Internet Engineering Task Force (IETF) A. Backman, Ed.
Request for Comments: 9493 Amazon
Category: Standards Track M. Scurtescu
ISSN: 2070-1721 Coinbase
P. Jain
Fastly
October
December 2023
Subject Identifiers for Security Event Tokens
Abstract
Security events communicated within Security Event Tokens may support
a variety of identifiers to identify subjects related to the event.
This specification formalizes the notion of Subject Identifiers as
structured information that describes a subject and named formats
that define the syntax and semantics for encoding Subject Identifiers
as JSON objects. It also establishes a registry for defining and
allocating names for such formats as well as the "sub_id" JSON Web Token (JWT) claim.
"sub_id" Claim.
Status of This Memo
This is an Internet Standards Track document.
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). Further information on
Internet Standards is available in 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/rfc9493.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction
2. Notational Conventions
2.1. Definitions
3. Subject Identifiers
3.1. Identifier Formats versus Principal Types
3.2. Identifier Format Definitions
3.2.1. Account Identifier Format
3.2.2. Email Identifier Format
3.2.3. Issuer and Subject Identifier Format
3.2.4. Opaque Identifier Format
3.2.5. Phone Number Identifier Format
3.2.6. Decentralized Identifier (DID) Format
3.2.7. Uniform Resource Identifier (URI) Format
3.2.8. Aliases Identifier Format
4. Subject Identifiers in JWTs
4.1. sub_id JWT "sub_id" Claim
4.2. sub_id JWT "sub_id" Claim and iss_sub "iss_sub" Subject Identifier
5. Considerations for Specifications that Define Identifier
Formats
6. Privacy Considerations
6.1. Identifier Correlation
7. Security Considerations
8. IANA Considerations
8.1. Security Event Identifier Formats Registry
8.1.1. Registration Template
8.1.2. Initial Registry Contents
8.1.3. Guidance for Expert Reviewers
8.2. JSON Web Token Claims Registration
8.2.1. Registry Contents
9. References
9.1. Normative References
9.2. Informative References
Acknowledgements
Authors' Addresses
1. Introduction
As described in Section 1.2 of [RFC8417] ("Security Event Token
(SET)"), subjects related to security events may take a variety of
forms, including but not limited to a JWT [RFC7519] principal, an IP
address, a URL, etc. Different types of subjects may need to be
identified in different ways (e.g., a user might be identified by an
email address, a phone number, or an account number). Furthermore,
even in the case where the type of the subject is known, there may be
multiple ways by which a given subject may be identified. For
example, an account may be identified by an opaque identifier, an
email address, a phone number, a JWT "iss" claim Claim and "sub" claim, Claim,
etc., depending on the nature and needs of the transmitter and
receiver. Even within the context of a given transmitter and
receiver relationship, it may be appropriate to identify different
accounts in different ways, for example, if some accounts only have
email addresses associated with them while others only have phone
numbers. Therefore, it can be necessary to indicate within a SET the
mechanism by which a subject is being identified.
To address this problem, this specification defines Subject
Identifiers as JSON [RFC8259] objects containing information
identifying a subject and defines Identifier Formats as named sets of
rules describing how to encode different kinds of subject-identifying
information (e.g., an email address or an issuer and subject pair) as
a Subject Identifier.
Below is a non-normative example of a Subject Identifier that
identifies a subject by email address, using the Email Identifier
Format.
{
"format": "email",
"email": "user@example.com"
}
Figure 1: Example: Subject Identifier Using the Email Identifier
Format
Subject Identifiers are intended to be a general-purpose mechanism
for identifying subjects within JSON objects, and their usage need
not be limited to SETs. Below is a non-normative example of a JWT
that uses a Subject Identifier in the JWT "sub_id" claim Claim (defined in
this specification) to identify the JWT Subject.
{
"iss": "issuer.example.com",
"sub_id": {
"format": "phone_number",
"phone_number": "+12065550100"
}
}
Figure 2: Example: JWT Using a Subject Identifier with the JWT
"sub_id" Claim
Usage of Subject Identifiers also need not be limited to identifying
JWT Subjects. They are intended as a general-purpose means of
expressing identifying information in an unambiguous manner. Below
is a non-normative example of a SET containing a hypothetical
security event describing the interception of a message, using
Subject Identifiers to identify the sender, intended recipient, and
interceptor.
