v: 3
title: > CoRE Target Attribute Registry abbrev: CoRE Target Attribute Registry docname: draft-ietf-core-target-attr-latest
keyword: Internet-Draft cat: info stream: IETF wg: CoRE Working group
venue: mail: "[email protected]" github: core-wg/core-target-attr
pi: [toc, sortrefs, symrefs, compact, comments]
name: Carsten Bormann
org: Universität Bremen TZI
street: Postfach 330440
city: Bremen
code: D-28359
country: Germany
phone: +49-421-218-63921
email: [email protected]
contributor:
- name: Jaime Jiménez organization: Ericsson email: [email protected] contribution: Jaime provided the list of initial registrations.
normative: RFC8288: linking BCP26: -: ianacons =: RFC8126 STD80: -: ascii =: RFC20
informative: RFC6690: link-format RFC7252: coap RFC7641: obs RFC8075: http-proxy RFC8613: oscore I-D.ietf-core-oscore-edhoc: oed I-D.tiloca-core-oscore-discovery: odi RFC5988: linking-old RFC9176: rd
--- abstract
The Constrained RESTful Environments (CoRE) specifications apply Web technologies to constrained environments. One important such technology is Web Linking {{-linking}}, which CoRE uses as the basis for a number of discovery protocols, such as the Link Format {{-link-format}} in CoAP's Resource Discovery Protocol ({{Section 7 of -coap}}) and the Resource Directory {{-rd}}.
Web Links can have Target Attributes, the names of which are not generally coordinated by the Web Linking specification ({{Section 2.2 of -linking}}). This short note introduces an IANA registry for coordinating names of Target Attributes when used in Constrained RESTful Environments.
--- middle
(Please see abstract.)
The original Web Linking specification {{Section 3 of -linking-old}} did not attempt to coordinate names of target attributes except for providing common target attributes for use in the Link HTTP header. The current revision of that specification clarifies ({{Section 2.2 of -linking}}):
{:quote}
This specification does not attempt to coordinate the name of target attributes, their cardinality, or use. Those creating and maintaining serialisations SHOULD coordinate their target attributes to avoid conflicts in semantics or syntax and MAY define their own registries of target attributes.
This short note introduces an IANA registry for coordinating names of Target Attributes when used in Constrained RESTful Environments.
With a registry now available, registration of target attributes is strongly encouraged. The incentive is that an unregistered attribute name might be registered with a different meaning at any time. (See also {{de-instructions}}.)
{::boilerplate bcp14-tagged}
This specification defines a new sub-registry for Target Attributes in the CoRE Parameters registry {{!IANA.core-parameters}}, with the policy "expert review" ({{Section 4.5 of -ianacons}}).
The expert is instructed to be frugal in the allocation of very short target attribute names, keeping them in reserve for applications that are likely to enjoy wide use and can make good use of their shortness. The expert is also instructed to direct the registrant to provide a specification ({{Section 4.6 of -ianacons}}), but can make exceptions, for instance when a specification is not available at the time of registration but is likely forthcoming. If the expert becomes aware of target attributes that are deployed and in use, they may also initiate a registration on their own if they deem such a registration can avert potential future collisions. {: #de-instructions}
Each entry in the registry must include:
{:vspace}
Attribute Name:
: a lower case ASCII {{-ascii}} string that starts with a letter and can
contain digits and hyphen-minus characters afterwards
([a-z][-a-z0-9]*).
(Note that {{-linking}} requires target attribute names to be
interpreted in a case-insensitive way; the restriction to lower case
here ensures that they are registered in a predictable form).
Brief description: : a brief description
Change Controller: : (see {{Section 2.3 of -ianacons}})
Reference: : a reference document that provides a description of the target attribute, including the semantics for when the target attribute appears more than once in a link.
