--- 1/draft-ietf-jose-json-web-key-01.txt 2012-05-28 12:16:29.861342116 +0200 +++ 2/draft-ietf-jose-json-web-key-02.txt 2012-05-28 12:16:29.877344060 +0200 @@ -1,23 +1,27 @@ JOSE Working Group M. Jones Internet-Draft Microsoft -Intended status: Standards Track March 12, 2012 -Expires: September 13, 2012 +Intended status: Standards Track May 12, 2012 +Expires: November 13, 2012 JSON Web Key (JWK) - draft-ietf-jose-json-web-key-01 + draft-ietf-jose-json-web-key-02 Abstract - A JSON Web Key (JWK) is a JSON data structure that represents a set - of public keys. + A JSON Web Key (JWK) is a 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 used with this specification + are enumerated in the separate JSON Web Algorithms (JWA) + specification. Requirements Language 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 RFC 2119 [RFC2119]. Status of this Memo This Internet-Draft is submitted in full conformance with the @@ -26,304 +30,287 @@ 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 September 13, 2012. + This Internet-Draft will expire on November 13, 2012. 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 described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 3. JSON Web Key (JWK) Overview . . . . . . . . . . . . . . . . . . 3 - 3.1. Example JWK . . . . . . . . . . . . . . . . . . . . . . . . 3 - 4. JWK Format . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 4.1. JWK Container Object Format . . . . . . . . . . . . . . . . 4 - 4.2. JWK Key Object Format . . . . . . . . . . . . . . . . . . . 5 - 4.2.1. JWK Key Object Members for Elliptic Curve Keys . . . . 5 - 4.2.2. JWK Key Object Members for RSA Keys . . . . . . . . . . 6 - 5. Base64url encoding as used by JWKs . . . . . . . . . . . . . . 7 - 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 - 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 - 8. Open Issues and Things To Be Done (TBD) . . . . . . . . . . . . 7 - 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 - 9.1. Normative References . . . . . . . . . . . . . . . . . . . 7 - 9.2. Informative References . . . . . . . . . . . . . . . . . . 8 - Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . . 8 - Appendix B. Document History . . . . . . . . . . . . . . . . . . . 8 + 3. Example JSON Web Key Set . . . . . . . . . . . . . . . . . . . 3 + 4. JSON Web Key (JWK) Format . . . . . . . . . . . . . . . . . . . 4 + 4.1. "alg" (Algorithm Family) Parameter . . . . . . . . . . . . 4 + 4.2. "use" (Key Use) Parameter . . . . . . . . . . . . . . . . . 5 + 4.3. "kid" (Key ID) Parameter . . . . . . . . . . . . . . . . . 5 + 5. JSON Web Key Set (JWK Set) Format . . . . . . . . . . . . . . . 5 + 5.1. "keys" (JSON Web Key Set) Parameter . . . . . . . . . . . . 5 + 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 + 6.1. JSON Web Key Set Parameters Registry . . . . . . . . . . . 6 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 + 8. Open Issues and Things To Be Done (TBD) . . . . . . . . . . . . 6 + 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 + 9.1. Normative References . . . . . . . . . . . . . . . . . . . 6 + 9.2. Informative References . . . . . . . . . . . . . . . . . . 7 + Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . . 7 + Appendix B. Document History . . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction - A JSON Web Key (JWK) is a JSON data structure that represents a set - of public keys as a JSON object [RFC4627]. The JWK format is used to - represent bare keys; representing certificate chains is an explicit - non-goal of this specification. JSON Web Keys are referenced in JSON - Web Signature (JWS) [JWS] using the "jku" (JSON Key URL) header - parameter and in JSON Web Encryption (JWE) [JWE] using the "jku" - (JSON Key URL) and "epk" (Ephemeral Public Key) header parameters. + A JSON Web Key (JWK) is a JSON data structure that represents a + public key as a JSON object [RFC4627]. This specification also + defines a JSON Web Key Set (JWK Set) JSON data structure for + representing a set of JWKs. Cryptographic algorithms and identifiers + used with this specification are enumerated in the separate JSON Web + Algorithms (JWA) [JWA] specification. -2. Terminology + Non-goals for this specification include representing private keys, + representing symmetric keys, representing certificate chains, + representing certified keys, and replacing X.509 certificates. - JSON Web Key (JWK) A JSON data structure that represents a set of - public keys. A JWK consists of a single JWK Container Object that - contains an array of JWK Key Objects. + JWKs are used in the JSON Web Signature (JWS) [JWS] "jwk" (JSON Web + Key) header parameter and the JSON Web Encryption (JWE) [JWE] "jwk" + (JSON Web Key) and "epk" (Ephemeral Public Key) header parameters. + The resources referenced by the JWS "jku" (JWK Set URL) and JWE "jku" + (JWK Set URL) header parameters contain JWK Sets. - JWK Container Object A JSON object that contains an array of JWK Key - Objects as a member. +2. Terminology - JWK Key Object A JSON object that represents a single public key. + 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 B of [JWS] for notes on implementing base64url encoding without padding.) -3. JSON