{
"iss": "issuer.example.com",
"iat": 1508184845,
"aud": "aud.example.com",
"events": {
"https://secevent.example.com/events/message-interception": {
"from": {
"format": "email",
"email": "alice@example.com"
},
"to": {
"format": "email",
"email": "bob@example.com"
},
"interceptor": {
"format": "email",
"email": "eve@example.com"
}
}
}
}
Figure 3: Example: SET with an Event Payload Containing Multiple
Subject Identifiers
2. Notational 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.
2.1. Definitions
This specification utilizes terminology defined in [RFC8259] and
[RFC8417].
Within this specification, the terms "Subject" and "subject" refer
generically to anything being identified via one or more pieces of
information. The term "JWT Subject" refers specifically to the
subject of a JWT (i.e., the subject that the JWT asserts claims
about).
3. Subject Identifiers
A Subject Identifier is a JSON object [RFC8259] whose contents may be
used to identify a subject within some context. An Identifier Format
is a named definition of a set of information that may be used to
identify a subject and the rules for encoding that information as a
Subject Identifier; they these rules define the syntax and semantics of
Subject Identifiers. A Subject Identifier MUST conform to a specific
Identifier Format and MUST contain a "format" member whose value is
the name of that Identifier Format.
Every Identifier Format MUST have a unique name registered in the
IANA "Security Event Identifier Formats" registry established in
Section 8.1 or a Collision-Resistant Name as defined in [RFC7519].
Identifier Formats that are expected to be used broadly by a variety
of parties SHOULD be registered in the "Security Event Identifier
Formats" registry.
An Identifier Format MAY describe more members than are strictly
necessary to identify a subject and MAY describe conditions under
which those members are required, optional, or prohibited. The
"format" member is reserved for use as described in this
specification; Identifier Formats MUST NOT declare any rules
regarding the "format" member.
Every member within a Subject Identifier MUST match the rules
specified for that member by this specification or by a Subject
Identifier's Identifier Format. A Subject Identifier MUST NOT
contain any members prohibited or not described by its Identifier
Format and MUST contain all members required by its Identifier
Format.
3.1. Identifier Formats versus Principal Types
Identifier Formats define how to encode identifying information for a
subject. Unlike Principal Types, they do not define the type or
nature of the subject itself. For example, while the "email" Email
Identifier Format declares that the value of the "email" member is an
email address, a subject in a security event that is identified by an
"email"
Email Subject Identifier could be an end user who controls that email
address, the mailbox itself, or anything else that the transmitter
and receiver both understand to be associated with that email
address. Consequently, Subject Identifiers remove ambiguity around
how a subject is being identified and how to parse an identifying
structure, but Subject Identifiers they do not remove ambiguity around how to resolve
that identifier to for a subject. For example, consider a directory
management API that allows callers to identify users and groups
through both opaque unique identifiers and email addresses. Such an
API could use Subject Identifiers to disambiguate between which of
these two types of identifiers is in use. However, the API would
have to determine whether the subject is a user or group via some
other means, such as by querying a database, interpreting other
parameters in the request, or inferring the type from the API
contract.
3.2. Identifier Format Definitions
The following Identifier Formats are registered in the IANA "Security
Event Identifier Formats" registry established in Section 8.1.
Since the Subject Identifier Format conveys semantic information,
applications SHOULD choose the most specific possible format for the
identifier in question. For example, an email address can be
conveyed using a mailto: "mailto:" URI and the uri URI Identifier Format, but
since the value is known to be an email address, the application
should prefer to use the "email" Email Identifier Format instead.
3.2.1. Account Identifier Format
The Account Identifier Format identifies a subject using an account
at a service provider, identified with an "acct" URI as defined in
[RFC7565]. An account is an arrangement or agreement through which a
user gets access to a service and gets a unique identity with the
service provider. Subject Identifiers in this format MUST contain a
"uri" member whose value is the "acct" URI for the subject. The
"uri" member is REQUIRED and MUST NOT be null or empty. The Account
Identifier Format is identified by a value of "account" in the
"format" member.
