rfc9493.original   rfc9493.txt 
Security Events Working Group A. Backman, Ed. Internet Engineering Task Force (IETF) A. Backman, Ed.
Internet-Draft Amazon Request for Comments: 9493 Amazon
Intended status: Standards Track M. Scurtescu Category: Standards Track M. Scurtescu
Expires: 26 December 2023 Coinbase ISSN: 2070-1721 Coinbase
P. Jain P. Jain
Fastly Fastly
24 June 2023 December 2023
Subject Identifiers for Security Event Tokens Subject Identifiers for Security Event Tokens
draft-ietf-secevent-subject-identifiers-18
Abstract Abstract
Security events communicated within Security Event Tokens may support Security events communicated within Security Event Tokens may support
a variety of identifiers to identify subjects related to the event. a variety of identifiers to identify subjects related to the event.
This specification formalizes the notion of subject identifiers as This specification formalizes the notion of Subject Identifiers as
structured information that describe a subject, and named formats structured information that describes a subject and named formats
that define the syntax and semantics for encoding subject identifiers that define the syntax and semantics for encoding Subject Identifiers
as JSON objects. It also defines a registry for defining and as JSON objects. It also establishes a registry for defining and
allocating names for such formats, as well as the "sub_id" JSON Web allocating names for such formats as well as the JSON Web Token (JWT)
Token (JWT) claim. "sub_id" Claim.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on 26 December 2023. 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 Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction
2. Notational Conventions . . . . . . . . . . . . . . . . . . . 5 2. Notational Conventions
2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 5 2.1. Definitions
3. Subject Identifiers . . . . . . . . . . . . . . . . . . . . . 5 3. Subject Identifiers
3.1. Identifier Formats versus Principal Types . . . . . . . . 6 3.1. Identifier Formats versus Principal Types
3.2. Identifier Format Definitions . . . . . . . . . . . . . . 6 3.2. Identifier Format Definitions
3.2.1. Account Identifier Format . . . . . . . . . . . . . . 7 3.2.1. Account Identifier Format
3.2.2. Email Identifier Format . . . . . . . . . . . . . . . 7 3.2.2. Email Identifier Format
3.2.3. Issuer and Subject Identifier Format . . . . . . . . 8 3.2.3. Issuer and Subject Identifier Format
3.2.4. Opaque Identifier Format . . . . . . . . . . . . . . 9 3.2.4. Opaque Identifier Format
3.2.5. Phone Number Identifier Format . . . . . . . . . . . 9 3.2.5. Phone Number Identifier Format
3.2.6. Decentralized Identifier (DID) Format . . . . . . . . 10 3.2.6. Decentralized Identifier (DID) Format
3.2.7. Uniform Resource Identifier (URI) Format . . . . . . 10 3.2.7. Uniform Resource Identifier (URI) Format
3.2.8. Aliases Identifier Format . . . . . . . . . . . . . . 11 3.2.8. Aliases Identifier Format
4. Subject Identifiers in JWTs . . . . . . . . . . . . . . . . . 12 4. Subject Identifiers in JWTs
4.1. sub_id Claim . . . . . . . . . . . . . . . . . . . . . . 12 4.1. JWT "sub_id" Claim
4.2. sub_id and iss_sub Subject Identifiers . . . . . . . . . 14 4.2. JWT "sub_id" Claim and "iss_sub" Subject Identifier
5. Considerations for Specifications that Define Identifier 5. Considerations for Specifications that Define Identifier
Formats . . . . . . . . . . . . . . . . . . . . . . . . . 15 Formats
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 15 6. Privacy Considerations
6.1. Identifier Correlation . . . . . . . . . . . . . . . . . 15 6.1. Identifier Correlation
7. Security Considerations . . . . . . . . . . . . . . . . . . . 16 7. Security Considerations
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 8. IANA Considerations
8.1. Security Event Identifier Formats Registry . . . . . . . 16 8.1. Security Event Identifier Formats Registry
8.1.1. Registry Location . . . . . . . . . . . . . . . . . . 16 8.1.1. Registration Template
8.1.2. Registration Template . . . . . . . . . . . . . . . . 16 8.1.2. Initial Registry Contents
8.1.3. Initial Registry Contents . . . . . . . . . . . . . . 17 8.1.3. Guidance for Expert Reviewers
8.1.4. Guidance for Expert Reviewers . . . . . . . . . . . . 19 8.2. JSON Web Token Claims Registration
8.2. JSON Web Token Claims Registration . . . . . . . . . . . 19 8.2.1. Registry Contents
8.2.1. Registry Contents . . . . . . . . . . . . . . . . . . 19 9. References
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 9.1. Normative References
9.1. Normative References . . . . . . . . . . . . . . . . . . 19 9.2. Informative References
9.2. Informative References . . . . . . . . . . . . . . . . . 21 Acknowledgements
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 21 Authors' Addresses
Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
1. Introduction 1. Introduction
As described in Section 1.2 of SET [RFC8417], subjects related to As described in Section 1.2 of [RFC8417] ("Security Event Token
security events may take a variety of forms, including but not (SET)"), subjects related to security events may take a variety of
limited to a JWT [RFC7519] principal, an IP address, a URL, etc. forms, including but not limited to a JWT [RFC7519] principal, an IP
Different types of subjects may need to be identified in different address, a URL, etc. Different types of subjects may need to be
ways (e.g., a user might be identified by an email address or a phone identified in different ways (e.g., a user might be identified by an
number or an account number). Furthermore, even in the case where email address, a phone number, or an account number). Furthermore,
the type of the subject is known, there may be multiple ways by which even in the case where the type of the subject is known, there may be
a given subject may be identified. For example, an account may be multiple ways by which a given subject may be identified. For
identified by an opaque identifier, an email address, a phone number, example, an account may be identified by an opaque identifier, an
a JWT "iss" claim and "sub" claim, etc., depending on the nature and email address, a phone number, a JWT "iss" Claim and "sub" Claim,
needs of the transmitter and receiver. Even within the context of a etc., depending on the nature and needs of the transmitter and
given transmitter and receiver relationship, it may be appropriate to receiver. Even within the context of a given transmitter and
identify different accounts in different ways, for example if some receiver relationship, it may be appropriate to identify different
accounts only have email addresses associated with them while others accounts in different ways, for example, if some accounts only have
only have phone numbers. Therefore it can be necessary to indicate email addresses associated with them while others only have phone
within a SET the mechanism by which a subject is being identified. 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 To address this problem, this specification defines Subject
Identifiers - JSON [RFC8259] objects containing information Identifiers as JSON [RFC8259] objects containing information
identifying a subject - and Identifier Formats - named sets of rules identifying a subject and defines Identifier Formats as named sets of
describing how to encode different kinds of subject identifying rules describing how to encode different kinds of subject-identifying
information (e.g., an email address, or an issuer and subject pair) information (e.g., an email address or an issuer and subject pair) as
as a Subject Identifier. a Subject Identifier.
