[Docs] [txt|pdf|xml|html] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-jones-json-web-key) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 RFC 7517

JOSE Working Group                                              M. Jones
Internet-Draft                                                 Microsoft
Intended status: Standards Track                            July 6, 2012
Expires: January 7, 2013


                           JSON Web Key (JWK)
                    draft-ietf-jose-json-web-key-03

Abstract

   A JSON Web Key (JWK) is a JavaScript Object Notation (JSON) data
   structure that represents a public key.  This specification also
   defines a JSON Web Key Set (JWK Set) JSON data structure for
   representing a set of JWKs.  Cryptographic algorithms and identifiers
   for use with this specification are described in the separate JSON
   Web Algorithms (JWA) specification.

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 January 7, 2013.

Copyright Notice

   Copyright (c) 2012 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



Jones                    Expires January 7, 2013                [Page 1]


Internet-Draft                     JWK                         July 2012


   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Notational Conventions . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Example JSON Web Key Set . . . . . . . . . . . . . . . . . . .  4
   4.  JSON Web Key (JWK) Format  . . . . . . . . . . . . . . . . . .  4
     4.1.  "alg" (Algorithm Family) Parameter . . . . . . . . . . . .  5
     4.2.  "use" (Key Use) Parameter  . . . . . . . . . . . . . . . .  5
     4.3.  "kid" (Key ID) Parameter . . . . . . . . . . . . . . . . .  5
   5.  JSON Web Key Set (JWK Set) Format  . . . . . . . . . . . . . .  6
     5.1.  "keys" (JSON Web Key Set) Parameter  . . . . . . . . . . .  6
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  6
     6.1.  JSON Web Key Parameters Registry . . . . . . . . . . . . .  7
       6.1.1.  Registration Template  . . . . . . . . . . . . . . . .  7
       6.1.2.  Initial Registry Contents  . . . . . . . . . . . . . .  7
     6.2.  JSON Web Key Set Parameters Registry . . . . . . . . . . .  8
       6.2.1.  Registration Template  . . . . . . . . . . . . . . . .  8
       6.2.2.  Initial Registry Contents  . . . . . . . . . . . . . .  8
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . .  8
   8.  Open Issues  . . . . . . . . . . . . . . . . . . . . . . . . .  9
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . .  9
     9.1.  Normative References . . . . . . . . . . . . . . . . . . .  9
     9.2.  Informative References . . . . . . . . . . . . . . . . . .  9
   Appendix A.  Acknowledgements  . . . . . . . . . . . . . . . . . . 10
   Appendix B.  Document History  . . . . . . . . . . . . . . . . . . 10
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 11





















Jones                    Expires January 7, 2013                [Page 2]


Internet-Draft                     JWK                         July 2012


1.  Introduction

   A JSON Web Key (JWK) is a JavaScript Object Notation (JSON) [RFC4627]
   data structure that represents a public key.  This specification also
   defines a JSON Web Key Set (JWK Set) JSON data structure for
   representing a set of JWKs.  Cryptographic algorithms and identifiers
   for use with this specification are described in the separate JSON
   Web Algorithms (JWA) [JWA] specification.

   Goals for this specification do not include representing private
   keys, representing symmetric keys, representing certificate chains,
   representing certified keys, and replacing X.509 certificates.

   JWKs and JWK Sets are used in the JSON Web Signature (JWS) [JWS] and
   JSON Web Encryption (JWE) [JWE] specifications.

1.1.  Notational Conventions

   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 Key words for use in
   RFCs to Indicate Requirement Levels [RFC2119].


2.  Terminology

   JSON Web Key (JWK)  A JSON data structure that represents a public
      key.

   JSON Web Key Set (JWK Set)  A JSON object that contains an array of
      JWKs as a member.

   Base64url Encoding  For the purposes of this specification, this term
      always refers to the URL- and filename-safe Base64 encoding
      described in RFC 4648 [RFC4648], Section 5, with the (non URL-
      safe) '=' padding characters omitted, as permitted by Section 3.2.
      (See Appendix C of [JWS] for notes on implementing base64url
      encoding without padding.)

