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Admin Interface for the OSCORE Group Manager
draft-ietf-ace-oscore-gm-admin-00

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This is an older version of an Internet-Draft whose latest revision state is "Active".
Authors Marco Tiloca , Rikard Höglund , Peter Van der Stok , Francesca Palombini , Klaus Hartke
Last updated 2020-07-30
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draft-ietf-ace-oscore-gm-admin-00
ACE Working Group                                              M. Tiloca
Internet-Draft                                               R. Hoeglund
Intended status: Standards Track                                 RISE AB
Expires: January 31, 2021                                P. van der Stok
                                                              Consultant
                                                            F. Palombini
                                                               K. Hartke
                                                             Ericsson AB
                                                           July 30, 2020

              Admin Interface for the OSCORE Group Manager
                   draft-ietf-ace-oscore-gm-admin-00

Abstract

   Group communication for CoAP can be secured using Group Object
   Security for Constrained RESTful Environments (Group OSCORE).  A
   Group Manager is responsible to handle the joining of new group
   members, as well as to manage and distribute the group key material.
   This document defines a RESTful admin interface at the Group Manager,
   that allows an Administrator entity to create and delete OSCORE
   groups, as well as to retrieve and update their configuration.  The
   ACE framework for Authentication and Authorization is used to enforce
   authentication and authorization of the Administrator at the Group
   Manager.  Protocol-specific transport profiles of ACE are used to
   achieve communication security, proof-of-possession and server
   authentication.

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 January 31, 2021.

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Copyright Notice

   Copyright (c) 2020 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
   (https://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
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Group Administration  . . . . . . . . . . . . . . . . . . . .   5
     2.1.  Getting Access to the Group Manager . . . . . . . . . . .   6
     2.2.  Managing OSCORE Groups  . . . . . . . . . . . . . . . . .   7
     2.3.  Group Configurations  . . . . . . . . . . . . . . . . . .   8
       2.3.1.  Group Configuration Representation  . . . . . . . . .   8
       2.3.2.  Default Values  . . . . . . . . . . . . . . . . . . .  10
     2.4.  Discovery . . . . . . . . . . . . . . . . . . . . . . . .  10
     2.5.  Collection Representation . . . . . . . . . . . . . . . .  10
     2.6.  Interactions  . . . . . . . . . . . . . . . . . . . . . .  11
       2.6.1.  Get All Groups Configurations . . . . . . . . . . . .  11
       2.6.2.  Fetch Group Configurations By Filters . . . . . . . .  12
       2.6.3.  Create a New Group Configuration  . . . . . . . . . .  13
       2.6.4.  Retrieve a Group Configuration  . . . . . . . . . . .  17
       2.6.5.  Update a Group Configuration  . . . . . . . . . . . .  18
       2.6.6.  Delete a Group Configuration  . . . . . . . . . . . .  21
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .  23
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  23
     4.1.  ACE Groupcomm Parameters Registry . . . . . . . . . . . .  23
     4.2.  Resource Types  . . . . . . . . . . . . . . . . . . . . .  24
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  24
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .  25
     5.2.  Informative References  . . . . . . . . . . . . . . . . .  27
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  28
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  28

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1.  Introduction

   The Constrained Application Protocol (CoAP) [RFC7252] can be used in
   group communication environments where messages are also exchanged
   over IP multicast [I-D.dijk-core-groupcomm-bis].  Applications
   relying on CoAP can achieve end-to-end security at the application
   layer by using Object Security for Constrained RESTful Environments
   (OSCORE) [RFC8613], and especially Group OSCORE
   [I-D.ietf-core-oscore-groupcomm] in group communication scenarios.

   When group communication for CoAP is protected with Group OSCORE,
   nodes are required to explicitly join the correct OSCORE group.  To
   this end, a joining node interacts with a Group Manager (GM) entity
   responsible for that group, and retrieves the required key material
   to securely communicate with other group members using Group OSCORE.

   The method in [I-D.ietf-ace-key-groupcomm-oscore] specifies how nodes
   can join an OSCORE group through the respective Group Manager.  Such
   a method builds on the ACE framework for Authentication and
   Authorization [I-D.ietf-ace-oauth-authz], so ensuring a secure
   joining process as well as authentication and authorization of
   joining nodes (clients) at the Group Manager (resource server).

   In some deployments, the application running on the Group Manager may
   know when a new OSCORE group has to be created, as well as how it
   should be configured and later on updated or deleted, e.g. based on
   the current application state or on pre-installed policies.  In this
   case, the Group Manager application can create and configure OSCORE
   groups when needed, by using a local application interface.  However,
   this requires the Group Manager to be application-specific, which in
   turn leads to error prone deployments and is poorly flexible.

   In other deployments, a separate Administrator entity, such as a
   Commissioning Tool, is directly responsible for creating and
   configuring the OSCORE groups at a Group Manager, as well as for
   maintaining them during their whole lifetime until their deletion.
   This allows the Group Manager to be agnostic of the specific
   applications using secure group communication.

   This document specifies a RESTful admin interface at the Group
   Manager, intended for an Administrator, as a separate entity external
   to the Group Manager and its application.  The interface allows the
   Administrator to create and delete OSCORE groups, as well as to
   configure and update their configuration.

   Interaction examples are provided, in Link Format [RFC6690] and CBOR
   [RFC7049], as well as in CoRAL [I-D.ietf-core-coral].  While all the
   CoRAL examples use the CoRAL textual serialization format, the CBOR

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   or JSON [RFC8259] binary serialization format is used when sending
   such messages on the wire.

   The ACE framework is used to ensure authentication and authorization
   of the Administrator (client) at the Group Manager (resource server).
   In order to achieve communication security, proof-of-possession and
   server authentication, the Administrator and the Group Manager
   leverage protocol-specific transport profiles of ACE, such as
   [I-D.ietf-ace-oscore-profile][I-D.ietf-ace-dtls-authorize].  These
   include also possible forthcoming transport profiles that comply with
   the requirements in Appendix C of [I-D.ietf-ace-oauth-authz].

