JSON Web Token (JWT)
draft-ietf-oauth-json-web-token-31

Abstract

JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties. The claims in a JWT are encoded as a JavaScript Object Notation (JSON) object that is used as the payload of a JSON Web Signature (JWS) structure or as the plaintext of a JSON Web Encryption (JWE) structure, enabling the claims to be digitally signed or MACed and/or encrypted.

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 http://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 May 23, 2015.

Copyright Notice

Copyright (c) 2014 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 (http://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 Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.

Table of Contents

1.  Introduction
    1.1.  Notational Conventions
2.  Terminology
3.  JSON Web Token (JWT) Overview
    3.1.  Example JWT
4.  JWT Claims
    4.1.  Registered Claim Names
        4.1.1.  "iss" (Issuer) Claim
        4.1.2.  "sub" (Subject) Claim
        4.1.3.  "aud" (Audience) Claim
        4.1.4.  "exp" (Expiration Time) Claim
        4.1.5.  "nbf" (Not Before) Claim
        4.1.6.  "iat" (Issued At) Claim
        4.1.7.  "jti" (JWT ID) Claim
    4.2.  Public Claim Names
    4.3.  Private Claim Names
5.  JOSE Header
    5.1.  "typ" (Type) Header Parameter
    5.2.  "cty" (Content Type) Header Parameter
    5.3.  Replicating Claims as Header Parameters
6.  Unsecured JWTs
    6.1.  Example Unsecured JWT
7.  Creating and Validating JWTs
    7.1.  Creating a JWT
    7.2.  Validating a JWT
    7.3.  String Comparison Rules
8.  Implementation Requirements
9.  URI for Declaring that Content is a JWT
10.  IANA Considerations
    10.1.  JSON Web Token Claims Registry
        10.1.1.  Registration Template
        10.1.2.  Initial Registry Contents
    10.2.  Sub-Namespace Registration of urn:ietf:params:oauth:token-type:jwt
        10.2.1.  Registry Contents
    10.3.  Media Type Registration
        10.3.1.  Registry Contents
    10.4.  Header Parameter Names Registration
        10.4.1.  Registry Contents
11.  Security Considerations
    11.1.  Trust Decisions
    11.2.  Signing and Encryption Order
12.  Privacy Considerations
13.  References
    13.1.  Normative References
    13.2.  Informative References
Appendix A.  JWT Examples
    A.1.  Example Encrypted JWT
    A.2.  Example Nested JWT
Appendix B.  Relationship of JWTs to SAML Assertions
Appendix C.  Relationship of JWTs to Simple Web Tokens (SWTs)
Appendix D.  Acknowledgements
Appendix E.  Document History
§  Authors' Addresses

1.  Introduction

JSON Web Token (JWT) is a compact claims representation format intended for space constrained environments such as HTTP Authorization headers and URI query parameters. JWTs encode claims to be transmitted as a JavaScript Object Notation (JSON) [RFC7159] (Bray, T., “The JavaScript Object Notation (JSON) Data Interchange Format,” March 2014.) object that is used as the payload of a JSON Web Signature (JWS) [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.) structure or as the plaintext of a JSON Web Encryption (JWE) [JWE] (Jones, M. and J. Hildebrand, “JSON Web Encryption (JWE),” November 2014.) structure, enabling the claims to be digitally signed or MACed and/or encrypted. JWTs are always represented using the JWS Compact Serialization or the JWE Compact Serialization.

The suggested pronunciation of JWT is the same as the English word "jot".

1.1.  Notational Conventions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in Key words for use in RFCs to Indicate Requirement Levels [RFC2119] (Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” March 1997.). If these words are used without being spelled in uppercase then they are to be interpreted with their normal natural language meanings.

2.  Terminology

These terms defined by the JSON Web Signature (JWS) [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.) specification are incorporated into this specification: "JSON Web Signature (JWS)", "Base64url Encoding", "Header Parameter", "JOSE Header", "JWS Compact Serialization", "JWS Payload", "JWS Signature", and "Unsecured JWS".

These terms defined by the JSON Web Encryption (JWE) [JWE] (Jones, M. and J. Hildebrand, “JSON Web Encryption (JWE),” November 2014.) specification are incorporated into this specification: "JSON Web Encryption (JWE)", "Content Encryption Key (CEK)", "JWE Compact Serialization", "JWE Encrypted Key", "JWE Initialization Vector", and "JWE Plaintext".

These terms defined by the Internet Security Glossary, Version 2 (Shirey, R., “Internet Security Glossary, Version 2,” August 2007.) [RFC4949] are incorporated into this specification: "Ciphertext", "Digital Signature" "Message Authentication Code (MAC)", and "Plaintext".

These terms are defined by this specification:

JSON Web Token (JWT)

A string representing a set of claims as a JSON object that is encoded in a JWS or JWE, enabling the claims to be digitally signed or MACed and/or encrypted.

JWT Claims Set

A JSON object that contains the Claims conveyed by the JWT.

Claim

A piece of information asserted about a subject. A Claim is represented as a name/value pair consisting of a Claim Name and a Claim Value.

Claim Name

The name portion of a Claim representation. A Claim Name is always a string.

Claim Value

The value portion of a Claim representation. A Claim Value can be any JSON value.

Encoded JOSE Header

Base64url encoding of the JOSE Header.

Nested JWT

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.

Unsecured JWT

A JWT whose Claims are not integrity protected or encrypted.

Collision-Resistant Name

A name in a namespace that enables names to be allocated in a manner such that they are highly unlikely to collide with other names. Examples of collision-resistant namespaces include: Domain Names, Object Identifiers (OIDs) as defined in the ITU-T X.660 and X.670 Recommendation series, and Universally Unique IDentifiers (UUIDs) [RFC4122] (Leach, P., Mealling, M., and R. Salz, “A Universally Unique IDentifier (UUID) URN Namespace,” July 2005.). When using an administratively delegated namespace, the definer of a name needs to take reasonable precautions to ensure they are in control of the portion of the namespace they use to define the name.

StringOrURI

A JSON string value, with the additional requirement that while arbitrary string values MAY be used, any value containing a ":" character MUST be a URI [RFC3986] (Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” January 2005.). StringOrURI values are compared as case-sensitive strings with no transformations or canonicalizations applied.

NumericDate

A JSON numeric value representing the number of seconds from 1970-01-01T00:00:00Z UTC until the specified UTC date/time, ignoring leap seconds. This is equivalent to the IEEE Std 1003.1, 2013 Edition (Institute of Electrical and Electronics Engineers, “The Open Group Base Specifications Issue 7,” 2013.) [POSIX.1] definition "Seconds Since the Epoch", in which each day is accounted for by exactly 86400 seconds, other than that non-integer values can be represented. See RFC 3339 (Klyne, G., Ed. and C. Newman, “Date and Time on the Internet: Timestamps,” July 2002.) [RFC3339] for details regarding date/times in general and UTC in particular.