Below is a non-normative example Subject Identifier for the Account
Identifier Format:
{
"format": "account",
"uri": "acct:example.user@service.example.com"
}
Figure 4: Example: Subject Identifier for the Account Identifier
Format
3.2.2. Email Identifier Format
The Email Identifier Format identifies a subject using an email
address. Subject Identifiers in this format MUST contain an "email"
member whose value is a string containing the email address of the
subject, formatted as an "addr-spec" as defined in Section 3.4.1 of
[RFC5322]. The "email" member is REQUIRED and MUST NOT be null or
empty. The value of the "email" member MUST identify a mailbox to
which email may be delivered, in accordance with [RFC5321]. The
Email Identifier Format is identified by the name "email".
Below is a non-normative example Subject Identifier in the Email
Identifier Format:
{
"format": "email",
"email": "user@example.com"
}
Figure 5: Example: Subject Identifier in the Email Identifier Format
3.2.2.1. Email Canonicalization
Many email providers will treat multiple email addresses as
equivalent. While the domain portion of an email address [RFC5322]
is consistently treated as case-insensitive per [RFC1034], most
providers treat the local part of the email address as case-
insensitive as well and consider "user@example.com",
"User@example.com", and "USER@example.com" as the same email address.
Some providers also treat dots (".") as optional; for example,
"user.name@example.com", "username@example.com",
"u.s.e.r.name@example.com", and "u.s.e.r.n.a.m.e@example.com" might
all be treated as equivalent. This has led users to view these
strings as equivalent, driving service providers to implement
proprietary email canonicalization algorithms to ensure that email
addresses entered by users resolve to the same canonical string.
Email canonicalization is not standardized, and there is no way for
the event recipient to determine the mail provider's canonicalization
method. Therefore, the recipient SHOULD apply its own
canonicalization algorithm to incoming events that reproduces in order to reproduce
the translation done by the local email system.
3.2.3. Issuer and Subject Identifier Format
The Issuer and Subject Identifier Format identifies a subject using a
pair of "iss" and "sub" members, analogous to how subjects are
identified using the JWT "iss" and "sub" claims Claims in OpenID Connect
[OpenID.Core] ID Tokens. These members MUST follow the formats of
the "iss" member and "sub" member defined by [RFC7519], respectively.
Both the "iss" member and the "sub" member are REQUIRED and MUST NOT
be null or empty. The Issuer and Subject Identifier Format is
identified by the name "iss_sub".
Below is a non-normative example Subject Identifier in the Issuer and
Subject Identifier Format:
{
"format": "iss_sub",
"iss": "https://issuer.example.com/",
"sub": "145234573"
}
Figure 6: Example: Subject Identifier in the Issuer and Subject
Identifier Format
3.2.4. Opaque Identifier Format
The Opaque Identifier Format describes a subject that is identified
with a string with no semantics asserted beyond its usage as an
identifier for the subject, such as a Universally Unique Identifier
(UUID) or hash used as a surrogate identifier for a record in a
database. Subject Identifiers in this format MUST contain an "id"
member whose value is a JSON string containing the opaque string
identifier for the subject. The "id" member is REQUIRED and MUST NOT
be null or empty. The Opaque Identifier Format is identified by the
name "opaque".
Below is a non-normative example Subject Identifier in the Opaque
Identifier Format:
{
"format": "opaque",
"id": "11112222333344445555"
}
Figure 7: Example: Subject Identifier in the Opaque Identifier Format
3.2.5. Phone Number Identifier Format
The Phone Number Identifier Format identifies a subject using a
telephone number. Subject Identifiers in this format MUST contain a
"phone_number" member whose value is a string containing the full
telephone number of the subject, including an international dialing
prefix, formatted according to E.164 [E164]. The "phone_number"
member is REQUIRED and MUST NOT be null or empty. The Phone Number
Identifier Format is identified by the name "phone_number".