1.1.  Terminology

   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.

   Readers are expected to be familiar with the terms and concepts
   related to CBOR [RFC7049] and COSE
   [I-D.ietf-cose-rfc8152bis-struct][I-D.ietf-cose-rfc8152bis-algs], the
   CoAP protocol [RFC7252], as well as the protection and processing of
   CoAP messages using OSCORE [RFC8613], also in group communication
   scenarios using Group OSCORE [I-D.ietf-core-oscore-groupcomm].  These
   include the concept of Group Manager, as the entity responsible for a
   set of groups where communications among members are secured using
   Group OSCORE.

   Readers are also expected to be familiar with the terms and concept
   related to the management of keying material for groups in ACE
   defined in [I-D.ietf-ace-key-groupcomm], and in particular to the
   joining process for OSCORE groups defined in
   [I-D.ietf-ace-key-groupcomm-oscore].  These include the concept of
   group-membership resource hosted by the Group Manager, that new
   members access to join the OSCORE group, while current members can
   access to retrieve updated keying material.

   Readers are also expected to be familiar with the terms and concepts
   described in the ACE framework for authentication and authorization
   [I-D.ietf-ace-oauth-authz].  The terminology for entities in the
   considered architecture is defined in OAuth 2.0 [RFC6749].  In
   particular, this includes Client (C), Resource Server (RS), and
   Authorization Server (AS).

   Note that, unless otherwise indicated, the term "endpoint" is used
   here following its OAuth definition, aimed at denoting resources such

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   as /token and /introspect at the AS, and /authz-info at the RS.  This
   document does not use the CoAP definition of "endpoint", which is "An
   entity participating in the CoAP protocol".

   This document also refers to the following terminology.

   o  Administrator: entity responsible to create, configure and delete
      OSCORE groups at a Group Manager.

   o  Group name: stable and invariant name of an OSCORE group.  The
      group name MUST be unique under the same Group Manager, and MUST
      include only characters that are valid for a URI path segment,
      namely unreserved and pct-encoded characters [RFC3986].

   o  Group-collection resource: a single-instance resource hosted by
      the Group Manager.  An Administrator accesses a group-collection
      resource to create a new OSCORE group, or to retrieve the list of
      existing OSCORE groups, under that Group Manager.  As an example,
      this document uses /manage as the url-path of the group-collection
      resource; implementations are not required to use this name, and
      can define their own instead.

   o  Group-configuration resource: a resource hosted by the Group
      Manager, associated to an OSCORE group under that Group Manager.
      A group-configuration resource is identifiable with the invariant
      group name of the respective group.  An Administrator accesses a
      group-configuration resource to retrieve or update the
      configuration of the respective OSCORE group, or to delete that
      group.  The url-path to a group-configuration resource has NAME as
      last segment, with NAME the invariant group name assigned upon its
      creation.  Building on the considered url-path of the group-
      collection resource, this document uses /manage/NAME as the url-
      path of a group-configuration resource; implementations are not
      required to use this name, and can define their own instead.

   o  Admin endpoint: an endpoint at the Group Manager associated to the
      group-collection resource or to a group-configuration resource
      hosted by that Group Manager.

2.  Group Administration

   With reference to the ACE framework and the terminology defined in
   OAuth 2.0 [RFC6749]:

   o  The Group Manager acts as Resource Server (RS).  It provides one
      single group-collection resource, and one group-configuration
      resource per existing OSCORE group.  Each of those is exported by
      a distinct admin endpoint.

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   o  The Administrator acts as Client (C), and requests to access the
      group-collection resource and group-configuration resources, by
      accessing the respective admin endpoint at the Group Manager.

   o  The Authorization Server (AS) authorizes the Administrator to
      access the group-collection resource and group-configuration
      resources at a Group Manager.  Multiple Group Managers can be
      associated to the same AS.  The AS MAY release Access Tokens to
      the Administrator for other purposes than accessing admin
      endpoints of registered Group Managers.

2.1.  Getting Access to the Group Manager

   All communications between the involved entities rely on the CoAP
   protocol and MUST be secured.

   In particular, communications between the Administrator and the Group
   Manager leverage protocol-specific transport profiles of ACE to
   achieve communication security, proof-of-possession and server
   authentication.  To this end, the AS may explicitly signal the
   specific transport profile to use, consistently with requirements and
   assumptions defined in the ACE framework [I-D.ietf-ace-oauth-authz].

   With reference to the AS, communications between the Administrator
   and the AS (/token endpoint) as well as between the Group Manager and
   the AS (/introspect endpoint) can be secured by different means, for
   instance using DTLS [RFC6347][I-D.ietf-tls-dtls13] or OSCORE
   [RFC8613].  Further details on how the AS secures communications
   (with the Administrator and the Group Manager) depend on the
   specifically used transport profile of ACE, and are out of the scope
   of this specification.

   In order to get access to the Group Manager for managing OSCORE
   groups, an Administrator performs the following steps.

   1.  The Administrator requests an Access Token from the AS, in order
       to access the group-collection and group-configuration resources
       on the Group Manager.  The Administrator will start or continue
       using secure communications with the Group Manager, according to
       the response from the AS.

   2.  The Administrator transfers authentication and authorization
       information to the Group Manager by posting the obtained Access
       Token, according to the used profile of ACE, such as
       [I-D.ietf-ace-dtls-authorize] and [I-D.ietf-ace-oscore-profile].
       After that, the Administrator must have secure communication
       established with the Group Manager, before performing any admin
       operation on that Group Manager.  Possible ways to provide secure

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       communication are DTLS [RFC6347][I-D.ietf-tls-dtls13] and OSCORE
       [RFC8613].  The Administrator and the Group Manager maintain the
       secure association, to support possible future communications.

   3.  The Administrator performs admin operations at the Group Manager,
       as described in the following sections.  These include the
       retrieval of the existing OSCORE groups, the creation of new
       OSCORE groups, the update and retrieval of group configurations,
       and the removal of OSCORE groups.  Messages exchanged among the
       Administrator and the Group Manager are specified in Section 2.6.

