenticator Protocol", n.d.,
              <https://fidoalliance.org/specs/fido-v2.0-id-20180227/
              fido-client-to-authenticator-protocol-v2.0-id-
              20180227.html>.

Current (2):
[CTAP]     FIDO Alliance, "Client to Authenticator Protocol (CTAP)",
              27 February 2018, <https://fidoalliance.org/specs/fido-
              v2.0-id-20180227/fido-client-to-authenticator-protocol-
              v2.0-id-20180227.html>.

Original (3): [TCG-DICE-SIBDA]
              Trusted Computing Group, "Symmetric Identity Based Device
              Attestation for DICE", 24 July 2019,
              <https://trustedcomputinggroup.org/wp-content/uploads/
              TCG_DICE_SymIDAttest_v1_r0p94_pubrev.pdf>.

Current (3): [TCG-DICE-SIBDA]
              Trusted Computing Group, "Symmetric Identity Based Device
              Attestation", 24 July 2019,
              <https://trustedcomputinggroup.org/wp-content/uploads/
              TCG_DICE_SymIDAttest_v1_r0p94_pubrev.pdf>.
-->


22) <!--[rfced] I-D.birkholz-rats-tuda has been replaced.  Please note that we have updated this reference entry to instead point to I-D.ietf-rats-uccs.  Please let us know any objections.-->


23) <!-- [rfced] The target URL for this reference leads to a PDF titled "A
     Technical Analysis of Confidential Computing". We found a different 
     URL that leads to a PDF with the reference's original title     
     "Confidential Computing Deep Dive v1.0". 
     Please review which URL should be used for this reference.

Original:
[CCC-DeepDive] Confidential Computing Consortium, "Confidential Computing Deep Dive", n.d.,
<https://confidentialcomputing.io/whitepaper-02-latest>.

Perhaps: 
[CCC-DeepDive] Confidential Computing Consortium, "Confidential
Computing Deep Dive", October 2020,
<https://confidentialcomputing.io/wp-content/uploads/sites/85/2020/10/Confidential-Computing-Deep-Dive-
white-paper.pdf>.
-->


24) <!-- [rfced] We note that "Example" was listed twice in the title of
     each appendix. We have updated as follows to avoid redundancy.
     Please let us know any objections.

Original:
A.1. Example 1: Timestamp-Based Passport Model Example

Current: 
A.1. Example 1: Timestamp-Based Passport Model -->


25) <!-- [rfced] The table in Appendix A does not have a title.
     Please review and provide a title for the untitled table if desired.

Perhaps:
Table 1: Events and Related IDs 
-->


26) <!-- [rfced] We suggest rearranging parts of this sentence for an improved flow of the text. Does the proposed text change the original meaning of the sentence?

Original:
Similarly if, based on an Attestation Result from a Verifier it
trusts, the Relying Party decides that the Attester can be trusted to
correctly provide time deltas, then it can determine whether the
Attestation Result is fresh by checking time(OP_r)-time(NS_r) +
time(RR_a)-time(EG_a) < Threshold.

Perhaps: 
Similarly, if the Relying Party decides that the Attester can be
trusted to correctly provide time deltas based on an Attestation
Result from a Verifier it trusts, then it can determine whether the
Attestation Result is fresh by checking time(OP_r)-time(NS_r) +
time(RR_a)-time(EG_a) < Threshold. -->


27) <!--[rfced] Please review our update to this text to ensure we've
     retained your intended meaning.


Original:
   The Verifier appraises that the received epoch ID I is "fresh"
   according to the definition provided in Section 10.3 whereby retries
   are required in the case of mismatching epoch IDs, and generates an
   Attestation Result.
   
Current:   
   The Verifier appraises that the received epoch ID I is "fresh"
   according to the definition provided in Section 10.3 whereby
   retries are required in the case of mismatching epoch IDs; then the
   Verifier generates an Attestation Result.
-->


28) <!--[rfced] Regarding the two contributors sections:

a) Please note that we have consolidated the Notable Contributions and
Contributors sections to match the guidance in the RFC Style Guide
(RFC 7322).

b) Please let us know if you would like to add some text prior to the
list of names in light of this change.

c) We note that some contributors do not have email listed.  Please
confirm this is intentional or provide the missing addresses as
desired.

d) In the following text, will "the first three architecture drafts"
be clear to the reader?  Or should this be clarified in some way
(e.g., in the first three draft versions of this document)?

Original:
Monty Wisemen created the content structure of the first three
architecture drafts.
-->


29) <!-- [rfced] Please review the "Inclusive Language" portion of the online Style Guide
     <https://www.rfc-editor.org/styleguide/part2/#inclusive_language> 
     and let us know if any changes are needed. 
     For example, the terms "native" and "natively" appear in Section 9.   
     Please consider whether these terms should updated.
-->


30) <!-- [rfced] Throughout the text, we had the following questions
     related to terminology marking/use.

a) Please review these occurrences and let us know if/how they may be
made consistent.

Passport Model vs. passport model vs. Passport model
Background-Check Model vs. background-check model 
Epoch ID vs. epoch ID
value vs. Value


b) We have updated these occurrences to the form on the right. Please
let us know any objections.

claims vs. Claims
target environment vs. Target Environment
evidence vs. Evidence

c) We see some variance in the following, but believe it to be
intentional.  We have left these occurrences as was.  Please let us
know any objections.

appraisal policy vs. Appraisal Policy (seems to use the latter with "for Evidence" and "for Attestation
 Results")


-->


Thank you.

RFC Editor/mc/mf



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--------------------------------------
RFC9334 (draft-ietf-rats-architecture-22)

Title            : Remote Attestation Procedures Architecture
Author(s)        : H. Birkholz, D. Thaler, M. Richardson, N. Smith, W. Pan
WG Chair(s)      : Ned Smith, Nancy Cam-Winget, Kathleen Moriarty

Area Director(s) : Roman Danyliw, Paul Wouters