--- 1/draft-ietf-ace-cbor-web-token-01.txt 2017-01-13 19:13:09.202945301 -0800 +++ 2/draft-ietf-ace-cbor-web-token-02.txt 2017-01-13 19:13:09.242946229 -0800 @@ -1,23 +1,23 @@ -ACE Working Group E. Wahlstroem -Internet-Draft -Intended status: Informational M. Jones -Expires: January 8, 2017 Microsoft - H. Tschofenig - ARM Ltd. +ACE Working Group M. Jones +Internet-Draft Microsoft +Intended status: Informational E. Wahlstroem +Expires: July 17, 2017 S. Erdtman Spotify AB - July 7, 2016 + H. Tschofenig + ARM Ltd. + January 13, 2017 CBOR Web Token (CWT) - draft-ietf-ace-cbor-web-token-01 + draft-ietf-ace-cbor-web-token-02 Abstract CBOR Web Token (CWT) is a compact means of representing claims to be transferred between two parties. CWT is a profile of the JSON Web Token (JWT) that is optimized for constrained devices. The claims in a CWT are encoded in the Concise Binary Object Representation (CBOR) and CBOR Object Signing and Encryption (COSE) is used for added application layer security protection. A claim is a piece of information asserted about a subject and is represented as a name/ @@ -31,25 +31,25 @@ 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 8, 2017. + This Internet-Draft will expire on July 17, 2017. Copyright Notice - Copyright (c) 2016 IETF Trust and the persons identified as the + Copyright (c) 2017 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 @@ -71,32 +71,34 @@ 4. Summary of the values, CBOR major types and encoded claim keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5. Creating and Validating CWTs . . . . . . . . . . . . . . . . 6 5.1. Creating a CWT . . . . . . . . . . . . . . . . . . . . . 6 5.2. Validating a CWT . . . . . . . . . . . . . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 7.1. CBOR Web Token (CWT) Claims Registry . . . . . . . . . . 8 7.1.1. Registration Template . . . . . . . . . . . . . . . . 8 7.1.2. Initial Registry Contents . . . . . . . . . . . . . . 9 - 7.2. CoAP Content-Format Registration . . . . . . . . . . . . 10 + 7.2. Media Type Registration . . . . . . . . . . . . . . . . . 10 7.2.1. Registry Contents . . . . . . . . . . . . . . . . . . 10 + 7.3. CoAP Content-Formats Registration . . . . . . . . . . . . 11 + 7.3.1. Registry Contents . . . . . . . . . . . . . . . . . . 11 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 8.1. Normative References . . . . . . . . . . . . . . . . . . 11 - 8.2. Informative References . . . . . . . . . . . . . . . . . 12 - Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 12 - A.1. CWT with "aud" and symmetric key . . . . . . . . . . . . 12 - A.2. CWT with "aud" and EC key . . . . . . . . . . . . . . . . 13 - A.3. Full CWT . . . . . . . . . . . . . . . . . . . . . . . . 15 - Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 18 - Appendix C. Document History . . . . . . . . . . . . . . . . . . 19 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19 + 8.2. Informative References . . . . . . . . . . . . . . . . . 13 + Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 13 + A.1. CWT with "aud" and symmetric key . . . . . . . . . . . . 13 + A.2. CWT with "aud" and EC key . . . . . . . . . . . . . . . . 14 + A.3. Full CWT . . . . . . . . . . . . . . . . . . . . . . . . 16 + Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 19 + Appendix C. Document History . . . . . . . . . . . . . . . . . . 20 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 1. Introduction The JSON Web Token (JWT) [RFC7519] is a standardized security token format that has found use in OAuth 2.0 and OpenID Connect deployments, among other applications. JWT uses JSON Web Signatures (JWS) [RFC7515] and JSON Web Encryption (JWE) [RFC7516] to secure the contents of the JWT, which is a set of claims represented in JSON [RFC7519]. The use of JSON for encoding information is popular for Web and native applications, but it is considered inefficient for @@ -135,32 +137,35 @@ Type6NumericDate: The "Type6NumericDate" term has the same meaning, syntax, and processing rules as the "NumericDate" term defined in Section 2 of JWT [RFC7519], except that Type6NumericDate uses CBOR major type 6, with tag value 1, instead of a numeric JSON value. CBOR encoded claim key: The key used to identify a claim value. + CWT Claims Set + A CBOR map that contains the claims conveyed by the CWT. + 3. Claims The set of claims that a CWT must contain to be considered valid is context dependent and is outside the scope of this specification. Specific applications of CWTs 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. To keep CWTs as small as possible, the CBOR encoded claim keys are - represented using CBOR major type 0. Section 4 summaries all keys - used to identity the claims defined in this document. + represented using CBOR major type 0. Section 4 summarizes all keys + used to identify the claims defined in this document. 