2.2.  Managing OSCORE Groups

   Figure 1 shows the resources of a Group Manager available to an
   Administrator.

                    ___
          Group    /   \
       Collection  \___/
                        \
                         \____________________
                          \___    \___        \___
                          /   \   /   \  ...  /   \        Group
                          \___/   \___/       \___/   Configurations

                  Figure 1: Resources of a Group Manager

   The Group Manager exports a single group-collection resource.  The
   full interface for the group-collection resource allows the
   Administrator to:

   o  Retrieve the list of existing OSCORE groups, possibly by filters.

   o  Create a new OSCORE group, specifying its invariant group name
      and, optionally, its configuration.

   The Group Manager exports one group-configuration resource for each
   of its OSCORE groups.  Each group-configuration resource is
   identified by the group name specified upon creating the group.  The
   full interface for a group-configuration resource allows the
   Administrator to:

   o  Retrieve the current configuration of the OSCORE group.

   o  Update the current configuration of the OSCORE group.

   o  Delete the OSCORE group.

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2.3.  Group Configurations

   A group configuration consists of a set of parameters.

2.3.1.  Group Configuration Representation

   The group configuration representation is a CBOR map which MUST
   include configuration properties and status properties.

2.3.1.1.  Configuration Properties

   The CBOR map MUST include the following configuration parameters:

   o  'hkdf', defined in Section 4.1 of this document, specifies the
      HKDF algorithm used in the OSCORE group, encoded as a CBOR text
      string.  Possible values are the same ones admitted for the 'hkdf'
      parameter of the "OSCORE Security Context Parameters" registry,
      defined in Section 3.2.1 of [I-D.ietf-ace-oscore-profile].

   o  'alg', defined in Section 4.1 of this document, specifies the AEAD
      algorithm used in the OSCORE group, encoded as a CBOR text string.
      Possible values are the same ones admitted for the 'alg' parameter
      of the "OSCORE Security Context Parameters" registry, defined in
      Section 3.2.1 of [I-D.ietf-ace-oscore-profile].

   o  'cs_alg', defined in Section 4.1 of this document, specifies the
      countersignature algorithm used in the OSCORE group, encoded as a
      CBOR text string or integer.  Possible values are the same ones
      admitted for the 'cs_alg' parameter of the "OSCORE Security
      Context Parameters" registry, defined in Section 6.4 of
      [I-D.ietf-ace-key-groupcomm-oscore].

   o  'cs_params', defined in Section 4.1 of this document, specifies
      the additional parameters for the countersignature algorithm used
      in the OSCORE group, encoded as a CBOR array.  Possible formats
      and values are the same ones admitted for the 'cs_params'
      parameter of the "OSCORE Security Context Parameters" registry,
      defined in Section 6.4 of [I-D.ietf-ace-key-groupcomm-oscore].

   o  'cs_key_params', defined in Section 4.1 of this document,
      specifies the additional parameters for the key used with the
      countersignature algorithm in the OSCORE group, encoded as a CBOR
      array.  Possible formats and values are the same ones admitted for
      the 'cs_key_params' parameter of the "OSCORE Security Context
      Parameters" registry, defined in Section 6.4 of
      [I-D.ietf-ace-key-groupcomm-oscore].

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   o  'cs_key_enc', defined in Section 4.1 of this document, specifies
      the encoding of the public keys of group members, encoded as a
      CBOR integer.  Possible values are the same ones admitted for the
      'cs_key_enc' parameter of the "OSCORE Security Context Parameters"
      registry, defined in Section 6.4 of
      [I-D.ietf-ace-key-groupcomm-oscore].

2.3.1.2.  Status Properties

   The CBOR map MUST include the following status parameters:

   o  'active', encoding the CBOR simple value True if the group is
      currently active, or the CBOR simple value False otherwise.  This
      parameter is defined in Section 4.1 of this specification.

   o  'group_name', with value the group name of the OSCORE group
      encoded as a CBOR text string.  This parameter is defined in
      Section 4.1 of this specification.

   o  'group_title', with value either a human-readable description of
      the group encoded as a CBOR text string, or the CBOR simple value
      Null if no description is specified.  This parameter is defined in
      Section 4.1 of this specification.

   o  'ace-groupcomm-profile', defined in Section 4.1.2.1 of
      [I-D.ietf-ace-key-groupcomm], with value "coap_group_oscore_app".

   o  'exp', defined in Section 4.1.2.1 of [I-D.ietf-ace-key-groupcomm].

   o  'joining_uri', with value the URI of the group-membership resource
      for joining the newly created OSCORE group, encoded as a CBOR text
      string.  This parameter is defined in Section 4.1 of this
      specification.

   The CBOR map MAY include the following status parameters:

   o  'group_policies', defined in Section 4.1.2.1 of
      [I-D.ietf-ace-key-groupcomm], and consistent with the format and
      content defined in Section 6.4 of
      [I-D.ietf-ace-key-groupcomm-oscore].

   o  'as_uri', defined in Section 4.1 of this document, specifies the
      URI of the Authorization Server associated to the Group Manager
      for the OSCORE group, encoded as a CBOR text string.  Candidate
      group members will have to obtain an Access Token from that
      Authorization Server, before starting the joining process with the
      Group Manager to join the OSCORE group (see
      [I-D.ietf-ace-key-groupcomm-oscore]).

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2.3.2.  Default Values

   This section defines the default values that the Group Manager
   assumes for configuration and status parameters.

2.3.2.1.  Configuration Parameters

   For each configuration parameter, the Group Manager MUST assume a
   pre-configured default value, if none is specified by the
   Administrator.

   In particular, the Group Manager SHOULD use the same default values
   defined in Section 18 of [I-D.ietf-ace-key-groupcomm-oscore].

2.3.2.2.  Status Parameters

   For the following status parameters, the Group Manager MUST assume a
   pre-configured default value, if none is specified by the
   Administrator.

   o  For 'active', the CBOR simple value False.

   o  For 'group_title', the CBOR simple value Null.