3.  JSON Web Token (JWT) Overview

JWTs represent a set of claims as a JSON object that is encoded in a JWS and/or JWE structure. This JSON object is the JWT Claims Set. As per Section 4 of RFC 7159 (Bray, T., “The JavaScript Object Notation (JSON) Data Interchange Format,” March 2014.) [RFC7159], the JSON object consists of zero or more name/value pairs (or members), where the names are strings and the values are arbitrary JSON values. These members are the claims represented by the JWT. This JSON object MAY contain white space and/or line breaks before or after any JSON values or structural characters, in accordance with Section 2 of RFC 7159 (Bray, T., “The JavaScript Object Notation (JSON) Data Interchange Format,” March 2014.) [RFC7159].

The member names within the JWT Claims Set are referred to as Claim Names. The corresponding values are referred to as Claim Values.

The contents of the JOSE Header describe the cryptographic operations applied to the JWT Claims Set. If the JOSE Header is for a JWS object, the JWT is represented as a JWS and the claims are digitally signed or MACed, with the JWT Claims Set being the JWS Payload. If the JOSE Header is for a JWE object, the JWT is represented as a JWE and the claims are encrypted, with the JWT Claims Set being the JWE Plaintext. A JWT may be enclosed in another JWE or JWS structure to create a Nested JWT, enabling nested signing and encryption to be performed.

A JWT is represented as a sequence of URL-safe parts separated by period ('.') characters. Each part contains a base64url encoded value. The number of parts in the JWT is dependent upon the representation of the resulting JWS or JWE object using the JWS Compact Serialization or the JWE Compact Serialization.

3.1.  Example JWT

The following example JOSE Header declares that the encoded object is a JSON Web Token (JWT) and the JWT is a JWS that is MACed using the HMAC SHA-256 algorithm:

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

To remove potential ambiguities in the representation of the JSON object above, the octet sequence for the actual UTF-8 representation used in this example for the JOSE Header above is also included below. (Note that ambiguities can arise due to differing platform representations of line breaks (CRLF versus LF), differing spacing at the beginning and ends of lines, whether the last line has a terminating line break or not, and other causes. In the representation used in this example, the first line has no leading or trailing spaces, a CRLF line break (13, 10) occurs between the first and second lines, the second line has one leading space (32) and no trailing spaces, and the last line does not have a terminating line break.) The octets representing the UTF-8 representation of the JOSE Header in this example (using JSON array notation) are:

[123, 34, 116, 121, 112, 34, 58, 34, 74, 87, 84, 34, 44, 13, 10, 32, 34, 97, 108, 103, 34, 58, 34, 72, 83, 50, 53, 54, 34, 125]

Base64url encoding the octets of the UTF-8 representation of the JOSE Header yields this Encoded JOSE Header value:

  eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9

The following is an example of a JWT Claims Set:

  {"iss":"joe",
   "exp":1300819380,
   "http://example.com/is_root":true}

The following octet sequence, which is the UTF-8 representation used in this example for the JWT Claims Set above, is the JWS Payload:

[123, 34, 105, 115, 115, 34, 58, 34, 106, 111, 101, 34, 44, 13, 10, 32, 34, 101, 120, 112, 34, 58, 49, 51, 48, 48, 56, 49, 57, 51, 56, 48, 44, 13, 10, 32, 34, 104, 116, 116, 112, 58, 47, 47, 101, 120, 97, 109, 112, 108, 101, 46, 99, 111, 109, 47, 105, 115, 95, 114, 111, 111, 116, 34, 58, 116, 114, 117, 101, 125]

Base64url encoding the JWS Payload yields this encoded JWS Payload (with line breaks for display purposes only):

  eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly
  9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ

Computing the MAC of the encoded JOSE Header and encoded JWS Payload with the HMAC SHA-256 algorithm and base64url encoding the HMAC value in the manner specified in [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.), yields this encoded JWS Signature:

  dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk

Concatenating these encoded parts in this order with period ('.') characters between the parts yields this complete JWT (with line breaks for display purposes only):

  eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9
  .
  eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFt
  cGxlLmNvbS9pc19yb290Ijp0cnVlfQ
  .
  dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk

This computation is illustrated in more detail in Appendix A.1 of [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.). See Appendix A.1 (Example Encrypted JWT) for an example of an encrypted JWT.

4.  JWT Claims

The JWT Claims Set represents a JSON object whose members are the claims conveyed by the JWT. The Claim Names within a JWT Claims Set MUST be unique; JWT parsers MUST either reject JWTs with duplicate Claim Names or use a JSON parser that returns only the lexically last duplicate member name, as specified in Section 15.12 (The JSON Object) of ECMAScript 5.1 [ECMAScript] (Ecma International, “ECMAScript Language Specification, 5.1 Edition,” June 2011.).

The set of claims that a JWT must contain to be considered valid is context-dependent and is outside the scope of this specification. Specific applications of JWTs will require implementations to understand and process some claims in particular ways. However, in the absence of such requirements, all claims that are not understood by implementations MUST be ignored.

There are three classes of JWT Claim Names: Registered Claim Names, Public Claim Names, and Private Claim Names.

4.1.  Registered Claim Names

The following Claim Names are registered in the IANA JSON Web Token Claims registry defined in Section 10.1 (JSON Web Token Claims Registry). None of the claims defined below are intended to be mandatory to use or implement in all cases, but rather, provide a starting point for a set of useful, interoperable claims. Applications using JWTs should define which specific claims they use and when they are required or optional. All the names are short because a core goal of JWTs is for the representation to be compact.

4.1.1.  "iss" (Issuer) Claim

The iss (issuer) claim identifies the principal that issued the JWT. The processing of this claim is generally application specific. The iss value is a case-sensitive string containing a StringOrURI value. Use of this claim is OPTIONAL.

4.1.2.  "sub" (Subject) Claim

The sub (subject) claim identifies the principal that is the subject of the JWT. The Claims in a JWT are normally statements about the subject. The subject value MUST either be scoped to be locally unique in the context of the issuer or be globally unique. The processing of this claim is generally application specific. The sub value is a case-sensitive string containing a StringOrURI value. Use of this claim is OPTIONAL.

4.1.3.  "aud" (Audience) Claim

The aud (audience) claim identifies the recipients that the JWT is intended for. Each principal intended to process the JWT MUST identify itself with a value in the audience claim. If the principal processing the claim does not identify itself with a value in the aud claim when this claim is present, then the JWT MUST be rejected. In the general case, the aud value is an array of case-sensitive strings, each containing a StringOrURI value. In the special case when the JWT has one audience, the aud value MAY be a single case-sensitive string containing a StringOrURI value. The interpretation of audience values is generally application specific. Use of this claim is OPTIONAL.

4.1.4.  "exp" (Expiration Time) Claim

The exp (expiration time) claim identifies the expiration time on or after which the JWT MUST NOT be accepted for processing. The processing of the exp claim requires that the current date/time MUST be before the expiration date/time listed in the exp claim. Implementers MAY provide for some small leeway, usually no more than a few minutes, to account for clock skew. Its value MUST be a number containing a NumericDate value. Use of this claim is OPTIONAL.