Below is a non-normative example of a Subject Identifier that Below is a non-normative example of a Subject Identifier that
identifies a subject by email address, using the Email Identifier identifies a subject by email address, using the Email Identifier
Format. Format.
{ {
"format": "email", "format": "email",
"email": "user@example.com" "email": "user@example.com"
} }
Figure 1: Example: Subject Identifier using the Email Identifier Figure 1: Example: Subject Identifier Using the Email Identifier
Format Format
Subject Identifiers are intended to be a general-purpose mechanism Subject Identifiers are intended to be a general-purpose mechanism
for identifying subjects within JSON objects and their usage need not for identifying subjects within JSON objects, and their usage need
be limited to SETs. Below is a non-normative example of a JWT that not be limited to SETs. Below is a non-normative example of a JWT
uses a Subject Identifier in the "sub_id" claim (defined in this that uses a Subject Identifier in the JWT "sub_id" Claim (defined in
specification) to identify the JWT Subject. this specification) to identify the JWT Subject.
{ {
"iss": "issuer.example.com", "iss": "issuer.example.com",
"sub_id": { "sub_id": {
"format": "phone_number", "format": "phone_number",
"phone_number": "+12065550100" "phone_number": "+12065550100"
} }
} }
Figure 2: Example: JWT using a Subject Identifier with the Figure 2: Example: JWT Using a Subject Identifier with the JWT
"sub_id" claim "sub_id" Claim
Usage of Subject Identifiers also need not be limited to identifying Usage of Subject Identifiers also need not be limited to identifying
JWT Subjects. They are intended as a general-purpose means of JWT Subjects. They are intended as a general-purpose means of
expressing identifying information in an unambiguous manner. Below expressing identifying information in an unambiguous manner. Below
is a non-normative example of a SET containing a hypothetical is a non-normative example of a SET containing a hypothetical
security event describing the interception of a message, using security event describing the interception of a message, using
Subject Identifiers to identify the sender, intended recipient, and Subject Identifiers to identify the sender, intended recipient, and
interceptor. interceptor.
{ {
skipping to change at page 4, line 46 skipping to change at line 175
"email": "bob@example.com" "email": "bob@example.com"
}, },
"interceptor": { "interceptor": {
"format": "email", "format": "email",
"email": "eve@example.com" "email": "eve@example.com"
} }
} }
} }
} }
Figure 3: Example: SET with an event payload containing multiple Figure 3: Example: SET with an Event Payload Containing Multiple
Subject Identifiers Subject Identifiers
2. Notational Conventions 2. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
document are to be interpreted as described in BCP 14 "OPTIONAL" in this document are to be interpreted as described in
[RFC2119][RFC8417]. BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2.1. Definitions 2.1. Definitions
This specification utilizes terminology defined in [RFC8259] and This specification utilizes terminology defined in [RFC8259] and
[RFC8417]. [RFC8417].
Within this specification, the terms "Subject" and "subject" refer Within this specification, the terms "Subject" and "subject" refer
generically to anything being identified via one or more pieces of generically to anything being identified via one or more pieces of
information. The term "JWT Subject" refers specifically to the information. The term "JWT Subject" refers specifically to the
subject of a JWT (i.e., the subject that the JWT asserts claims subject of a JWT (i.e., the subject that the JWT asserts claims
about). about).
3. Subject Identifiers 3. Subject Identifiers
A Subject Identifier is a JSON [RFC8259] object whose contents may be A Subject Identifier is a JSON object [RFC8259] whose contents may be
used to identify a subject within some context. An Identifier Format 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 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 identify a subject and the rules for encoding that information as a
Subject Identifier; they define the syntax and semantics of Subject Subject Identifier; these rules define the syntax and semantics of
Identifiers. A Subject Identifier MUST conform to a specific Subject Identifiers. A Subject Identifier MUST conform to a specific
Identifier Format, and MUST contain a "format" member whose value is Identifier Format and MUST contain a "format" member whose value is
the name of that Identifier Format. the name of that Identifier Format.
Every Identifier Format MUST have a unique name registered in the Every Identifier Format MUST have a unique name registered in the
IANA "Security Event Identifier Formats" registry established by IANA "Security Event Identifier Formats" registry established in
Section 8.1, or a Collision-Resistant Name as defined in [RFC7519]. Section 8.1 or a Collision-Resistant Name as defined in [RFC7519].
Identifier Formats that are expected to be used broadly by a variety Identifier Formats that are expected to be used broadly by a variety
of parties SHOULD be registered in the "Security Event Identifier of parties SHOULD be registered in the "Security Event Identifier
Formats" registry. Formats" registry.
An Identifier Format MAY describe more members than are strictly An Identifier Format MAY describe more members than are strictly
necessary to identify a subject, and MAY describe conditions under necessary to identify a subject and MAY describe conditions under
which those members are required, optional, or prohibited. The which those members are required, optional, or prohibited. The
"format" member is reserved for use as described in this "format" member is reserved for use as described in this
specification; Identifier Formats MUST NOT declare any rules specification; Identifier Formats MUST NOT declare any rules
regarding the "format" member. regarding the "format" member.
Every member within a Subject Identifier MUST match the rules Every member within a Subject Identifier MUST match the rules
specified for that member by this specification or by Subject specified for that member by this specification or by a Subject
Identifier's Identifier Format. A Subject Identifier MUST NOT Identifier's Identifier Format. A Subject Identifier MUST NOT
contain any members prohibited or not described by its Identifier contain any members prohibited or not described by its Identifier
Format, and MUST contain all members required by its Identifier Format and MUST contain all members required by its Identifier
Format. Format.
3.1. Identifier Formats versus Principal Types 3.1. Identifier Formats versus Principal Types
Identifier Formats define how to encode identifying information for a Identifier Formats define how to encode identifying information for a
subject. Unlike Principal Types, they do not define the type or subject. Unlike Principal Types, they do not define the type or
nature of the subject itself. For example, while the "email" nature of the subject itself. For example, while the Email
Identifier Format declares that the value of the "email" member is an 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 address, a subject in a security event that is identified by an
"email" Subject Identifier could be an end user who controls that Email Subject Identifier could be an end user who controls that email
email address, the mailbox itself, or anything else that the address, the mailbox itself, or anything else that the transmitter
transmitter and receiver both understand to be associated with that and receiver both understand to be associated with that email
email address. Consequently Subject Identifiers remove ambiguity address. Consequently, Subject Identifiers remove ambiguity around
around how a subject is being identified, and how to parse an how a subject is being identified and how to parse an identifying
identifying structure, but do not remove ambiguity around how to structure, but they do not remove ambiguity around how to resolve
resolve that identifier to a subject. For example, consider a that identifier for a subject. For example, consider a directory
directory management API that allows callers to identify users and management API that allows callers to identify users and groups
groups through both opaque unique identifiers and email addresses. through both opaque unique identifiers and email addresses. Such an
Such an API could use Subject Identifiers to disambiguate between API could use Subject Identifiers to disambiguate between which of
which of these two types of identifiers is in use. However, the API these two types of identifiers is in use. However, the API would
would have to determine whether the subject is a user or group via have to determine whether the subject is a user or group via some
some other means, such as by querying a database, interpreting other other means, such as by querying a database, interpreting other
parameters in the request, or inferring the type from the API parameters in the request, or inferring the type from the API
contract. contract.