   Collision Resistant Namespace  A namespace that allows names to be
      allocated in a manner such that they are highly unlikely to
      collide with other names.  For instance, collision resistance can
      be achieved through administrative delegation of portions of the
      namespace or through use of collision-resistant name allocation
      functions.  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].  When using an administratively



Jones                    Expires January 7, 2013                [Page 3]


Internet-Draft                     JWK                         July 2012


      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.


3.  Example JSON Web Key Set

   The following example JWK Set contains two public keys represented as
   JWKs: one using an Elliptic Curve algorithm and a second one using an
   RSA algorithm.  The first specifies that the key is to be used for
   encryption.  Both provide a Key ID for key matching purposes.  In
   both cases, integers are represented using the base64url encoding of
   their big endian representations.  (Long lines are broken are for
   display purposes only.)
   {"keys":
     [
       {"alg":"EC",
        "crv":"P-256",
        "x":"MKBCTNIcKUSDii11ySs3526iDZ8AiTo7Tu6KPAqv7D4",
        "y":"4Etl6SRW2YiLUrN5vfvVHuhp7x8PxltmWWlbbM4IFyM",
        "use":"enc",
        "kid":"1"},

       {"alg":"RSA",
        "mod": "0vx7agoebGcQSuuPiLJXZptN9nndrQmbXEps2aiAFbWhM78LhWx
   4cbbfAAtVT86zwu1RK7aPFFxuhDR1L6tSoc_BJECPebWKRXjBZCiFV4n3oknjhMs
   tn64tZ_2W-5JsGY4Hc5n9yBXArwl93lqt7_RN5w6Cf0h4QyQ5v-65YGjQR0_FDW2
   QvzqY368QQMicAtaSqzs8KJZgnYb9c7d0zgdAZHzu6qMQvRL5hajrn1n91CbOpbI
   SD08qNLyrdkt-bFTWhAI4vMQFh6WeZu0fM4lFd2NcRwr3XPksINHaQ-G_xBniIqb
   w0Ls1jF44-csFCur-kEgU8awapJzKnqDKgw",
        "exp":"AQAB",
        "kid":"2011-04-29"}
     ]
   }


4.  JSON Web Key (JWK) Format

   A JSON Web Key (JWK) is a JSON object containing specific members, as
   specified below.  Those members that are common to all key types are
   defined below.

   A JWK also requires members that are specific to the particular kind
   of key to represent the key parameters.  See Section 5 of the JSON
   Web Algorithms (JWA) [JWA] specification for definitions of the
   members specific to the kinds of keys defined there.

   The member names within a JWK MUST be unique; objects with duplicate



Jones                    Expires January 7, 2013                [Page 4]


Internet-Draft                     JWK                         July 2012


   member names MUST be rejected.

   Additional members MAY be present in the JWK.  If present, they MUST
   be understood by implementations using them.  Member names for
   representing specific kinds of keys SHOULD either be registered in
   the IANA JSON Web Key Parameters registry Section 6.1 or be URIs that
   contain a Collision Resistant Namespace.

4.1.  "alg" (Algorithm Family) Parameter

   The "alg" (algorithm family) member identifies the cryptographic
   algorithm family used with the key.  The "alg" value is case
   sensitive.  Its value MUST be a string.

   A list of defined "alg" values is presented in Section 5.1 of the
   JSON Web Algorithms (JWA) [JWA] specification.  Additional members
   used with these "alg" values are defined in Sections 5.2 and 5.3 of
   the JSON Web Algorithms (JWA) [JWA] specification. "alg" values
   SHOULD either be registered in the IANA JSON Web Key Algorithm
   Families registry [JWA] or be a URI that contains a Collision
   Resistant Namespace.

4.2.  "use" (Key Use) Parameter

   The "use" (key use) member identifies the intended use of the key.
   Values defined by this specification are:

   o  "sig" (signature)

   o  "enc" (encryption)

   Other values MAY be used.  The "use" value is case sensitive.  Its
   value MUST be a string.  This member is OPTIONAL.

4.3.  "kid" (Key ID) Parameter

   The "kid" (key ID) member can be used to match a specific key.  This
   can be used, for instance, to choose among a set of keys within the
   JWK during key rollover.  The interpretation of the "kid" value is
   unspecified.  Key ID values within a JWK Set need not be unique; for
   instance, in some contexts different keys using the same Key ID value
   might be present, with the keys being disambiguated using other
   information, such as the "alg" or "use" values.  The "kid" value is
   case sensitive.  Its value MUST be a string.  This member is
   OPTIONAL.

