Nested JSON Web Token (JWT)
draft-yusef-oauth-nested-jwt-00

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
• 1.1. Terminology
• 2. Overview
• 3. JWT Content Type Header Parameter
• 4. JWT Content
• 5. Example
• 6. Security Considerations
• 7. IANA Considerations
• 8. Acknowledgments
• 9. Normative References
• Author's Address

1. Introduction

JSON Web Token (JWT) 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.

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 [RFC2119].

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. 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".

4. 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.

5. Example

{
  "alg": "HS256",
  "typ": "JWT",
  "cty": "NJWT"
}

{
  "sub": "1234567890",
  "name": "John Doe",
  "iat": 1516239022,
  "njwt": "<njwt>"
}

6. Security Considerations

TODO

7. IANA Considerations

TODO

8. Acknowledgments

TODO

9. Normative References

Author's Address