3.2. Identifier Format Definitions 3.2. Identifier Format Definitions
The following Identifier Formats are registered in the IANA "Security The following Identifier Formats are registered in the IANA "Security
Event Identifier Formats" registry established by Section 8.1. Event Identifier Formats" registry established in Section 8.1.
Since the subject identifier format conveys semantic information, Since the Subject Identifier Format conveys semantic information,
applications SHOULD choose the most specific possible format for the applications SHOULD choose the most specific possible format for the
identifier in question. For example, an email address can be identifier in question. For example, an email address can be
conveyed using a mailto: URI and the uri identifier format, but since conveyed using a "mailto:" URI and the URI Identifier Format, but
the value is known to be an email address, the application should since the value is known to be an email address, the application
prefer to use the "email" identifier format instead. should prefer to use the Email Identifier Format instead.
3.2.1. Account Identifier Format 3.2.1. Account Identifier Format
The Account Identifier Format identifies a subject using an account The Account Identifier Format identifies a subject using an account
at a service provider, identified with an "acct" URI as defined in at a service provider, identified with an "acct" URI as defined in
[RFC7565]. An account is an arrangement or agreement through which a [RFC7565]. An account is an arrangement or agreement through which a
user gets access to a service and gets a unique identity with the user gets access to a service and gets a unique identity with the
service provider. Subject Identifiers in this format MUST contain a service provider. Subject Identifiers in this format MUST contain a
"uri" member whose value is the "acct" URI for the subject. The "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 "uri" member is REQUIRED and MUST NOT be null or empty. The Account
skipping to change at page 8, line 8 skipping to change at line 311
{ {
"format": "email", "format": "email",
"email": "user@example.com" "email": "user@example.com"
} }
Figure 5: Example: Subject Identifier in the Email Identifier Format Figure 5: Example: Subject Identifier in the Email Identifier Format
3.2.2.1. Email Canonicalization 3.2.2.1. Email Canonicalization
Many email providers will treat multiple email addresses as Many email providers will treat multiple email addresses as
equivalent. While the domain portion of an [RFC5322] email address equivalent. While the domain portion of an email address [RFC5322]
is consistently treated as case-insensitive per [RFC1034], most is consistently treated as case-insensitive per [RFC1034], most
providers treat the local part of the email address as case- providers treat the local part of the email address as case-
insensitive as well, and consider "user@example.com", insensitive as well and consider "user@example.com",
"User@example.com", and "USER@example.com" as the same email address. "User@example.com", and "USER@example.com" as the same email address.
Some providers also treat dots (".") as optional; for example, Some providers also treat dots (".") as optional; for example,
"user.name@example.com", "username@example.com", "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 "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 all be treated as equivalent. This has led users to view these
strings as equivalent, driving service providers to implement strings as equivalent, driving service providers to implement
proprietary email canonicalization algorithms to ensure that email proprietary email canonicalization algorithms to ensure that email
addresses entered by users resolve to the same canonical string. addresses entered by users resolve to the same canonical string.
Email canonicalization is not standardized, and there is no way for Email canonicalization is not standardized, and there is no way for
the event recipient to determine the mail provider’s canonicalization the event recipient to determine the mail provider's canonicalization
method. Therefore, the recipient SHOULD apply its own method. Therefore, the recipient SHOULD apply its own
canonicalization algorithm to incoming events that reproduces the canonicalization algorithm to incoming events in order to reproduce
translation done by the local email system. the translation done by the local email system.
3.2.3. Issuer and Subject Identifier Format 3.2.3. Issuer and Subject Identifier Format
The Issuer and Subject Identifier Format identifies a subject using a The Issuer and Subject Identifier Format identifies a subject using a
pair of "iss" and "sub" members, analogous to how subjects are pair of "iss" and "sub" members, analogous to how subjects are
identified using the "iss" and "sub" claims in OpenID Connect identified using the JWT "iss" and "sub" Claims in OpenID Connect
[OpenID.Core] ID Tokens. These members MUST follow the formats of [OpenID.Core] ID Tokens. These members MUST follow the formats of
the "iss" member and "sub" member defined by [RFC7519], respectively. the "iss" member and "sub" member defined by [RFC7519], respectively.
Both the "iss" member and the "sub" member are REQUIRED and MUST NOT Both the "iss" member and the "sub" member are REQUIRED and MUST NOT
be null or empty. The Issuer and Subject Identifier Format is be null or empty. The Issuer and Subject Identifier Format is
identified by the name "iss_sub". identified by the name "iss_sub".
Below is a non-normative example Subject Identifier in the Issuer and Below is a non-normative example Subject Identifier in the Issuer and
Subject Identifier Format: Subject Identifier Format:
{ {
skipping to change at page 9, line 9 skipping to change at line 356
"sub": "145234573" "sub": "145234573"
} }
Figure 6: Example: Subject Identifier in the Issuer and Subject Figure 6: Example: Subject Identifier in the Issuer and Subject
Identifier Format Identifier Format
3.2.4. Opaque Identifier Format 3.2.4. Opaque Identifier Format
The Opaque Identifier Format describes a subject that is identified The Opaque Identifier Format describes a subject that is identified
with a string with no semantics asserted beyond its usage as an with a string with no semantics asserted beyond its usage as an
identifier for the subject, such as a UUID or hash used as a identifier for the subject, such as a Universally Unique Identifier
surrogate identifier for a record in a database. Subject Identifiers (UUID) or hash used as a surrogate identifier for a record in a
in this format MUST contain an "id" member whose value is a JSON database. Subject Identifiers in this format MUST contain an "id"
string containing the opaque string identifier for the subject. The member whose value is a JSON string containing the opaque string
"id" member is REQUIRED and MUST NOT be null or empty. The Opaque identifier for the subject. The "id" member is REQUIRED and MUST NOT
Identifier Format is identified by the name "opaque". 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 Below is a non-normative example Subject Identifier in the Opaque
Identifier Format: Identifier Format:
{ {
"format": "opaque", "format": "opaque",
"id": "11112222333344445555" "id": "11112222333344445555"
} }
Figure 7: Example: Subject Identifier in the Opaque Identifier Format Figure 7: Example: Subject Identifier in the Opaque Identifier Format
3.2.5. Phone Number Identifier Format 3.2.5. Phone Number Identifier Format
The Phone Number Identifier Format identifies a subject using a The Phone Number Identifier Format identifies a subject using a
telephone number. Subject Identifiers in this format MUST contain a telephone number. Subject Identifiers in this format MUST contain a
"phone_number" member whose value is a string containing the full "phone_number" member whose value is a string containing the full
telephone number of the subject, including international dialing telephone number of the subject, including an international dialing
prefix, formatted according to E.164 [E164]. The "phone_number" prefix, formatted according to E.164 [E164]. The "phone_number"
member is REQUIRED and MUST NOT be null or empty. 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". Identifier Format is identified by the name "phone_number".
