WebAuthn registries: Registries for Web Authentication (WebAuthn)
Official IANA registries for WebAuthn features.
Hodges, J., Mandyam, G., and M. Jones, "Registries for Web Authentication (WebAuthn)", RFC 8809, DOI 10.17487/RFC8809, August 2020, <https://www.rfc-editor.org/info/rfc8809>.
@misc{rfc8809,
series = {Request for Comments},
number = 8809,
howpublished = {RFC 8809},
publisher = {RFC Editor},
doi = {10.17487/RFC8809},
url = {https://www.rfc-editor.org/info/rfc8809},
author = {J. Hodges and G. Mandyam and M. Jones},
title = {{Registries for Web Authentication (WebAuthn)}},
pagetotal = 7,
year = 2020,
month = aug,
} RFC text
Contents
Internet Engineering Task Force (IETF) J. Hodges
Request for Comments: 8809 Google
Category: Informational G. Mandyam
ISSN: 2070-1721 Qualcomm Technologies Inc.
M. Jones
Microsoft
August 2020
Registries for Web Authentication (WebAuthn)
Abstract
This specification defines IANA registries for W3C Web Authentication
(WebAuthn) attestation statement format identifiers and extension
identifiers.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are candidates for any level of Internet
Standard; see Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8809.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
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include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction
1.1. Requirements Notation and Conventions
2. IANA Considerations
2.1. WebAuthn Attestation Statement Format Identifiers Registry
2.1.1. Registering Attestation Statement Format Identifiers
2.1.2. Registration Request Processing
2.1.3. Initial Values in the WebAuthn Attestation Statement
Format Identifiers Registry
2.2. WebAuthn Extension Identifiers Registry
2.2.1. Registering Extension Identifiers
2.2.2. Registration Request Processing
2.2.3. Initial Values in the WebAuthn Extension Identifiers
Registry
3. Security Considerations
4. Normative References
Acknowledgements
Authors' Addresses
1. Introduction
This specification establishes IANA registries for W3C Web
Authentication [WebAuthn] attestation statement format identifiers
and extension identifiers. The initial values for these registries
are in the IANA Considerations section of the [WebAuthn]
specification.
1.1. Requirements Notation and Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. IANA Considerations
This specification establishes two registries:
* the "WebAuthn Attestation Statement Format Identifiers" registry
(see Section 2.1)
* the "WebAuthn Extension Identifiers" registry (see Section 2.2)
Any additional processes established by the expert(s) after the
publication of this document will be recorded on the registry web
page at the discretion of the expert(s).
2.1. WebAuthn Attestation Statement Format Identifiers Registry
WebAuthn attestation statement format identifiers are strings whose
semantic, syntactic, and string-matching criteria are specified in
the "Attestation Statement Format Identifiers"
(https://www.w3.org/TR/2019/REC-webauthn-1-20190304/#sctn-attstn-fmt-
ids) section of [WebAuthn], along with the concepts of attestation
and attestation statement formats.
Registered attestation statement format identifiers are those that
have been added to the registry by following the procedure in
Section 2.1.1.
Each attestation statement format identifier added to this registry
MUST be unique amongst the set of registered attestation statement
format identifiers.
Registered attestation statement format identifiers MUST be a maximum
of 32 octets in length and MUST consist only of printable ASCII
[RFC20] characters, excluding backslash and double quote, i.e., VCHAR
as defined in [RFC5234] but without %x22 and %x5c. Attestation
statement format identifiers are case sensitive and may not match
other registered identifiers in a case-insensitive manner unless the
designated experts determine that there is a compelling reason to
allow an exception.
2.1.1. Registering Attestation Statement Format Identifiers
WebAuthn attestation statement format identifiers are registered
using the Specification Required policy (see Section 4.6 of
[RFC8126]).
The "WebAuthn Attestation Statement Format Identifiers" registry is
located at <https://www.iana.org/assignments/webauthn>. Registration
requests can be made by following the instructions located there or
by sending an email to the webauthn-reg-review@ietf.org mailing list.
Registration requests consist of at least the following information:
WebAuthn Attestation Statement Format Identifier:
An identifier meeting the requirements given in Section 2.1.
Description:
A relatively short description of the attestation format.
Specification Document(s):
Reference to the document or documents that specify the
attestation statement format.
Change Controller:
For Standards Track RFCs, list "IETF". For others, give the name
of the responsible party. Other details (e.g., postal address,
email address, home page URI) may also be included.
Notes:
[optional]
Registrations MUST reference a freely available, stable
specification, e.g., as described in Section 4.6 of [RFC8126]. This
specification MUST include security and privacy considerations
relevant to the attestation statement format.
