Internet DRAFT - draft-fossati-cose-profiles
draft-fossati-cose-profiles
CBOR Object Signing and Encryption T. Fossati
Internet-Draft Linaro
Intended status: Standards Track H. Birkholz
Expires: 17 March 2024 Fraunhofer SIT
O. Steele
Transmute
14 September 2023
COSE Profiles
draft-fossati-cose-profiles-01
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.
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Copyright (c) 2023 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
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. Profiling Rules . . . . . . . . . . . . . . . . . . . . . . . 3
4. COSE profile header parameter . . . . . . . . . . . . . . . . 4
5. Profile Registration Template . . . . . . . . . . . . . . . . 4
6. CoSWID COSE Profile Definition . . . . . . . . . . . . . . . 5
6.1. CDDL Definition . . . . . . . . . . . . . . . . . . . . . 5
6.2. Checklist . . . . . . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . 6
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
8.1. New COSE Profile Header Parameter . . . . . . . . . . . . 6
8.2. COSE Profile Sub-registry . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . 8
Appendix A. GlueCOSE Test Cases . . . . . . . . . . . . . . . . 8
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
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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:
* MUST be specified in a document
* MUST NOT change the syntax or semantics of any already defined
header attribute
- but does allow restricting their values
* MAY define new header attributes
- if so, it MUST provide their definition in the same document
* MUST use CDDL [RFC8610] to fully specify the syntax rules for the
profile
* MUST use the cose-profile header attribute (see Section 4) in the
protected header
- The value of cose-profile MUST be globally unique. Possible
choices include:
o IANA registry (Section 8.2)
o using an OID [RFC9090], URI [STD66] or CRI
[I-D.ietf-core-href]
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o using a UUID [RFC4122]
- The chosen value SHOULD be appropriate for the intended usage
scope (e.g., a short value when used in constrained node
environments)
* MAY define its own CBOR tag that can be used together with, or in
lieu of, the underlying COSE CBOR tag (Table 1, Section 2 of
[STD96])
* SHOULD define its complementary media-type and content-format
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
* What is the profile identifier?
* Requires certain header keys?
* Constrains any header keys?
* Constrains any header values?
* Defines new header keys?
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* Defines its own CBOR Tag?
* Defines its own Media Type?
* What payload(s) allows?
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
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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, 10 July 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-core-
href-13>.
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[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, 24
February 2023, <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, March 1997,
<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, July 2005,
<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, June 2017,
<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,
May 2017, <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,
June 2019, <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, July 2021,
<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, January 2005,
<https://www.rfc-editor.org/rfc/rfc3986>.
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[STD96] Schaad, J., "CBOR Object Signing and Encryption (COSE):
Structures and Process", STD 96, RFC 9052,
DOI 10.17487/RFC9052, August 2022,
<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
Email: thomas.fossati@linaro.org
Henk Birkholz
Fraunhofer SIT
Email: henk.birkholz@sit.fraunhofer.de
Orie Steele
Transmute
Email: orie@transmute.industries
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