Below is a non-normative example Subject Identifier in the Phone
Number Identifier Format:
{
"format": "phone_number",
"phone_number": "+12065550100"
}
Figure 8: Example: Subject Identifier in the Phone Number
Identifier Format
3.2.6. Decentralized Identifier (DID) Format
The Decentralized Identifier (DID) Format identifies a subject using
a DID URL as defined in [DID]. Subject Identifiers in this format
MUST contain a "URL" "url" member whose value is a DID URL for the DID
Subject being identified. The value of the "url" member MUST be a
valid DID URL and MAY be a bare DID. The "url" member is REQUIRED
and MUST NOT be null or empty. The Decentralized Identifier Format
is identified by the name "did".
Below are non-normative example Subject Identifiers for the
Decentralized Identifier Format:
{
"format": "did",
"url": "did:example:123456"
}
Figure 9: Example: Subject Identifier for the Decentralized
Identifier Format, Identifying a Subject with a Bare DID
{
"format": "did",
"url": "did:example:123456/did/url/path?versionId=1"
}
Figure 10: Example: Subject Identifier for the Decentralized
Identifier Format, Identifying a Subject with a DID URL with Non-
empty Path and Query Components
3.2.7. Uniform Resource Identifier (URI) Format
The Uniform Resource Identifier (URI) Format identifies a subject
using a URI as defined in [RFC3986]. This Identifier Format makes no
assumptions or guarantees with regard to the content, scheme, or
reachability of the URI within the field. Subject Identifiers in
this format MUST contain a "uri" member whose value is a URI for the
subject being identified. The "uri" member is REQUIRED and MUST NOT
be null or empty. The URI Format is identified by the name "uri".
Below are non-normative example Subject Identifiers for the URI
Format:
{
"format": "uri",
"uri": "https://user.example.com/"
}
Figure 11: Example: Subject Identifier for the URI Format,
Identifying a Subject with a Website URI
{
"format": "uri",
"uri": "urn:uuid:4e851e98-83c4-4743-a5da-150ecb53042f"
}
Figure 12: Example: Subject Identifier for the URI Format,
Identifying a Subject with a Random URN
3.2.8. Aliases Identifier Format
The Aliases Identifier Format describes a subject that is identified
with a list of different Subject Identifiers. It is intended for use
when a variety of identifiers have been shared with the party that
will be interpreting the Subject Identifier, and it is unknown which
of those identifiers they will recognize or support. Subject
Identifiers in this format MUST contain an "identifiers" member whose
value is a JSON array containing one or more Subject Identifiers.
Each Subject Identifier in the array MUST identify the same entity.
The "identifiers" member is REQUIRED and MUST NOT be null or empty.
It MAY contain multiple instances of the same Identifier Format
(e.g., multiple Email Subject Identifiers) but SHOULD NOT contain
exact duplicates. This format is identified by the name "aliases".
"aliases" Subject Identifiers MUST NOT be nested, i.e., the
"identifiers" member of an "aliases" Subject Identifier MUST NOT
contain a Subject Identifier in the "aliases" format. Aliases Identifier Format.
Below is a non-normative example Subject Identifier in the Aliases
Identifier Format:
{
"format": "aliases",
"identifiers": [
{
"format": "email",
"email": "user@example.com"
},
{
"format": "phone_number",
"phone_number": "+12065550100"
},
{
"format": "email",
"email": "user+qualifier@example.com"
}
]
}
Figure 13: Example: Subject Identifier in the Aliases Identifier
Format
4. Subject Identifiers in JWTs
4.1. sub_id JWT "sub_id" Claim
The "sub" JWT "sub" Claim is defined in Section 4.1.2 of [RFC7519] as
containing a string value; therefore, it cannot contain a Subject
Identifier (which is a JSON object) as its value. This document
defines the "sub_id" JWT "sub_id" Claim, in accordance with Section 4.2 of
[RFC7519], as a common claim that identifies the JWT Subject using a
Subject Identifier. When present, the value of this claim MUST be a
Subject Identifier that identifies the subject of the JWT. The JWT
"sub_id" claim Claim MAY be included in a JWT, whether or not the JWT "sub"
claim
Claim is present. When both the JWT "sub" and "sub_id" claims Claims are
present in a JWT, they MUST identify the same subject, as a JWT has
one and only one JWT Subject.