Below is a non-normative example Subject Identifier in the Email Below is a non-normative example Subject Identifier in the Phone
Identifier Format: Number Identifier Format:
{ {
"format": "phone_number", "format": "phone_number",
"phone_number": "+12065550100" "phone_number": "+12065550100"
} }
Figure 8: Example: Subject Identifier in the Phone Number Figure 8: Example: Subject Identifier in the Phone Number
Identifier Format Identifier Format
3.2.6. Decentralized Identifier (DID) Format 3.2.6. Decentralized Identifier (DID) Format
The Decentralized Identifier Format identifies a subject using a The Decentralized Identifier (DID) Format identifies a subject using
Decentralized Identifier (DID) URL as defined in [DID]. Subject a DID URL as defined in [DID]. Subject Identifiers in this format
Identifiers in this format MUST contain a "URL" member whose value is MUST contain a "url" member whose value is a DID URL for the DID
a DID URL for the DID Subject being identified. The value of the Subject being identified. The value of the "url" member MUST be a
"url" member MUST be a valid DID URL and MAY be a bare DID. The valid DID URL and MAY be a bare DID. The "url" member is REQUIRED
"url" member is REQUIRED and MUST NOT be null or empty. The and MUST NOT be null or empty. The Decentralized Identifier Format
Decentralized Identifier Format is identified by the name "did". is identified by the name "did".
Below are non-normative example Subject Identifiers for the Below are non-normative example Subject Identifiers for the
Decentralized Identifier Format: Decentralized Identifier Format:
{ {
"format": "did", "format": "did",
"url": "did:example:123456" "url": "did:example:123456"
} }
Figure 9: Example: Subject Identifier for the Decentralized Figure 9: Example: Subject Identifier for the Decentralized
Identifier Format, identifying a subject with a bare DID Identifier Format, Identifying a Subject with a Bare DID
{ {
"format": "did", "format": "did",
"url": "did:example:123456/did/url/path?versionId=1" "url": "did:example:123456/did/url/path?versionId=1"
} }
Figure 10: Example: Subject Identifier for the Decentralized Figure 10: Example: Subject Identifier for the Decentralized
Identifier Format, identifying a subject with a DID URL with non- Identifier Format, Identifying a Subject with a DID URL with Non-
empty path and query components empty Path and Query Components
3.2.7. Uniform Resource Identifier (URI) Format 3.2.7. Uniform Resource Identifier (URI) Format
The Uniform Resource Identifier (URI) Format identifies a subject The Uniform Resource Identifier (URI) Format identifies a subject
using a URI as defined in [RFC3986]. This identifier format makes no using a URI as defined in [RFC3986]. This Identifier Format makes no
assumptions or guarantees with regard to the content, scheme, or assumptions or guarantees with regard to the content, scheme, or
reachability of the URI within the field. Subject Identifiers in reachability of the URI within the field. Subject Identifiers in
this format MUST contain a "uri" member whose value is a URI for the 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 subject being identified. The "uri" member is REQUIRED and MUST NOT
be null or empty. The URI format is identified by the name "uri". be null or empty. The URI Format is identified by the name "uri".
Below are non-normative example Subject Identifiers for the URI Below are non-normative example Subject Identifiers for the URI
format: Format:
{ {
"format": "uri", "format": "uri",
"uri": "https://user.example.com/" "uri": "https://user.example.com/"
} }
Figure 11: Example: Subject Identifier for the URI Format, Figure 11: Example: Subject Identifier for the URI Format,
identifying a subject with a website URI Identifying a Subject with a Website URI
{ {
"format": "uri", "format": "uri",
"uri": "urn:uuid:4e851e98-83c4-4743-a5da-150ecb53042f" "uri": "urn:uuid:4e851e98-83c4-4743-a5da-150ecb53042f"
} }
Figure 12: Example: Subject Identifier for the URI Format, Figure 12: Example: Subject Identifier for the URI Format,
identifying a subject with a random URN Identifying a Subject with a Random URN
3.2.8. Aliases Identifier Format 3.2.8. Aliases Identifier Format
The Aliases Identifier Format describes a subject that is identified The Aliases Identifier Format describes a subject that is identified
with a list of different Subject Identifiers. It is intended for use with a list of different Subject Identifiers. It is intended for use
when a variety of identifiers have been shared with the party that when a variety of identifiers have been shared with the party that
will be interpreting the Subject Identifier, and it is unknown which will be interpreting the Subject Identifier, and it is unknown which
of those identifiers they will recognize or support. Subject of those identifiers they will recognize or support. Subject
Identifiers in this format MUST contain an "identifiers" member whose Identifiers in this format MUST contain an "identifiers" member whose
value is a JSON array containing one or more Subject Identifiers. value is a JSON array containing one or more Subject Identifiers.
Each Subject Identifier in the array MUST identify the same entity. Each Subject Identifier in the array MUST identify the same entity.
The "identifiers" member is REQUIRED and MUST NOT be null or empty. The "identifiers" member is REQUIRED and MUST NOT be null or empty.
It MAY contain multiple instances of the same Identifier Format It MAY contain multiple instances of the same Identifier Format
(e.g., multiple Email Subject Identifiers), but SHOULD NOT contain (e.g., multiple Email Subject Identifiers) but SHOULD NOT contain
exact duplicates. This format is identified by the name "aliases". exact duplicates. This format is identified by the name "aliases".
"aliases" Subject Identifiers MUST NOT be nested; i.e., the "aliases" Subject Identifiers MUST NOT be nested, i.e., the
"identifiers" member of an "aliases" Subject Identifier MUST NOT "identifiers" member of an "aliases" Subject Identifier MUST NOT
contain a Subject Identifier in the "aliases" format. contain a Subject Identifier in the Aliases Identifier Format.