4.1.5.  "nbf" (Not Before) Claim

The nbf (not before) claim identifies the time before which the JWT MUST NOT be accepted for processing. The processing of the nbf claim requires that the current date/time MUST be after or equal to the not-before date/time listed in the nbf claim. Implementers MAY provide for some small leeway, usually no more than a few minutes, to account for clock skew. Its value MUST be a number containing a NumericDate value. Use of this claim is OPTIONAL.

4.1.6.  "iat" (Issued At) Claim

The iat (issued at) claim identifies the time at which the JWT was issued. This claim can be used to determine the age of the JWT. Its value MUST be a number containing a NumericDate value. Use of this claim is OPTIONAL.

4.1.7.  "jti" (JWT ID) Claim

The jti (JWT ID) claim provides a unique identifier for the JWT. The identifier value MUST be assigned in a manner that ensures that there is a negligible probability that the same value will be accidentally assigned to a different data object; if the application uses multiple issuers, collisions MUST be prevented among values produced by different issuers as well. The jti claim can be used to prevent the JWT from being replayed. The jti value is a case-sensitive string. Use of this claim is OPTIONAL.

4.2.  Public Claim Names

Claim Names can be defined at will by those using JWTs. However, in order to prevent collisions, any new Claim Name should either be registered in the IANA JSON Web Token Claims registry defined in Section 10.1 (JSON Web Token Claims Registry) or be a Public Name: a value that contains a Collision-Resistant Name. In each case, the definer of the name or value needs to take reasonable precautions to make sure they are in control of the part of the namespace they use to define the Claim Name.

4.3.  Private Claim Names

A producer and consumer of a JWT MAY agree to use Claim Names that are Private Names: names that are not Registered Claim Names Section 4.1 (Registered Claim Names) or Public Claim Names Section 4.2 (Public Claim Names). Unlike Public Claim Names, Private Claim Names are subject to collision and should be used with caution.

5.  JOSE Header

For a JWT object, the members of the JSON object represented by the JOSE Header describe the cryptographic operations applied to the JWT and optionally, additional properties of the JWT. Depending upon whether the JWT is a JWS or JWE, the corresponding rules for the JOSE Header values apply.

This specification further specifies the use of the following Header Parameters in both the cases where the JWT is a JWS and where it is a JWE.

5.1.  "typ" (Type) Header Parameter

The typ (type) Header Parameter defined by [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.) and [JWE] (Jones, M. and J. Hildebrand, “JSON Web Encryption (JWE),” November 2014.) is used by JWT applications to declare the MIME Media Type [IANA.MediaTypes] (Internet Assigned Numbers Authority (IANA), “MIME Media Types,” 2005.) of this complete JWT. This is intended for use by the JWT application when values that are not JWTs could also be present in an application data structure that can contain a JWT object; the application can use this value to disambiguate among the different kinds of objects that might be present. It will typically not be used by applications when it is already known that the object is a JWT. This parameter is ignored by JWT implementations; any processing of this parameter is performed by the JWT application. If present, it is RECOMMENDED that its value be JWT to indicate that this object is a JWT. While media type names are not case-sensitive, it is RECOMMENDED that JWT always be spelled using uppercase characters for compatibility with legacy implementations. Use of this Header Parameter is OPTIONAL.

5.2.  "cty" (Content Type) Header Parameter

The cty (content type) Header Parameter defined by [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.) and [JWE] (Jones, M. and J. Hildebrand, “JSON Web Encryption (JWE),” November 2014.) is used by this specification to convey structural information about the JWT.

In the normal case in which nested signing or encryption operations are not employed, the use of this Header Parameter is NOT RECOMMENDED. In the case that nested signing or encryption is employed, this Header Parameter MUST be present; in this case, the value MUST be JWT, to indicate that a Nested JWT is carried in this JWT. While media type names are not case-sensitive, it is RECOMMENDED that JWT always be spelled using uppercase characters for compatibility with legacy implementations. See Appendix A.2 (Example Nested JWT) for an example of a Nested JWT.

5.3.  Replicating Claims as Header Parameters

In some applications using encrypted JWTs, it is useful to have an unencrypted representation of some Claims. This might be used, for instance, in application processing rules to determine whether and how to process the JWT before it is decrypted.

This specification allows Claims present in the JWT Claims Set to be replicated as Header Parameters in a JWT that is a JWE, as needed by the application. If such replicated Claims are present, the application receiving them SHOULD verify that their values are identical, unless the application defines other specific processing rules for these Claims. It is the responsibility of the application to ensure that only claims that are safe to be transmitted in an unencrypted manner are replicated as Header Parameter values in the JWT.

Section 10.4.1 (Registry Contents) of this specification registers the iss (issuer), sub (subject), and aud (audience) Header Parameter names for the purpose of providing unencrypted replicas of these Claims in encrypted JWTs for applications that need them. Other specifications MAY similarly register other names that are registered Claim Names as Header Parameter names, as needed.

6.  Unsecured JWTs

To support use cases in which the JWT content is secured by a means other than a signature and/or encryption contained within the JWT (such as a signature on a data structure containing the JWT), JWTs MAY also be created without a signature or encryption. An Unsecured JWT is a JWS using the alg Header Parameter value none and with the empty string for its JWS Signature value, as defined in JSON Web Algorithms (JWA) [JWA] (Jones, M., “JSON Web Algorithms (JWA),” November 2014.); it is an Unsecured JWS with the JWT Claims Set as its JWS Payload.

6.1.  Example Unsecured JWT

The following example JOSE Header declares that the encoded object is an Unsecured JWT:

  {"alg":"none"}

Base64url encoding the octets of the UTF-8 representation of the JOSE Header yields this Encoded JOSE Header:

  eyJhbGciOiJub25lIn0

The following is an example of a JWT Claims Set:

  {"iss":"joe",
   "exp":1300819380,
   "http://example.com/is_root":true}

Base64url encoding the octets of the UTF-8 representation of the JWT Claims Set yields this encoded JWS Payload (with line breaks for display purposes only):

  eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFt
  cGxlLmNvbS9pc19yb290Ijp0cnVlfQ

The encoded JWS Signature is the empty string.

Concatenating these encoded parts in this order with period ('.') characters between the parts yields this complete JWT (with line breaks for display purposes only):

  eyJhbGciOiJub25lIn0
  .
  eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFt
  cGxlLmNvbS9pc19yb290Ijp0cnVlfQ
  .

7.  Creating and Validating JWTs

7.1.  Creating a JWT

To create a JWT, the following steps MUST be taken. The order of the steps is not significant in cases where there are no dependencies between the inputs and outputs of the steps.