When processing a JWT with both JWT "sub" and "sub_id" claims, Claims,
implementations MUST NOT rely on both claims to determine the JWT
Subject. An implementation MAY attempt to determine the JWT Subject
from one claim and fall back to using the other if it determines it
does not understand the format of the first claim. For example, an
implementation may attempt to use "sub_id" and fall back to using
"sub" upon finding that "sub_id" contains a Subject Identifier with a
format that is not recognized by the implementation.
Below are non-normative examples of JWTs containing the JWT "sub_id"
claim:
Claim:
{
"iss": "issuer.example.com",
"sub_id": {
"format": "email",
"email": "user@example.com"
}
}
Figure 14: Example: JWT Containing a JWT "sub_id" Claim and No
"sub" Claim
{
"iss": "issuer.example.com",
"sub": "user@example.com",
"sub_id": {
"format": "email",
"email": "user@example.com"
}
}
Figure 15: Example: JWT Where the JWT "sub" and "sub_id" Claims
Identify the JWT Subject Using the Same Identifier
{
"iss": "issuer.example.com",
"sub": "liz@example.com",
"sub_id": {
"format": "email",
"email": "elizabeth@example.com"
}
}
Figure 16: Example: JWT Where the JWT "sub" and "sub_id" Claims
Identify the JWT Subject Using Different Values of the Same
Identifier Type
{
"iss": "issuer.example.com",
"sub": "user@example.com",
"sub_id": {
"format": "account",
"uri": "acct:example.user@service.example.com"
}
}
Figure 17: Example: JWT Where the JWT "sub" and "sub_id" Claims
Identify the JWT Subject via Different Types of Identifiers
4.2. sub_id JWT "sub_id" Claim and iss_sub "iss_sub" Subject Identifier
The JWT "sub_id" claim Claim MAY contain an "iss_sub" Subject Identifier.
In this case, the JWT's "iss" claim Claim and the Subject Identifier's
"iss" member MAY be different. For example, an OpenID Connect
[OpenID.Core] client may construct such a JWT when sending JWTs back
to its OpenID Connect Identity Provider in order to identify the JWT
Subject using an identifier known to be understood by both parties.
Similarly, the JWT's "sub" claim Claim and the Subject Identifier's "sub"
member MAY be different. For example, this may be used by an OpenID
Connect client to communicate the JWT Subject's local identifier at
the client back to its Identity Provider.
Below are non-normative examples of a JWT where the JWT "iss" claim Claim
and "iss" member within the JWT "sub_id" claim Claim are the same and a JWT
where they are different.
{
"iss": "issuer.example.com",
"sub_id": {
"format": "iss_sub",
"iss": "issuer.example.com",
"sub": "example_user"
}
}
Figure 18: Example: JWT with an "iss_sub" Subject Identifier
Where the JWT Issuer and JWT Subject Issuer Are the Same
{
"iss": "client.example.com",
"sub_id": {
"format": "iss_sub",
"iss": "issuer.example.com",
"sub": "example_user"
}
}
Figure 19: Example: JWT with an "iss_sub" Subject Identifier
Where the JWT Issuer and JWT Subject Issuer Are Different
{
"iss": "client.example.com",
"sub": "client_user",
"sub_id": {
"format": "iss_sub",
"iss": "issuer.example.com",
"sub": "example_user"
}
}
Figure 20: Example: JWT with an "iss_sub" Subject Identifier
Where the JWT "iss" and "sub" Claims Differ from the JWT
Subject's "iss" and "sub" Members
5. Considerations for Specifications that Define Identifier Formats
Identifier Format definitions MUST NOT make assertions or
declarations regarding the subject being identified by the Subject
Identifier (e.g., an Identifier Format cannot be defined as
specifically identifying human end users). Such statements are
outside the scope of Identifier Formats and Subject Identifiers.
Expanding that scope for some Identifier Formats but not others would
harm interoperability because applications that depend on this
expanded scope to disambiguate the subject type would be unable to
use Identifier Formats that do not provide such rules.