3.1. Claim Names None of the claims defined below are intended to be mandatory to use or implement. They rather provide a starting point for a set of useful, interoperable claims. Applications using CWTs should define which specific claims they use and when they are required or optional. 3.1.1. iss (Issuer) Claim @@ -236,21 +241,21 @@ To create a CWT, the following steps are performed. 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 CWT Claims Set containing the desired claims. 2. Let the Message be the binary representation of the CWT Claims Set. 3. Create a COSE Header containing the desired set of Header - Parameters. The CWT Header MUST be a valid according to the + Parameters. The COSE Header MUST be valid according to the [I-D.ietf-cose-msg] specification. 4. Depending upon whether the CWT is signed, MACed or encrypted, there are three cases: * If the CWT is signed, create a COSE_Sign/COSE_Sign1 object using the Message as the COSE_Sign/COSE_Sign1 Payload; all steps specified in [I-D.ietf-cose-msg] for creating a COSE_Sign/COSE_Sign1 object MUST be followed. @@ -261,43 +266,44 @@ * Else, if the CWT is a COSE_Encrypt/COSE_Encrypt0 object, create a COSE_Encrypt/COSE_Encrypt0 using the Message as the plaintext for the COSE_Encrypt/COSE_Encrypt0 object; all steps specified in [I-D.ietf-cose-msg] for creating a COSE_Encrypt/ COSE_Encrypt0 object MUST be followed. 5. If a nested signing, MACing or encryption operation will be performed, let the Message be the COSE_Sign/COSE_Sign1, COSE_Mac/ COSE_Mac0 or COSE_Encrypt/COSE_Encrypt0, and return to Step 3, - using "content type" header value of "CWT" in the new COSE Header - created in that step. + using a "content type" header value corresponding to the media + type "application/cwt" in the new COSE Header created in that + step. Note: If integrity (signing/MACing) and confidentiality (encryption) protection are needed, it is recommended to use an authenticated encryption algorithm to save space and processing. 5.2. Validating a CWT When validating a CWT, the following steps are performed. 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 fail, then the CWT MUST be rejected -- that is, treated by the application as an invalid input. 1. Verify that the CWT is a valid CBOR object. 2. Verify that the resulting COSE 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. - 3. Use the CBOR tag to determine the type the CWT, COSE_Sign/ - COSE_Sign1, COSE_Mac/COSE_Mac0 or COSE_Encrypt/COSE_Encrypt0. + 3. Use the CBOR tag to determine the type of the CWT, COSE_Sign/ + COSE_Sign1, COSE_Mac/COSE_Mac0, or COSE_Encrypt/COSE_Encrypt0. 4. Depending upon whether the CWT is a COSE_Sign/COSE_Sign1, COSE_Mac/COSE_Mac0 or COSE_Encrypt/COSE_Encrypt0, there are three cases: * If the CWT is a COSE_Sign/COSE_Sign1, follow the steps specified in [I-D.ietf-cose-msg] Section 4 (Signing Objects) for validating a COSE_Sign/COSE_Sign1 object. Let the Message be the COSE_Sign/COSE_Sign1 payload. @@ -305,22 +311,23 @@ specified in [I-D.ietf-cose-msg] Section 6 (MAC Objects) for validating a COSE_Mac/COSE_Mac0 object. Let the Message be the COSE_Mac/COSE_Mac0 payload. * Else, if the CWT is a COSE_Encrypt/COSE_Encrypt0 object, follow the steps specified in [I-D.ietf-cose-msg] Section 5 (Encryption Objects) for validating a COSE_Encrypt/ COSE_Encrypt0 object. Let the Message be the resulting plaintext. - 5. If the JOSE Header contains a "content type" value of "CWT", then - the Message is a CWT that was the subject of nested signing or + 5. If the COSE Header contains a "content type" header value + corresponding to the media type "application/cwt", then the + Message is a CWT that was the subject of nested signing or encryption operations. In this case, return to Step 1, using the Message as the CWT. 6. Verify that the Message is a valid CBOR object; let the CWT Claims Set be this CBOR object. 