Internet-Draft COSE Profiles September 2023
Fossati, et al. Expires 17 March 2024 [Page]
Workgroup:
CBOR Object Signing and Encryption
Internet-Draft:
draft-fossati-cose-profiles-01
Published:
Intended Status:
Standards Track
Expires:
Authors:
T. Fossati
Linaro
H. Birkholz
Fraunhofer SIT
O. Steele
Transmute

COSE Profiles

Abstract

COSE (STD96) is not an end-to-end system with guaranteed interoperability. It is designed to serve a range of use cases and therefore it has a lot of options. In general, two COSE implementations that want to interoperate require an agreement on which subset of COSE features they will use. This document provides a set of rules for specifying such agreements as "COSE profiles" and registers a new COSE header parameter for in-band signalling of profile information.

About This Document

This note is to be removed before publishing as an RFC.

The latest revision of this draft can be found at https://thomas-fossati.github.io/draft-fossati-cose-profile/draft-fossati-cose-profiles.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-fossati-cose-profiles/.

Discussion of this document takes place on the CBOR Object Signing and Encryption Working Group mailing list (mailto:cose@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/cose/. Subscribe at https://www.ietf.org/mailman/listinfo/cose/.

Source for this draft and an issue tracker can be found at https://github.com/thomas-fossati/draft-fossati-cose-profile.

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 https://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 17 March 2024.

Table of Contents

1. Introduction

COSE [STD96] is not an end-to-end system with guaranteed interoperability. It is designed to serve a range of use cases and therefore it has a lot of options. In general, two COSE implementations that want to interoperate require an agreement on which subset of COSE features they will use.

This document provides a set of rules for specifying such agreements as "COSE profiles" and registers a new COSE header parameter for in-band signalling of profile information.

2. Conventions and Definitions

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 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

3. Profiling Rules

A COSE profile:

4. COSE profile header parameter

COSE-profile = registered-profile / oid-profile / uri-profile
             / cri-profile / uuid-profile
registered-profile = int
oid-profile = oid ; tagged
uri-profile = ~uri ; unwrapped -- any tstr is a uri
cri-profile = cri
uuid-profile = uuid ; naked bstr is a UUID

uuid = bstr .size 16

; imported from RFC 9090
oid = #6.111(bstr)
; import from CRI spec when ready
cri = [*any]

5. Profile Registration Template

Note: This is just an initial sketch.

Tracked at: https://github.com/ietf-rats-wg/draft-ietf-rats-corim/issues/10

6. CoSWID COSE Profile Definition

Note: This is just an initial sketch.

Tracked at: https://github.com/ietf-rats-wg/draft-ietf-rats-corim/issues/10

This section defines the COSE profile for CoSWID [I-D.ietf-sacm-coswid].

This definition is semantically and syntactically equivalent with what is described in Section 7 of [I-D.ietf-sacm-coswid], with the exception of the explicit CoSWID COSE profile indicator that is added to the protected header.

6.1. CDDL Definition

protected-signed-coswid-header = {
  &(alg: 1) => int
  &(content-type: 3) => "application/swid+cbor"
  &(cose-profile-CPA: 13) => &(CoSWID-COSE-profile-CPA: 0)
  * cose-label => cose-values
}

cose-label = int / text
cose-values = any

6.2. Checklist

  • Mandatory header keys? YES
  • Constrains header keys? NO
  • Constrains header values? YES (alg is only int)
  • New header keys? NO
  • Defines its own CBOR Tag? YES
  • Defines its own Media Type? YES

7. Security Considerations

TODO Security

8. IANA Considerations

8.1. New COSE Profile Header Parameter

This document requests IANA to allocate a new header parameter cose-profile-CPA (suggested value 13) in the "COSE Header Parameters" [IANA.cose] registry.

8.2. COSE Profile Sub-registry

This specification requests IANA to create a new sub-registry for COSE [IANA.cose], with the policy "specification required" (Section 4.6 of [RFC8126]).

Each entry in the registry must include:

Key value:

integer value for the profile

Brief description:

a brief description

Change Controller:

(see Section 2.3 of [RFC8126])

Reference:

a reference document

The expert is requested to assign the shortest key values (1+0 and 1+1 encoding) to registrations that are likely to enjoy wide use and can benefit from short encodings.

9. References

9.1. Normative References

[I-D.ietf-core-href]
Bormann, C. and H. Birkholz, "Constrained Resource Identifiers", Work in Progress, Internet-Draft, draft-ietf-core-href-13, , <https://datatracker.ietf.org/doc/html/draft-ietf-core-href-13>.
[I-D.ietf-sacm-coswid]
Birkholz, H., Fitzgerald-McKay, J., Schmidt, C., and D. Waltermire, "Concise Software Identification Tags", Work in Progress, Internet-Draft, draft-ietf-sacm-coswid-24, , <https://datatracker.ietf.org/doc/html/draft-ietf-sacm-coswid-24>.
[IANA.cose]
IANA, "CBOR Object Signing and Encryption (COSE)", <http://www.iana.org/assignments/cose>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC4122]
Leach, P., Mealling, M., and R. Salz, "A Universally Unique IDentifier (UUID) URN Namespace", RFC 4122, DOI 10.17487/RFC4122, , <https://www.rfc-editor.org/rfc/rfc4122>.
[RFC8126]
Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, , <https://www.rfc-editor.org/rfc/rfc8126>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8610]
Birkholz, H., Vigano, C., and C. Bormann, "Concise Data Definition Language (CDDL): A Notational Convention to Express Concise Binary Object Representation (CBOR) and JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610, , <https://www.rfc-editor.org/rfc/rfc8610>.
[RFC9090]
Bormann, C., "Concise Binary Object Representation (CBOR) Tags for Object Identifiers", RFC 9090, DOI 10.17487/RFC9090, , <https://www.rfc-editor.org/rfc/rfc9090>.
[STD66]
Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, DOI 10.17487/RFC3986, , <https://www.rfc-editor.org/rfc/rfc3986>.
[STD96]
Schaad, J., "CBOR Object Signing and Encryption (COSE): Structures and Process", STD 96, RFC 9052, DOI 10.17487/RFC9052, , <https://www.rfc-editor.org/rfc/rfc9052>.

9.2. Informative References

[GlueCOSE]
The GlueCOSE Community, "Test Vectors", <https://github.com/gluecose/test-vectors>.

Appendix A. GlueCOSE Test Cases

The community effort [GlueCOSE] provides test vectors for the COSE specification.

The CDDL definition for the test vector format used for COSE profiles will be provided in a future version of this document.

Tracked at: https://github.com/ietf-rats-wg/draft-ietf-rats-corim/issues/4

Acknowledgments

Laurence Lundblade who - unknowingly :-) - provided the introduction.

Authors' Addresses

Thomas Fossati
Linaro
Henk Birkholz
Fraunhofer SIT
Orie Steele
Transmute