draft-ietf-ace-key-groupcomm-oscore-04.txt   draft-ietf-ace-key-groupcomm-oscore-05.txt 
ACE Working Group M. Tiloca ACE Working Group M. Tiloca
Internet-Draft RISE AB Internet-Draft RISE AB
Intended status: Standards Track J. Park Intended status: Standards Track J. Park
Expires: July 18, 2020 Universitaet Duisburg-Essen Expires: September 10, 2020 Universitaet Duisburg-Essen
F. Palombini F. Palombini
Ericsson AB Ericsson AB
January 15, 2020 March 09, 2020
Key Management for OSCORE Groups in ACE Key Management for OSCORE Groups in ACE
draft-ietf-ace-key-groupcomm-oscore-04 draft-ietf-ace-key-groupcomm-oscore-05
Abstract Abstract
This specification defines an application profile of the ACE This specification defines an application profile of the ACE
framework for Authentication and Authorization, to request and framework for Authentication and Authorization, to request and
provision keying material in group communication scenarios that are provision keying material in group communication scenarios that are
based on CoAP and secured with Group Object Security for Constrained based on CoAP and secured with Group Object Security for Constrained
RESTful Environments (OSCORE). This application profile delegates RESTful Environments (OSCORE). This application profile delegates
the authentication and authorization of Clients that join an OSCORE the authentication and authorization of Clients that join an OSCORE
group through a Resource Server acting as Group Manager for that group through a Resource Server acting as Group Manager for that
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This Internet-Draft will expire on July 18, 2020. This Internet-Draft will expire on September 10, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 5 2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 5
2.1. Overview of the Joining Process . . . . . . . . . . . . . 5 2.1. Overview of the Joining Process . . . . . . . . . . . . . 5
2.2. Overview of the Group Rekeying Process . . . . . . . . . 6 2.2. Overview of the Group Rekeying Process . . . . . . . . . 6
3. Joining Node to Authorization Server . . . . . . . . . . . . 6 3. Joining Node to Authorization Server . . . . . . . . . . . . 6
3.1. Authorization Request . . . . . . . . . . . . . . . . . . 6 3.1. Authorization Request . . . . . . . . . . . . . . . . . . 6
3.2. Authorization Response . . . . . . . . . . . . . . . . . 7 3.2. Authorization Response . . . . . . . . . . . . . . . . . 7
4. Joining a Group . . . . . . . . . . . . . . . . . . . . . . . 7 4. Interface at the Group Manager . . . . . . . . . . . . . . . 7
4.1. Token Post . . . . . . . . . . . . . . . . . . . . . . . 7 4.1. GET Handler . . . . . . . . . . . . . . . . . . . . . . . 8
4.2. Sending the Joining Request . . . . . . . . . . . . . . . 8 5. Joining a Group . . . . . . . . . . . . . . . . . . . . . . . 8
4.2.1. Value of the N_S Challenge . . . . . . . . . . . . . 9 5.1. Token Post . . . . . . . . . . . . . . . . . . . . . . . 8
4.3. Processing the Joining Request . . . . . . . . . . . . . 10 5.2. Sending the Joining Request . . . . . . . . . . . . . . . 9
4.4. Joining Response . . . . . . . . . . . . . . . . . . . . 11 5.2.1. Value of the N_S Challenge . . . . . . . . . . . . . 10
5. Public Keys of Joining Nodes . . . . . . . . . . . . . . . . 14 5.3. Processing the Joining Request . . . . . . . . . . . . . 11
6. Retrieval of Updated Keying Material . . . . . . . . . . . . 15 5.4. Joining Response . . . . . . . . . . . . . . . . . . . . 12
6.1. Retrieval of Group Keying Material . . . . . . . . . . . 16 6. Public Keys of Joining Nodes . . . . . . . . . . . . . . . . 15
6.2. Retrieval of Group Keying Material and Sender ID . . . . 16 7. Retrieval of Updated Keying Material . . . . . . . . . . . . 17
7. Retrieval of New Keying Material . . . . . . . . . . . . . . 16 7.1. Retrieval of Group Keying Material . . . . . . . . . . . 17
8. Retrieval of Public Keys of Group Members . . . . . . . . . . 17 7.2. Retrieval of Group Keying Material and Sender ID . . . . 17
9. Retrieval of Group Policies . . . . . . . . . . . . . . . . . 18 8. Retrieval of New Keying Material . . . . . . . . . . . . . . 18
10. Retrieval of Keying Material Version . . . . . . . . . . . . 18 9. Retrieval of Public Keys of Group Members . . . . . . . . . . 19
11. Request to Leave the Group . . . . . . . . . . . . . . . . . 18 10. Update of Public Key . . . . . . . . . . . . . . . . . . . . 19
12. Removal of a Group Member . . . . . . . . . . . . . . . . . . 18 11. Retrieval of Group Policies . . . . . . . . . . . . . . . . . 20
13. Group Rekeying Process . . . . . . . . . . . . . . . . . . . 19 12. Retrieval of Keying Material Version . . . . . . . . . . . . 20
14. Security Considerations . . . . . . . . . . . . . . . . . . . 20 13. Retrieval of Group Status . . . . . . . . . . . . . . . . . . 21
15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 14. Request to Leave the Group . . . . . . . . . . . . . . . . . 21
15.1. ACE Groupcomm Key Registry . . . . . . . . . . . . . . . 21 15. Removal of a Group Member . . . . . . . . . . . . . . . . . . 21
15.2. OSCORE Security Context Parameters Registry . . . . . . 22 16. Group Rekeying Process . . . . . . . . . . . . . . . . . . . 22
15.3. ACE Groupcomm Profile Registry . . . . . . . . . . . . . 23 17. Security Considerations . . . . . . . . . . . . . . . . . . . 23
15.4. Sequence Number Synchronization Method Registry . . . . 23 17.1. Management of OSCORE Groups . . . . . . . . . . . . . . 24
15.5. ACE Groupcomm Parameters Registry . . . . . . . . . . . 24 17.2. Size of Nonces for Signature Challenge . . . . . . . . . 25
16. References . . . . . . . . . . . . . . . . . . . . . . . . . 24 18. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
16.1. Normative References . . . . . . . . . . . . . . . . . . 24 18.1. ACE Groupcomm Profile Registry . . . . . . . . . . . . . 26
16.2. Informative References . . . . . . . . . . . . . . . . . 26 18.2. ACE Groupcomm Key Registry . . . . . . . . . . . . . . . 27
Appendix A. Profile Requirements . . . . . . . . . . . . . . . . 27 18.3. OSCORE Security Context Parameters Registry . . . . . . 27
Appendix B. Document Updates . . . . . . . . . . . . . . . . . . 29 18.4. Sequence Number Synchronization Method Registry . . . . 28
B.1. Version -03 to -04 . . . . . . . . . . . . . . . . . . . 29 18.5. ACE Groupcomm Parameters Registry . . . . . . . . . . . 29
B.2. Version -02 to -03 . . . . . . . . . . . . . . . . . . . 29 18.6. TLS Exporter Label Registry . . . . . . . . . . . . . . 29
B.3. Version -01 to -02 . . . . . . . . . . . . . . . . . . . 30 19. References . . . . . . . . . . . . . . . . . . . . . . . . . 29
B.4. Version -00 to -01 . . . . . . . . . . . . . . . . . . . 31 19.1. Normative References . . . . . . . . . . . . . . . . . . 29
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 31 19.2. Informative References . . . . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31 Appendix A. Profile Requirements . . . . . . . . . . . . . . . . 32
Appendix B. Document Updates . . . . . . . . . . . . . . . . . . 34
B.1. Version -04 to -05 . . . . . . . . . . . . . . . . . . . 34
B.2. Version -03 to -04 . . . . . . . . . . . . . . . . . . . 35
B.3. Version -02 to -03 . . . . . . . . . . . . . . . . . . . 35
B.4. Version -01 to -02 . . . . . . . . . . . . . . . . . . . 36
B.5. Version -00 to -01 . . . . . . . . . . . . . . . . . . . 37
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 37
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 37
1. Introduction 1. Introduction
Object Security for Constrained RESTful Environments (OSCORE) Object Security for Constrained RESTful Environments (OSCORE)
[RFC8613] is a method for application-layer protection of the [RFC8613] is a method for application-layer protection of the
Constrained Application Protocol (CoAP) [RFC7252], using CBOR Object Constrained Application Protocol (CoAP) [RFC7252], using CBOR Object
Signing and Encryption (COSE) [RFC8152] and enabling end-to-end Signing and Encryption (COSE) [RFC8152] and enabling end-to-end
security of CoAP payload and options. security of CoAP payload and options.