1. Create a JWT Claims Set containing the desired claims. Note that white space is explicitly allowed in the representation and no canonicalization need be performed before encoding.
2. Let the Message be the octets of the UTF-8 representation of the JWT Claims Set.
3. Create a JOSE Header containing the desired set of Header Parameters. The JWT MUST conform to either the [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.) or [JWE] (Jones, M. and J. Hildebrand, “JSON Web Encryption (JWE),” November 2014.) specification. Note that white space is explicitly allowed in the representation and no canonicalization need be performed before encoding.
4. Depending upon whether the JWT is a JWS or JWE, there are two cases:
   • If the JWT is a JWS, create a JWS using the Message as the JWS Payload; all steps specified in [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.) for creating a JWS MUST be followed.
   • Else, if the JWT is a JWE, create a JWE using the Message as the JWE Plaintext; all steps specified in [JWE] (Jones, M. and J. Hildebrand, “JSON Web Encryption (JWE),” November 2014.) for creating a JWE MUST be followed.
5. If a nested signing or encryption operation will be performed, let the Message be the JWS or JWE, and return to Step 3, using a cty (content type) value of JWT in the new JOSE Header created in that step.
6. Otherwise, let the resulting JWT be the JWS or JWE.

7.2.  Validating a JWT

When validating a JWT, the following steps MUST be taken. The order of the steps is not significant in cases where there are no dependencies between the inputs and outputs of the steps. If any of the listed steps fails then the JWT MUST be rejected -- treated by the application as an invalid input.

1. Verify that the JWT contains at least one period ('.') character.
2. Let the Encoded JOSE Header be the portion of the JWT before the first period ('.') character.
3. Base64url decode the Encoded JOSE Header following the restriction that no line breaks, white space, or other additional characters have been used.
4. Verify that the resulting octet sequence is a UTF-8 encoded representation of a completely valid JSON object conforming to RFC 7159 (Bray, T., “The JavaScript Object Notation (JSON) Data Interchange Format,” March 2014.) [RFC7159]; let the JOSE Header be this JSON object.
5. Verify that the resulting JOSE Header includes only parameters and values whose syntax and semantics are both understood and supported or that are specified as being ignored when not understood.
6. Determine whether the JWT is a JWS or a JWE using any of the methods described in Section 9 of [JWE] (Jones, M. and J. Hildebrand, “JSON Web Encryption (JWE),” November 2014.).
7. Depending upon whether the JWT is a JWS or JWE, there are two cases:
   • If the JWT is a JWS, follow the steps specified in [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.) for validating a JWS. Let the Message be the result of base64url decoding the JWS Payload.
   • Else, if the JWT is a JWE, follow the steps specified in [JWE] (Jones, M. and J. Hildebrand, “JSON Web Encryption (JWE),” November 2014.) for validating a JWE. Let the Message be the JWE Plaintext.
8. If the JOSE Header contains a cty (content type) value of JWT, then the Message is a JWT that was the subject of nested signing or encryption operations. In this case, return to Step 1, using the Message as the JWT.
9. Otherwise, base64url decode the Message following the restriction that no line breaks, white space, or other additional characters have been used.
10. Verify that the resulting octet sequence is a UTF-8 encoded representation of a completely valid JSON object conforming to RFC 7159 (Bray, T., “The JavaScript Object Notation (JSON) Data Interchange Format,” March 2014.) [RFC7159]; let the JWT Claims Set be this JSON object.

Finally, note that it is an application decision which algorithms may be used in a given context. Even if a JWT can be successfully validated, unless the algorithm(s) used in the JWT are acceptable to the application, it SHOULD reject the JWT.

7.3.  String Comparison Rules

Processing a JWT inevitably requires comparing known strings to members and values in JSON objects. For example, in checking what the algorithm is, the Unicode string encoding alg will be checked against the member names in the JOSE Header to see if there is a matching Header Parameter name.

The JSON rules for doing member name comparison are described in Section 8.3 of RFC 7159 (Bray, T., “The JavaScript Object Notation (JSON) Data Interchange Format,” March 2014.) [RFC7159]. Since the only string comparison operations that are performed are equality and inequality, the same rules can be used for comparing both member names and member values against known strings.

These comparison rules MUST be used for all JSON string comparisons except in cases where the definition of the member explicitly calls out that a different comparison rule is to be used for that member value. In this specification, only the typ and cty member values do not use these comparison rules.

Some applications may include case-insensitive information in a case-sensitive value, such as including a DNS name as part of the iss (issuer) claim value. In those cases, the application may need to define a convention for the canonical case to use for representing the case-insensitive portions, such as lowercasing them, if more than one party might need to produce the same value so that they can be compared. (However if all other parties consume whatever value the producing party emitted verbatim without attempting to compare it to an independently produced value, then the case used by the producer will not matter.)

8.  Implementation Requirements

This section defines which algorithms and features of this specification are mandatory to implement. Applications using this specification can impose additional requirements upon implementations that they use. For instance, one application might require support for encrypted JWTs and Nested JWTs, while another might require support for signing JWTs with ECDSA using the P-256 curve and the SHA-256 hash algorithm (ES256).

Of the signature and MAC algorithms specified in JSON Web Algorithms (JWA) [JWA] (Jones, M., “JSON Web Algorithms (JWA),” November 2014.), only HMAC SHA-256 (HS256) and none MUST be implemented by conforming JWT implementations. It is RECOMMENDED that implementations also support RSASSA-PKCS1-V1_5 with the SHA-256 hash algorithm (RS256) and ECDSA using the P-256 curve and the SHA-256 hash algorithm (ES256). Support for other algorithms and key sizes is OPTIONAL.

Support for encrypted JWTs is OPTIONAL. If an implementation provides encryption capabilities, of the encryption algorithms specified in [JWA] (Jones, M., “JSON Web Algorithms (JWA),” November 2014.), only RSAES-PKCS1-V1_5 with 2048 bit keys (RSA1_5), AES Key Wrap with 128 and 256 bit keys (A128KW and A256KW), and the composite authenticated encryption algorithm using AES CBC and HMAC SHA-2 (A128CBC-HS256 and A256CBC-HS512) MUST be implemented by conforming implementations. It is RECOMMENDED that implementations also support using ECDH-ES to agree upon a key used to wrap the Content Encryption Key (ECDH-ES+A128KW and ECDH-ES+A256KW) and AES in Galois/Counter Mode (GCM) with 128 bit and 256 bit keys (A128GCM and A256GCM). Support for other algorithms and key sizes is OPTIONAL.

Support for Nested JWTs is OPTIONAL.

9.  URI for Declaring that Content is a JWT

This specification registers the URN urn:ietf:params:oauth:token-type:jwt for use by applications that declare content types using URIs (rather than, for instance, MIME Media Types) to indicate that the content referred to is a JWT.

10.  IANA Considerations

10.1.  JSON Web Token Claims Registry

This specification establishes the IANA JSON Web Token Claims registry for JWT Claim Names. The registry records the Claim Name and a reference to the specification that defines it. This specification registers the Claim Names defined in Section 4.1 (Registered Claim Names).