6. Security Considerations The security of the CWT is dependent on the protection offered by COSE. Without protecting the claims contained in a CWT an adversary @@ -366,21 +373,21 @@ [IANA.JWT.Claims]. CWT claims should normally have a corresponding JWT claim. If a corresponding JWT claim would not make sense, the Designated Experts can choose to accept registrations for which the JWT Claim Name is listed as "N/A". CBOR Key Value: Key value for the claim. The key value MUST be an integer in the range of 1 to 65536. CBOR Major Type: - CBOR Major type and optional tag for the claim. + CBOR major type and optional tag for the claim. Change Controller: For Standards Track RFCs, list the "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 or documents that specify the parameter, preferably including URIs that can be used to retrieve copies of the documents. An indication of the relevant sections may also be @@ -444,55 +451,109 @@ o Claim Name: "cti" o Claim Description: CWT ID o JWT Claim Name: "jti" o CBOR Key Value: 7 o CBOR Major Type: 2 o Change Controller: IESG o Specification Document(s): Section 3.1.7 of [[ this specification ]] -7.2. CoAP Content-Format Registration +7.2. Media Type Registration - This section registers the "application/cwt" CoAP Content-Format ID - in the "CoRE Parameters" sub-registry "CoAP Content-Format" in the - manner described in [RFC7252]. + This section registers the "application/cwt" media type [RFC2046] in + the "Media Types" registry [IANA.MediaTypes] in the manner described + in RFC 6838 [RFC6838], which can be used to indicate that the content + is a CWT. 7.2.1. Registry Contents + o Type name: application + o Subtype name: cwt + o Required parameters: N/A + o Optional parameters: N/A + o Encoding considerations: binary + o Security considerations: See the Security Considerations section + of [[ this specification ]] + o Interoperability considerations: N/A + o Published specification: [[ this specification ]] + o Applications that use this media type: IoT applications sending + security tokens over HTTP(S) and other transports. + o Fragment identifier considerations: N/A + o Additional information: + + Magic number(s): N/A + File extension(s): N/A + Macintosh file type code(s): N/A + + o Person & email address to contact for further information: + IESG, iesg@ietf.org + o Intended usage: COMMON + o Restrictions on usage: none + o Author: Michael B. Jones, mbj@microsoft.com + o Change controller: IESG + o Provisional registration? No + +7.3. CoAP Content-Formats Registration + + This section registers the CoAP Content-Format ID for the + "application/cwt" media type in the "CoAP Content-Formats" registry + [IANA.CoAP.Content-Formats] established by [RFC7252]. + +7.3.1. Registry Contents + o Media Type: application/cwt o Encoding: - o Id: TBD (maybe 61) o Reference: [[ this specification ]] 8. References 8.1. Normative References [I-D.ietf-cose-msg] Schaad, J., "CBOR Object Signing and Encryption (COSE)", - draft-ietf-cose-msg-14 (work in progress), June 2016. + draft-ietf-cose-msg-24 (work in progress), November 2016. + + [IANA.CoAP.Content-Formats] + IANA, "CoAP Content-Formats", + . [IANA.JWT.Claims] IANA, "JSON Web Token Claims", . + [IANA.MediaTypes] + IANA, "Media Types", + . + + [RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail + Extensions (MIME) Part Two: Media Types", RFC 2046, + DOI 10.17487/RFC2046, November 1996, + . + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, DOI 10.17487/RFC5226, May 2008, . + [RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type + Specifications and Registration Procedures", BCP 13, + RFC 6838, DOI 10.17487/RFC6838, January 2013, + . + [RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049, October 2013, . [RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March 2014, . [RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained Application Protocol (CoAP)", RFC 7252, @@ -767,51 +828,56 @@ This specification is based on JSON Web Token (JWT) [RFC7519], the authors of which also include Nat Sakimura and John Bradley. A straw man proposal of CWT was written in the draft "Authorization for the Internet of Things using OAuth 2.0" [I-D.seitz-ace-oauth-authz] with the help of Ludwig Seitz and Goeran Selander. Appendix C. Document History [[ to be removed by the RFC Editor before publication as an RFC ]] + -02 + + o Added IANA registration for the application/cwt media type. + o Clarified the nested CWT language. + o Corrected nits identified by Ludwig Seitz. + -01 o Added IANA registration for CWT Claims. o Added IANA registration for the application/cwt CoAP content- format type. o Added Samuel Erdtman as an editor. o Changed Erik's e-mail address. -00 o Created the initial working group version based on draft- wahlstroem-ace-cbor-web-token-00. Authors' Addresses - Erik Wahlstroem - Sweden - - Email: erik@wahlstromstekniska.se - Michael B. Jones Microsoft Email: mbj@microsoft.com URI: http://self-issued.info/ - Hannes Tschofenig - ARM Ltd. - Hall in Tirol 6060 - Austria + Erik Wahlstroem + Sweden - Email: Hannes.Tschofenig@arm.com + Email: erik@wahlstromstekniska.se Samuel Erdtman Spotify AB Birger Jarlsgatan 61, 4tr Stockholm 113 56 Sweden Phone: +46702691499 Email: erdtman@spotify.com + Hannes Tschofenig + ARM Ltd. + Hall in Tirol 6060 + Austria + + Email: Hannes.Tschofenig@arm.com