JSON Web Token (JWT) Embedded Tokens
draft-yusef-oauth-nested-jwt-07
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Rifaat Shekh-Yusef , Dick Hardt , Giuseppe De Marco | ||
| Last updated | 2023-06-25 | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-yusef-oauth-nested-jwt-07
OAuth Working Group R. Shekh-Yusef
Internet-Draft Ernst & Young
Intended status: Standards Track D. Hardt
Expires: 27 December 2023 Hellō
G. De Marco
Dipartimento per la trasformazione digitale
25 June 2023
JSON Web Token (JWT) Embedded Tokens
draft-yusef-oauth-nested-jwt-07
Abstract
This specification defines a mechanism for embedding tokens into a
JWT token. The JWT token and the embedded tokens are issued by
different issuers.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
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
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 27 December 2023.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Shekh-Yusef, et al. Expires 27 December 2023 [Page 1]
Internet-Draft JWT Embedded Tokens June 2023
This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this
material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other
than English.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. STIR . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Network Service Mesh (NSM) . . . . . . . . . . . . . . . 3
2.3. Multiple Issuers for same Subject . . . . . . . . . . . . 4
2.4. Multiple tokens for multiple resources . . . . . . . . . 4
3. Authorization Request and Response . . . . . . . . . . . . . 4
3.1. Authorization Request . . . . . . . . . . . . . . . . . . 4
3.2. Authorization Successful Response . . . . . . . . . . . . 6
3.2.1. Embedded Tokens By Value . . . . . . . . . . . . . . 6
3.2.2. Embedded Tokens By Reference . . . . . . . . . . . . 7
3.3. Authorization Error Response . . . . . . . . . . . . . . 8
4. JSON Web Token Claims . . . . . . . . . . . . . . . . . . . . 8
4.1. "tokens" Claim . . . . . . . . . . . . . . . . . . . . . 8
4.1.1. "type" Claim . . . . . . . . . . . . . . . . . . . . 9
4.1.2. "token" Claim . . . . . . . . . . . . . . . . . . . . 9
4.1.3. "digest" Claim . . . . . . . . . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
8.1. Normative References . . . . . . . . . . . . . . . . . . 9
8.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
JWT is a mechanism that is used to transfer claims between two
parties across security domains. There are a number of use cases
that need to embed tokens into another JWT token.
Shekh-Yusef, et al. Expires 27 December 2023 [Page 2]
Internet-Draft JWT Embedded Tokens June 2023
This specification defines a mechanism for embedding tokens into a
JWT token. The JWT token and the embedded tokens are issued by
different issuers.
Such a mechanism allows for a proper auditing trail that allows the
Resource Server to identify who accessed what resource and on behalf
of whom. In some cases, this allows the service consuming such a
token to present some of the information contained in the nested
token or claims to the end user in real-time. In addition, in some
cases, this allows the Resource Server to apply authorization
policies based on who requested the access to the resource and on
behalf of whom is the request.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC8174].
2. Use Cases
The following are few use cases that might benefit from such a
concept:
2.1. STIR
[RFC8225] defines a PASSporT, which is a JWT, that is used to verify
the identity of a caller in an incoming call.
The PASSporT Extension for Diverted Calls draft [STIR] uses a nested
PASSporT to deliver the details of an incoming call that get
redirected. An authentication service acting for a retargeting
entity generates new PASSporT and embeds the original PASSporT inside
the new one. When the new target receives the nested PASSporT it
will be able to validate the enclosing PASSporT and use the details
of the enclosed PASSporT to identify the original target.
In this case, the original JWT is issued by the calling service, and
the new enclosing JWT is issued by the retargeting service.
2.2. Network Service Mesh (NSM)
Network Service Mesh [NSM] is a mechanism that maps the concept of a
service mesh in Kubernetes to L2/L3 payloads.
Shekh-Yusef, et al. Expires 27 December 2023 [Page 3]
Internet-Draft JWT Embedded Tokens June 2023
NSM GRPS messages may pass through multiple intermediaries, each of
which may transform the message. Each intermediary is expected to
create its own JWT token, and include a claim that contains the JWT
it received with the message it has transformed.
In this case, the original JWT is issued by the entity sending the
initial message, and the new enclosing JWT is issued by the
intermediate entity.
2.3. Multiple Issuers for same Subject
A JWT may have embedded claims from one or more separate Issuers.