Values are registered on a Specification Required [RFC5226] (Narten, T. and H. Alvestrand, “Guidelines for Writing an IANA Considerations Section in RFCs,” May 2008.) basis after a three-week review period on the jwt-reg-review@ietf.org mailing list, on the advice of one or more Designated Experts. However, to allow for the allocation of values prior to publication, the Designated Expert(s) may approve registration once they are satisfied that such a specification will be published.

Registration requests must be sent to the jwt-reg-review@ietf.org mailing list for review and comment, with an appropriate subject (e.g., "Request to register claim: example").

Within the review period, the Designated Expert(s) will either approve or deny the registration request, communicating this decision to the review list and IANA. Denials should include an explanation and, if applicable, suggestions as to how to make the request successful. Registration requests that are undetermined for a period longer than 21 days can be brought to the IESG's attention (using the iesg@ietf.org mailing list) for resolution.

Criteria that should be applied by the Designated Expert(s) includes determining whether the proposed registration duplicates existing functionality, determining whether it is likely to be of general applicability or whether it is useful only for a single application, and whether the registration description is clear.

IANA must only accept registry updates from the Designated Expert(s) and should direct all requests for registration to the review mailing list.

It is suggested that multiple Designated Experts be appointed who are able to represent the perspectives of different applications using this specification, in order to enable broadly-informed review of registration decisions. In cases where a registration decision could be perceived as creating a conflict of interest for a particular Expert, that Expert should defer to the judgment of the other Expert(s).

[[ Note to the RFC Editor and IANA: Pearl Liang of ICANN had requested that the draft supply the following proposed registry description information.

• Protocol Category: JSON Web Token (JWT)
• Registry Location: http://www.iana.org/assignments/jwt
• Webpage Title: (same as the protocol category)
• Registry Name: JSON Web Token Claims

]]

10.1.1.  Registration Template

Claim Name:

The name requested (e.g., "iss"). Because a core goal of this specification is for the resulting representations to be compact, it is RECOMMENDED that the name be short -- not to exceed 8 characters without a compelling reason to do so. This name is case-sensitive. Names may not match other registered names in a case-insensitive manner unless the Designated Expert(s) state that there is a compelling reason to allow an exception in this particular case.

Claim Description:

Brief description of the Claim (e.g., "Issuer").

Change Controller:

For Standards Track RFCs, state "IESG". For others, give the name of the responsible party. Other details (e.g., postal address, email address, home page URI) may also be included.

Specification Document(s):

Reference to the document(s) that specify the parameter, preferably including URI(s) that can be used to retrieve copies of the document(s). An indication of the relevant sections may also be included but is not required.

10.1.2.  Initial Registry Contents

• Claim Name: iss
• Claim Description: Issuer
• Change Controller: IESG
• Specification Document(s): Section 4.1.1 ("iss" (Issuer) Claim) of [[ this document ]]

• Claim Name: sub
• Claim Description: Subject
• Change Controller: IESG
• Specification Document(s): Section 4.1.2 ("sub" (Subject) Claim) of [[ this document ]]

• Claim Name: aud
• Claim Description: Audience
• Change Controller: IESG
• Specification Document(s): Section 4.1.3 ("aud" (Audience) Claim) of [[ this document ]]

• Claim Name: exp
• Claim Description: Expiration Time
• Change Controller: IESG
• Specification Document(s): Section 4.1.4 ("exp" (Expiration Time) Claim) of [[ this document ]]

• Claim Name: nbf
• Claim Description: Not Before
• Change Controller: IESG
• Specification Document(s): Section 4.1.5 ("nbf" (Not Before) Claim) of [[ this document ]]

• Claim Name: iat
• Claim Description: Issued At
• Change Controller: IESG
• Specification Document(s): Section 4.1.6 ("iat" (Issued At) Claim) of [[ this document ]]

• Claim Name: jti
• Claim Description: JWT ID
• Change Controller: IESG
• Specification Document(s): Section 4.1.7 ("jti" (JWT ID) Claim) of [[ this document ]]

10.2.  Sub-Namespace Registration of urn:ietf:params:oauth:token-type:jwt

10.2.1.  Registry Contents

This specification registers the value token-type:jwt in the IANA urn:ietf:params:oauth registry established in An IETF URN Sub-Namespace for OAuth (Campbell, B. and H. Tschofenig, “An IETF URN Sub-Namespace for OAuth,” October 2012.) [RFC6755], which can be used to indicate that the content is a JWT.

• URN: urn:ietf:params:oauth:token-type:jwt
• Common Name: JSON Web Token (JWT) Token Type
• Change Controller: IESG
• Specification Document(s): [[this document]]

10.3.  Media Type Registration

10.3.1.  Registry Contents

This specification registers the application/jwt Media Type [RFC2046] (Freed, N. and N. Borenstein, “Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types,” November 1996.) in the MIME Media Types registry [IANA.MediaTypes] (Internet Assigned Numbers Authority (IANA), “MIME Media Types,” 2005.) in the manner described in RFC 6838 (Freed, N., Klensin, J., and T. Hansen, “Media Type Specifications and Registration Procedures,” January 2013.) [RFC6838], which can be used to indicate that the content is a JWT.

• Type Name: application
• Subtype Name: jwt
• Required Parameters: n/a
• Optional Parameters: n/a
• Encoding considerations: 8bit; JWT values are encoded as a series of base64url encoded values (some of which may be the empty string) separated by period ('.') characters.
• Security Considerations: See the Security Considerations section of [[ this document ]]
• Interoperability Considerations: n/a
• Published Specification: [[ this document ]]
• Applications that use this media type: OpenID Connect, Mozilla Persona, Salesforce, Google, Android, Windows Azure, Amazon Web Services, and numerous others
• Fragment identifier considerations: n/a
• Additional Information: Magic number(s): n/a, File extension(s): n/a, Macintosh file type code(s): n/a
• Person & email address to contact for further information: Michael B. Jones, mbj@microsoft.com
• Intended Usage: COMMON
• Restrictions on Usage: none
• Author: Michael B. Jones, mbj@microsoft.com
• Change Controller: IESG
• Provisional registration? No

10.4.  Header Parameter Names Registration

This specification registers specific Claim Names defined in Section 4.1 (Registered Claim Names) in the IANA JSON Web Signature and Encryption Header Parameters registry defined in [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.) for use by Claims replicated as Header Parameters in JWE objects, per Section 5.3 (Replicating Claims as Header Parameters).