Below is a non-normative example Subject Identifier in the Aliases Below is a non-normative example Subject Identifier in the Aliases
Identifier Format: Identifier Format:
{ {
"format": "aliases", "format": "aliases",
"identifiers": [ "identifiers": [
{ {
"format": "email", "format": "email",
"email": "user@example.com" "email": "user@example.com"
skipping to change at page 12, line 28 skipping to change at line 499
"email": "user+qualifier@example.com" "email": "user+qualifier@example.com"
} }
] ]
} }
Figure 13: Example: Subject Identifier in the Aliases Identifier Figure 13: Example: Subject Identifier in the Aliases Identifier
Format Format
4. Subject Identifiers in JWTs 4. Subject Identifiers in JWTs
4.1. sub_id Claim 4.1. JWT "sub_id" Claim
The "sub" JWT Claim is defined in Section 4.1.2 of [RFC7519] as The JWT "sub" Claim is defined in Section 4.1.2 of [RFC7519] as
containing a string value, and therefore cannot contain a Subject containing a string value; therefore, it cannot contain a Subject
Identifier (which is a JSON object) as its value. This document Identifier (which is a JSON object) as its value. This document
defines the "sub_id" JWT Claim, in accordance with Section 4.2 of defines the JWT "sub_id" Claim, in accordance with Section 4.2 of
[RFC7519], as a common claim that identifies the JWT Subject using a [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. When present, the value of this claim MUST be a
Subject Identifier that identifies the subject of the JWT. The Subject Identifier that identifies the subject of the JWT. The JWT
"sub_id" claim MAY be included in a JWT, whether or not the "sub" "sub_id" Claim MAY be included in a JWT, whether or not the JWT "sub"
claim is present. When both the "sub" and "sub_id" claims are Claim is present. When both the JWT "sub" and "sub_id" Claims are
present in a JWT, they MUST identify the same subject, as a JWT has present in a JWT, they MUST identify the same subject, as a JWT has
one and only one JWT Subject. one and only one JWT Subject.
When processing a JWT with both "sub" and "sub_id" claims, When processing a JWT with both JWT "sub" and "sub_id" Claims,
implementations MUST NOT rely on both claims to determine the JWT implementations MUST NOT rely on both claims to determine the JWT
Subject. An implementation MAY attempt to determine the JWT Subject Subject. An implementation MAY attempt to determine the JWT Subject
from one claim and fall back to using the other if it determines it 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 does not understand the format of the first claim. For example, an
implementation may attempt to use "sub_id", and fall back to using implementation may attempt to use "sub_id" and fall back to using
"sub" upon finding that "sub_id" contains a Subject Identifier whose "sub" upon finding that "sub_id" contains a Subject Identifier with a
format is not recognized by the implementation. format that is not recognized by the implementation.
Below are non-normative examples of JWTs containing the "sub_id" Below are non-normative examples of JWTs containing the JWT "sub_id"
claim: Claim:
{ {
"iss": "issuer.example.com", "iss": "issuer.example.com",
"sub_id": { "sub_id": {
"format": "email", "format": "email",
"email": "user@example.com" "email": "user@example.com"
} }
} }
Figure 14: Example: JWT containing a "sub_id" claim and no "sub" Figure 14: Example: JWT Containing a JWT "sub_id" Claim and No
claim "sub" Claim
{ {
"iss": "issuer.example.com", "iss": "issuer.example.com",
"sub": "user@example.com", "sub": "user@example.com",
"sub_id": { "sub_id": {
"format": "email", "format": "email",
"email": "user@example.com" "email": "user@example.com"
} }
} }
Figure 15: Example: JWT where both the "sub" and "sub_id" claims Figure 15: Example: JWT Where the JWT "sub" and "sub_id" Claims
identify the JWT Subject using the same identifier Identify the JWT Subject Using the Same Identifier
{ {
"iss": "issuer.example.com", "iss": "issuer.example.com",
"sub": "liz@example.com", "sub": "liz@example.com",
"sub_id": { "sub_id": {
"format": "email", "format": "email",
"email": "elizabeth@example.com" "email": "elizabeth@example.com"
} }
} }
Figure 16: Example: JWT where both the "sub" and "sub_id" claims Figure 16: Example: JWT Where the JWT "sub" and "sub_id" Claims
identify the JWT Subject using different values of the same Identify the JWT Subject Using Different Values of the Same
identifier type Identifier Type
{ {
"iss": "issuer.example.com", "iss": "issuer.example.com",
"sub": "user@example.com", "sub": "user@example.com",
"sub_id": { "sub_id": {
"format": "account", "format": "account",
"uri": "acct:example.user@service.example.com" "uri": "acct:example.user@service.example.com"
} }
} }
Figure 17: Example: JWT where the "sub" and "sub_id" claims Figure 17: Example: JWT Where the JWT "sub" and "sub_id" Claims
identify the JWT Subject via different types of identifiers Identify the JWT Subject via Different Types of Identifiers
4.2. sub_id and iss_sub Subject Identifiers 4.2. JWT "sub_id" Claim and "iss_sub" Subject Identifier
The "sub_id" claim MAY contain an "iss_sub" Subject Identifier. In The JWT "sub_id" Claim MAY contain an "iss_sub" Subject Identifier.
this case, the JWT's "iss" claim and the Subject Identifier's "iss" In this case, the JWT's "iss" Claim and the Subject Identifier's
member MAY be different. For example, in OpenID Connect "iss" member MAY be different. For example, an OpenID Connect
[OpenID.Core] client may construct such a JWT when sending JWTs back [OpenID.Core] client may construct such a JWT when sending JWTs back
to its OpenID Connect Identity Provider, in order to identify the JWT to its OpenID Connect Identity Provider in order to identify the JWT
Subject using an identifier known to be understood by both parties. Subject using an identifier known to be understood by both parties.
Similarly, the JWT's "sub" claim and the Subject Identifier's "sub" Similarly, the JWT's "sub" Claim and the Subject Identifier's "sub"
member MAY be different. For example, this may be used by an OpenID member MAY be different. For example, this may be used by an OpenID
Connect client to communicate the JWT Subject's local identifier at Connect client to communicate the JWT Subject's local identifier at
the client back to its Identity Provider. the client back to its Identity Provider.
Below are non-normative examples of a JWT where the "iss" claim and Below are non-normative examples of a JWT where the JWT "iss" Claim
"iss" member within the "sub_id" claim are the same, and a JWT where and "iss" member within the JWT "sub_id" Claim are the same and a JWT
they are different. where they are different.