An ID Token may have identity claims from independent issuers such as
DOB and a professional accreditation.
2.4. Multiple tokens for multiple resources
A JWT may embeds tokens for different audiences and scopes.
An Authorization Server issues a JWT Token that contains multiple
tokens. Each token has a specialized set of attributes and values.
The tokens can be used by the client to consume protected resources
or to obtain access tokens through a token exchange mechanism, over
different domains, releasing the minimum possible number of
information, related on the main subject, necessary for the
operation.
3. Authorization Request and Response
This section describes the mechanism to request an existing token or
tokens to be embedded in a new token. The mechanism defines a new
grant type embedded-tokens for this purpose.
In some cases, the embedding of tokens into a new token could be done
locally, if that entity is trusted to so. If this is the case, then
this request/response process defined below is not needed, and the
trusted entity can then issue the tokens in the format specified in
section 4; see the examples provided in sections 3.2.1 or 3.2.2.
3.1. Authorization Request
When a client receives a token, and it needs to transform or/and
enhance the permissions of the token, the client will send a token
request to the AS, and include the received token or tokens to be
embedded in the newly issued token that contains the transformed
token details or permissions.
Shekh-Yusef, et al. Expires 27 December 2023 [Page 4]
Internet-Draft JWT Embedded Tokens June 2023
The Client requests a token by sending an authorization request to
the authorization server’s token endpoint and include the following
parameters in a JSON payload:
grant_type (REQUIRED)
Carries the new grant type to indicate to the token endpoint that
the provided token(s) to be embedded into the newly issued token.
The parameter value MUST be urn:ietf:params:oauth:grant-
type:embedded-tokens
tokens (REQUIRED)
An array of objects, where each object represents a token that
contains the "type" claim and either the "token" claim, or the
"digest" and "jti" claims, as defined in section 4 of this
specification.
The request MAY include any of the following parameters, defined in
Section 2.1 of RFC8693: resource, audience, scope, and
requested_token_type.
The following is an example of this new token request:
POST /token
Host: as.example.com
Content-Type: application/json
{
"grant_type": "urn:ietf:params:oauth:grant-type:embedded-tokens",
"requested_token_type": "urn:ietf:params:oauth:token-type:access_token"
"tokens": [
{
"type": "urn:ietf:params:oauth:token-type:access_token",
"token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.
eyJzdWIiOiIyMzQ1Njc4OTAxIiwibmFtZSI6IkFsZXggRG9lIiwia
WF0IjoxNTE2MjM5MDIyLCJqdGkiOiJYRkVYYlNDMHhpTXUifQ.
wyycbcY9i0U5YldltNhp4WbM-gF3Q1-jtnc-Wvzyxcg"
}
]
}
The following is the decoded example embedded token in the above
example:
Shekh-Yusef, et al. Expires 27 December 2023 [Page 5]
Internet-Draft JWT Embedded Tokens June 2023
{
"alg": "HS256",
"typ": "JWT"
}
.
{
"sub": "2345678901",
"name": "Alex Doe",
"iat": 1516239022,
"jti": "XFEXbSC0xiMu"
}
3.2. Authorization Successful Response
Before issuing the requested token, the authorization server MUST
ensure that the request is valid and that the embedded token(s)
provided in the subject_token is coming from a trusted and approved
entity
In the case that the authorization server validated and approved the
request, the authorization server responds to the above request with
the standard token exchange response, as defined in section 2.2.1 of
[RFC8693].
The type of token issued is as specified in the requested_token_type
parameter, if provided. Otherwise, the type of token issued is at
the discretion of the authorization server.
3.2.1. Embedded Tokens By Value
The authorization server will typically embed the provided tokens
directly into the newly issued token, when there are no concerns
around the size of the new token with the embedded tokens.
The following is an example for a JWT token with an embedded token:
Shekh-Yusef, et al. Expires 27 December 2023 [Page 6]
Internet-Draft JWT Embedded Tokens June 2023
{
"alg": "HS256",
"typ": "JWT",
}
.