10.4.1.  Registry Contents

• Header Parameter Name: iss
• Header Parameter Description: Issuer
• Header Parameter Usage Location(s): JWE
• Change Controller: IESG
• Specification Document(s): Section 4.1.1 ("iss" (Issuer) Claim) of [[ this document ]]

• Header Parameter Name: sub
• Header Parameter Description: Subject
• Header Parameter Usage Location(s): JWE
• Change Controller: IESG
• Specification Document(s): Section 4.1.2 ("sub" (Subject) Claim) of [[ this document ]]

• Header Parameter Name: aud
• Header Parameter Description: Audience
• Header Parameter Usage Location(s): JWE
• Change Controller: IESG
• Specification Document(s): Section 4.1.3 ("aud" (Audience) Claim) of [[ this document ]]

11.  Security Considerations

All of the security issues that are pertinent to any cryptographic application must be addressed by JWT/JWS/JWE/JWK agents. Among these issues are protecting the user's asymmetric private and symmetric secret keys and employing countermeasures to various attacks.

All the security considerations in the JWS specification also apply to JWT, as do the JWE security considerations when encryption is employed. In particular, the JWS JSON Security Considerations and Unicode Comparison Security Considerations apply equally to the JWT Claims Set in the same manner that they do to the JOSE Header.

11.1.  Trust Decisions

The contents of a JWT cannot be relied upon in a trust decision unless its contents have been cryptographically secured and bound to the context necessary for the trust decision. In particular, the key(s) used to sign and/or encrypt the JWT will typically need to verifiably be under the control of the party identified as the issuer of the JWT.

11.2.  Signing and Encryption Order

While syntactically the signing and encryption operations for Nested JWTs may be applied in any order, if both signing and encryption are necessary, normally producers should sign the message and then encrypt the result (thus encrypting the signature). This prevents attacks in which the signature is stripped, leaving just an encrypted message, as well as providing privacy for the signer. Furthermore, signatures over encrypted text are not considered valid in many jurisdictions.

Note that potential concerns about security issues related to the order of signing and encryption operations are already addressed by the underlying JWS and JWE specifications; in particular, because JWE only supports the use of authenticated encryption algorithms, cryptographic concerns about the potential need to sign after encryption that apply in many contexts do not apply to this specification.

12.  Privacy Considerations

A JWT may contain privacy-sensitive information. When this is the case, measures MUST be taken to prevent disclosure of this information to unintended parties. One way to achieve this is to use an encrypted JWT and authenticate the recipient. Another way is to ensure that JWTs containing unencrypted privacy-sensitive information are only transmitted using protocols utilizing encryption that support endpoint authentication, such as TLS. Omitting privacy-sensitive information from a JWT is the simplest way of minimizing privacy issues.

13.  References

13.1. Normative References

13.2. Informative References

Appendix A.  JWT Examples

This section contains examples of JWTs. For other example JWTs, see Section 6.1 (Example Unsecured JWT) and Appendices A.1, A.2, and A.3 of [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.).

A.1.  Example Encrypted JWT

This example encrypts the same claims as used in Section 3.1 (Example JWT) to the recipient using RSAES-PKCS1-V1_5 and AES_128_CBC_HMAC_SHA_256.

The following example JOSE Header declares that:

• The Content Encryption Key is encrypted to the recipient using the RSAES-PKCS1-V1_5 algorithm to produce the JWE Encrypted Key.
• Authenticated encryption is performed on the Plaintext using the AES_128_CBC_HMAC_SHA_256 algorithm to produce the JWE Ciphertext and the JWE Authentication Tag.

  {"alg":"RSA1_5","enc":"A128CBC-HS256"}

Other than using the octets of the UTF-8 representation of the JWT Claims Set from Section 3.1 (Example JWT) as the plaintext value, the computation of this JWT is identical to the computation of the JWE in Appendix A.2 of [JWE] (Jones, M. and J. Hildebrand, “JSON Web Encryption (JWE),” November 2014.), including the keys used.

The final result in this example (with line breaks for display purposes only) is:

  eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.
  QR1Owv2ug2WyPBnbQrRARTeEk9kDO2w8qDcjiHnSJflSdv1iNqhWXaKH4MqAkQtM
  oNfABIPJaZm0HaA415sv3aeuBWnD8J-Ui7Ah6cWafs3ZwwFKDFUUsWHSK-IPKxLG
  TkND09XyjORj_CHAgOPJ-Sd8ONQRnJvWn_hXV1BNMHzUjPyYwEsRhDhzjAD26ima
  sOTsgruobpYGoQcXUwFDn7moXPRfDE8-NoQX7N7ZYMmpUDkR-Cx9obNGwJQ3nM52
  YCitxoQVPzjbl7WBuB7AohdBoZOdZ24WlN1lVIeh8v1K4krB8xgKvRU8kgFrEn_a
  1rZgN5TiysnmzTROF869lQ.
  AxY8DCtDaGlsbGljb3RoZQ.
  MKOle7UQrG6nSxTLX6Mqwt0orbHvAKeWnDYvpIAeZ72deHxz3roJDXQyhxx0wKaM
  HDjUEOKIwrtkHthpqEanSBNYHZgmNOV7sln1Eu9g3J8.
  fiK51VwhsxJ-siBMR-YFiA

A.2.  Example Nested JWT

This example shows how a JWT can be used as the payload of a JWE or JWS to create a Nested JWT. In this case, the JWT Claims Set is first signed, and then encrypted.

The inner signed JWT is identical to the example in Appendix A.2 of [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.). Therefore, its computation is not repeated here. This example then encrypts this inner JWT to the recipient using RSAES-PKCS1-V1_5 and AES_128_CBC_HMAC_SHA_256.

The following example JOSE Header declares that:

• The Content Encryption Key is encrypted to the recipient using the RSAES-PKCS1-V1_5 algorithm to produce the JWE Encrypted Key.
• Authenticated encryption is performed on the Plaintext using the AES_128_CBC_HMAC_SHA_256 algorithm to produce the JWE Ciphertext and the JWE Authentication Tag.
• The Plaintext is itself a JWT.

  {"alg":"RSA1_5","enc":"A128CBC-HS256","cty":"JWT"}

Base64url encoding the octets of the UTF-8 representation of the JOSE Header yields this encoded JOSE Header value:

  eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwiY3R5IjoiSldUIn0

The computation of this JWT is identical to the computation of the JWE in Appendix A.2 of [JWE] (Jones, M. and J. Hildebrand, “JSON Web Encryption (JWE),” November 2014.), other than that different JOSE Header, Plaintext, JWE Initialization Vector, and Content Encryption Key values are used. (The RSA key used is the same.)

The Payload used is the octets of the ASCII [RFC20] (Cerf, V., “ASCII format for Network Interchange,” October 1969.) representation of the JWT at the end of Appendix A.2.1 of [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” November 2014.) (with all whitespace and line breaks removed), which is a sequence of 458 octets.