6. Privacy Considerations
6.1. Identifier Correlation
The act of presenting two or more identifiers for a single subject
together (e.g., within an "aliases" Subject Identifier or via the JWT
"sub" and "sub_id" JWT claims) Claims) may communicate more information about the
subject than was intended. For example, the entity to which the
identifiers are presented now knows that both identifiers relate to
the same subject and may be able to correlate additional data based
on that. When transmitting Subject Identifiers, the transmitter
SHOULD take care that they are only transmitting multiple identifiers
together when it is known that the recipient already knows that the
identifiers are related (e.g., because they were previously sent to
the recipient as claims in an OpenID Connect ID Token) or when
correlation is essential to the use case. Implementers must consider
such risks, and specifications that use Subject Identifiers must
provide appropriate privacy considerations of their own.
The considerations described in Section 6 of [RFC8417] also apply
when Subject Identifiers are used within SETs. The considerations
described in Section 12 of [RFC7519] also apply when Subject
Identifiers are used within JWTs.
7. Security Considerations
This specification does not define any mechanism for ensuring the
confidentiality or integrity of a Subject Identifier. Where such
properties are required, implementations MUST use mechanisms provided
by the containing format (e.g., integrity protecting SETs or JWTs
using JSON Web Signature (JWS) [RFC7515]) or at the transport layer
or other layer in the application stack (e.g., using TLS [RFC8446]).
Further considerations regarding confidentiality and integrity of
SETs can be found in Section 5.1 of [RFC8417].
8. IANA Considerations
8.1. Security Event Identifier Formats Registry
This document defines Identifier Formats, for which IANA has created
and maintains a new registry titled "Security Event Identifier
Formats". Initial values for the "Security Event Identifier Formats"
registry are given in Section 3. Future assignments are to be made
through the Specification Required registration policy [BCP26] and
shall follow the template presented in Section 8.1.1.
It is suggested that multiple Designated Experts designated experts be appointed who are
able to represent the perspectives of different applications using
this specification in order to enable broadly informed review of
registration decisions.
8.1.1. Registration Template
Format Name:
The name of the Identifier Format, as described in Section 3. The
name MUST be an ASCII string consisting only of lowercase
characters ("a" - "z"), digits ("0" - "9"), underscores ("_"), and
hyphens ("-") and SHOULD NOT exceed 20 characters in length.
Format Description:
A brief description of the Identifier Format.
Change Controller:
For formats defined in documents published by the IETF or its
working groups, list "IETF". For all other formats, list the name
of the party responsible for the registration. Contact
information, such as mailing address, email address, or phone
number, must also be provided.
Reference:
A reference to the document or documents that define the
Identifier Format. The reference document(s) MUST specify the
name, format, and meaning of each member that may occur within a
Subject Identifier of the defined format as well as whether each
member is optional, required, or conditional and the circumstances
under which these optional or conditional fields would be used.
URIs that can be used to retrieve copies of each document SHOULD
be included.
8.1.2. Initial Registry Contents
8.1.2.1. Account Identifier Format
Format Name: account
Format Description: Subject Identifier based on acct "acct" URI
Change Controller: IETF
Reference: Section 3 of RFC 9493
8.1.2.2. Email Identifier Format
Format Name: email
Format Description: Subject Identifier based on an email address
Change Controller: IETF
Reference: Section 3 of RFC 9493
8.1.2.3. Issuer and Subject Identifier Format
Format Name: iss_sub
Format Description: Subject Identifier based on an issuer and
subject
Change Controller: IETF
Reference: Section 3 of RFC 9493
8.1.2.4. Opaque Identifier Format
Format Name: opaque
Format Description: Subject Identifier based on an opaque string
Change Controller: IETF
Reference: Section 3 of RFC 9493
8.1.2.5. Phone Number Identifier Format
Format Name: phone_number
Format Description: Subject Identifier based on a phone number
Change Controller: IETF
Reference: Section 3 of RFC 9493
8.1.2.6. Decentralized Identifier Format
Format Name: did
Format Description: Subject Identifier based on a decentralized
identifier (DID)
Change Controller: IETF
Reference: Section 3 of RFC 9493
8.1.2.7. Uniform Resource Identifier Format
Format Name: uri
Format Description: Subject Identifier based on a Uniform Resource
Identifier (URI)
Change Controller: IETF
Reference: Section 3 of RFC 9493
8.1.2.8. Aliases Identifier Format
Format Name: aliases
Format Description: Subject Identifier that groups together multiple
different Subject Identifiers for the same subject
Change Controller: IETF
Reference: Section 3 of RFC 9493
8.1.3. Guidance for Expert Reviewers
The Expert Reviewer is expected to review the documentation
referenced in a registration request to verify its completeness. The
Expert Reviewer must base their decision to accept or reject the
request on a fair and impartial assessment of the request. If the
Expert Reviewer has a conflict of interest, such as being an author
of a defining document referenced by the request, they must recuse
themselves from the approval process for that request.