{
"sub": "1234567890",
"name": "John Doe",
"iat": 1516239022,
"tokens": [
{
"type": "urn:ietf:params:oauth:token-type:access_token",
"token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.
eyJzdWIiOiIyMzQ1Njc4OTAxIiwibmFtZSI6IkFsZXggRG9lIiwia
WF0IjoxNTE2MjM5MDIyLCJqdGkiOiJYRkVYYlNDMHhpTXUifQ.
wyycbcY9i0U5YldltNhp4WbM-gF3Q1-jtnc-Wvzyxcg"
}
]
}
3.2.2. Embedded Tokens By Reference
In some cases, embedding the tokens into the JWT directly might cause
the token size to become too large. In this case, instead of
embedding the tokens, the AS will embed a hash of the token(s) and
its associated 'jti' claim(s). This allows the Client to send these
tokens directly to the RS with the newly issued JWT, to allow the RS
to validate that the tokens are indeed associated with this new
issued JWT.
The following is an example for a JWT token with a reference to the
token:
Shekh-Yusef, et al. Expires 27 December 2023 [Page 7]
Internet-Draft JWT Embedded Tokens June 2023
{
"alg": "HS256",
"typ": "JWT",
}
.
{
"sub": "1234567890",
"name": "John Doe",
"iat": 1516239022,
"tokens": [
{
"type": "urn:ietf:params:oauth:token-type:access_token:reference",
"digest":
{
"alg": "sha-256",
"hash": "68e439fd95964da902a8654d47c51d6bc0a7791ea9895173989b263374a9a125"
}
"jti": "XFEXbSC0xiMu"
}
]
}
3.3. Authorization Error Response
If the authorization fails to validate the embedded token, then the
authorization server MUST construct an error response, as specified
in section 5.2 of RFC6749. The value of the error parameter MUST be
invalid_embedded_token error code.
The authorization server MAY include additional information regarding
the reasons for the error using the error_description as discussed in
Section 5.2 of [RFC6749].
4. JSON Web Token Claims
This section defines the new claims that will be used to represent
the embedded tokens. It defines one top-level claim, "tokens" claim,
and 3 sub claims under that, 'type', "token", and "digest" claims.
4.1. "tokens" Claim
The "tokens" claim is an array of objects, where each object
represents a token, that contains the “type” claim and either the
“token” claim, or the “digest" and “jti” claims.
Shekh-Yusef, et al. Expires 27 December 2023 [Page 8]
Internet-Draft JWT Embedded Tokens June 2023
4.1.1. "type" Claim
The "type" claim is used to indicate the type of embedded token,
which takes one of the values defined in Section 3, RFC8693.
4.1.2. "token" Claim
The "token" claim is used to hold the details of the embedded token.
4.1.3. "digest" Claim
The "digest" claim is an object that is used to hold the hash of the
token, to be used to reference the token instead of embedding it
directly in the new JWT.ß
The object contains the following two claims:
4.1.3.1. "alg" Claim
Holds the algorithm used to hash the token. By default this is "sha-
256".
4.1.3.2. "hash" Claim
Holds the hash value of the token using the algorithm defined in the
"alg" claim.
5. Security Considerations
The entity handling the incoming authorization request MUST validate
the token and ensure that it is coming from a trusted entity, before
attempting to embed that into a newly issued JWT.
6. IANA Considerations
TODO
7. Acknowledgments
TODO
8. References
8.1. Normative References
[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>.
Shekh-Yusef, et al. Expires 27 December 2023 [Page 9]
Internet-Draft JWT Embedded Tokens June 2023
[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>.
8.2. Informative References
[RFC8225] Wendt, C. and J. Peterson, "PASSporT: Personal Assertion
Token", RFC 8225, DOI 10.17487/RFC8225, February 2018,
<https://www.rfc-editor.org/info/rfc8225>.
[RFC8693] Jones, M., Nadalin, A., Campbell, B., Bradley, J., and C.
Mortimore, "OAuth 2.0 Token Exchange", October 2018.
[STIR] Peterson, J., "PASSporT Extension for Diverted Calls",
October 2018.
Authors' Addresses
Rifaat Shekh-Yusef
Ernst & Young
Ottawa, Ontario, Canada
Email: rifaat.s.ietf@gmail.com
Dick Hardt
Hellō
Seattle, Washington, USA
Email: dick.hardt@gmail.com
Giuseppe De Marco
Dipartimento per la trasformazione digitale
Italy
Email: giuseppe.demarco@teamdigitale.governo.it
Shekh-Yusef, et al. Expires 27 December 2023 [Page 10]