OAuth Working Group R. Shekh-Yusef Internet-Draft Auth0 Intended status: Standards Track March 10, 2021 Expires: September 11, 2021 Multi-Subject JSON Web Token (JWT) draft-yusef-oauth-nested-jwt-04 Abstract This specification defines a mechanism for including multiple subjects in a JWT. A primary subject in an enclosing JWT with its own claims, and a related subject in a nested JWT with its own claims. 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. 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Shekh-Yusef Expires September 11, 2021 [Page 1] Internet-Draft Nested JWT March 2021 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. Primary Subject with Secondary Authority Subject . . . . 3 2.2. Multiple Primary Subjects . . . . . . . . . . . . . . . . 3 2.3. Delegation of Authority . . . . . . . . . . . . . . . . . 3 2.4. Replaced Primary Subjects . . . . . . . . . . . . . . . . 4 2.4.1. STIR . . . . . . . . . . . . . . . . . . . . . . . . 4 2.4.2. Network Service Mesh (NSM) . . . . . . . . . . . . . 4 3. JWT Content . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 8.1. Normative References . . . . . . . . . . . . . . . . . . 5 8.2. 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. There are a number of use cases where there is a need to represent multiple related subjects in one JWT; a primary subject and a related secondary subject. This specification defines a mechanism for including multiple subjects in a JWT. A primary subject in an enclosing JWT with its Shekh-Yusef Expires September 11, 2021 [Page 2] Internet-Draft Nested JWT March 2021 own claims, and a related subject in a nested JWT with its own claims. 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 categories of use cases that might benefit from such a concept: 2.1. Primary Subject with Secondary Authority Subject A primary subject with a related secondary subject that has authority over the primary subject, e.g. Child/Parent, Pet/Owner. The secondary user (e.g., parent) logs in to an application (e.g., pharmacy application), gets redirected to the authorization server, authenticates, and asks for permission to access resources (e.g., medication) for the primary subject (e.g., child). The authorization server then issues a JWT with the primary subject in the enclosing JWT and the secondary subject in the nested JWT. In this case, both JWTs are issued by the same issuer. 2.2. Multiple Primary Subjects Two or more primary related subjects e.g. a married couple. The authorization server is setup to provide one of the subjects with permissions to access the other related subject resources. One user (e.g., wife) logs in to a application (e.g., pharmacy application), gets redirected to the authorization server, authenticates, and asks for permission to access resources (e.g., medication) for the other primary subject (e.g., husband). The authorization server then issues a JWT with the primary subject in the enclosing JWT and the other primary subject in the nested JWT. In this case, both JWTs are issued by the same issuer. 2.3. Delegation of Authority A primary subject delegates authority over a resource to a secondary subject who acts on behalf of the primary subject, as defined in [RFC8693]. Shekh-Yusef Expires September 11, 2021 [Page 3] Internet-Draft Nested JWT March 2021 In this case, both JWTs are issued by the same issuer. 2.4. Replaced Primary Subjects A primary subject is replaced with a new primary subject, and the original primary subject included in the new issued JWT as a nested JWT. 2.4.1. 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 origianl target. In this case, the original JWT is issued by the calling service, and the new enclosing JWT is issued by the retargeting service. 2.4.2. 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. 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. 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. 3. JWT Content The payload of the enclosing JWT is JSON object that contains the Claims Set of the primary subject, and one new claim that is used to hold the enclosed JWT and its relation to the primary subject. This document defines a new claim, "rsub" (Related Subject) Claim, that is used to contain the enclosed JWT and its relation to the primary subject. Shekh-Yusef Expires September 11, 2021 [Page 4] Internet-Draft Nested JWT March 2021 4. Example { "alg": "HS256", "typ": "JWT", } { "sub": "1234567890", "name": "John Doe", "iat": 1516239022, "rsub": { "rel" : urn:ietf:params:oauth:subject-type:authority | urn:ietf:params:oauth:subject-type:primary | urn:ietf:params:oauth:subject-type:actor | urn:ietf:params:oauth:subject-type:original "jwt" : "" } } 5. Security Considerations TODO 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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . Shekh-Yusef Expires September 11, 2021 [Page 5] Internet-Draft Nested JWT March 2021 8.2. Informative References [RFC8225] Wendt, C. and J. Peterson, "PASSporT: Personal Assertion Token", RFC 8225, DOI 10.17487/RFC8225, February 2018, . [RFC8693] Jpnes, 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. Author's Address Rifaat Shekh-Yusef Auth0 Ottawa, Ontario, Canada Email: rifaat.s.ietf@gmail.com Shekh-Yusef Expires September 11, 2021 [Page 6]