As described in [I-D.ietf-core-oscore-groupcomm], Group OSCORE is As described in [I-D.ietf-core-oscore-groupcomm], Group OSCORE is
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These include the concept of Group Manager, as the entity These include the concept of Group Manager, as the entity
responsible for a set of groups where communications are secured responsible for a set of groups where communications are secured
with Group OSCORE. In this specification, the Group Manager acts with Group OSCORE. In this specification, the Group Manager acts
as Resource Server. as Resource Server.
Additionally, this document makes use of the following terminology. Additionally, this document makes use of the following terminology.
o Group name is used as a synonym for group identifier in o Group name is used as a synonym for group identifier in
[I-D.ietf-ace-key-groupcomm]. [I-D.ietf-ace-key-groupcomm].
o GROUPNAME and NODENAME are used to indicate the variant parts of
the resource endpoint, i.e. "gid" and "node" URI path in
[I-D.ietf-ace-key-groupcomm].
o Requester: member of an OSCORE group that sends request messages o Requester: member of an OSCORE group that sends request messages
to other members of the group. to other members of the group.
o Responder: member of an OSCORE group that receives request o Responder: member of an OSCORE group that receives request
messages from other members of the group. A responder may reply messages from other members of the group. A responder may reply
back, by sending a response message to the requester which has back, by sending a response message to the requester which has
sent the request message. sent the request message.
o Monitor: member of an OSCORE group that is configured as responder o Monitor: member of an OSCORE group that is configured as responder
and never replies back to requesters after receiving request and never replies back to requesters after receiving request
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authentication. Note that it is expected that in the commonly authentication. Note that it is expected that in the commonly
referred base-case of this specification, the transport profile to referred base-case of this specification, the transport profile to
use is pre-configured and well-known to nodes participating in use is pre-configured and well-known to nodes participating in
constrained applications. constrained applications.
2.1. Overview of the Joining Process 2.1. Overview of the Joining Process
A node performs the steps described in Section 4.2 of A node performs the steps described in Section 4.2 of
[I-D.ietf-ace-key-groupcomm] in order to join an OSCORE group. The [I-D.ietf-ace-key-groupcomm] in order to join an OSCORE group. The
format and processing of messages exchanged among the participants format and processing of messages exchanged among the participants
are further specified in Section 3 and Section 4 of this document. are further specified in Section 3 and Section 5 of this document.
2.2. Overview of the Group Rekeying Process 2.2. Overview of the Group Rekeying Process
If the application requires backward and forward security, the Group If the application requires backward and forward security, the Group
Manager MUST generate new security parameters and group keying Manager MUST generate new keying material and distribute it to the
material, and distribute them to the group (rekeying) upon membership group (rekeying) upon membership changes.
changes.
That is, the group is rekeyed when a node joins the group as a new That is, the group is rekeyed when a node joins the group as a new
member, or after a current member leaves the group. By doing so, a member, or after a current member leaves the group. By doing so, a
joining node cannot access communications in the group prior its joining node cannot access communications in the group prior its
joining, while a leaving node cannot access communications in the joining, while a leaving node cannot access communications in the
group after its leaving. group after its leaving.
Parameters and group keying material include a new Group Identifier The keying material distributed through a group rekeying MUST include
(Gid) for the group and a new Master Secret for the OSCORE Common a new Group Identifier (Gid) for the group and a new value for the
Security Context of that group (see Section 2 of Master Secret parameter of the OSCORE Common Security Context of that
[I-D.ietf-core-oscore-groupcomm]). Once completed a group rekeying, group (see Section 2 of [I-D.ietf-core-oscore-groupcomm]). Also, it
the GM MUST increment the version number of the group keying MAY include a new value for the Master Salt parameter of the OSCORE
material. Common Security Context of that group.
Upon generating the new group keying material and before starting its
distribution, the Group Manager MUST increment the version number of
the group keying material. When rekeying a group, the Group Manager
MUST preserve the current value of the Sender ID of each member in
that group.
The Group Manager MUST support the Group Rekeying Process described The Group Manager MUST support the Group Rekeying Process described
in Section 13. Future application profiles may define alternative in Section 16. Future application profiles may define alternative
message formats and distribution schemes to perform group rekeying. message formats and distribution schemes to perform group rekeying.
3. Joining Node to Authorization Server 3. Joining Node to Authorization Server
This section describes how the joining node interacts with the AS in This section describes how the joining node interacts with the AS in
order to be authorized to join an OSCORE group under a given Group order to be authorized to join an OSCORE group under a given Group
Manager. In particular, it considers a joining node that intends to Manager. In particular, it considers a joining node that intends to
contact that Group Manager for the first time. contact that Group Manager for the first time.
The message exchange between the joining node and the AS consists of The message exchange between the joining node and the AS consists of
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defined in [I-D.ietf-ace-key-groupcomm] applies, and only additions defined in [I-D.ietf-ace-key-groupcomm] applies, and only additions
or modifications to that specification are defined here. or modifications to that specification are defined here.
3.1. Authorization Request 3.1. Authorization Request
The Authorization Request message defined in Section 3.1 of The Authorization Request message defined in Section 3.1 of
[I-D.ietf-ace-key-groupcomm], with the following additions: [I-D.ietf-ace-key-groupcomm], with the following additions:
o The 'scope' parameter MUST be present. o The 'scope' parameter MUST be present.
o The group name of the OSCORE group to join under the Group Manager * The group name of the OSCORE group to join under the Group
is encoded as a CBOR text string. Manager is encoded as a CBOR text string (REQ1).
o The role in the OSCORE group to join is encoded as a text string. * Accepted values for role identifiers in the OSCORE group to
Accepted values of roles are: "requester", "responder", and join are: "requester", "responder", and "monitor" (REQ2).
"monitor". Possible combinations are: ["requester" , Possible combinations are: ["requester" , "responder"];
"responder"]; ["requester" , "monitor"]. ["requester" , "monitor"]. Each role identifier MUST be
encoded as a CBOR integer (REQ2), by using for abbreviation the
values specified in Figure 1 (OPT7).
+-----------+------------+
| Name | CBOR Value |
+-----------+------------+
| requester | TBD8 |
| responder | TBD9 |
| monitor | TBD10 |
+-----------+------------+
Figure 1: CBOR Abbreviations for Role Identifiers in the Group
o The 'audience' parameter MUST be present. o The 'audience' parameter MUST be present.
3.2. Authorization Response 3.2. Authorization Response
The Authorization Response message defined in Section 3.2 of The Authorization Response message defined in Section 3.2 of
[I-D.ietf-ace-key-groupcomm], with the following additions: [I-D.ietf-ace-key-groupcomm], with the following additions:
o The AS MUST include the 'exp' parameter. Other means for the AS o The AS MUST include the 'expires_in' parameter. Other means for
to specify the lifetime of Access Tokens are out of the scope of the AS to specify the lifetime of Access Tokens are out of the
this specification. scope of this specification.
o The AS MUST include the 'scope' parameter, when the value included o The AS MUST include the 'scope' parameter, when the value included
in the Access Token differs from the one specified by the joining in the Access Token differs from the one specified by the joining
node in the request. In such a case, the second element of node in the request. In such a case, the second element of each
'scope' MUST be present and includes the role or CBOR array of scope entry MUST be present, and includes the role or CBOR array
roles that the joining node is actually authorized to take in the of roles that the joining node is actually authorized to take in
OSCORE group, encoded as specified in Section 3.1 of this the OSCORE group for that scope entry, encoded as specified in
document. Section 3.1 of this document.
4. Joining a Group 4. Interface at the Group Manager
The Group Manager provides the interface defined in Section 4.1 of
[I-D.ietf-ace-key-groupcomm], with the following additional resource:
o /group-manager/GROUPNAME/active: this sub-resource is fixed and
supports the GET method, whose handler is defined in Section 4.1.
4.1. GET Handler
The handler expects a GET request.