   When used with JWS or JWE, the "kid" value MAY be used to match a JWS
   or JWE "kid" header parameter value.



Jones                    Expires January 7, 2013                [Page 5]


Internet-Draft                     JWK                         July 2012


5.  JSON Web Key Set (JWK Set) Format

   A JSON Web Key Set (JWK Set) is a JSON object that contains an array
   of JSON Web Key values as the value of its "keys" member.

   The member names within a JWK Set MUST be unique; objects with
   duplicate member names MUST be rejected.

   Additional members MAY be present in the JWK Set. If present, they
   MUST be understood by implementations using them.  Parameters for
   representing additional properties of JWK Sets SHOULD either be
   registered in the IANA JSON Web Key Set Parameters registry
   Section 6.2 or be a URI that contains a Collision Resistant
   Namespace.

5.1.  "keys" (JSON Web Key Set) Parameter

   The value of the "keys" (JSON Web Key Set) member is an array of JSON
   Web Key (JWK) values.  This member is REQUIRED.


6.  IANA Considerations

   The following registration procedure is used for all the registries
   established by this specification.

   Values are registered with a Specification Required [RFC5226] after a
   two week review period on the [TBD]@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 [TBD]@ietf.org mailing list
   for review and comment, with an appropriate subject (e.g., "Request
   for access token type: example"). [[ Note to RFC-EDITOR: The name of
   the mailing list should be determined in consultation with the IESG
   and IANA.  Suggested name: jose-reg-review. ]]

   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.

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



Jones                    Expires January 7, 2013                [Page 6]


Internet-Draft                     JWK                         July 2012


6.1.  JSON Web Key Parameters Registry

   This specification establishes the IANA JSON Web Key Parameters
   registry for reserved JWK parameter names.  The registry records the
   reserved parameter name and a reference to the specification that
   defines it.  This specification registers the parameter names defined
   in Section 4.

6.1.1.  Registration Template

   Parameter Name:
      The name requested (e.g., "example").

   Change Controller:
      For standards-track RFCs, state "IETF".  For others, give the name
      of the responsible party.  Other details (e.g., postal address,
      e-mail address, home page URI) may also be included.

   Specification Document(s):
      Reference to the document that specifies the parameter, preferably
      including a URI that can be used to retrieve a copy of the
      document.  An indication of the relevant sections may also be
      included, but is not required.

6.1.2.  Initial Registry Contents

   o  Parameter Name: "alg"

   o  Change Controller: IETF

   o  Specification Document(s): Section 4.1 of [[ this document ]]

   o  Parameter Name: "use"

   o  Change Controller: IETF

   o  Specification Document(s): Section 4.2 of [[ this document ]]

   o  Parameter Name: "kid"

   o  Change Controller: IETF

   o  Specification Document(s): Section 4.3 of [[ this document ]]








Jones                    Expires January 7, 2013                [Page 7]


Internet-Draft                     JWK                         July 2012


6.2.  JSON Web Key Set Parameters Registry

   This specification establishes the IANA JSON Web Key Set Parameters
   registry for reserved JWK Set parameter names.  The registry records
   the reserved parameter name and a reference to the specification that
   defines it.  This specification registers the parameter names defined
   in Section 5.

6.2.1.  Registration Template

   Parameter Name:
      The name requested (e.g., "example").

   Change Controller:
      For standards-track RFCs, state "IETF".  For others, give the name
      of the responsible party.  Other details (e.g., postal address,
      e-mail address, home page URI) may also be included.

   Specification Document(s):
      Reference to the document that specifies the parameter, preferably
      including a URI that can be used to retrieve a copy of the
      document.  An indication of the relevant sections may also be
      included, but is not required.

6.2.2.  Initial Registry Contents

   o  Parameter Name: "keys"

   o  Change Controller: IETF

   o  Specification Document(s): Section 5.1 of [[ this document ]]


7.  Security Considerations

   All of the security issues faced by any cryptographic application
   must be faced by a JWS/JWE/JWK agent.  Among these issues are
   protecting the user's private key, preventing various attacks, and
   helping the user avoid mistakes such as inadvertently encrypting a
   message for the wrong recipient.  The entire list of security
   considerations is beyond the scope of this document, but some
   significant concerns are listed here.