{ {
"iss": "issuer.example.com", "iss": "issuer.example.com",
"sub_id": { "sub_id": {
"format": "iss_sub", "format": "iss_sub",
"iss": "issuer.example.com", "iss": "issuer.example.com",
"sub": "example_user" "sub": "example_user"
} }
} }
Figure 18: Example: JWT with an "iss_sub" Subject Identifier Figure 18: Example: JWT with an "iss_sub" Subject Identifier
where JWT issuer and JWT Subject issuer are the same Where the JWT Issuer and JWT Subject Issuer Are the Same
{ {
"iss": "client.example.com", "iss": "client.example.com",
"sub_id": { "sub_id": {
"format": "iss_sub", "format": "iss_sub",
"iss": "issuer.example.com", "iss": "issuer.example.com",
"sub": "example_user" "sub": "example_user"
} }
} }
Figure 19: Example: JWT with an "iss_sub" Subject Identifier Figure 19: Example: JWT with an "iss_sub" Subject Identifier
where the JWT issuer and JWT Subject issuer are different Where the JWT Issuer and JWT Subject Issuer Are Different
{ {
"iss": "client.example.com", "iss": "client.example.com",
"sub": "client_user", "sub": "client_user",
"sub_id": { "sub_id": {
"format": "iss_sub", "format": "iss_sub",
"iss": "issuer.example.com", "iss": "issuer.example.com",
"sub": "example_user" "sub": "example_user"
} }
} }
Figure 20: Example: JWT with an "iss_sub" Subject Identifier Figure 20: Example: JWT with an "iss_sub" Subject Identifier
where the JWT "iss" and "sub" claims differ from the JWT Where the JWT "iss" and "sub" Claims Differ from the JWT
Subject's "iss" and "sub" members Subject's "iss" and "sub" Members
5. Considerations for Specifications that Define Identifier Formats 5. Considerations for Specifications that Define Identifier Formats
Identifier Format definitions MUST NOT make assertions or Identifier Format definitions MUST NOT make assertions or
declarations regarding the subject being identified by the Subject declarations regarding the subject being identified by the Subject
Identifier (e.g., an Identifier Format cannot be defined as Identifier (e.g., an Identifier Format cannot be defined as
specifically identifying human end users), as such statements are specifically identifying human end users). Such statements are
outside the scope of Identifier Formats and Subject Identifiers, and outside the scope of Identifier Formats and Subject Identifiers.
expanding that scope for some Identifier Formats but not others would Expanding that scope for some Identifier Formats but not others would
harm interoperability, as applications that depend on this expanded harm interoperability because applications that depend on this
scope to disambiguate the subject type would be unable to use expanded scope to disambiguate the subject type would be unable to
Identifier Formats that do not provide such rules. use Identifier Formats that do not provide such rules.
6. Privacy Considerations 6. Privacy Considerations
6.1. Identifier Correlation 6.1. Identifier Correlation
The act of presenting two or more identifiers for a single subject The act of presenting two or more identifiers for a single subject
together (e.g., within an "aliases" Subject Identifier, or via the together (e.g., within an "aliases" Subject Identifier or via the JWT
"sub" and "sub_id" JWT claims) may communicate more information about "sub" and "sub_id" Claims) may communicate more information about the
the subject than was intended. For example, the entity to which the subject than was intended. For example, the entity to which the
identifiers are presented now knows that both identifiers relate to identifiers are presented now knows that both identifiers relate to
the same subject, and may be able to correlate additional data based the same subject and may be able to correlate additional data based
on that. When transmitting Subject Identifiers, the transmitter on that. When transmitting Subject Identifiers, the transmitter
SHOULD take care that they are only transmitting multiple identifiers SHOULD take care that they are only transmitting multiple identifiers
together when it is known that the recipient already knows that the together when it is known that the recipient already knows that the
identifiers are related (e.g., because they were previously sent to identifiers are related (e.g., because they were previously sent to
the recipient as claims in an OpenID Connect ID Token), or when the recipient as claims in an OpenID Connect ID Token) or when
correlation is essential to the use case. Implementers must consider correlation is essential to the use case. Implementers must consider
such risks, and specifications that use subject identifiers must such risks, and specifications that use Subject Identifiers must
provide appropriate privacy considerations of their own. provide appropriate privacy considerations of their own.
The considerations described in Section 6 of [RFC8417] also apply The considerations described in Section 6 of [RFC8417] also apply
when Subject Identifiers are used within SETs. The considerations when Subject Identifiers are used within SETs. The considerations
described in Section 12 of [RFC7519] also apply when Subject described in Section 12 of [RFC7519] also apply when Subject
Identifiers are used within JWTs. Identifiers are used within JWTs.
7. Security Considerations 7. Security Considerations
This specification does not define any mechanism for ensuring the This specification does not define any mechanism for ensuring the
confidentiality or integrity of a Subject Identifier. Where such confidentiality or integrity of a Subject Identifier. Where such
properties are required, implementations MUST use mechanisms provided properties are required, implementations MUST use mechanisms provided
by the containing format (e.g., integrity protecting SETs or JWTs by the containing format (e.g., integrity protecting SETs or JWTs
using JWS [RFC7515]), or at the transport layer or other layer in the using JSON Web Signature (JWS) [RFC7515]) or at the transport layer
application stack (e.g., using TLS [RFC8446]). or other layer in the application stack (e.g., using TLS [RFC8446]).
Further considerations regarding confidentiality and integrity of Further considerations regarding confidentiality and integrity of
SETs can be found in Section 5.1 of [RFC8417]. SETs can be found in Section 5.1 of [RFC8417].
8. IANA Considerations 8. IANA Considerations
8.1. Security Event Identifier Formats Registry 8.1. Security Event Identifier Formats Registry
This document defines Identifier Formats, for which IANA is asked to This document defines Identifier Formats, for which IANA has created
create and maintain a new registry titled "Security Event Identifier and maintains a new registry titled "Security Event Identifier
Formats". Initial values for the Security Event Identifier Formats Formats". Initial values for the "Security Event Identifier Formats"
registry are given in Section 3. Future assignments are to be made registry are given in Section 3. Future assignments are to be made
through the Specification Required registration policy [BCP26] and through the Specification Required registration policy [BCP26] and
shall follow the template presented in Section 8.1.2. shall follow the template presented in Section 8.1.1.
It is suggested that multiple Designated Experts be appointed who are It is suggested that multiple designated experts be appointed who are
able to represent the perspectives of different applications using able to represent the perspectives of different applications using
this specification, in order to enable broadly informed review of this specification in order to enable broadly informed review of
registration decisions. registration decisions.
8.1.1. Registry Location 8.1.1. Registration Template
(This section to be removed by the RFC Editor before publication as
an RFC.)
The authors recommend that the Identifier Formats registry be located
at https://www.iana.org/assignments/secevent/.
8.1.2. Registration Template
Format Name Format Name:
The name of the Identifier Format, as described in Section 3. The The name of the Identifier Format, as described in Section 3. The
name MUST be an ASCII string consisting only of lower-case name MUST be an ASCII string consisting only of lowercase
characters ("a" - "z"), digits ("0" - "9"), underscores ("_"), and characters ("a" - "z"), digits ("0" - "9"), underscores ("_"), and
hyphens ("-"), and SHOULD NOT exceed 20 characters in length. hyphens ("-") and SHOULD NOT exceed 20 characters in length.
Format Description Format Description:
A brief description of the Identifier Format. A brief description of the Identifier Format.
Change Controller Change Controller:
For formats defined in documents published by the IETF or its For formats defined in documents published by the IETF or its
working groups, list "IETF". For all other formats, list the name working groups, list "IETF". For all other formats, list the name
of the party responsible for the registration. Contact of the party responsible for the registration. Contact
information such as mailing address, email address, or phone information, such as mailing address, email address, or phone
number must also be provided. number, must also be provided.