The handler verifies that the group identifier of the /group-
manager/GROUPNAME/active path is a subset of the 'scope' stored in
the Access Token associated to the requesting client. If
verification fails, the Group Manager MUST respond with a 4.01
(Unauthorized) error message.
If verification succeeds, the handler returns a 2.05 (Content)
message containing the CBOR simple value True if the group is
currently active, or the CBOR simple value False otherwise. The
group is considered active if it is set to allow new members to join,
and if communication within the group is expected.
The method to set the current group status, i.e. active or inactive,
is out of the scope of this specification, and is defined for the
administrator interface of the Group Manager specified in
[I-D.tiloca-ace-oscore-gm-admin].
5. Joining a Group
The following subsections describe the interactions between the The following subsections describe the interactions between the
joining node and the Group Manager, i.e. the sending of the Access joining node and the Group Manager, i.e. the sending of the Access
Token and the Request-Response exchange to join the OSCORE group. Token and the Request-Response exchange to join the OSCORE group.
The message exchange between the joining node and the KDC consists of The message exchange between the joining node and the KDC consists of
the messages defined in Section 3.3 and 4.2 of the messages defined in Section 3.3 and 4.2 of
[I-D.ietf-ace-key-groupcomm]. Note that what is defined in [I-D.ietf-ace-key-groupcomm]. Note that what is defined in
[I-D.ietf-ace-key-groupcomm] applies, and only additions or [I-D.ietf-ace-key-groupcomm] applies, and only additions or
modifications to that specification are defined here. modifications to that specification are defined here.
4.1. Token Post 5.1. Token Post
The Token post exchange is defined in Section 3.3 of The Token post exchange is defined in Section 3.3 of
[I-D.ietf-ace-key-groupcomm]. [I-D.ietf-ace-key-groupcomm].
Additionally to what defined in [I-D.ietf-ace-key-groupcomm], the Additionally to what defined in [I-D.ietf-ace-key-groupcomm], the
following applies. following applies.
o The 'rsnonce' parameter contains a dedicated 8-byte nonce N_S o The 'rsnonce' parameter contains a dedicated nonce N_S generated
generated by the Group Manager. The joining node may use this by the Group Manager. For the N_S value, it is RECOMMENDED to use
nonce in order to prove the possession of its own private key, a 8-byte long random nonce. The joining node may use this nonce
upon joining the group (see Section 4.2). in order to prove the possession of its own private key, upon
joining the group (see Section 5.2).
o If 'sign_info' is present in the response: o If 'sign_info' is present in the response:
TODO: have 'sign_info' as an array of arrays, if 'scope' in the
Access Token covers multiple groups/topics.
* 'sign_alg' takes value from Tables 5 and 6 of [RFC8152]. * 'sign_alg' takes value from Tables 5 and 6 of [RFC8152].
* 'sign_parameters' takes values from the "Counter Signature * 'sign_parameters' takes values from the "Counter Signature
Parameters" Registry (see Section 9.1 of Parameters" Registry (see Section 11.1 of
[I-D.ietf-core-oscore-groupcomm]). Its structure depends on [I-D.ietf-core-oscore-groupcomm]). Its structure depends on
the value of 'sign_alg'. If no parameters of the counter the value of 'sign_alg'. If no parameters of the counter
signature algorithm are specified, 'sign_parameters' MUST be signature algorithm are specified, 'sign_parameters' MUST be
encoding the CBOR simple value Null. encoding the CBOR simple value Null.
* 'sign_key_parameters' takes values from the "Counter Signature * 'sign_key_parameters' takes values from the "Counter Signature
Key Parameters" Registry (see Section 9.2 of Key Parameters" Registry (see Section 11.2 of
[I-D.ietf-core-oscore-groupcomm]). Its structure depends on [I-D.ietf-core-oscore-groupcomm]). Its structure depends on
the value of 'sign_alg'. If no parameters of the key used with the value of 'sign_alg'. If no parameters of the key used with
the counter signature algorithm are specified, the counter signature algorithm are specified,
'sign_key_parameters' MUST be encoding the CBOR simple value 'sign_key_parameters' MUST be encoding the CBOR simple value
Null. Null.
* 'pub_key_enc' takes value 1 ("COSE_Key") from the 'Confirmation TODO: have 'pub_key_enc' as an array of arrays, if 'scope' in the
Key' column of the "CWT Confirmation Method" Registry defined Access Token covers multiple groups/topics.
in [I-D.ietf-ace-cwt-proof-of-possession], so indicating that
public keys in the OSCORE group are encoded as COSE Keys
[RFC8152]. Future specifications may define additional values
for this parameter.
Note that, other than through the above parameters as defined in o If 'pub_key_enc' is present in the response, it takes value 1
Section 3.3 of [I-D.ietf-ace-key-groupcomm], the joining node MAY ("COSE_Key") from the 'Confirmation Key' column of the "CWT
have previously retrieved this information by other means, e.g. by Confirmation Method" Registry defined in
using the approach described in [I-D.ietf-ace-cwt-proof-of-possession], so indicating that public
[I-D.tiloca-core-oscore-discovery]. keys in the OSCORE group are encoded as COSE Keys [RFC8152].
Future specifications may define additional values for this
parameter.
Note that, other than through the above parameters as defined in
Section 3.3 of [I-D.ietf-ace-key-groupcomm], the joining node MAY
have previously retrieved this information by other means, e.g. by
using the approach described in [I-D.tiloca-core-oscore-discovery].
Additionally, if allowed by the used transport profile of ACE, the Additionally, if allowed by the used transport profile of ACE, the
joining node may instead provide the Access Token to the Group joining node may instead provide the Access Token to the Group
Manager by other means, e.g. during a secure session establishment Manager by other means, e.g. during a secure session establishment
(see Section 3.3.1 of [I-D.ietf-ace-dtls-authorize]). (see Section 3.3.1 of [I-D.ietf-ace-dtls-authorize]).
4.2. Sending the Joining Request 5.2. Sending the Joining Request
The joining node requests to join the OSCORE group, by sending a The joining node requests to join the OSCORE group, by sending a
Joining Request message to the related group-membership resource at Joining Request message to the related group-membership resource at
the Group Manager, as per Section 4.2 of the Group Manager, as per Section 4.2 of
[I-D.ietf-ace-key-groupcomm]. [I-D.ietf-ace-key-groupcomm].
Additionally to what defined in [I-D.ietf-ace-key-groupcomm], the Additionally to what defined in [I-D.ietf-ace-key-groupcomm], the
following applies. following applies.
o The string "group-oscore" is used instead of "ace-group" (see o The string "group-oscore" is used instead of "ace-group" (see
Section 4.1 of [I-D.ietf-ace-key-groupcomm]) as the top level path Section 4.1 of [I-D.ietf-ace-key-groupcomm]) as the top level path
to the group-membership resource. The url-path /group-oscore/ is to the group-membership resource. The url-path /group-oscore/ is
a default name of this specifications: implementations are not a default name of this specifications: implementations are not
required to use this name, and can define their own instead. required to use this name, and can define their own instead.
o The 'scope' parameter MUST be present. o The 'scope' parameter MUST be present.
o The 'get_pub_keys' parameter is present only if the joining node o The 'get_pub_keys' parameter is present only if the joining node
wants to retrieve the public keys of the group members from the wants to retrieve the public keys of the group members from the
Group Manager during the joining process (see Section 5). Group Manager during the joining process (see Section 6).
Otherwise, this parameter MUST NOT be present. Otherwise, this parameter MUST NOT be present.
o 'cnonce' contains a dedicated 8-byte nonce N_C generated by the o 'cnonce' contains a dedicated nonce N_C generated by the joining
joining node. node. For the N_C value, it is RECOMMENDED to use a 8-byte long
random nonce.
o The signature encoded in the 'client_cred_verify' parameter is o The signature encoded in the 'client_cred_verify' parameter is
computed by the joining node by using the same private key and computed by the joining node by using the same private key and
countersignature algorithm it intends to use for signing messages countersignature algorithm it intends to use for signing messages
in the OSCORE group. Moreover, N_S is as defined in in the OSCORE group. Moreover, N_S is as defined in
Section 4.2.1. Section 5.2.1.
4.2.1. Value of the N_S Challenge 5.2.1. Value of the N_S Challenge
The N_S challenge takes one of the following values. The N_S challenge takes one of the following values.