Note that WebAuthn attestation statement format identifiers can be
registered by third parties (including the expert(s) themselves), if
the expert(s) determines that an unregistered attestation statement
format is widely deployed and not likely to be registered in a timely
manner otherwise. Such registrations still are subject to the
requirements defined, including the need to reference a
specification.
2.1.2. Registration Request Processing
As noted in Section 2.1.1, WebAuthn attestation statement format
identifiers are registered using the Specification Required policy.
The expert(s) will clearly identify any issues that cause a
registration to be refused, such as an incompletely specified
attestation format.
When a request is approved, the expert(s) will inform IANA, and the
registration will be processed. The IESG is the arbiter of any
objection.
2.1.3. Initial Values in the WebAuthn Attestation Statement Format
Identifiers Registry
The initial values for the "WebAuthn Attestation Statement Format
Identifiers" registry have been populated with the values listed in
the "WebAuthn Attestation Statement Format Identifier Registrations"
(https://www.w3.org/TR/2019/REC-webauthn-1-20190304/#sctn-att-fmt-
reg) section of [WebAuthn]. Also, the Change Controller entry for
each of those registrations is:
Change Controller:
W3C Web Authentication Working Group (public-webauthn@w3.org)
2.2. WebAuthn Extension Identifiers Registry
WebAuthn extension identifiers are strings whose semantic, syntactic,
and string-matching criteria are specified in the "Extension
Identifiers" (https://www.w3.org/TR/2019/REC-webauthn-1-
20190304/#sctn-extension-id) section of [WebAuthn].
Registered extension identifiers are those that have been added to
the registry by following the procedure in Section 2.2.1.
Each extension identifier added to this registry MUST be unique
amongst the set of registered extension identifiers.
Registered extension identifiers MUST be a maximum of 32 octets in
length and MUST consist only of printable ASCII characters, excluding
backslash and double quote, i.e., VCHAR as defined in [RFC5234] but
without %x22 and %x5c. Extension identifiers are case sensitive and
may not match other registered identifiers in a case-insensitive
manner unless the designated experts determine that there is a
compelling reason to allow an exception.
2.2.1. Registering Extension Identifiers
WebAuthn extension identifiers are registered using the Specification
Required policy (see Section 4.6 of [RFC8126]).
The "WebAuthn Extension Identifiers" registry is located at
<https://www.iana.org/assignments/webauthn>. Registration requests
can be made by following the instructions located there or by sending
an email to the webauthn-reg-review@ietf.org mailing list.
Registration requests consist of at least the following information:
WebAuthn Extension Identifier:
An identifier meeting the requirements given in Section 2.2.
Description:
A relatively short description of the extension.
Specification Document(s):
Reference to the document or documents that specify the extension.
Change Controller:
For Standards Track RFCs, list "IETF". For others, give the name
of the responsible party. Other details (e.g., postal address,
email address, home page URI) may also be included.
Notes:
[optional]
Registrations MUST reference a freely available, stable
specification, e.g., as described in Section 4.6 of [RFC8126]. This
specification MUST include security and privacy considerations
relevant to the extension.
Note that WebAuthn extensions can be registered by third parties
(including the expert(s) themselves), if the expert(s) determines
that an unregistered extension is widely deployed and not likely to
be registered in a timely manner otherwise. Such registrations still
are subject to the requirements defined, including the need to
reference a specification.
2.2.2. Registration Request Processing
As noted in Section 2.2.1, WebAuthn extension identifiers are
registered using the Specification Required policy.
The expert(s) will clearly identify any issues that cause a
registration to be refused, such as an incompletely specified
extension.
When a request is approved, the expert(s) will inform IANA, and the
registration will be processed. The IESG is the arbiter of any
objection.
2.2.3. Initial Values in the WebAuthn Extension Identifiers Registry
The initial values for the "WebAuthn Extension Identifiers" registry
have been populated with the values listed in the "WebAuthn Extension
Identifier Registrations" (https://www.w3.org/TR/2019/REC-webauthn-1-
20190304/#sctn-extensions-reg) section of [WebAuthn]. Also, the
Change Controller entry for each of those registrations is:
Change Controller:
W3C Web Authentication Working Group (public-webauthn@w3.org)
3. Security Considerations
See [WebAuthn] for relevant security considerations.