2.4.  Discovery

   The Administrator can discover the group-collection resource from a
   resource directory, for instance [I-D.ietf-core-resource-directory]
   and [I-D.hartke-t2trg-coral-reef], or from .well-known/core , by
   using the resource type "ace.oscore.gm" defined in Section 4.2 of
   this specification.

   The Administrator can discover group-configuration resources for the
   group-collection resource as specified below in Section 2.6.1 and
   Section 2.6.2.

2.5.  Collection Representation

   A list of group configurations is represented as a document
   containing the corresponding group-configuration resources in the
   list.  Each group-configuration is represented as a link, where the
   link target is the URI of the group-configuration resource.

   The list can be represented as a Link Format document [RFC6690] or a
   CoRAL document [I-D.ietf-core-coral].  In the latter case, the CoRAL
   document contains the group-configuration resources in the list as
   top-level elements.  In particular, the link to each group-

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   configuration resource has http://coreapps.org/ace.oscore.gm#item as
   relation type.

2.6.  Interactions

   This section describes the operations available on the group-
   collection resource and the group-configuration resources.

   When custom CBOR is used, the Content-Format in messages containing a
   payload is set to application/ace-groupcomm+cbor, defined in
   Section 8.2 of [I-D.ietf-ace-key-groupcomm].  Furthermore, the entry
   labels defined in Section 4.1 MUST be used, when specifying the
   corresponding configuration and status parameters.

2.6.1.  Get All Groups Configurations

   The Administrator can send a GET request to the group-collection
   resource, in order to retrieve the list of the existing OSCORE groups
   at the Group Manager.  This is returned as a list of links to the
   corresponding group-configuration resources.

   Example in Link Format:

   => 0.01 GET
      Uri-Path: manage

   <= 2.05 Content
      Content-Format: 40 (application/link-format)

      <coap://[2001:db8::ab]/manage/gp1>,
      <coap://[2001:db8::ab]/manage/gp2>,
      <coap://[2001:db8::ab]/manage/gp3>

   Example in CoRAL:

   => 0.01 GET
      Uri-Path: manage

   <= 2.05 Content
      Content-Format: TBD1 (application/coral+cbor)

      #using <http://coreapps.org/ace.oscore.gm#>
      #base </manage/>
      item <gp1>
      item <gp2>
      item <gp3>

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2.6.2.  Fetch Group Configurations By Filters

   The Administrator can send a FETCH request to the group-collection
   resource, in order to retrieve the list of the existing OSCORE groups
   at the Group Manager that fully match a set of specified filter
   criteria.  This is returned as a list of links to the corresponding
   group-configuration resources.

   The set of filter criteria is specified in the request payload as a
   CBOR map, where possible entry labels are all the ones used for
   configuration properties (see Section 2.3.1.1), as well as
   "group_name" and "active" for the corresponding status property (see
   Section 2.3.1.2).

   Entry values are the ones admitted for the corresponding labels in
   the POST request for creating a group configuration (see
   Section 2.6.3).  A valid request MUST NOT include the same entry
   multiple times.

   Example in custom CBOR and Link Format:

   => 0.05 FETCH
      Uri-Path: manage
      Content-Format: TBD2 (application/ace-groupcomm+cbor)

      {
          "alg" : 10,
          "hkdf" : 5
      }

   <= 2.05 Content
      Content-Format: 40 (application/link-format)

      <coap://[2001:db8::ab]/manage/gp1>,
      <coap://[2001:db8::ab]/manage/gp2>,
      <coap://[2001:db8::ab]/manage/gp3>

   Example in CoRAL:

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   => 0.05 FETCH
      Uri-Path: manage
      Content-Format: TBD1 (application/coral+cbor)

      alg 10
      hkdf 5

   <= 2.05 Content
      Content-Format: TBD1 (application/coral+cbor)

      #using <http://coreapps.org/ace.oscore.gm#>
      #base </manage/>
      item <gp1>
      item <gp2>
      item <gp3>

2.6.3.  Create a New Group Configuration

   The Administrator can send a POST request to the group-collection
   resource, in order to create a new OSCORE group at the Group Manager.
   The request MAY specify the intended group name NAME and group title,
   and MAY specify pieces of information concerning the group
   configuration.

   The request payload is a CBOR map, whose possible entries are
   specified in Section 2.3.1.  In particular:

   o  The CBOR map MAY include any of the configuration parameter
      defined in Section 2.3.1.1.

   o  The CBOR map MAY include any of the status parameter 'group_name',
      'group_title', 'exp', 'group_policies', 'as_uri' and 'active'
      defined in Section 2.3.1.2.

   o  The CBOR map MUST NOT include any of the status parameter 'ace-
      groupcomm-profile' and 'joining_uri' defined in Section 2.3.1.2.

   If any of the following occurs, the Group Manager MUST respond with a
   4.00 (Bad Request) response, which MAY include additional information
   to clarify what went wrong.

   o  Any of the received parameters is specified multiple times.

   o  Any of the received parameters is not recognized, or not valid, or
      not consistent with respect to other related parameters.

   o  The 'group_name' parameter specifies the group name of an already
      existing OSCORE group.

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   o  The Group Manager does not trust the Authorization Server with URI
      specified in the 'as_uri' parameter, and has no alternative
      Authorization Server to consider for the OSCORE group to create.

   After a successful processing of the request above, the Group Manager
   performs the following actions.

   First, the Group Manager creates a new group-configuration resource,
   accessible to the administrator at /manage/NAME , where NAME is the
   group name as either indicated in the parameter 'group_name' of the
   request or uniquely assigned by the Group Manager.  The values
   specified in the request are used as group configuration information
   for the newly created OSCORE group.  For each configuration parameter
   not specified in the request, the Group Manager MUST assume the
   default value specified in Section 2.3.2.