1. If the joining node has posted the Access Token to the /authz- 1. If the joining node has posted the Access Token to the /authz-
info endpoint of the Group Manager as in Section 4.1, N_S takes info endpoint of the Group Manager as in Section 5.1, N_S takes
the same value of the 'rsnonce' parameter in the 2.01 (Created) the same value of the 'rsnonce' parameter in the 2.01 (Created)
response to the Token POST. response to the Token POST.
2. If the Token posting has relied on the DTLS profile of ACE 2. If the Token posting has relied on the DTLS profile of ACE
[I-D.ietf-ace-dtls-authorize] and the joining node included the [I-D.ietf-ace-dtls-authorize] and the joining node included the
Access Token as content of the "psk_identity" field of the Access Token as content of the "psk_identity" field of the
ClientKeyExchange message [RFC6347], N_S is an exporter value ClientKeyExchange message [RFC6347], N_S is an exporter value
computed as defined in Section 7.5 of [RFC8446]. Specifically, computed as defined in Section 7.5 of [RFC8446]. Specifically,
N_S is exported from the DTLS session between the joining node N_S is exported from the DTLS session between the joining node
and the Group Manager, using an empty 'context_value', 32 bytes and the Group Manager, using an empty 'context_value', 32 bytes
as 'key_length', and the exporter label "EXPORTER-ACE-Sign- as 'key_length', and the exporter label "EXPORTER-ACE-Sign-
Challenge" defined in Section 7 of Challenge-coap-group-oscore-app" defined in Section 18.6 of this
[I-D.ietf-ace-mqtt-tls-profile]. specification.
3. If the joining node is in fact re-joining the group, without 3. If the joining node is in fact re-joining the group, without
posting again the same and still valid Access Token: posting again the same and still valid Access Token:
* If the joining node and the Group Manager communicates using * If the joining node and the Group Manager communicates using
DTLS, N_S is an exporter value, computed as described in point DTLS, N_S is an exporter value, computed as described in point
(2) above. (2) above.
* If the joining node and the Group Manager communicates using * If the joining node and the Group Manager communicates using
OSCORE [RFC8613], the N_S is the output PRK of a HKDF-Extract OSCORE [RFC8613], the N_S is the output PRK of a HKDF-Extract
skipping to change at page 10, line 21 skipping to change at page 11, line 25
that Context, and | denotes byte string concatenation. Also, that Context, and | denotes byte string concatenation. Also,
'IKM' is the OSCORE Master Secret of the OSCORE Security 'IKM' is the OSCORE Master Secret of the OSCORE Security
Context between the joining node and the Group Manager. The Context between the joining node and the Group Manager. The
HKDF MUST be one of the HMAC-based HKDF [RFC5869] algorithms HKDF MUST be one of the HMAC-based HKDF [RFC5869] algorithms
defined for COSE [RFC8152]. HKDF SHA-256 is mandatory to defined for COSE [RFC8152]. HKDF SHA-256 is mandatory to
implement. implement.
It is up to applications to define how N_S is computed in further It is up to applications to define how N_S is computed in further
alternative settings. alternative settings.
4.3. Processing the Joining Request 5.3. Processing the Joining Request
The Group Manager processes the Joining Request as defined in The Group Manager processes the Joining Request as defined in
Section 4.1.2.1 of [I-D.ietf-ace-key-groupcomm]. Additionally, the Section 4.1.2.1 of [I-D.ietf-ace-key-groupcomm]. Additionally, the
following applies. following applies.
o In case the Joining Request does not include the 'client_cred' o In case the Joining Request does not include the 'client_cred'
parameter, the joining process fails if the Group Manager either: parameter, the joining process fails if the Group Manager either:
i) does not store a public key with an accepted format for the i) does not store a public key with an accepted format for the
joining node; or ii) stores multiple public keys with an accepted joining node; or ii) stores multiple public keys with an accepted
format for the joining node. format for the joining node.
o To compute the signature contained in 'client_cred_verify', the GM o To compute the signature contained in 'client_cred_verify', the GM
considers: i) as signed value, N_S concatenated with N_C, where considers: i) as signed value, N_S concatenated with N_C, where
N_S is determined as described in Section 4.2.1, while N_C is the N_S is determined as described in Section 5.2.1, while N_C is the
nonce provided in the 'cnonce' parameter of the Joining Request; nonce provided in the 'cnonce' parameter of the Joining Request;
ii) the countersignature algorithm used in the OSCORE group, and ii) the countersignature algorithm used in the OSCORE group, and
possible correponding parameters; and iii) the public key of the possible correponding parameters; and iii) the public key of the
joining node, either retrieved from the 'client_cred' parameter, joining node, either retrieved from the 'client_cred' parameter,
or already stored as acquired from previous interactions with the or already stored as acquired from previous interactions with the
joining node. joining node.
o A 4.00 Bad Request response from the Group Manager to the joining o A 4.00 Bad Request response from the Group Manager to the joining
node MUST have content format application/ace-group+cbor. The node MUST have content format application/ace-group+cbor. The
response payload is a CBOR map which MUST contain the 'sign_info' response payload is a CBOR map which MUST contain the 'sign_info'
as well as the 'pub_key_enc' parameters. and 'pub_key_enc' parameters. The CBOR map SHOULD additionally
contain the 'rsnonce' parameter, specifying a new dedicated 8-byte
nonce generated by the Group Manager (see Section 5.1).
o The Group Manager MUST return a 4.00 (Bad Request) response in o The Group Manager MUST return a 4.00 (Bad Request) response in
case the Joining Request includes the 'client_cred' parameter but case the Joining Request includes the 'client_cred' parameter but
does not include both the 'cnonce' and 'client_cred_verify' does not include both the 'cnonce' and 'client_cred_verify'
parameters. parameters.
o The Group Manager MUST return a 4.00 (Bad Request) response in o The Group Manager MUST return a 4.00 (Bad Request) response in
case it cannot retrieve a public key with an accepted format for case it cannot retrieve a public key with an accepted format for
the joining node, either from the 'client_cred' parameter or as the joining node, either from the 'client_cred' parameter or as
already stored. already stored.
o When receiving a 4.00 Bad Request response, the joining node o When receiving a 4.00 Bad Request response, the joining node
SHOULD send a new Joining Request to the Group Manager, SHOULD send a new Joining Request to the Group Manager, where:
containing:
* The 'client_cred' parameter, including a public key compatible * The 'cnonce' parameter MUST include a new dedicated nonce N_C
with the encoding, countersignature algorithm and possible generated by the joining node.
associated parameters indicated by the Group Manager.
* The 'client_cred_verify' parameter, including a signature * The 'client_cred' parameter MUST include a public key
computed as described in Section 4.2, by using the public key compatible with the encoding, countersignature algorithm and
possible associated parameters indicated by the Group Manager.
* The 'client_cred_verify' parameter MUST include a signature
computed as described in Section 5.2, by using the public key
indicated in the current 'client_cred' parameter, with the indicated in the current 'client_cred' parameter, with the
countersignature algorithm and possible associated parameters countersignature algorithm and possible associated parameters
indicated by the Group Manager. indicated by the Group Manager. If the error response from the
Group Manager included the 'rsnonce' parameter, the joining
node MUST use its content as new N_S challenge to compute the
signature.
4.4. Joining Response 5.4. Joining Response
If the processing of the Joining Request described in Section 4.3 is If the processing of the Joining Request described in Section 5.3 is
successful, the Group Manager updates the group membership by successful, the Group Manager updates the group membership by
registering the joining node NODENAME as a new member of the OSCORE registering the joining node NODENAME as a new member of the OSCORE
group GROUPNAME, as described in Section 4.1.2.1 of group GROUPNAME, as described in Section 4.1.2.1 of
[I-D.ietf-ace-key-groupcomm]. [I-D.ietf-ace-key-groupcomm].
If the joining node is not exclusively configured as monitor, the If the joining node is not exclusively configured as monitor, the
Group Manager performs also the following actions. Group Manager performs also the following actions.
o The Group Manager selects an available OSCORE Sender ID in the o The Group Manager selects an available OSCORE Sender ID in the
OSCORE group, and exclusively assigns it to the joining node. OSCORE group, and exclusively assigns it to the joining node.
skipping to change at page 11, line 51 skipping to change at page 13, line 12
the OSCORE Sender ID assigned to the joining node in the group. the OSCORE Sender ID assigned to the joining node in the group.