Identifier Formats need not be generally applicable and may be highly
specific to a particular domain; it is expected that formats may be
registered for niche or industry-specific use cases. The Expert
Reviewer should focus on whether the format is thoroughly documented
and whether its registration will promote or harm interoperability.
In most cases, the Expert Reviewer should not approve a request if
the registration would contribute to confusion or amount to a synonym
for an existing format.
8.2. JSON Web Token Claims Registration
This document defines the sub_id JWT "sub_id" Claim, which IANA has
registered in the "JSON Web Token Claims" registry [IANA.JWT.Claims]
established by [RFC7519].
8.2.1. Registry Contents
Claim Name: sub_id
Claim Description: Subject Identifier
Change Controller: IETF
Reference: Section 4.1 of RFC 9493
9. References
9.1. Normative References
[BCP26] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, June 2017.
<https://www.rfc-editor.org/info/bcp26>
[DID] Sporny, M., Ed., Guy, A., Ed., Sabadello, M., Ed., Reed,
D., Ed., Longley, D., Steele, O., and C. Allen,
"Decentralized Identifiers (DIDs) v1.0", July 2022,
<https://www.w3.org/TR/did-core/>.
[E164] ITU-T, "E.164: The international public telecommunication
numbering plan", ITU-T Recommendation E.164, November
2010, <https://www.itu.int/rec/T-REC-E.164-201011-I/en>.
[IANA.JWT.Claims]
IANA, "JSON Web Token Claims",
<https://www.iana.org/assignments/jwt>.
[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>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
DOI 10.17487/RFC5321, October 2008,
<https://www.rfc-editor.org/info/rfc5321>.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
DOI 10.17487/RFC5322, October 2008,
<https://www.rfc-editor.org/info/rfc5322>.
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<https://www.rfc-editor.org/info/rfc7519>.
[RFC7565] Saint-Andre, P., "The 'acct' URI Scheme", RFC 7565,
DOI 10.17487/RFC7565, May 2015,
<https://www.rfc-editor.org/info/rfc7565>.
[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>.
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/info/rfc8259>.
[RFC8417] Hunt, P., Ed., Jones, M., Denniss, W., and M. Ansari,
"Security Event Token (SET)", RFC 8417,
DOI 10.17487/RFC8417, July 2018,
<https://www.rfc-editor.org/info/rfc8417>.
9.2. Informative References
[OpenID.Core]
Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and
C. Mortimore, "OpenID Connect Core 1.0 incorporating
errata set 1", November 2014,
<https://openid.net/specs/openid-connect-core-1_0.html>.
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
<https://www.rfc-editor.org/info/rfc1034>.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/info/rfc7515>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
Acknowledgements
The authors would like to thank the members of the IETF Security
Events Working Group, as well as those of the OpenID Shared Signals
and Events Working Group, whose work provided the original basis for
this document. We would also like to acknowledge Aaron Parecki,
Denis Pinkas, Justin Richer, Mike Jones, and other members of the
working group for reviewing this document.
Authors' Addresses
Annabelle Backman (editor)
Amazon
Email: richanna@amazon.com
Marius Scurtescu
Coinbase
Email: marius.scurtescu@coinbase.com
Prachi Jain
Fastly
Email: prachi.jain1288@gmail.com