Defining Document(s) Reference:
A reference to the document or documents that define the A reference to the document or documents that define the
Identifier Format. The reference document(s) MUST specify the Identifier Format. The reference document(s) MUST specify the
name, format,and meaning of each member that may occur within a name, format, and meaning of each member that may occur within a
Subject Identifier of the defined format, as well as whether each Subject Identifier of the defined format as well as whether each
member is optional, required or conditional, and the circumstances member is optional, required, or conditional and the circumstances
under which these optional or conditional fields would be used. under which these optional or conditional fields would be used.
URIs that can be used to retrieve copies of each document SHOULD URIs that can be used to retrieve copies of each document SHOULD
be included. be included.
8.1.3. Initial Registry Contents 8.1.2. Initial Registry Contents
8.1.3.1. Account Identifier Format
* Format Name: "account"
* Format Description: Subject identifier based on acct URI.
* Change Controller: IETF
* Defining Document(s): Section 3 of this document.
8.1.3.2. Email Identifier Format
* Format Name: email
* Format Description: Subject identifier based on email address.
* Change Controller: IETF
* Defining Document(s): Section 3 of this document.
8.1.3.3. Issuer and Subject Identifier Format
* Format Name: "iss_sub"
* Format Description: Subject identifier based on an issuer and
subject.
* Change Controller: IETF
* Defining Document(s): Section 3 of this document.
8.1.3.4. Opaque Identifier Format
* Format Name: "opaque"
* Format Description: Subject identifier based on an opaque string.
* Change Controller: IETF
* Defining Document(s): Section 3 of this document.
8.1.3.5. Phone Number Identifier Format
* Format Name: "phone_number"
* Format Description: Subject identifier based on an phone number.
* Change Controller: IETF 8.1.2.1. Account Identifier Format
* Defining Document(s): Section 3 of this document. Format Name: account
Format Description: Subject Identifier based on "acct" URI
Change Controller: IETF
Reference: Section 3 of RFC 9493
8.1.3.6. Decentralized Identifier Format 8.1.2.2. Email Identifier Format
* Format Name: "did" Format Name: email
Format Description: Subject Identifier based on an email address
Change Controller: IETF
Reference: Section 3 of RFC 9493
* Format Description: Subject identifier based on a decentralized 8.1.2.3. Issuer and Subject Identifier Format
identifier (DID).
* Change Controller: IETF Format Name: iss_sub
Format Description: Subject Identifier based on an issuer and
subject
Change Controller: IETF
Reference: Section 3 of RFC 9493
* Defining Document(s): Section 3 of this document. 8.1.2.4. Opaque Identifier Format
8.1.3.7. Uniform Resource Identifier Format Format Name: opaque
Format Description: Subject Identifier based on an opaque string
Change Controller: IETF
Reference: Section 3 of RFC 9493
* Format Name: "uri" 8.1.2.5. Phone Number Identifier Format
* Format Description: Subject identifier based on a uniform resource Format Name: phone_number
identifier (URI). Format Description: Subject Identifier based on a phone number
Change Controller: IETF
Reference: Section 3 of RFC 9493
* Change Controller: IETF 8.1.2.6. Decentralized Identifier Format
* Defining Document(s): Section 3 of this document. Format Name: did
Format Description: Subject Identifier based on a decentralized
identifier (DID)
Change Controller: IETF
Reference: Section 3 of RFC 9493
8.1.3.8. Aliases Identifier Format 8.1.2.7. Uniform Resource Identifier Format
* Format Name: "aliases"
* Format Description: Subject identifier that groups together Format Name: uri
multiple different subject identifiers for the same subject. Format Description: Subject Identifier based on a Uniform Resource
Identifier (URI)
Change Controller: IETF
Reference: Section 3 of RFC 9493
* Change Controller: IETF 8.1.2.8. Aliases Identifier Format
* Defining Document(s): Section 3 of this document. 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
8.1.4. Guidance for Expert Reviewers 8.1.3. Guidance for Expert Reviewers
The Expert Reviewer is expected to review the documentation The Expert Reviewer is expected to review the documentation
referenced in a registration request to verify its completeness. The referenced in a registration request to verify its completeness. The
Expert Reviewer must base their decision to accept or reject the Expert Reviewer must base their decision to accept or reject the
request on a fair and impartial assessment of the request. If 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 Expert Reviewer has a conflict of interest, such as being an author
of a defining document referenced by the request, they must recuse of a defining document referenced by the request, they must recuse
themselves from the approval process for that request. themselves from the approval process for that request.
Identifier Formats need not be generally applicable and may be highly Identifier Formats need not be generally applicable and may be highly
specific to a particular domain; it is expected that formats may be specific to a particular domain; it is expected that formats may be
registered for niche or industry-specific use cases. The Expert registered for niche or industry-specific use cases. The Expert
Reviewer should focus on whether the format is thoroughly documented, Reviewer should focus on whether the format is thoroughly documented
and whether its registration will promote or harm interoperability. and whether its registration will promote or harm interoperability.
In most cases, the Expert Reviewer should not approve a request if In most cases, the Expert Reviewer should not approve a request if
the registration would contribute to confusion, or amount to a the registration would contribute to confusion or amount to a synonym
synonym for an existing format. for an existing format.
8.2. JSON Web Token Claims Registration 8.2. JSON Web Token Claims Registration
This document defines the sub_id JWT Claim, which IANA is asked to This document defines the JWT "sub_id" Claim, which IANA has
register in the "JSON Web Token Claims" registry IANA JSON Web Token registered in the "JSON Web Token Claims" registry [IANA.JWT.Claims]
Claims Registry [IANA.JWT.Claims] established by [RFC7519]. established by [RFC7519].
8.2.1. Registry Contents 8.2.1. Registry Contents
* Claim Name: "sub_id" Claim Name: sub_id
Claim Description: Subject Identifier
* Claim Description: Subject Identifier Change Controller: IETF
Reference: Section 4.1 of RFC 9493
* Change Controller: IETF
* Specification Document(s): Section 4.1 of this document.
9. References 9. References
9.1. Normative References 9.1. Normative References
[BCP26] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [BCP26] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, June 2017.
<https://www.rfc-editor.org/info/rfc8126>.
[DID] World Wide Web Consortium (W3C), "Decentralized <https://www.rfc-editor.org/info/bcp26>
Identifiers (DIDs) v1.0", 2021,
[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/>. <https://www.w3.org/TR/did-core/>.
[E164] International Telecommunication Union, "The international [E164] ITU-T, "E.164: The international public telecommunication
public telecommunication numbering plan", 2010, numbering plan", ITU-T Recommendation E.164, November
<https://www.itu.int/rec/T-REC-E.164-201011-I/en>. 2010, <https://www.itu.int/rec/T-REC-E.164-201011-I/en>.