The Group Manager MUST keep this association updated over time. The Group Manager MUST keep this association updated over time.
Then, the Group Manager replies to the joining node, providing the Then, the Group Manager replies to the joining node, providing the
updated security parameters and keying meterial necessary to updated security parameters and keying meterial necessary to
participate in the group communication. This success Joining participate in the group communication. This success Joining
Response is formatted as defined in Section 4.1.2.1 of Response is formatted as defined in Section 4.1.2.1 of
[I-D.ietf-ace-key-groupcomm], with the following additions: [I-D.ietf-ace-key-groupcomm], with the following additions:
o The 'gkty' parameter identifies a key of type o The 'gkty' parameter identifies a key of type
"Group_OSCORE_Security_Context object", defined in Section 15.1 of "Group_OSCORE_Security_Context object", defined in Section 18.2 of
this specification. this specification.
o The 'key' parameter includes what the joining node needs in order o The 'key' parameter includes what the joining node needs in order
to set up the OSCORE Security Context as per Section 2 of to set up the OSCORE Security Context as per Section 2 of
[I-D.ietf-core-oscore-groupcomm]. This parameter has as value a [I-D.ietf-core-oscore-groupcomm]. This parameter has as value a
Group_OSCORE_Security_Context object, which is defined in this Group_OSCORE_Security_Context object, which is defined in this
specification and extends the OSCORE_Security_Context object specification and extends the OSCORE_Security_Context object
encoded in CBOR as defined in Section 3.2.1 of encoded in CBOR as defined in Section 3.2.1 of
[I-D.ietf-ace-oscore-profile]. In particular, it contains the [I-D.ietf-ace-oscore-profile]. In particular, it contains the
additional parameters 'cs_alg', 'cs_params', 'cs_key_params' and additional parameters 'cs_alg', 'cs_params', 'cs_key_params' and
'cs_key_enc' defined in Section 15.2 of this specification. More 'cs_key_enc' defined in Section 18.3 of this specification. More
specifically, the 'key' parameter is composed as follows. specifically, the 'key' parameter is composed as follows.
* The 'ms' parameter MUST be present and includes the OSCORE * The 'ms' parameter MUST be present and includes the OSCORE
Master Secret value. Master Secret value.
* The 'clientId' parameter, if present, has as value the OSCORE * The 'clientId' parameter, if present, has as value the OSCORE
Sender ID assigned to the joining node by the Group Manager, as Sender ID assigned to the joining node by the Group Manager, as
described above. This parameter is not present if the node described above. This parameter is not present if the node
joins the group exclusively as monitor, according to what joins the group exclusively as monitor, according to what
specified in the Access Token (see Section 3.2). In any other specified in the Access Token (see Section 3.2). In any other
skipping to change at page 12, line 39 skipping to change at page 13, line 49
* The 'alg' parameter, if present, has as value the AEAD * The 'alg' parameter, if present, has as value the AEAD
algorithm used in the group. algorithm used in the group.
* The 'salt' parameter, if present, has as value the OSCORE * The 'salt' parameter, if present, has as value the OSCORE
Master Salt. Master Salt.
* The 'contextId' parameter MUST be present and has as value the * The 'contextId' parameter MUST be present and has as value the
Group Identifier (Gid), i.e. the OSCORE ID Context of the Group Identifier (Gid), i.e. the OSCORE ID Context of the
OSCORE group. OSCORE group.
* The 'rpl' parameter, if present, specifies the OSCORE Replay
Window Size and Type value.
* The 'cs_alg' parameter MUST be present and specifies the * The 'cs_alg' parameter MUST be present and specifies the
algorithm used to countersign messages in the group. This algorithm used to countersign messages in the group. This
parameter takes values from Tables 5 and 6 of [RFC8152]. parameter takes values from Tables 5 and 6 of [RFC8152].
* The 'cs_params' parameter MAY be present and specifies the * The 'cs_params' parameter MAY be present and specifies the
additional parameters for the counter signature algorithm. additional parameters for the counter signature algorithm.
This parameter is a CBOR map whose content depends on the This parameter is a CBOR map whose content depends on the
counter signature algorithm, as specified in Section 2 and counter signature algorithm, as specified in Section 2 and
Section 9.1 of [I-D.ietf-core-oscore-groupcomm]. Section 11.1 of [I-D.ietf-core-oscore-groupcomm].
* The 'cs_key_params' parameter MAY be present and specifies the * The 'cs_key_params' parameter MAY be present and specifies the
additional parameters for the key used with the counter additional parameters for the key used with the counter
signature algorithm. This parameter is a CBOR map whose signature algorithm. This parameter is a CBOR map whose
content depends on the counter signature algorithm, as content depends on the counter signature algorithm, as
specified in Section 2 and Section 9.2 of specified in Section 2 and Section 11.2 of
[I-D.ietf-core-oscore-groupcomm]. [I-D.ietf-core-oscore-groupcomm].
* The 'cs_key_enc' parameter MAY be present and specifies the * The 'cs_key_enc' parameter MAY be present and specifies the
encoding of the public keys of the group members. This encoding of the public keys of the group members. This
parameter is a CBOR integer, whose value is 1 ("COSE_Key") parameter is a CBOR integer, whose value is 1 ("COSE_Key")
taken from the 'Confirmation Key' column of the "CWT taken from the 'Confirmation Key' column of the "CWT
Confirmation Method" Registry defined in Confirmation Method" Registry defined in
[I-D.ietf-ace-cwt-proof-of-possession], so indicating that [I-D.ietf-ace-cwt-proof-of-possession], so indicating that
public keys in the OSCORE group are encoded as COSE Keys public keys in the OSCORE group are encoded as COSE Keys
[RFC8152]. Future specifications may define additional values [RFC8152]. Future specifications may define additional values
for this parameter. If this parameter is not present, 1 for this parameter. If this parameter is not present, 1
("COSE_Key") MUST be assumed as default value. ("COSE_Key") MUST be assumed as default value.
o The 'num' parameter MUST be present. o The 'num' parameter MUST be present.
o The 'ace-groupcomm-profile' parameter MUST be present and has o The 'ace-groupcomm-profile' parameter MUST be present and has
value coap_group_oscore_app (TBD), which is defined in value coap_group_oscore_app (TBD1), which is defined in
Section 15.3 of this specification. Section 18.1 of this specification.
o The 'exp' parameter MUST be present. o The 'exp' parameter MUST be present.
o The 'pub_keys' parameter, if present, includes the public keys of o The 'pub_keys' parameter, if present, includes the public keys of
the group members that are relevant to the joining node. That is, the group members that are relevant to the joining node. That is,
it includes: i) the public keys of the responders currently in the it includes: i) the public keys of the responders currently in the
group, in case the joining node is configured (also) as requester; group, in case the joining node is configured (also) as requester;
and ii) the public keys of the requesters currently in the group, and ii) the public keys of the requesters currently in the group,
in case the joining node is configured (also) as responder or in case the joining node is configured (also) as responder or
monitor. If public keys are encoded as COSE_Keys, each of them monitor. If public keys are encoded as COSE_Keys, each of them
has as 'kid' the Sender ID that the corresponding owner has in the has as 'kid' the Sender ID that the corresponding owner has in the
group, thus used as group member identifier. group, thus used as group member identifier.
o The 'group_policies' parameter SHOULD be present, and SHOULD o The 'group_policies' parameter SHOULD be present, and SHOULD
include the elements "Sequence Number Synchronization Method" and include the elements "Sequence Number Synchronization Method" and
"Key Update Check Interval" defined in Section 4.1.2. of "Key Update Check Interval" defined in Section 4.1.2. of
[I-D.ietf-ace-key-groupcomm]. [I-D.ietf-ace-key-groupcomm].
Finally, the joining node uses the information received in the Finally, the joining node uses the information received in the
Joining Response to set up the OSCORE Security Context, as described Joining Response to set up the OSCORE Security Context, as described
in Section 2 of [I-D.ietf-core-oscore-groupcomm]. From then on, the in Section 2 of [I-D.ietf-core-oscore-groupcomm]. In addition, the
joining node can exchange group messages secured with Group OSCORE as joining node maintains an association between each public key
described in [I-D.ietf-core-oscore-groupcomm]. retrieved from the 'pub_keys' parameter and the role(s) that the
corresponding group member has in the group.
