OAuth Working Group R. Shekh-Yusef
Internet-Draft Avaya
Intended status: Standards Track September 10, 2019
Expires: March 13, 2020
Nested JSON Web Token (JWT)
draft-yusef-oauth-nested-jwt-03
Abstract
This specification extends the scope of the Nested JSON Web Token
(JWT) to allow the enclosing JWT to contain its own Claims Set in
addition to the enclosed JWT.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Native App . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. STIR . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.3. Network Service Mesh (NSM) . . . . . . . . . . . . . . . 4
4. JWT Content Type Header Parameter . . . . . . . . . . . . . . 4
5. JWT Content . . . . . . . . . . . . . . . . . . . . . . . . . 4
6. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
10.1. Normative References . . . . . . . . . . . . . . . . . . 5
10.2. Informative References . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
JSON Web Token (JWT) [RFC7519] is a mechanism that is used to
transfer claims between two parties across security domains. Nested
JWT is a JWT in which the payload is another JWT. The current
specification does not define a means by which the enclosing JWT
could have its own Claims Set, only the enclosed JWT would have
claims.
This specification extends the scope of the Nested JWT to allow the
enclosing JWT to contain its own Claims Set in addition to the
enclosed JWT.
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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. Overview
RFC7519 defines Nested JWT as a JWT in which nested signing and/or
encryption are employed. In Nested JWTs, a JWT is used as the
payload or plaintext value of an enclosing JWS or JWE structure,
respectively.
To indicate that the payload of an enclosing JWT is yet another JWT,
the value of the Content Type Parameter of the JOSE header, i.e.
"cty", must be set to "JWT", which means that the enclosing JWT
cannot have its own claims.
This document updates the enclosing JWT content to allow it to
represent a Claims Set and an enclosed JWT, using JSON data
structures, and updates the Content Type to indicate this new nested
content.
3. Use Cases
3.1. Native App
The use case is for a telephony application that is based on the
"Native Apps Using the Browser" flow defined in RFC8252. The Native
App needs access to a telephony and non-telephony services that are
controlled by different authorization servers, where the Native App
can validate tokens issued by only one of these authorization
servers.
The Native App starts the process by interacting with a Client that
requires the user to authenticate itself using a Browser. The
Browser starts by contacting an AS, which redirects it to an OP. The
user authenticates to the OP and obtains a Code, and then gets
redirected back to AS. The Native App gets access to the Code, then
sends the Code to the AS, which then interacts with the OP to
exchange the Code for an ID Token and OP Access Token. Since the
Native App has no way of validating the OP Access Token, when the AS
creates an AS Access Token, it embeds the OP Access Token inside the
AS Access Token, and returns it back to the Native App. The Native
App gets the AS Access Token and is able to validate it and extract
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the OP Access Token, and access the different services protected with
these tokens.
3.2. 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 origianl target.
3.3. 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.
NSM GRPS messages may pass throught multiple intermediaries, each of
which may transform the message. Each intermediary is expected to
create its own JWT token, and include a claim that conains the JWT it
received with the message it has transformed.
4. JWT Content Type Header Parameter
The JOSE Header contains an optional parameter that could be used to
indicate the type of the payload of a JWT. With a typical Nested
JWT, the value of the "cty" header must be "JWT". To indicate that
the payload contains a Claims Set in addition to the JWT, the value
of the "cty" header must be "NJWT".
5. JWT Content
The payload of the enclosing JWT is JSON object that contains the
Claims Set, and one new claim that is used to hold the enclosed JWT.
This document defines a new claim, "njwt", that is used to contain
the enclosed JWT.
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6. Example
{
"alg": "HS256",
"typ": "JWT",
"cty": "NJWT"
}
{
"sub": "1234567890",
"name": "John Doe",
"iat": 1516239022,
"njwt": "<njwt>"
}
7. Security Considerations
TODO
8. IANA Considerations
TODO
9. Acknowledgments
TODO
10. References
10.1. 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>.
[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>.
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10.2. Informative References
[NSM] "Network Service Mesh (NSM),
https://networkservicemesh.io".
[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>.
[STIR] Peterson, J., "PASSporT Extension for Diverted Calls",
October 2018.
Author's Address
Rifaat Shekh-Yusef
Avaya
425 Legget Drive
Ottawa, Ontario
Canada
Phone: +1-613-595-9106
EMail: rifaat.ietf@gmail.com
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