   After that, the Group Manager creates a new group-membership
   resource, accessible to joining nodes and future group members at
   group-oscore/NAME , as specified in
   [I-D.ietf-ace-key-groupcomm-oscore].  In particular, the Group
   Manager will rely on the current group configuration to build the
   Joining Response message defined in Section 5.4 of
   [I-D.ietf-ace-key-groupcomm-oscore], when handling the joining of a
   new group member.  Furthermore, the Group Manager generates the
   following pieces of information, and assigns them to the newly
   created OSCORE group:

   o  The OSCORE Master Secret.

   o  The OSCORE Master Salt (optionally).

   o  The OSCORE ID Context, acting as Group ID, which MUST be unique
      within the set of OSCORE groups under the Group Manager.

   Finally, the Group Manager replies to the Administrator with a 2.01
   (Created) response.  The Location-Path option MUST be included in the
   response, indicating the location of the just created group-
   configuration resource.  The response MUST NOT include a Location-
   Query option.  The response payload is a CBOR map, which MUST include
   the following parameters:

   o  'group_name', with value the group name of the OSCORE group
      encoded as a CBOR text string.  This value can be different from
      the group name possibly specified by the Administrator in the POST
      request, and reflects the final choice of the Group Manager as
      'group_name' status property for the OSCORE group.

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   o  'joining_uri', with value the URI of the group-membership resource
      for joining the newly created OSCORE group, encoded as a CBOR text
      string.

   o  'as_uri', with value the URI of the Authorization Server
      associated to the Group Manager for the newly created OSCORE
      group, encoded as a CBOR text string.  This value can be different
      from the URI possibly specified by the Administrator in the POST
      request, and reflects the final choice of the Group Manager as
      'as_uri' status property for the OSCORE group.

   At this point, the Group Manager can register the link to the group-
   membership resource with URI specified in 'joining_uri' to the CoRE
   Resource Directory [I-D.ietf-core-resource-directory], as defined in
   Section 2 of [I-D.tiloca-core-oscore-discovery].

   Alternatively, the Administrator can perform the registration to the
   Resource Directory on behalf of the Group Manager, acting as
   Commissioning Tool.  The Administrator considers the following when
   specifying additional information for the link to register.

   o  The name of the OSCORE group MUST take the value specified in
      'group_name' from the 2.01 (Created) response above.

   o  If present, parameters describing the cryptographic algorithms
      used in the group MUST follow the values that the Administrator
      specified in the POST request above, or the corresponding default
      values specified in Section 2.3.2.1 otherwise.

   o  If also registering a related link to the Authorization Server
      associated to the OSCORE group, the related link MUST have the URI
      specified in 'as_uri' from the 2.01 (Created) response above.

   Example in custom CBOR:

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   => 0.02 POST
      Uri-Path: manage
      Content-Format: TBD2 (application/ace-groupcomm+cbor)

      {
        "alg" : 10,
        "hkdf" : 5,
        "active" : True,
        "group_title" : "rooms 1 and 2",
        "as_uri" : "coap://as.example.com/token"
      }

   <= 2.01 Created
      Location-Path: manage
      Location-Path: gp4
      Content-Format: TBD2 (application/ace-groupcomm+cbor)

      {
        "group_name" : "gp4",
        "joining_uri" : "coap://[2001:db8::ab]/group-oscore/gp4/",
        "as_uri" : "coap://as.example.com/token"
      }

   Example in CoRAL:

   => 0.02 POST
      Uri-Path: manage
      Content-Format: TBD1 (application/coral+cbor)

      #using <http://coreapps.org/ace.oscore.gm#>
      alg 10
      hkdf 5
      active True
      group_title "rooms 1 and 2"
      as_uri <coap://as.example.com/token>

   <= 2.01 Created
      Location-Path: manage
      Location-Path: gp4
      Content-Format: TBD1 (application/coral+cbor)

      #using <http://coreapps.org/ace.oscore.gm#>
      group_name "gp4"
      joining_uri <coap://[2001:db8::ab]/group-oscore/gp4/>
      as_uri <coap://as.example.com/token>

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2.6.4.  Retrieve a Group Configuration

   The Administrator can send a GET request to the group-configuration
   resource manage/NAME associated to an OSCORE group with group name
   NAME, in order to retrieve the current configuration of that group.

   After a successful processing of the request above, the Group Manager
   replies to the Administrator with a 2.05 (Content) response.  The
   response has as payload the representation of the group configuration
   as specified in Section 2.3.1.  The exact content of the payload
   reflects the current configuration of the OSCORE group.  This
   includes both configuration properties and status properties.

   Example in custom CBOR:

   => 0.01 GET
      Uri-Path: manage
      Uri-Path: gp4

   <= 2.05 Content
      Content-Format: TBD2 (application/ace-groupcomm+cbor)

      {
        "alg" : 10,
        "hkdf" : 5,
        "cs_alg" : -8,
        "cs_params" : [[1], [1, 6]],
        "cs_key_params" : [1, 6],
        "cs_key_enc" : 1,
        "active" : True,
        "group_name" : "gp4",
        "group_title" : "rooms 1 and 2",
        "ace-groupcomm-profile" : "coap_group_oscore_app",
        "exp" : "1360289224",
        "joining_uri" : "coap://[2001:db8::ab]/group-oscore/gp4/",
        "as_uri" : "coap://as.example.com/token"
      }

   Example in CoRAL:

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   => 0.01 GET
      Uri-Path: manage
      Uri-Path: gp4

   <= 2.05 Content
      Content-Format: TBD1 (application/coral+cbor)

      #using <http://coreapps.org/ace.oscore.gm#>
      alg 10
      hkdf 5
      cs_alg -8
      cs_params.alg_capab.key_type 1
      cs_params.key_type_capab.key_type 1
      cs_params.key_type_capab.curve 6
      cs_key_params.key_type 1
      cs_key_params.curve 6
      cs_key_enc 1
      active True
      group_name "gp4"
      group_title "rooms 1 and 2"
      ace-groupcomm-profile "coap_group_oscore_app"
      exp "1360289224"
      joining_uri <coap://[2001:db8::ab]/group-oscore/gp4/>
      as_uri <coap://as.example.com/token>

2.6.5.  Update a Group Configuration

   The Administrator can send a PUT request to the group-configuration
   resource associated to an OSCORE group, in order to update the
   current configuration of that group.  The payload of the request has
   the same format of the POST request defined in Section 2.6.3, with
   the exception of the status parameter 'group_name' that MUST NOT be
   included.