From then on, the joining node can exchange group messages secured
with Group OSCORE as described in [I-D.ietf-core-oscore-groupcomm].
When doing so:
o The joining node MUST NOT process an incoming request message, if
signed by a group member whose public key is not associated to the
role "Requester".
o The joining node MUST NOT process an incoming response message, if
signed by a group member whose public key is not associated to the
role "Responder".
If the application requires backward security, the Group Manager MUST If the application requires backward security, the Group Manager MUST
generate updated security parameters and group keying material, and generate updated security parameters and group keying material, and
provide it to the current group members upon the new node's joining provide it to the current group members upon the new node's joining
(see Section 13). As a consequence, the joining node is not able to (see Section 16). As a consequence, the joining node is not able to
access secure communication in the group occurred prior its joining. access secure communication in the group occurred prior its joining.
5. Public Keys of Joining Nodes 6. Public Keys of Joining Nodes
Source authentication of OSCORE messages exchanged within the group Source authentication of OSCORE messages exchanged within the group
is ensured by means of digital counter signatures (see Sections 2 and is ensured by means of digital counter signatures (see Sections 2 and
3 of [I-D.ietf-core-oscore-groupcomm]). Therefore, group members 4 of [I-D.ietf-core-oscore-groupcomm]). Therefore, group members
must be able to retrieve each other's public key from a trusted key must be able to retrieve each other's public key from a trusted key
repository, in order to verify source authenticity of incoming group repository, in order to verify source authenticity of incoming group
messages. messages.
As also discussed in [I-D.ietf-core-oscore-groupcomm], the Group As also discussed in [I-D.ietf-core-oscore-groupcomm], the Group
Manager acts as trusted repository of the public keys of the group Manager acts as trusted repository of the public keys of the group
members, and provides those public keys to group members if requested members, and provides those public keys to group members if requested
to. Upon joining an OSCORE group, a joining node is thus expected to to. Upon joining an OSCORE group, a joining node is thus expected to
provide its own public key to the Group Manager. provide its own public key to the Group Manager.
skipping to change at page 14, line 46 skipping to change at page 16, line 16
node. node.
o The Group Manager already acquired the public key of the joining o The Group Manager already acquired the public key of the joining
node during a past joining process. In this case, the joining node during a past joining process. In this case, the joining
node MAY choose not to provide again its own public key to the node MAY choose not to provide again its own public key to the
Group Manager, in order to limit the size of the Joining Request. Group Manager, in order to limit the size of the Joining Request.
The joining node MUST provide its own public key again if it has The joining node MUST provide its own public key again if it has
provided the Group Manager with multiple public keys during past provided the Group Manager with multiple public keys during past
joining processes, intended for different OSCORE groups. If the joining processes, intended for different OSCORE groups. If the
joining node provides its own public key, the Group Manager joining node provides its own public key, the Group Manager
performs consistency checks as per Section 4.3 and, in case of performs consistency checks as per Section 5.3 and, in case of
success, considers it as the public key associated to the joining success, considers it as the public key associated to the joining
node in the OSCORE group. node in the OSCORE group.
o The joining node and the Group Manager use an asymmetric proof-of- o The joining node and the Group Manager use an asymmetric proof-of-
possession key to establish a secure communication channel. Then, possession key to establish a secure communication channel. Then,
two cases can occur. two cases can occur.
1. The proof-of-possession key is compatible with the encoding as 1. The proof-of-possession key is compatible with the encoding as
well as with the counter signature algorithm and possible well as with the counter signature algorithm and possible
associated parameters used in the OSCORE group. Then, the associated parameters used in the OSCORE group. Then, the
Group Manager considers the proof-of-possession key as the Group Manager considers the proof-of-possession key as the
public key associated to the joining node in the OSCORE group. public key associated to the joining node in the OSCORE group.
If the joining node is aware that the proof-of-possession key If the joining node is aware that the proof-of-possession key
is also valid for the OSCORE group, it MAY not provide it is also valid for the OSCORE group, it MAY not provide it
again as its own public key to the Group Manager. The joining again as its own public key to the Group Manager. The joining
node MUST provide its own public key again if it has provided node MUST provide its own public key again if it has provided
the Group Manager with multiple public keys during past the Group Manager with multiple public keys during past
joining processes, intended for different OSCORE groups. If joining processes, intended for different OSCORE groups. If
the joining node provides its own public key in the the joining node provides its own public key in the
'client_cred' parameter of the Joining Request (see 'client_cred' parameter of the Joining Request (see
Section 4.2), the Group Manager performs consistency checks as Section 5.2), the Group Manager performs consistency checks as
per Section 4.3 and, in case of success, considers it as the per Section 5.3 and, in case of success, considers it as the
public key associated to the joining node in the OSCORE group. public key associated to the joining node in the OSCORE group.
2. The proof-of-possession key is not compatible with the 2. The proof-of-possession key is not compatible with the
encoding or with the counter signature algorithm and possible encoding or with the counter signature algorithm and possible
associated parameters used in the OSCORE group. In this case, associated parameters used in the OSCORE group. In this case,
the joining node MUST provide a different compatible public the joining node MUST provide a different compatible public
key to the Group Manager in the 'client_cred' parameter of the key to the Group Manager in the 'client_cred' parameter of the
Joining Request (see Section 4.2). Then, the Group Manager Joining Request (see Section 5.2). Then, the Group Manager
performs consistency checks on this latest provided public key performs consistency checks on this latest provided public key
as per Section 4.3 and, in case of success, considers it as as per Section 5.3 and, in case of success, considers it as
the public key associated to the joining node in the OSCORE the public key associated to the joining node in the OSCORE
group. group.
o The joining node and the Group Manager use a symmetric proof-of- o The joining node and the Group Manager use a symmetric proof-of-
possession key to establish a secure communication channel. In possession key to establish a secure communication channel. In
this case, upon performing a joining process with that Group this case, upon performing a joining process with that Group
Manager for the first time, the joining node specifies its own Manager for the first time, the joining node specifies its own
public key in the 'client_cred' parameter of the Joining Request public key in the 'client_cred' parameter of the Joining Request
targeting the group-membership endpoint (see Section 4.2). targeting the group-membership endpoint (see Section 5.2).
6. Retrieval of Updated Keying Material 7. Retrieval of Updated Keying Material
At some point, a group member considers the OSCORE Security Context At some point, a group member considers the OSCORE Security Context
invalid and to be renewed. This happens, for instance, after a invalid and to be renewed. This happens, for instance, after a
number of unsuccessful security processing of incoming messages from number of unsuccessful security processing of incoming messages from
other group members, or when the Security Context expires as other group members, or when the Security Context expires as
specified by the 'exp' parameter of the Joining Response. specified by the 'exp' parameter of the Joining Response.
When this happens, the group member retrieves updated security When this happens, the group member retrieves updated security
parameters and group keying material. This can occur in the two parameters and group keying material. This can occur in the two
different ways described below. different ways described below.
6.1. Retrieval of Group Keying Material 7.1. Retrieval of Group Keying Material
If the group member wants to retrieve only the latest group keying If the group member wants to retrieve only the latest group keying
material, it sends a Key Distribution Request to the Group Manager. material, it sends a Key Distribution Request to the Group Manager.
In particular, it sends a CoAP GET request to the endpoint /group- In particular, it sends a CoAP GET request to the endpoint /group-
oscore/GROUPNAME at the Group Manager. oscore/GROUPNAME at the Group Manager.
The Group Manager processes the Key Distribution Request according to The Group Manager processes the Key Distribution Request according to
Section 4.1.2.2 of [I-D.ietf-ace-key-groupcomm]. The Key Section 4.1.2.2 of [I-D.ietf-ace-key-groupcomm]. The Key
Distribution Response is formatted as defined in Section 4.1.2.2 of Distribution Response is formatted as defined in Section 4.1.2.2 of
[I-D.ietf-ace-key-groupcomm]. [I-D.ietf-ace-key-groupcomm]. In particular, the 'key' parameter is
formatted as defined in Section 5.4 of this specification, with the
difference that it does not include the 'clientId' parameter.