The JWE Initialization Vector value used (using JSON array notation) is:

[82, 101, 100, 109, 111, 110, 100, 32, 87, 65, 32, 57, 56, 48, 53, 50]

This example uses the Content Encryption Key represented by the base64url encoded value below:

  GawgguFyGrWKav7AX4VKUg

The final result for this Nested JWT (with line breaks for display purposes only) is:

  eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwiY3R5IjoiSldU
  In0.
  g_hEwksO1Ax8Qn7HoN-BVeBoa8FXe0kpyk_XdcSmxvcM5_P296JXXtoHISr_DD_M
  qewaQSH4dZOQHoUgKLeFly-9RI11TG-_Ge1bZFazBPwKC5lJ6OLANLMd0QSL4fYE
  b9ERe-epKYE3xb2jfY1AltHqBO-PM6j23Guj2yDKnFv6WO72tteVzm_2n17SBFvh
  DuR9a2nHTE67pe0XGBUS_TK7ecA-iVq5COeVdJR4U4VZGGlxRGPLRHvolVLEHx6D
  YyLpw30Ay9R6d68YCLi9FYTq3hIXPK_-dmPlOUlKvPr1GgJzRoeC9G5qCvdcHWsq
  JGTO_z3Wfo5zsqwkxruxwA.
  UmVkbW9uZCBXQSA5ODA1Mg.
  VwHERHPvCNcHHpTjkoigx3_ExK0Qc71RMEParpatm0X_qpg-w8kozSjfNIPPXiTB
  BLXR65CIPkFqz4l1Ae9w_uowKiwyi9acgVztAi-pSL8GQSXnaamh9kX1mdh3M_TT
  -FZGQFQsFhu0Z72gJKGdfGE-OE7hS1zuBD5oEUfk0Dmb0VzWEzpxxiSSBbBAzP10
  l56pPfAtrjEYw-7ygeMkwBl6Z_mLS6w6xUgKlvW6ULmkV-uLC4FUiyKECK4e3WZY
  Kw1bpgIqGYsw2v_grHjszJZ-_I5uM-9RA8ycX9KqPRp9gc6pXmoU_-27ATs9XCvr
  ZXUtK2902AUzqpeEUJYjWWxSNsS-r1TJ1I-FMJ4XyAiGrfmo9hQPcNBYxPz3GQb2
  8Y5CLSQfNgKSGt0A4isp1hBUXBHAndgtcslt7ZoQJaKe_nNJgNliWtWpJ_ebuOpE
  l8jdhehdccnRMIwAmU1n7SPkmhIl1HlSOpvcvDfhUN5wuqU955vOBvfkBOh5A11U
  zBuo2WlgZ6hYi9-e3w29bR0C2-pp3jbqxEDw3iWaf2dc5b-LnR0FEYXvI_tYk5rd
  _J9N0mg0tQ6RbpxNEMNoA9QWk5lgdPvbh9BaO195abQ.
  AVO9iT5AV4CzvDJCdhSFlQ

Appendix B.  Relationship of JWTs to SAML Assertions

SAML 2.0 (Cantor, S., Kemp, J., Philpott, R., and E. Maler, “Assertions and Protocol for the OASIS Security Assertion Markup Language (SAML) V2.0,” March 2005.) [OASIS.saml‑core‑2.0‑os] provides a standard for creating security tokens with greater expressivity and more security options than supported by JWTs. However, the cost of this flexibility and expressiveness is both size and complexity. SAML's use of XML [W3C.CR‑xml11‑20021015] (Cowan, J., “Extensible Markup Language (XML) 1.1,” October 2002.) and XML DSIG [RFC3275] (Eastlake, D., Reagle, J., and D. Solo, “(Extensible Markup Language) XML-Signature Syntax and Processing,” March 2002.) contributes to the size of SAML assertions; its use of XML and especially XML Canonicalization [W3C.REC‑xml‑c14n‑20010315] (Boyer, J., “Canonical XML Version 1.0,” March 2001.) contributes to their complexity.

JWTs are intended to provide a simple security token format that is small enough to fit into HTTP headers and query arguments in URIs. It does this by supporting a much simpler token model than SAML and using the JSON [RFC7159] (Bray, T., “The JavaScript Object Notation (JSON) Data Interchange Format,” March 2014.) object encoding syntax. It also supports securing tokens using Message Authentication Codes (MACs) and digital signatures using a smaller (and less flexible) format than XML DSIG.

Therefore, while JWTs can do some of the things SAML assertions do, JWTs are not intended as a full replacement for SAML assertions, but rather as a token format to be used when ease of implementation or compactness are considerations.

SAML Assertions are always statements made by an entity about a subject. JWTs are often used in the same manner, with the entity making the statements being represented by the iss (issuer) claim, and the subject being represented by the sub (subject) claim. However, with these claims being optional, other uses of the JWT format are also permitted.

Appendix C.  Relationship of JWTs to Simple Web Tokens (SWTs)

Both JWTs and Simple Web Tokens SWT (Hardt, D. and Y. Goland, “Simple Web Token (SWT),” November 2009.) [SWT], at their core, enable sets of claims to be communicated between applications. For SWTs, both the claim names and claim values are strings. For JWTs, while claim names are strings, claim values can be any JSON type. Both token types offer cryptographic protection of their content: SWTs with HMAC SHA-256 and JWTs with a choice of algorithms, including signature, MAC, and encryption algorithms.

Appendix D.  Acknowledgements

The authors acknowledge that the design of JWTs was intentionally influenced by the design and simplicity of Simple Web Tokens (Hardt, D. and Y. Goland, “Simple Web Token (SWT),” November 2009.) [SWT] and ideas for JSON tokens that Dick Hardt discussed within the OpenID community.

Solutions for signing JSON content were previously explored by Magic Signatures (Panzer (editor), J., Laurie, B., and D. Balfanz, “Magic Signatures,” January 2011.) [MagicSignatures], JSON Simple Sign (Bradley, J. and N. Sakimura (editor), “JSON Simple Sign,” September 2010.) [JSS], and Canvas Applications (Facebook, “Canvas Applications,” 2010.) [CanvasApp], all of which influenced this draft.

This specification is the work of the OAuth Working Group, which includes dozens of active and dedicated participants. In particular, the following individuals contributed ideas, feedback, and wording that influenced this specification:

Dirk Balfanz, Richard Barnes, Brian Campbell, Alissa Cooper, Breno de Medeiros, Stephen Farrell, Dick Hardt, Joe Hildebrand, Jeff Hodges, Edmund Jay, Yaron Y. Goland, Warren Kumari, Ben Laurie, Barry Leiba, Ted Lemon, James Manger, Prateek Mishra, Kathleen Moriarty, Tony Nadalin, Axel Nennker, John Panzer, Emmanuel Raviart, David Recordon, Eric Rescorla, Jim Schaad, Paul Tarjan, Hannes Tschofenig, Sean Turner, and Tom Yu.

Hannes Tschofenig and Derek Atkins chaired the OAuth working group and Sean Turner, Stephen Farrell, and Kathleen Moriarty served as Security area directors during the creation of this specification.

Appendix E.  Document History

[[ to be removed by the RFC Editor before publication as an RFC ]]

-31

• Updated the example IANA registration request subject line.

-30

• Applied privacy wording supplied by Stephen Farrell.
• Clarified where white space and line breaks may occur in JSON objects by referencing Section 2 of RFC 7159.
• Specified that registration reviews occur on the jwt-reg-review@ietf.org mailing list.