   The error handling for the PUT request is the same as for the POST
   request defined in Section 2.6.3.  If no error occurs, the Group
   Manager performs the following actions.

   First, the Group Manager updates the configuration of the OSCORE
   group, consistently with the values indicated in the PUT request from
   the Administrator.  For each configuration parameter not specified in
   the PUT request, the Group Manager MUST use the default value
   specified in Section 2.3.2.  From then on, the Group Manager relies
   on the latest update configuration to build the Joining Response
   message defined in Section 5.4 of
   [I-D.ietf-ace-key-groupcomm-oscore], when handling the joining of a
   new group member.

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   Then, the Group Manager replies to the Administrator with a 2.04
   (Changed) response.  The payload of the response has the same format
   of the 2.01 (Created) response defined in Section 2.6.3.

   If the link to the group-membership resource was registered in the
   Resource Directory (see [I-D.ietf-core-resource-directory]), the GM
   is responsible to refresh the registration, as defined in Section 3
   of [I-D.tiloca-core-oscore-discovery].

   Alternatively, the Administrator can update the registration to the
   Resource Directory on behalf of the Group Manager, acting as
   Commissioning Tool.  The Administrator considers the following when
   specifying additional information for the link to update.

   o  The name of the OSCORE group MUST take the value specified in
      'group_name' from the 2.04 (Changed) response above.

   o  If present, parameters describing the cryptographic algorithms
      used in the group MUST follow the values that the Administrator
      specified in the POST request above, or the corresponding default
      values specified in Section 2.3.2.1 otherwise.

   o  If also registering a related link to the Authorization Server
      associated to the OSCORE group, the related link MUST have the URI
      specified in 'as_uri' from the 2.04 (Changed) response above.

   Example in custom CBOR:

   => PUT
      Uri-Path: manage
      Uri-Path: gp4
      Content-Format: TBD2 (application/ace-groupcomm+cbor)

      {
        "alg" : 11 ,
        "hkdf" : 5
      }

   <= 2.04 Changed
      Content-Format: TBD2 (application/ace-groupcomm+cbor)

      {
        "group_name" : "gp4",
        "joining_uri" : "coap://[2001:db8::ab]/group-oscore/gp4/",
        "as_uri" : "coap://as.example.com/token"
      }

   Example in CoRAL:

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   => PUT
      Uri-Path: manage
      Uri-Path: gp4
      Content-Format: TBD1 (application/coral+cbor)

      #using <http://coreapps.org/ace.oscore.gm#>
      alg 11
      hkdf 5

   <= 2.04 Changed
      Content-Format: TBD1 (application/coral+cbor)

      #using <http://coreapps.org/ace.oscore.gm#>
      group_name "gp4"
      joining_uri <coap://[2001:db8::ab]/group-oscore/gp4/>
      as_uri <coap://as.example.com/token>

2.6.5.1.  Effects on Joining Nodes

   If the value of the status parameter 'active' is changed from True to
   False, the Group Manager MUST stop admitting new members in the
   group.  In particular, upon receiving a Joining Request (see
   Section 5.3 of [I-D.ietf-ace-key-groupcomm-oscore]), the Group
   Manager MUST respond with a 5.03 (Service Unavailable) response to
   the joining node, and MAY include additional information to clarify
   what went wrong.

   If the value of the status parameter 'active' is changed from False
   to True, the Group Manager resumes admitting new members in the
   group, by processing their Joining Requests (see Section 5.3 of
   [I-D.ietf-ace-key-groupcomm-oscore]).

2.6.5.2.  Effects on the Group Members

   After having updated a group configuration, the Group Manager informs
   the group members, over the pairwise secure communication channels
   established when joining the OSCORE group (see Section 5 of
   [I-D.ietf-ace-key-groupcomm-oscore]).

   To this end, the Group Manager can individually target the
   'control_path' URI path of each group member (see Section 4.1.2.1 of
   [I-D.ietf-ace-key-groupcomm]), if provided by the intended recipient
   upon joining the group (see Section 5 of
   [I-D.ietf-ace-key-groupcomm-oscore]).  Alternatively, group members
   can subscribe for updates to the group-membership resource of the
   OSCORE group, e.g. by using CoAP Observe [RFC7641].

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   Every group member, upon learning that the group has been deactivated
   (i.e. 'active' has value False), SHOULD stop communicating in the
   OSCORE group.

   Every group member, upon learning that the group has been reactivated
   (i.e. 'active' has value True again), can resume communicating in the
   OSCORE group.

   Every group member, upon receiving updated values for 'alg' and
   'hkdf', MUST either:

   o  Leave the group (see Section 14 of
      [I-D.ietf-ace-key-groupcomm-oscore]), e.g. if not supporting the
      indicated new algorithms; or

   o  Use the new parameter values, and accordingly re-derive the OSCORE
      Security Context for the group (see Section 2 of
      [I-D.ietf-core-oscore-groupcomm]).

   Every group member, upon receiving updated values for 'cs_alg',
   'cs_params', 'cs_key_params' and 'cs_key_enc', MUST either:

   o  Leave the group, e.g. if not supporting the indicated new
      algorithm, parameters and encoding; or

   o  Leave the group and rejoin it (see Section 5 of
      [I-D.ietf-ace-key-groupcomm-oscore]), providing the Group Manager
      with a public key which is compatible with the indicated new
      algorithm, parameters and encoding; or

   o  Use the new parameter values, and, if required, provide the Group
      Manager with a new public key to use in the group, as compatible
      with the indicated parameters (see Section 10 of
      [I-D.ietf-ace-key-groupcomm-oscore]).

2.6.6.  Delete a Group Configuration

   The Administrator can send a DELETE request to the group-
   configuration resource, in order to delete that group.  A group
   deletion would be successful only on an inactive group.