Upon receiving the Key Distribution Response, the group member Upon receiving the Key Distribution Response, the group member
retrieves the updated security parameters and group keying material, retrieves the updated security parameters and group keying material,
and, if they differ from the current ones, use them to set up the new and, if they differ from the current ones, use them to set up the new
OSCORE Security Context as described in Section 2 of OSCORE Security Context as described in Section 2 of
[I-D.ietf-core-oscore-groupcomm]. [I-D.ietf-core-oscore-groupcomm].
6.2. Retrieval of Group Keying Material and Sender ID 7.2. Retrieval of Group Keying Material and Sender ID
If the group member wants to retrieve the latest group keying If the group member wants to retrieve the latest group keying
material as well as the Sender ID that it has in the OSCORE group, it material as well as the Sender ID that it has in the OSCORE group, it
sends a Key Distribution Request to the Group Manager. sends a Key Distribution Request to the Group Manager.
In particular, it sends a CoAP GET request to the endpoint /group- In particular, it sends a CoAP GET request to the endpoint /group-
oscore/GROUPNAME/NODENAME at the Group Manager. oscore/GROUPNAME/nodes/NODENAME at the Group Manager.
The Group Manager processes the Key Distribution Request according to The Group Manager processes the Key Distribution Request according to
Section 4.1.6.2 of [I-D.ietf-ace-key-groupcomm]. The Key Section 4.1.6.2 of [I-D.ietf-ace-key-groupcomm]. The Key
Distribution Response is formatted as defined in Section 4.1.6.2 of Distribution Response is formatted as defined in Section 4.1.6.2 of
[I-D.ietf-ace-key-groupcomm]. Note that the current Sender ID of the [I-D.ietf-ace-key-groupcomm].
group member is not specified as a separate parameter, but rather
included as 'clientId' in the 'key' parameter. In particular, the 'key' parameter is formatted as defined in
Section 5.4 of this specification, with the difference that if the
requesting group member is configured exclusively as monitor, no
'clientId' is specified within the 'key' parameter. Note that, in
any other case, the current Sender ID of the group member is not
specified as a separate parameter, but rather specified as 'clientId'
within the 'key' parameter.
Upon receiving the Key Distribution Response, the group member Upon receiving the Key Distribution Response, the group member
retrieves the updated security parameters, group keying material and retrieves the updated security parameters, group keying material and
Sender ID, and, if they differ from the current ones, use them to set Sender ID, and, if they differ from the current ones, use them to set
up the new OSCORE Security Context as described in Section 2 of up the new OSCORE Security Context as described in Section 2 of
[I-D.ietf-core-oscore-groupcomm]. [I-D.ietf-core-oscore-groupcomm].
7. Retrieval of New Keying Material 8. Retrieval of New Keying Material
As discussed in Section 2.2 of [I-D.ietf-core-oscore-groupcomm], a As discussed in Section 2.5 of [I-D.ietf-core-oscore-groupcomm], a
group member may at some point experience a wrap-around of its own group member may at some point experience a wrap-around of its own
Sender Sequence Number in the group. Sender Sequence Number in the group.
When this happens, the group member MUST send a Key Renewal Request When this happens, the group member MUST send a Key Renewal Request
message to the Group Manager, as per Section 4.4 of message to the Group Manager, as per Section 4.4 of
[I-D.ietf-ace-key-groupcomm]. In particular, it sends a CoAP PUT [I-D.ietf-ace-key-groupcomm]. In particular, it sends a CoAP PUT
request to the endpoint /group-oscore/GROUPNAME/NODENAME at the Group request to the endpoint /group-oscore/GROUPNAME/nodes/NODENAME at the
Manager. Group Manager.
Upon receiving the Key Renewal Request, the Group Manager processes Upon receiving the Key Renewal Request, the Group Manager processes
it as defined in Section 4.1.6.2 of [I-D.ietf-ace-key-groupcomm], and it as defined in Section 4.1.6.1 of [I-D.ietf-ace-key-groupcomm], and
performs one of the following actions. performs one of the following actions.
1. The Group Manager replies to the group member with a 4.06 (Not 1. If the requesting group member is configured exclusively as
Acceptable) error response, and rekeys the whole OSCORE group as monitor, the Group Manager replies with a 4.00 (Bad Request)
discussed in Section 13. error response.
2. The Group Manager generates a new Sender ID for that group member 2. Otherwise, depending on the policies configured (OPT8):
and replies with a Key Renewal Response, formatted as defined in
Section 4.1.6.2 of [I-D.ietf-ace-key-groupcomm]. In particular,
the CBOR Map in the response payload includes a single parameter
'clientId' defined in Section 15.5 of this document, specifying
the new Sender ID of the group member encoded as a CBOR byte
string.
8. Retrieval of Public Keys of Group Members a. Either the Group Manager replies to the group member with a
4.00 (Bad Request) error response, and rekeys the whole OSCORE
group as discussed in Section 16;
b. Or the Group Manager generates a new Sender ID for that group
member and replies with a Key Renewal Response, formatted as
defined in Section 4.1.6.1 of [I-D.ietf-ace-key-groupcomm]. In
particular, the CBOR Map in the response payload includes a
single parameter 'clientId' defined in Section 18.5 of this
document, specifying the new Sender ID of the group member
encoded as a CBOR byte string.
9. Retrieval of Public Keys of Group Members
A group member may need to retrieve the public keys of other group A group member may need to retrieve the public keys of other group
members. To this end, the group member sends a Public Key Request members. To this end, the group member sends a Public Key Request
message to the Group Manager, as per Section 4.5 of message to the Group Manager, as per Section 4.5 of
[I-D.ietf-ace-key-groupcomm]. In particular, it sends the request to [I-D.ietf-ace-key-groupcomm]. In particular, it sends the request to
the endpoint /group-oscore/GROUPNAME/pub-key at the Group Manager. the endpoint /group-oscore/GROUPNAME/pub-key at the Group Manager.
If the Public Key Request uses the method FETCH, the Public Key If the Public Key Request uses the method FETCH, the Public Key
Request is formatted as defined in Section 4.1.3.1 of Request is formatted as defined in Section 4.1.3.1 of
[I-D.ietf-ace-key-groupcomm]. In particular, each element of the [I-D.ietf-ace-key-groupcomm]. In particular, each element of the
skipping to change at page 18, line 5 skipping to change at page 19, line 36
depending on the request method being FETCH or GET, respectively. depending on the request method being FETCH or GET, respectively.
Additionally, if the Public Key Request uses the method FETCH, the Additionally, if the Public Key Request uses the method FETCH, the
Group Manager silently ignores identifiers included in the Group Manager silently ignores identifiers included in the
'get_pub_keys' parameter of the request that are not associated to 'get_pub_keys' parameter of the request that are not associated to
any current group member. any current group member.
The success Public Key Response is formatted as defined in The success Public Key Response is formatted as defined in
Section 4.1.3.1 or 4.1.3.2 of [I-D.ietf-ace-key-groupcomm], depending Section 4.1.3.1 or 4.1.3.2 of [I-D.ietf-ace-key-groupcomm], depending
on the request method being FETCH or GET, respectively. on the request method being FETCH or GET, respectively.
9. Retrieval of Group Policies 10. Update of Public Key
A group member may need to provide the Group Manager with its new
public key to use in the group from then on, hence replacing the
current one. This can be the case, for instance, if the
countersignature algorithm and possible associated parameters used in
the OSCORE group have been changed, and the current public key is not
compatible with them.
To this end, the group member sends a Public Key Update Request
message to the Group Manager, as per Section 4.6 of
[I-D.ietf-ace-key-groupcomm]. In particular, it sends a CoAP POST
request to the endpoint /group-oscore/GROUPNAME/nodes/NODENAME/pub-
key at the Group Manager.
Upon receiving the Group Leaving Request, the Group Manager processes
it as per Section 4.1.7.1 of [I-D.ietf-ace-key-groupcomm], with the
following additions.
o If the requesting group member is configured exclusively as
monitor, the Group Manager replies with a 4.00 (Bad request) error
response.
o The N_S signature challenge is computed as per point (3) in
Section 5.2.1 (REQ17).
o If the request is successfully processed, the Group Manager stores
the association between i) the new public key of the group member;
and ii) the Group Identifier (Gid), i.e. the OSCORE ID Context,
associated to the OSCORE group together with the OSCORE Sender ID
assigned to the group member in the group. The Group Manager MUST
keep this association updated over time.