   A key is no more trustworthy than the method by which it was
   received.

   Per Section 4.3, applications should not assume that "kid" values are
   unique within a JWK Set.



Jones                    Expires January 7, 2013                [Page 8]


Internet-Draft                     JWK                         July 2012


   The security considerations in XML DSIG 2.0
   [W3C.CR-xmldsig-core2-20120124], about public key representations
   also apply to this specification, other than those that are XML
   specific.


8.  Open Issues

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

   The following items remain to be considered or done in this draft:

   o  (None at present)


9.  References

9.1.  Normative References

   [JWA]      Jones, M., "JSON Web Algorithms (JWA)", July 2012.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4627]  Crockford, D., "The application/json Media Type for
              JavaScript Object Notation (JSON)", RFC 4627, July 2006.

   [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
              Encodings", RFC 4648, October 2006.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.

9.2.  Informative References

   [JWE]      Jones, M., Rescorla, E., and J. Hildebrand, "JSON Web
              Encryption (JWE)", July 2012.

   [JWS]      Jones, M., Bradley, J., and N. Sakimura, "JSON Web
              Signature (JWS)", July 2012.

   [MagicSignatures]
              Panzer (editor), J., Laurie, B., and D. Balfanz, "Magic
              Signatures", January 2011.

   [RFC4122]  Leach, P., Mealling, M., and R. Salz, "A Universally
              Unique IDentifier (UUID) URN Namespace", RFC 4122,



Jones                    Expires January 7, 2013                [Page 9]


Internet-Draft                     JWK                         July 2012


              July 2005.

   [W3C.CR-xmldsig-core2-20120124]
              Reagle, J., Solo, D., Datta, P., Hirsch, F., Eastlake, D.,
              Roessler, T., Cantor, S., and K. Yiu, "XML Signature
              Syntax and Processing Version 2.0", World Wide Web
              Consortium CR CR-xmldsig-core2-20120124, January 2012,
              <http://www.w3.org/TR/2012/CR-xmldsig-core2-20120124>.


Appendix A.  Acknowledgements

   A JSON representation for RSA public keys was previously introduced
   by John Panzer, Ben Laurie, and Dirk Balfanz in Magic Signatures
   [MagicSignatures].


Appendix B.  Document History

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

   -03

   o  Clarified that "kid" values need not be unique within a JWK Set.

   o  Moved JSON Web Key Parameters registry to the JWK specification.

   o  Added "Collision Resistant Namespace" to the terminology section.

   o  Changed registration requirements from RFC Required to
      Specification Required with Expert Review.

   o  Added Registration Template sections for defined registries.

   o  Added Registry Contents sections to populate registry values.

   o  Numerous editorial improvements.

   -02

   o  Simplified JWK terminology to get replace the "JWK Key Object" and
      "JWK Container Object" terms with simply "JSON Web Key (JWK)" and
      "JSON Web Key Set (JWK Set)" and to eliminate potential confusion
      between single keys and sets of keys.  As part of this change, the
      top-level member name for a set of keys was changed from "jwk" to
      "keys".





Jones                    Expires January 7, 2013               [Page 10]


Internet-Draft                     JWK                         July 2012


   o  Clarified that values with duplicate member names MUST be
      rejected.

   o  Established JSON Web Key Set Parameters registry.

   o  Explicitly listed non-goals in the introduction.

   o  Moved algorithm-specific definitions from JWK to JWA.

   o  Reformatted to give each member definition its own section
      heading.

   -01

   o  Corrected the Magic Signatures reference.

   -00

   o  Created the initial IETF draft based upon
      draft-jones-json-web-key-03 with no normative changes.


Author's Address

   Michael B. Jones
   Microsoft

   Email: mbj@microsoft.com
   URI:   http://self-issued.info/






















Jones                    Expires January 7, 2013               [Page 11]


Html markup produced by rfcmarkup 1.126, available from https://tools.ietf.org/tools/rfcmarkup/