   That is, the DELETE request actually yields a successful deletion of
   the group, only if the corresponding status parameter 'active' has
   current value False.  The administrator can ensure that, by first
   performing an update of the group-configuration resource associated
   to the group (see Section 2.6.5), and setting the corresponding
   status parameter 'active' to False.

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   If, upon receiving the DELETE request, the current value of the
   status parameter 'active' is True, the Group Manager MUST respond
   with a 4.09 (Conflict) response, which MAY include additional
   information to clarify what went wrong.

   After a successful processing of the request above, the Group Manager
   performs the following actions.

   First, the Group Manager deletes the OSCORE group and deallocates
   both the group-configuration resource as well as the group-membership
   resource.

   Then, the Group Manager replies to the Administrator with a 2.02
   (Deleted) response.

   Example:

   => DELETE
      Uri-Path: manage
      Uri-Path: gp4

   <= 2.02 Deleted

2.6.6.1.  Effects on the Group Members

   After having deleted a group, the Group Manager can inform the group
   members by means of the following two methods.  When contacting a
   group member, the Group Manager uses the pairwise secure
   communication channel established with that member during its joining
   process (see Section 5 of [I-D.ietf-ace-key-groupcomm-oscore]).

   o  The Group Manager sends an individual request message to each
      group member, targeting the respective resource used to perform
      the group rekeying process (see Section 16 of
      [I-D.ietf-ace-key-groupcomm-oscore]).  The Group Manager uses the
      same format of the Joining Response message in Section 5.4 of
      [I-D.ietf-ace-key-groupcomm-oscore], where only the parameters
      'gkty', 'key', and 'ace-groupcomm-profile' are present, and the
      'key' parameter is empty.

   o  A group member may subscribe for updates to the group-membership
      resource of the group.  In particular, if this relies on CoAP
      Observe [RFC7641], a group member would receive a 4.04 (Not Found)
      notification response from the Group Manager, since the group-
      configuration resource has been deallocated upon deleting the
      group.

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   When being informed about the group deletion, a group member deletes
   the OSCORE Security Context that it stores as associated to that
   group, and possibly deallocates any dedicated control resource
   intended for the Group Manager that it has for that group.

3.  Security Considerations

   Security considerations are inherited from the ACE framework for
   Authentication and Authorization [I-D.ietf-ace-oauth-authz], and from
   the specific transport ace-groupcomm-profile of ACE used between the
   Administrator and the Group Manager, such as
   [I-D.ietf-ace-dtls-authorize] and [I-D.ietf-ace-oscore-profile].

4.  IANA Considerations

   This document has the following actions for IANA.

4.1.  ACE Groupcomm Parameters Registry

   IANA is asked to register the following entries in the "ACE Groupcomm
   Parameters" Registry defined in Section 8.5 of
   [I-D.ietf-ace-key-groupcomm].

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   +---------------+----------+--------------------+-------------------+
   | Name          | CBOR Key | CBOR Type          | Reference         |
   +---------------+----------+--------------------+-------------------+
   |               |          |                    |                   |
   | hkdf          | TBD3     | tstr               | [[this document]] |
   |               |          |                    |                   |
   | alg           | TBD4     | tstr               | [[this document]] |
   |               |          |                    |                   |
   | cs_alg        | TBD5     | tstr / int         | [[this document]] |
   |               |          |                    |                   |
   | cs_params     | TBD6     | array              | [[this document]] |
   |               |          |                    |                   |
   | cs_key_params | TBD7     | array              | [[this document]] |
   |               |          |                    |                   |
   | cs_key_enc    | TBD8     | int                | [[this document]] |
   |               |          |                    |                   |
   | active        | TBD9     | simple type        | [[this document]] |
   |               |          |                    |                   |
   | group_name    | TBD10    | tstr               | [[this document]] |
   |               |          |                    |                   |
   | group_title   | TBD11    | tstr / simple type | [[this document]] |
   |               |          |                    |                   |
   | joining_uri   | TBD12    | tstr               | [[this document]] |
   |               |          |                    |                   |
   | as_uri        | TBD13    | tstr               | [[this document]] |
   |               |          |                    |                   |
   +---------------+----------+--------------------+-------------------+

4.2.  Resource Types

   IANA is asked to enter the following value into the Resource Type
   (rt=) Link Target Attribute Values subregistry within the Constrained
   Restful Environments (CoRE) Parameters registry defined in [RFC6690].

    +---------------+----------------------------+-------------------+
    | Value         | Description                | Reference         |
    +---------------+----------------------------+-------------------+
    |               |                            |                   |
    | ace.oscore.gm | Group-collection resource  | [[this document]] |
    |               | of an OSCORE Group Manager |                   |
    |               |                            |                   |
    +---------------+----------------------------+-------------------+

5.  References

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5.1.  Normative References

   [COSE.Algorithms]
              IANA, "COSE Algorithms",
              <https://www.iana.org/assignments/cose/
              cose.xhtml#algorithms>.

   [COSE.Elliptic.Curves]
              IANA, "COSE Elliptic Curves",
              <https://www.iana.org/assignments/cose/
              cose.xhtml#elliptic-curves>.

   [COSE.Key.Types]
              IANA, "COSE Key Types",
              <https://www.iana.org/assignments/cose/
              cose.xhtml#key-type>.

   [I-D.ietf-ace-key-groupcomm]
              Palombini, F. and M. Tiloca, "Key Provisioning for Group
              Communication using ACE", draft-ietf-ace-key-groupcomm-08
              (work in progress), July 2020.

   [I-D.ietf-ace-key-groupcomm-oscore]
              Tiloca, M., Park, J., and F. Palombini, "Key Management
              for OSCORE Groups in ACE", draft-ietf-ace-key-groupcomm-
              oscore-08 (work in progress), July 2020.

   [I-D.ietf-ace-oauth-authz]
              Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and
              H. Tschofenig, "Authentication and Authorization for
              Constrained Environments (ACE) using the OAuth 2.0
              Framework (ACE-OAuth)", draft-ietf-ace-oauth-authz-35
              (work in progress), June 2020.