Web Key (JWK) Overview - - It is sometimes useful to be able to reference public key - representations, for instance, in order to verify the digital - signature on content signed with the corresponding private key. The - JSON Web Key (JWK) data structure provides a convenient JSON - representation for sets of public keys utilizing either the Elliptic - Curve or RSA families of algorithms. - -3.1. Example JWK +3. Example JSON Web Key Set - The following example JWK contains two public keys: 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 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.) - {"jwk": + 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. JWK Format - - A JWK consists of a JWK Container Object, which is a JSON object that - contains an array of JWK Key Objects as a member. This section - specifies the format of these objects. - -4.1. JWK Container Object Format - - A JWK Container Object is a JSON object containing a specific member. - This member is: - - +--------+----------+-----------------------------------------------+ - | Member | JSON | Container Object Member Semantics | - | Name | Value | | - | | Type | | - +--------+----------+-----------------------------------------------+ - | jwk | array | The "jwk" member value contains an array of | - | | | JWK Key Objects. This member is REQUIRED. | - +--------+----------+-----------------------------------------------+ +4. JSON Web Key (JWK) Format - JWK Container Object Member + 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. - Additional members MAY be present in the JWK Container Object. If - present, they MUST be understood by implementations using that JWK. + JWKs also require members that are specific to the particular key + algorithm family to represent the key parameters. These algorithm + specific members are defined in Section 5 of the JSON Web Algorithms + (JWA) [JWA] specification. -4.2. JWK Key Object Format + The member names within a JWK MUST be unique; objects with duplicate + member names MUST be rejected. - A JWK Key Object is a JSON object containing specific members. Those - members that are common to all key types are as follows: + Additional members MAY be present in the JWK. If present, they MUST + be understood by implementations using them. Parameters for + representing keys for additional algorithm families or additional key + properties SHOULD either be defined in the IANA JSON Web Key + Parameters registry [JWA] or be a URI that contains a collision + resistant namespace. - +--------+--------+-------------------------------------------------+ - | Member | JSON | Key Object Member Semantics | - | Name | Value | | - | | Type | | - +--------+--------+-------------------------------------------------+ - | alg | string | The "alg" member identifies the cryptographic | - | | | algorithm family used with the key. Values | - | | | defined by this specification are "EC" and | - | | | "RSA". Specific additional members are | - | | | required to represent the key, depending upon | - | | | the "alg" value. The "alg" value is case | - | | | sensitive. This member is REQUIRED. | - | use | string | The "use" member identifies the intended use of | - | | | the key. Values defined by this specification | - | | | are "sig" (signature) and "enc" (encryption). | - | | | Other values MAY be used. The "use" value is | - | | | case sensitive. This member is OPTIONAL. | - | kid | string | 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 "kid" value | - | | | MAY correspond to a JWS "kid" value. The | - | | | interpretation of the "kid" value is | - | | | unspecified. This member is OPTIONAL. | - +--------+--------+-------------------------------------------------+ +4.1. "alg" (Algorithm Family) Parameter - JWK Key Object Members + The "alg" (algorithm family) member identifies the cryptographic + algorithm family used with the key. A list of defined "alg" values + is presented in Section 5.1 of the JSON Web Algorithms (JWA) [JWA] + specification. Specific additional members are required to represent + the key, depending upon the algorithm family. These members are + specified in Section 5 of the JSON Web Algorithms (JWA) [JWA] + specification. The "alg" value is case sensitive. Its value MUST be + a string. - Additional members MAY be present in the JWK Key Object. If present, - they MUST be understood by implementations using that key. + "alg" values SHOULD either be defined in the IANA JSON Web Key + Algorithm Families registry [JWA] or be a URI that contains a + collision resistant namespace. -4.2.1. JWK Key Object Members for Elliptic Curve Keys +4.2. "use" (Key Use) Parameter - JWKs can represent Elliptic Curve [FIPS.186-3] keys. In this case, - the "alg" member value MUST be "EC". Furthermore, these additional - members MUST be present: + The "use" (key use) member identifies the intended use of the key. + Values defined by this specification are "sig" (signature) and "enc" + (encryption). Other values MAY be used. The "use" value is case + sensitive. Its value MUST be a string. This member is OPTIONAL. - +--------+--------+-------------------------------------------------+ - | Member | JSON | Key Object Member Semantics | - | Name | Value | | - | | Type | | - +--------+--------+-------------------------------------------------+ - | crv | string | The "crv" member identifies the cryptographic | - | | | curve used with the key. Values defined by | - | | | this specification are "P-256", "P-384" and | - | | | "P-521". Additional "crv" values MAY be used, | - | | | provided they are understood by implementations | - | | | using that Elliptic Curve key. The "crv" value | - | | | is case sensitive. | - | x | string | The "x" member contains the x coordinate for | - | | | the elliptic curve point. It is represented as | - | | | the base64url encoding of the coordinate's big | - | | | endian representation. | - | y | string | The "y" member contains the y coordinate for | - | | | the elliptic curve point. It is represented as | - | | | the base64url encoding of the coordinate's big | - | | | endian representation. | - +--------+--------+-------------------------------------------------+ +4.3. "kid" (Key ID) Parameter - Members for Elliptic Curve Keys + 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. When used with JWS or JWE, the "kid" value + MAY be used to match a JWS or JWE "kid" header parameter value. The + interpretation of the "kid" value is unspecified. Its value MUST be + a string. This member is OPTIONAL. -4.2.2. JWK Key Object Members for RSA Keys +5. JSON Web Key Set (JWK Set) Format - JWKs can represent RSA [RFC3447] keys. In this case, the "alg" - member value MUST be "RSA". Furthermore, these additional members - MUST be present: + 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. - +--------+--------+-------------------------------------------------+ - | Member | JSON | Key Object Member Semantics | - | Name | Value | | - | | Type | | - +--------+--------+-------------------------------------------------+ - | mod | string | The "mod" member contains the modulus value for | - | | | the RSA public key. It is represented as the | - | | | base64url encoding of the value's big endian | - | | | representation. | - | exp | string | The "exp" member contains the exponent value | - | | | for the RSA public key. It is represented as | - | | | the base64url encoding of the value's big | - | | | endian representation. | - +--------+--------+-------------------------------------------------+ + The member names within a JWK Set MUST be unique; objects with + duplicate member names MUST be rejected. - Members for RSA Keys + 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 + defined in the IANA JSON Web Key Set Parameters registry Section 6.1 + or be a URI that contains a collision resistant namespace. -5. Base64url encoding as used by JWKs +5.1. "keys" (JSON Web Key Set) Parameter - JWKs make use of the base64url encoding as defined in RFC 4648 - [RFC4648]. As allowed by Section 3.2 of the RFC, this specification - mandates that base64url encoding when used with JWKs MUST NOT use - padding. Notes on implementing base64url encoding can be found in - the JWS [JWS] specification. + 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 - No IANA actions are required by this specification. +6.1. JSON Web Key Set Parameters Registry + + This specification establishes the IANA JSON Web Key Set Parameters + registry for reserved JWK Set parameter names. Inclusion in the + registry is RFC Required in the RFC 5226 [RFC5226] sense. The + registry records the reserved parameter name and a reference to the + RFC that defines it. This specification registers the parameter + names defined in Section 5. 7. Security Considerations - TBD + A key is no more trustworthy than the method by which it was + received. + + 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 and Things To Be Done (TBD) The following items remain to be done in this draft: - o Consider how additional key families would be added. - - o Write the Security Considerations section. + o (None at present) 9. References 9.1. Normative References - [FIPS.186-3] - National Institute of Standards and Technology, "Digital - Signature Standard (DSS)", FIPS PUB 186-3, June 2009. + [JWA] Jones, M., "JSON Web Algorithms (JWA)", May 2012. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. - [RFC3447] Jonsson, J. and B. Kaliski, "Public-Key Cryptography - Standards (PKCS) #1: RSA Cryptography Specifications - Version 2.1", RFC 3447, February 2003. - [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)", March 2012. + Encryption (JWE)", May 2012. [JWS] Jones, M., Bradley, J., and N. Sakimura, "JSON Web - Signature (JWS)", March 2012. + Signature (JWS)", May 2012. [MagicSignatures] Panzer (editor), J., Laurie, B., and D. Balfanz, "Magic Signatures", January 2011. + [W3C.CR-xmldsig-core2-20120124] + Eastlake, D., Reagle, J., Yiu, K., Solo, D., Datta, P., + Hirsch, F., Cantor, S., and T. Roessler, "XML Signature + Syntax and Processing Version 2.0", World Wide Web + Consortium CR CR-xmldsig-core2-20120124, January 2012, + . + Appendix A. Acknowledgements A JSON representation for RSA public keys was previously introduced in Magic Signatures [MagicSignatures]. Appendix B. Document History + -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". + + 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