Shepherd writeup
rfc8471-19

Shepherd Write-Up for "The Token Binding Protocol Version 1.0”
<draft-ietf-tokbind-protocol-15> 

(1) What type of RFC is being requested (BCP, Proposed Standard,
Internet Standard, Informational, Experimental, or Historic)?  Why
is this the proper type of RFC?  Is this type of RFC indicated in the
title page header?

This specification is proposed as a 'Proposed Standard' document. The 
type of RFC is indicated. This document specifies Version 1.0 of the Token Binding protocol.  

(2) The IESG approval announcement includes a Document Announcement
Write-Up. Please provide such a Document Announcement Write-Up. Recent
examples can be found in the "Action" announcements for approved
documents. The approval announcement contains the following sections:

Technical Summary

The Token Binding protocol allows client/server applications to create long-lived, uniquely identifiable TLS bindings spanning multiple TLS sessions and connections.  Applications are then enabled to cryptographically bind security tokens to the TLS layer, preventing token export and replay attacks.  To protect privacy, the Token Binding identifiers are only conveyed over TLS and can be reset by the user at any time.

Working Group Summary

 This document achieved WG consensus and had one objection.

Document Quality

Multiple Implementations of Token Binding exist and have undergone informal interoperability testing.
Google has token binding behind a feature flag in Chrome that is currently defaulted off.  They have also implemented it in their reverse proxy infrastructure. They have also added support to the boringssl open source project.
Microsoft added support in Windows 10 RS2 at the beginning of 2017 (later back ported to RS1) .  Edge and IE use that platform support.  It is also available to other applications via system API.  There is also support in ADFS. https://docs.microsoft.com/en-us/windows-server/security/token-binding/introducing-token-binding 
NGINX has an open source module https://github.com/google/ngx_token_binding
Token Binding support for Apache https://github.com/zmartzone/mod_token_binding
Openssl patches in opensource https://github.com/google/token_bind
Ping Identity has tested patches to Java and set up a test environment. https://www.ietf.org/mail-archive/web/unbearable/current/msg01332.html
A useful slide share overview https://www.slideshare.net/Identiverse/beyond-bearer-token-binding-as-the-foundation-for-a-more-secure-web-cis-2017
Drafts using token binding exist in the OAuth work group and for OpenID Connect.

Personnel

John Bradley is the document shepherd and the responsible area 
director is Eric Rescorla. 

(3) Briefly describe the review of this document that was performed by
the Document Shepherd.  If this version of the document is not ready
for publication, please explain why the document is being forwarded to
the IESG.

The document shepherd was involved in the working group review process
and verified the document for correctness.

(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?  

There are no concerns regarding the document reviews. 

(5) Do portions of the document need review from a particular or from
broader perspective, e.g., security, operational complexity, AAA, DNS,
DHCP, XML, or internationalization? If so, describe the review that
took place.

No

(6) Describe any specific concerns or issues that the Document Shepherd
has with this document that the Responsible Area Director and/or the
IESG should be aware of? For example, perhaps he or she is uncomfortable
with certain parts of the document, or has concerns whether there really
is a need for it. In any event, if the WG has discussed those issues and
has indicated that it still wishes to advance the document, detail those
concerns here.

The document shepherd has no concerns with the document. 

(7) Has each author confirmed that any and all appropriate IPR
disclosures required for full conformance with the provisions of BCP 78
and BCP 79 have already been filed. If not, explain why.

The authors have confirmed full conformance with the provisions of BCP 78
and BCP 79: 

A. Popov: https://mailarchive.ietf.org/arch/msg/unbearable/Z_E1_h7hMV1mmvjax2USpuzeGho

M. Nystroem: https://mailarchive.ietf.org/arch/msg/unbearable/xQ1R-WbUyjcJkTqncNVoSNkmch4

D. Balfanz: https://mailarchive.ietf.org/arch/msg/unbearable/SFbtjN8H7kTgtpRYRcgpYx4C8gQ
A. Langley: https://mailarchive.ietf.org/arch/msg/unbearable/SFbtjN8H7kTgtpRYRcgpYx4C8gQ

J. Hodges: https://mailarchive.ietf.org/arch/msg/unbearable/l6IyBK035xv02zoPQEdUIViYLXY
                                                          



(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR
disclosures.

No IPR disclosures have been filed for this document. 

(9) How solid is the WG consensus behind this document? Does it 
represent the strong concurrence of a few individuals, with others
being silent, or does the WG as a whole understand and agree with it?   

There is solid consensus in the working group for publishing this 
document. 

(10) Has anyone threatened an appeal or otherwise indicated extreme 
discontent? If so, please summarise the areas of conflict in separate
email messages to the Responsible Area Director. (It should be in a
separate email because this questionnaire is publicly available.) 

Denis Pinkas raised objections.   The working group added security and privacy considerations in an attempt to address his concerns around users colluding to share private keys or using their key to sign EKM from other devices to actively circumvent token binding. 
The working group felt that the specific attribute based credentials use case he is concerned about is out of scope for token binding.   Token binding protects users from attackers but not servers from sophisticated users actively attempting to share cookies or other security tokens.  I expect that he will raise objections to the IESG.

(11) Identify any ID nits the Document Shepherd has found in this
document. (See http://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

The shepherd checked the document. 

(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.

No formal review is needed. 

(13) Have all references within this document been identified as
either normative or informative?

Yes. The references are split into normative and informative references. 

(14) Are there normative references to documents that are not ready for
advancement or are otherwise in an unclear state? If such normative
references exist, what is the plan for their completion?

All normative references are published RFCs. 

(15) Are there downward normative references references (see RFC 3967)?
If so, list these downward references to support the Area Director in 
the Last Call procedure. 

There are no downward normative references. 

(16) Will publication of this document change the status of any
existing RFCs? Are those RFCs listed on the title page header, listed
in the abstract, and discussed in the introduction? If the RFCs are not
listed in the Abstract and Introduction, explain why, and point to the
part of the document where the relationship of this document to the
other RFCs is discussed. If this information is not in the document,
explain why the WG considers it unnecessary.

This document does not change the status of an existing RFC. 

(17) Describe the Document Shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of the
document. Confirm that all protocol extensions that the document makes
are associated with the appropriate reservations in IANA registries.
Confirm that any referenced IANA registries have been clearly
identified. Confirm that newly created IANA registries include a
detailed specification of the initial contents for the registry, that
allocations procedures for future registrations are defined, and a
reasonable name for the new registry has been suggested (see RFC 5226).

The document includes a detailed specification of the contents of the three new registries.

(18) List any new IANA registries that require Expert Review for future
allocations. Provide any public guidance that the IESG would find
useful in selecting the IANA Experts for these new registries.

This document establishes three new registries.

This document establishes a registry for identifiers of Token Binding key parameters entitled "Token Binding Key Parameters" under the "Token Binding Protocol" heading.
This document establishes a registry for Token Binding type identifiers entitled "Token Binding Types" under the "Token Binding Protocol" heading.
This document establishes a registry for Token Binding type identifiers entitled "Token Binding Types" under the "Token Binding Protocol" heading.


These registries operate under the "Expert Review" policy as defined in [RFC8126].  The designated expert is advised to encourage the inclusion of a reference to a permanent and readily available specification that enables the creation of interoperable implementations using the identified set of Token Binding key parameters.
IANA experts should have experience with toen binding.  The registries can share experts and a single list.

(19) Describe reviews and automated checks performed by the Document
Shepherd to validate sections of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, etc.

There is no text in formal languages in the document.
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