   [I-D.ietf-ace-oscore-profile]
              Palombini, F., Seitz, L., Selander, G., and M. Gunnarsson,
              "OSCORE profile of the Authentication and Authorization
              for Constrained Environments Framework", draft-ietf-ace-
              oscore-profile-11 (work in progress), June 2020.

   [I-D.ietf-core-coral]
              Hartke, K., "The Constrained RESTful Application Language
              (CoRAL)", draft-ietf-core-coral-03 (work in progress),
              March 2020.

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   [I-D.ietf-core-oscore-groupcomm]
              Tiloca, M., Selander, G., Palombini, F., and J. Park,
              "Group OSCORE - Secure Group Communication for CoAP",
              draft-ietf-core-oscore-groupcomm-09 (work in progress),
              June 2020.

   [I-D.ietf-cose-rfc8152bis-algs]
              Schaad, J., "CBOR Object Signing and Encryption (COSE):
              Initial Algorithms", draft-ietf-cose-rfc8152bis-algs-11
              (work in progress), July 2020.

   [I-D.ietf-cose-rfc8152bis-struct]
              Schaad, J., "CBOR Object Signing and Encryption (COSE):
              Structures and Process", draft-ietf-cose-rfc8152bis-
              struct-11 (work in progress), July 2020.

   [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/info/rfc2119>.

   [RFC3986]  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/info/rfc3986>.

   [RFC6690]  Shelby, Z., "Constrained RESTful Environments (CoRE) Link
              Format", RFC 6690, DOI 10.17487/RFC6690, August 2012,
              <https://www.rfc-editor.org/info/rfc6690>.

   [RFC6749]  Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
              RFC 6749, DOI 10.17487/RFC6749, October 2012,
              <https://www.rfc-editor.org/info/rfc6749>.

   [RFC7049]  Bormann, C. and P. Hoffman, "Concise Binary Object
              Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
              October 2013, <https://www.rfc-editor.org/info/rfc7049>.

   [RFC7252]  Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
              Application Protocol (CoAP)", RFC 7252,
              DOI 10.17487/RFC7252, June 2014,
              <https://www.rfc-editor.org/info/rfc7252>.

   [RFC7641]  Hartke, K., "Observing Resources in the Constrained
              Application Protocol (CoAP)", RFC 7641,
              DOI 10.17487/RFC7641, September 2015,
              <https://www.rfc-editor.org/info/rfc7641>.

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   [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/info/rfc8174>.

   [RFC8613]  Selander, G., Mattsson, J., Palombini, F., and L. Seitz,
              "Object Security for Constrained RESTful Environments
              (OSCORE)", RFC 8613, DOI 10.17487/RFC8613, July 2019,
              <https://www.rfc-editor.org/info/rfc8613>.

5.2.  Informative References

   [I-D.dijk-core-groupcomm-bis]
              Dijk, E., Wang, C., and M. Tiloca, "Group Communication
              for the Constrained Application Protocol (CoAP)", draft-
              dijk-core-groupcomm-bis-03 (work in progress), March 2020.

   [I-D.hartke-t2trg-coral-reef]
              Hartke, K., "Resource Discovery in Constrained RESTful
              Environments (CoRE) using the Constrained RESTful
              Application Language (CoRAL)", draft-hartke-t2trg-coral-
              reef-04 (work in progress), May 2020.

   [I-D.ietf-ace-dtls-authorize]
              Gerdes, S., Bergmann, O., Bormann, C., Selander, G., and
              L. Seitz, "Datagram Transport Layer Security (DTLS)
              Profile for Authentication and Authorization for
              Constrained Environments (ACE)", draft-ietf-ace-dtls-
              authorize-12 (work in progress), July 2020.

   [I-D.ietf-core-resource-directory]
              Shelby, Z., Koster, M., Bormann, C., Stok, P., and C.
              Amsuess, "CoRE Resource Directory", draft-ietf-core-
              resource-directory-25 (work in progress), July 2020.

   [I-D.ietf-tls-dtls13]
              Rescorla, E., Tschofenig, H., and N. Modadugu, "The
              Datagram Transport Layer Security (DTLS) Protocol Version
              1.3", draft-ietf-tls-dtls13-38 (work in progress), May
              2020.

   [I-D.tiloca-core-oscore-discovery]
              Tiloca, M., Amsuess, C., and P. Stok, "Discovery of OSCORE
              Groups with the CoRE Resource Directory", draft-tiloca-
              core-oscore-discovery-06 (work in progress), July 2020.

   [RFC6347]  Rescorla, E. and N. Modadugu, "Datagram Transport Layer
              Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
              January 2012, <https://www.rfc-editor.org/info/rfc6347>.

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Internet-Draft      Admin Interface for the OSCORE GM          July 2020

   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", STD 90, RFC 8259,
              DOI 10.17487/RFC8259, December 2017,
              <https://www.rfc-editor.org/info/rfc8259>.

Acknowledgments

   The authors sincerely thank Christian Amsuess, Carsten Bormann and
   Jim Schaad for their comments and feedback.

   The work on this document has been partly supported by VINNOVA and
   the Celtic-Next project CRITISEC.

Authors' Addresses

   Marco Tiloca
   RISE AB
   Isafjordsgatan 22
   Kista  SE-16440 Stockholm
   Sweden

   Email: marco.tiloca@ri.se

   Rikard Hoeglund
   RISE AB
   Isafjordsgatan 22
   Kista  SE-16440 Stockholm
   Sweden

   Email: rikard.hoglund@ri.se

   Peter van der Stok
   Consultant

   Phone: +31-492474673 (Netherlands), +33-966015248 (France)
   Email: consultancy@vanderstok.org
   URI:   www.vanderstok.org

   Francesca Palombini
   Ericsson AB
   Torshamnsgatan 23
   Kista  SE-16440 Stockholm
   Sweden

   Email: francesca.palombini@ericsson.com

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   Klaus Hartke
   Ericsson AB
   Torshamnsgatan 23
   Kista  SE-16440 Stockholm
   Sweden

   Email: klaus.hartke@ericsson.com

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