4. Normative References
[RFC20] Cerf, V., "ASCII format for network interchange", STD 80,
RFC 20, DOI 10.17487/RFC0020, October 1969,
<https://www.rfc-editor.org/info/rfc20>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[WebAuthn] Balfanz, D., Czeskis, A., Hodges, J., Jones, J.C., Jones,
M., Kumar, A., Liao, A., Lindemann, R., and E. Lundberg,
"Web Authentication: An API for accessing Public Key
Credentials", World Wide Web Consortium
(W3C) Recommendation, 4 March 2019,
<https://www.w3.org/TR/2019/REC-webauthn-1-20190304/>.
Acknowledgements
Thanks to Mark Nottingham for valuable comments and suggestions.
Thanks to Kathleen Moriarty and Benjamin Kaduk for their Area
Director sponsorship of this specification. Thanks to Amanda Baber,
Sarah Banks, Alissa Cooper, Roman Danyliw, Murray Kucherawy, Paul
Kyzivat, Barry Leiba, Hilarie Orman, Magnus Westerlund, and Robert
Wilton for their reviews.
Authors' Addresses
Jeff Hodges
Google
1600 Amphitheatre Parkway
Mountain View, CA 94043
United States of America
Email: jdhodges@google.com
URI: https://kingsmountain.com/people/Jeff.Hodges/
Giridhar Mandyam
Qualcomm Technologies Inc.
5775 Morehouse Drive
San Diego, CA 92121
United States of America
Phone: +1 858 651 7200
Email: mandyam@qti.qualcomm.com
Michael B. Jones
Microsoft
Email: mbj@microsoft.com
URI: https://self-issued.info/
AI ELI5
On this page
§1What Is WebAuthn?
Web Authentication (WebAuthn) is a W3C web standard that lets websites authenticate users by verifying possession of a cryptographic key, such as a hardware security key or a device's biometric fingerprint. Unlike passwords, a WebAuthn credential is specific to the website and cannot be stolen or phished as easily.
WebAuthn allows for different methods of attesting (proving) that a key is genuine, called attestation statement formats. It also allows optional extensions to add extra features—such as user verification hints or custom data. For an ecosystem to function, these pluggable components need registered, agreed-upon identifiers so that a client and server can recognize the same attestation format or extension.
WebAuthn is a way to log into websites using a hardware key or your phone instead of a password. New features are added over time. This creates official lists so every company knows what to call each feature.
§2Attestation Statement Format Identifiers
An attestation statement is proof that a key is genuine—that it comes from a real hardware key or device, not a fake. Different types of keys produce attestations in different formats. For instance, a FIDO2 security key might produce one format, while an Apple device might produce another.
The RFC establishes an IANA registry for these format identifiers. Each entry must be a string of 32 octets or less, using printable ASCII characters only. Format identifiers are case-sensitive and must be unique. New formats are registered using the "Specification Required" policy—meaning a freely available, stable specification must accompany the request and be reviewed by designated experts.
Initial entries in the registry come from the W3C WebAuthn specification itself. The W3C Web Authentication Working Group is named as the change controller, meaning they manage updates to those core formats.
Different keys prove themselves in different ways. This registry lists all the official ways and what to call them, so everyone's software recognizes them.
§3Extension Identifiers
WebAuthn is designed to be extensible. Extensions allow the WebAuthn protocol to be enhanced with optional features without breaking existing implementations. For example, an extension might request that the authenticator verify the user's identity with a PIN or fingerprint, or might ask for custom data to be signed along with the normal WebAuthn response.
Like attestation formats, extensions need registered identifiers. The RFC establishes a second IANA registry for extension identifiers with the same rules: 32 octets or less, printable ASCII, case-sensitive, and unique. Registration uses the "Specification Required" policy with expert review. Initial entries come from the W3C WebAuthn specification, with the W3C Web Authentication Working Group as the change controller.
Extensions are extra features that websites can ask for. This registry lists all the official extensions and what to call them.
§4How to Register New Formats and Extensions
A vendor or researcher who develops a new attestation format or extension can request registration by providing a brief description, a reference to a freely available, stable specification that includes security and privacy considerations, and naming a change controller (the responsible party who will maintain the entry). The request goes to the webauthn-reg-review@ietf.org mailing list.
Designated experts (appointed and maintained by the IETF and the WebAuthn community) review the request for completeness and technical soundness. They may refuse a request if it is incompletely specified or if it raises security or privacy concerns. When approved, IANA processes the registration. The IESG acts as a final arbiter for objections.
As a special accommodation, an expert may register an unregistered but widely-deployed format or extension if the original developer is not registering it themselves and timely registration seems unlikely.
If you create a new feature for WebAuthn, you can officially register it by writing a specification and asking the experts. They check that it is safe and makes sense, then add it to the list.