-29

• Used real values for examples in the IANA Registration Template.

-28

• Addressed IESG review comments by Alissa Cooper, Barry Leiba, Stephen Farrell, Ted Lemon, and Richard Barnes.
• Changed the RFC 6755 reference to be informative, based upon related IESG review feedback on draft-ietf-oauth-saml2-bearer.

-27

• Removed unused reference to RFC 4648.
• Changed to use the term "authenticated encryption" instead of "encryption", where appropriate.
• Changed the registration review period to three weeks.
• Acknowledged additional contributors.

-26

• Removed an ambiguity in numeric date representations by specifying that leap seconds are handled in the manner specified by POSIX.1.
• Addressed Gen-ART review comments by Russ Housley.
• Addressed secdir review comments by Warren Kumari and Stephen Kent.
• Replaced the terms Plaintext JWS and Plaintext JWT with Unsecured JWS and Unsecured JWT.

-25

• Reworded the language about JWT implementations ignoring the typ parameter, explicitly saying that its processing is performed by JWT applications.
• Added a Privacy Considerations section.

-24

• Cleaned up the reference syntax in a few places.
• Applied minor wording changes to the Security Considerations section.

-23

• Replaced the terms JWS Header, JWE Header, and JWT Header with a single JOSE Header term defined in the JWS specification. This also enabled a single Header Parameter definition to be used and reduced other areas of duplication between specifications.

-22

• Revised the introduction to the Security Considerations section. Also introduced subsection headings for security considerations items.
• Added text about when applications typically would and would not use the typ header parameter.

-21

• Removed unnecessary informative JWK spec reference.

-20

• Changed the RFC 6755 reference to be normative.
• Changed the JWK reference to be informative.
• Described potential sources of ambiguity in representing the JSON objects used in the examples. The octets of the actual UTF-8 representations of the JSON objects used in the examples are included to remove these ambiguities.
• Noted that octet sequences are depicted using JSON array notation.

-19

• Specified that support for Nested JWTs is optional and that applications using this specification can impose additional requirements upon implementations that they use.
• Updated the JSON reference to RFC 7159.

-18

• Clarified that the base64url encoding includes no line breaks, white space, or other additional characters.
• Removed circularity in the audience claim definition.
• Clarified that it is entirely up to applications which claims to use.
• Changed "SHOULD" to "MUST" in "in the absence of such requirements, all claims that are not understood by implementations MUST be ignored".
• Clarified that applications can define their own processing rules for claims replicated in header parameters, rather than always requiring that they be identical in the JWT Header and JWT Claims Set.
• Removed a JWT creation step that duplicated a step in the underlying JWS or JWE creation.
• Added security considerations about using JWTs in trust decisions.

-17

• Corrected RFC 2119 terminology usage.
• Replaced references to draft-ietf-json-rfc4627bis with RFC 7158.

-16

• Changed some references from being normative to informative, per JOSE issue #90.

-15

• Replaced references to RFC 4627 with draft-ietf-json-rfc4627bis.

-14

• Referenced the JWE section on Distinguishing between JWS and JWE Objects.

-13

• Added Claim Description registry field.
• Used Header Parameter Description registry field.
• Removed the phrases "JWA signing algorithms" and "JWA encryption algorithms".
• Removed the term JSON Text Object.

-12

• Tracked the JOSE change refining the typ and cty definitions to always be MIME Media Types, with the omission of "application/" prefixes recommended for brevity. For compatibility with legacy implementations, it is RECOMMENDED that JWT always be spelled using uppercase characters when used as a typ or cty value. As side effects, this change removed the typ Claim definition and narrowed the uses of the URI urn:ietf:params:oauth:token-type:jwt.
• Updated base64url definition to match JOSE definition.
• Changed terminology from "Reserved Claim Name" to "Registered Claim Name" to match JOSE terminology change.
• Applied other editorial changes to track parallel JOSE changes.
• Clarified that the subject value may be scoped to be locally unique in the context of the issuer or may be globally unique.

-11

• Added a Nested JWT example.
• Added sub to the list of Claims registered for use as Header Parameter values when an unencrypted representation is required in an encrypted JWT.

-10

• Allowed Claims to be replicated as Header Parameters in encrypted JWTs as needed by applications that require an unencrypted representation of specific Claims.

-09

• Clarified that the typ header parameter is used in an application-specific manner and has no effect upon the JWT processing.
• Stated that recipients MUST either reject JWTs with duplicate Header Parameter Names or with duplicate Claim Names or use a JSON parser that returns only the lexically last duplicate member name.

-08

• Tracked a change to how JWEs are computed (which only affected the example encrypted JWT value).

-07

• Defined that the default action for claims that are not understood is to ignore them unless otherwise specified by applications.
• Changed from using the term "byte" to "octet" when referring to 8 bit values.
• Tracked encryption computation changes in the JWE specification.

-06

• Changed the name of the prn claim to sub (subject) both to more closely align with SAML name usage and to use a more intuitive name.
• Allow JWTs to have multiple audiences.
• Applied editorial improvements suggested by Jeff Hodges, Prateek Mishra, and Hannes Tschofenig. Many of these simplified the terminology used.
• Explained why Nested JWTs should be signed and then encrypted.
• Clarified statements of the form "This claim is OPTIONAL" to "Use of this claim is OPTIONAL".
• Referenced String Comparison Rules in JWS.
• Added seriesInfo information to Internet Draft references.

-05

• Updated values for example AES CBC calculations.

-04

• Promoted Initialization Vector from being a header parameter to being a top-level JWE element. This saves approximately 16 bytes in the compact serialization, which is a significant savings for some use cases. Promoting the Initialization Vector out of the header also avoids repeating this shared value in the JSON serialization.
• Applied changes made by the RFC Editor to RFC 6749's registry language to this specification.
• Reference RFC 6755 -- An IETF URN Sub-Namespace for OAuth.

-03

• Added statement that "StringOrURI values are compared as case-sensitive strings with no transformations or canonicalizations applied".
• Indented artwork elements to better distinguish them from the body text.

-02

• Added an example of an encrypted JWT.
• Added this language to Registration Templates: "This name is case sensitive. Names that match other registered names in a case insensitive manner SHOULD NOT be accepted."
• Applied editorial suggestions.

-01

• Added the cty (content type) header parameter for declaring type information about the secured content, as opposed to the typ (type) header parameter, which declares type information about this object. This significantly simplified nested JWTs.
• Moved description of how to determine whether a header is for a JWS or a JWE from the JWT spec to the JWE spec.
• Changed registration requirements from RFC Required to Specification Required with Expert Review.
• Added Registration Template sections for defined registries.
• Added Registry Contents sections to populate registry values.
• Added "Collision Resistant Namespace" to the terminology section.
• Numerous editorial improvements.

-00

• Created the initial IETF draft based upon draft-jones-json-web-token-10 with no normative changes.

Authors' Addresses