[IANA.JWT.Claims] [IANA.JWT.Claims]
IANA, "JSON Web Token Claims", n.d., IANA, "JSON Web Token Claims",
<https://www.iana.org/assignments/jwt>. <https://www.iana.org/assignments/jwt>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005, RFC 3986, DOI 10.17487/RFC3986, January 2005,
skipping to change at page 20, line 48 skipping to change at line 863
<https://www.rfc-editor.org/info/rfc5322>. <https://www.rfc-editor.org/info/rfc5322>.
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token [RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015, (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<https://www.rfc-editor.org/info/rfc7519>. <https://www.rfc-editor.org/info/rfc7519>.
[RFC7565] Saint-Andre, P., "The 'acct' URI Scheme", RFC 7565, [RFC7565] Saint-Andre, P., "The 'acct' URI Scheme", RFC 7565,
DOI 10.17487/RFC7565, May 2015, DOI 10.17487/RFC7565, May 2015,
<https://www.rfc-editor.org/info/rfc7565>. <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 [RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259, Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017, DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/info/rfc8259>. <https://www.rfc-editor.org/info/rfc8259>.
[RFC8417] Hunt, P., Ed., Jones, M., Denniss, W., and M. Ansari, [RFC8417] Hunt, P., Ed., Jones, M., Denniss, W., and M. Ansari,
"Security Event Token (SET)", RFC 8417, "Security Event Token (SET)", RFC 8417,
DOI 10.17487/RFC8417, July 2018, DOI 10.17487/RFC8417, July 2018,
<https://www.rfc-editor.org/info/rfc8417>. <https://www.rfc-editor.org/info/rfc8417>.
9.2. Informative References 9.2. Informative References
[OpenID.Core] [OpenID.Core]
Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and
C. Mortimore, "OpenID Connect Core 1.0", November 2014, C. Mortimore, "OpenID Connect Core 1.0 incorporating
errata set 1", November 2014,
<https://openid.net/specs/openid-connect-core-1_0.html>. <https://openid.net/specs/openid-connect-core-1_0.html>.
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities", [RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
<https://www.rfc-editor.org/info/rfc1034>. <https://www.rfc-editor.org/info/rfc1034>.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web [RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/info/rfc7515>. 2015, <https://www.rfc-editor.org/info/rfc7515>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>. <https://www.rfc-editor.org/info/rfc8446>.
Acknowledgements Acknowledgements
The authors would like to thank the members of the IETF Security The authors would like to thank the members of the IETF Security
Events working group, as well as those of the OpenID Shared Signals Events Working Group, as well as those of the OpenID Shared Signals
and Events Working Group, whose work provided the original basis for and Events Working Group, whose work provided the original basis for
this document. We would also like to acknowledge Aaron Parecki, this document. We would also like to acknowledge Aaron Parecki,
Denis Pinkas, Justin Richer, Mike Jones and other members of the Denis Pinkas, Justin Richer, Mike Jones, and other members of the
working group for reviewing this document. working group for reviewing this document.
Change Log
(This section to be removed by the RFC Editor before publication as
an RFC.)
Draft 00 - AB - First draft
Draft 01 - AB:
* Added reference to RFC 5322 for format of email claim.
* Renamed iss_sub type to iss-sub.
* Renamed id_token_claims type to id-token-claims.
* Added text specifying the nature of the subjects described by each
type.
Draft 02 - AB:
* Corrected format of phone numbers in examples.
* Updated author info.
Draft 03 - AB:
* Added account type for acct URIs.
* Replaced id-token-claims type with aliases type.
* Added email canonicalization guidance.
* Updated semantics for email, phone, and iss-sub types.
Draft 04 - AB:
* Added sub_id JWT Claim definition, guidance, examples.
* Added text prohibiting aliases nesting.
* Added privacy considerations for identifier correlation.
Draft 05 - AB:
* Renamed the phone type to phone-number and its phone claim to
phone_number.
Draft 06 - AB:
* Replaced usage of the word "claim" to describe members of a
Subject Identifier with the word "member", in accordance with
terminology in RFC8259.
* Renamed the phone-number type to phone_number and iss-sub to
iss_sub.
* Added normative requirements limiting the use of both sub and
sub_id claims together when processing a JWT.
* Clarified that identifier correlation may be acceptable when it is
a core part of the use case.
* Replaced references to OIDF with IETF in IANA Considerations.
* Recommended the appointment of multiple Designated Experts, and a
location for the Subject Identifier Types registry.
* Added "_" to list of allowed characters in the Type Name for
Subject Identifier Types.
* Clarified that Subject Identifiers don't provide confidentiality
or integrity protection.
* Added references to SET, JWT privacy and security considerations.
* Added section describing the difference between subject identifier
type and principal type that hopefully clarifies things and
doesn't just muddy the water further.
Draft 07 - AB:
* Emphasized that the spec is about identifiers, not the things they
identify:
- Renamed "Subject Identifier Type" to "Identifier Format".
- Renamed subject_type to format.
- Renamed "Security Event Subject Identifier Type Registry" to
"Security Event Identifier Format Registry".
- Added new section with guidance for specs defining Identifier
Formats, with normative prohibition on formats that describe
the subject itself, rather than the identifier.
* Clarified the meaning of "subject":
- Defined "subject" as applying generically and "JWT Subject" as
applying specifically to the subject of a JWT.
- Replaced most instances of the word "principal" with "subject".
* Added opaque Identifier Format
Draft 08 - JR, AB:
* Added did Identifier Format
* Alphabetized identifier format definitions
* Replaced "type" with "format" in places that had been missed in
the -07 change. (mostly IANA Considerations)
* Miscellaneous editorial fixes
Draft 09 - AB:
* Miscellaneous editorial fixes
Draft 10 - PJ:
* Added author
* Editorial nits
Draft 11 - PJ:
* Miscellaneous editorial fixes
* Moved aliases to the last in identifier format definitions
* Acknowledged individual reviewers
Draft 12 - PJ:
* Restore the DID format that was removed in -11
* Added a generic "URI" format
* Normative advice on choosing the format
Draft 13 - PJ:
* Editorial nits found during AD review
Draft 14 - PJ:
* Fix IANA issues found during AD review
Draft 15 - PJ:
* Fix issues found during review
Draft 16 - PJ:
* Change controller updated to IETF
Draft 17 -PJ:
* Fixed nits identified during IESG reviews
Draft 18 -PJ:
* Fixed issues identified during IESG reviews
Authors' Addresses Authors' Addresses
Annabelle Backman (editor) Annabelle Backman (editor)
Amazon Amazon
Email: richanna@amazon.com Email: richanna@amazon.com
Marius Scurtescu Marius Scurtescu
Coinbase Coinbase
Email: marius.scurtescu@coinbase.com Email: marius.scurtescu@coinbase.com
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