Initial entries in this sub-registry are as listed in {{pre-reg}}:
| Attribute Name | Brief description | Change Controller | Reference | | href | reserved (not useful as target attribute name) | IESG | {{RFC6690}} | | anchor | reserved (not useful as target attribute name) | IESG | {{RFC6690}} | | rel | reserved (not useful as target attribute name) | IESG | {{RFC6690}} | | rev | reserved (not useful as target attribute name) | IESG | {{RFC6690}} | | hreflang | (Web Linking) | IESG | {{-linking}} | | media | (Web Linking) | IESG | {{-linking}} | | title | (Web Linking) | IESG | {{-linking}} | | type | (Web Linking) | IESG | {{-linking}} | | rt | resource type | IESG | {{Section 3.1 of RFC6690}} | | if | interface description | IESG | {{Section 3.2 of RFC6690}} | | sz | maximum size estimate | IESG | {{Section 3.3 of RFC6690}} | | ct | Content-Format hint | IESG | {{Section 7.2.1 of RFC7252}} | | obs | observable resource | IESG | {{Section 6 of RFC7641}} | | hct | HTTP-CoAP URI mapping template | IESG | {{Section 5 of RFC8075}} | | osc | hint: resource only accessible using OSCORE | IESG | {{Section 9 of RFC8613}} | | method | A supported authentication method for EDHOC | IESG | {{Section 6 of -oed}} | | csuite | A supported cipher suite for EDHOC | IESG | {{Section 6 of -oed}} | | cred_t | A supported type of authentication credential for EDHOC | IESG | {{Section 6 of -oed}} | | idcred_t | A supported type of authentication credential identifier for EDHOC | IESG | {{Section 6 of -oed}} | | ead_1 | A supported EDHOC EAD_1 item | IESG | {{Section 6 of -oed}} | | ead_2 | A supported EDHOC EAD_2 item | IESG | {{Section 6 of -oed}} | | ead_3 | A supported EDHOC EAD_3 item | IESG | {{Section 6 of -oed}} | | ead_4 | A supported EDHOC EAD_4 item | IESG | {{Section 6 of -oed}} | | comb_req | Hint: support for the EDHOC+OSCORE request | IESG | {{Section 6 of -oed}} | | sec-gp | Name of the security group that can be joined through this resource | IESG | {{Section 2.1 of -odi}} | | app-gp | Name of an application group associated with a security group | IESG | {{Section 2.1 of -odi}} | | hkdf | The HKDF algorithm to use | IESG | {{Section 2.1 of -odi}} | | cred_fmt | The format of authentication credential to use | IESG | {{Section 2.1 of -odi}} | | sign_enc_alg | The encryption algorithm to use for encrypting signed messages | IESG | {{Section 2.1 of -odi}} | | sign_alg | The signature algorithm to use | IESG | {{Section 2.1 of -odi}} | | sign_alg_crv | The elliptic curve of the used signature algorithm | IESG | {{Section 2.1 of -odi}} | | sign_key_kty | The key type of the used signing keys | IESG | {{Section 2.1 of -odi}} | | sign_key_crv | The curve of the used signing keys | IESG | {{Section 2.1 of -odi}} | | alg | The encryption algorithm to use for encrypting non-signed messages | IESG | {{Section 2.1 of -odi}} | | ecdh_alg | The ECDH algorithm to use | IESG | {{Section 2.1 of -odi}} | | ecdh_alg_crv | The elliptic curve of the used ECDH algorithm | IESG | {{Section 2.1 of -odi}} | | ecdh_key_kty | The key type of the used ECDH keys | IESG | {{Section 2.1 of -odi}} | | ecdh_key_crv | The curve of the used ECDH keys | IESG | {{Section 2.1 of -odi}} | | det_hash_alg | The hash algorithm to use for computing deterministic requests | IESG | {{Section 2.1 of -odi}} | | rekeying_scheme | The rekeying scheme used to distribute new keying material | IESG | {{Section 2.1 of -odi}} | {: #pre-reg title="Initial Entries in the Target Attributes Registry"}
A number of names are reserved as they are used for parameters in links other than target attributes, a further set is predefined in {{-linking}}.
The security considerations of {{-linking}} apply, as do those of the discovery specifications {{-link-format}}, {{-coap}}, and {{-rd}}.
--- back
{: numbered="no"}
TBD