11. Retrieval of Group Policies
A group member may request the current policies used in the OSCORE A group member may request the current policies used in the OSCORE
group. To this end, the group member sends a Policies Request, as group. To this end, the group member sends a Policies Request, as
per Section 4.6 of [I-D.ietf-ace-key-groupcomm]. In particular, it per Section 4.7 of [I-D.ietf-ace-key-groupcomm]. In particular, it
sends a CoAP GET request to the endpoint /group-oscore/GROUPNAME/ sends a CoAP GET request to the endpoint /group-oscore/GROUPNAME/
policies at the Group Manager, where GROUPNAME is the name of the policies at the Group Manager, where GROUPNAME is the name of the
OSCORE group. OSCORE group.
Upon receiving the Policies Request, the Group Manager processes it Upon receiving the Policies Request, the Group Manager processes it
as per Section 4.1.4.1 of [I-D.ietf-ace-key-groupcomm]. The success as per Section 4.1.4.1 of [I-D.ietf-ace-key-groupcomm]. The success
Policies Response is formatted as defined in Section 4.1.4.1 of Policies Response is formatted as defined in Section 4.1.4.1 of
[I-D.ietf-ace-key-groupcomm]. [I-D.ietf-ace-key-groupcomm].
10. Retrieval of Keying Material Version 12. Retrieval of Keying Material Version
A group member may request the current version of the keying material A group member may request the current version of the keying material
used in the OSCORE group. To this end, the group member sends a used in the OSCORE group. To this end, the group member sends a
Version Request, as per Section 4.7 of [I-D.ietf-ace-key-groupcomm]. Version Request, as per Section 4.8 of [I-D.ietf-ace-key-groupcomm].
In particular, it sends a CoAP GET request to the endpoint /group- In particular, it sends a CoAP GET request to the endpoint /group-
oscore/GROUPNAME/ctx-num at the Group Manager, where GROUPNAME is the oscore/GROUPNAME/ctx-num at the Group Manager, where GROUPNAME is the
name of the OSCORE group. name of the OSCORE group.
Upon receiving the Version Request, the Group Manager processes it as Upon receiving the Version Request, the Group Manager processes it as
per Section 4.1.5.1 of [I-D.ietf-ace-key-groupcomm]. The success per Section 4.1.5.1 of [I-D.ietf-ace-key-groupcomm]. The success
Version Response is formatted as defined in Section 4.1.5.1 of Version Response is formatted as defined in Section 4.1.5.1 of
[I-D.ietf-ace-key-groupcomm]. [I-D.ietf-ace-key-groupcomm].
11. Request to Leave the Group 13. Retrieval of Group Status
A group member may request the current status of the the OSCORE
group, i.e. active or inactive. To this end, the group member sends
a Group Status Request to the Group Manager.
In particular, the group member sends a CoAP GET request to the
endpoint /group-oscore/GROUPNAME/active at the Group Manager defined
in Section 4 of this specification, where GROUPNAME is the name of
the OSCORE group. The success Group Version Response is formatted as
defined in Section 4 of this specification.
Upon learning from a 2.05 (Content) response that the group is
currently inactive, the group member SHOULD stop taking part in
communications within the group, until it becomes active again.
Upon learning from a 2.05 (Content) response that the group has
become active again, the group member can resume taking part in
communications within the group.
Figure 2 gives an overview of the exchange described above.
Group Group
Member Manager
| |
|------ Group Status Request: GET ace-group/GID/active ------>|
| |
|<---------- Group Status Response: 2.05 (Content) -----------|
| |
Figure 2: Message Flow of Group Status Request-Response
14. Request to Leave the Group
A group member may request to leave the OSCORE group. To this end, A group member may request to leave the OSCORE group. To this end,
the group member sends a Group Leaving Request, as per Section 4.8 of the group member sends a Group Leaving Request, as per Section 4.9 of
[I-D.ietf-ace-key-groupcomm]. In particular, it sends a CoAP DELETE [I-D.ietf-ace-key-groupcomm]. In particular, it sends a CoAP DELETE
request to the endpoint /group-oscore/GROUPNAME/NODENAME at the Group request to the endpoint /group-oscore/GROUPNAME/nodes/NODENAME at the
Manager. Group Manager.
Upon receiving the Group Leaving Request, the Group Manager processes Upon receiving the Group Leaving Request, the Group Manager processes
it as per Section 4.1.6.3 of [I-D.ietf-ace-key-groupcomm]. it as per Section 4.1.6.3 of [I-D.ietf-ace-key-groupcomm].
12. Removal of a Group Member 15. Removal of a Group Member
Other than after a spontaneous request to the Group Manager as Other than after a spontaneous request to the Group Manager as
described in Section 11, a node may be forcibly removed from the described in Section 14, a node may be forcibly removed from the
OSCORE group, e.g. due to expired or revoked authorization. OSCORE group, e.g. due to expired or revoked authorization.
In either case, if the leaving node is not configured exclusively as In either case, if the leaving node is not configured exclusively as
monitor, the Group Manager performs the following actions. monitor, the Group Manager performs the following actions.
o The Group Manager frees the OSCORE Sender ID value of the leaving o The Group Manager frees the OSCORE Sender ID value of the leaving
node, which becomes available for possible upcoming joining nodes. node, which becomes available for possible upcoming joining nodes.
o The Group Manager cancels the association between, on one hand, o The Group Manager cancels the association between, on one hand,
the public key of the leaving node and, on the other hand, the the public key of the leaving node and, on the other hand, the
Group Identifier (Gid) associated to the OSCORE group together Group Identifier (Gid) associated to the OSCORE group together
with the freed OSCORE Sender ID value. The Group Manager deletes with the freed OSCORE Sender ID value. The Group Manager deletes
the public key of the leaving node, if that public key has no the public key of the leaving node, if that public key has no
remaining association with any pair (Gid, Sender ID). remaining association with any pair (Gid, Sender ID).
If the application requires forward security, the Group Manager MUST If the application requires forward security, the Group Manager MUST
generate updated security parameters and group keying material, and generate updated security parameters and group keying material, and
provide it to the remaining group members (see Section 13). As a provide it to the remaining group members (see Section 16). As a
consequence, the leaving node is not able to acquire the new security consequence, the leaving node is not able to acquire the new security
parameters and group keying material distributed after its leaving. parameters and group keying material distributed after its leaving.
Same considerations in Section 5 of [I-D.ietf-ace-key-groupcomm] Same considerations in Section 5 of [I-D.ietf-ace-key-groupcomm]
apply here as well, considering the Group Manager acting as KDC. apply here as well, considering the Group Manager acting as KDC.
13. Group Rekeying Process 16. Group Rekeying Process
In order to rekey the OSCORE group, the Group Manager distributes a In order to rekey the OSCORE group, the Group Manager distributes a
new Group Identifier (Gid), i.e. a new OSCORE ID Context, and a new new Group Identifier (Gid), i.e. a new OSCORE ID Context; a new
OSCORE Master Secret for that group. When doing so, the Group OSCORE Master Secret; and, optionally, a new OSCORE Master Salt for
Manager MUST increment the version number of the group keying that group. When doing so, the Group Manager MUST increment the
material. Also, the Group Manager MUST preserve the same unchanged version number of the group keying material, before starting its
distribution.
Furthermore, the Group Manager MUST preserve the same unchanged
Sender IDs for all group members. This avoids affecting the Sender IDs for all group members. This avoids affecting the
retrieval of public keys from the Group Manager as well as the retrieval of public keys from the Group Manager as well as the
verification of message countersignatures. verification of message countersignatures.
The Group Manager MUST support at least the following group rekeying The Group Manager MUST support at least the following group rekeying
scheme. Future application profiles may define alternative message scheme. Future application profiles may define alternative message
formats and distribution schemes. formats and distribution schemes.
The Group Manager uses the same format of the Joining Response The Group Manager uses the same format of the Joining Response
message in Section 4.4. In particular: message in Section 5.4. In particular:
o Only the parameters 'gkty', 'key', 'num', 'ace-groupcomm-profile' o Only the parameters 'gkty', 'key', 'num', 'ace-groupcomm-profile'
and 'exp' are present. and 'exp' are present.
o The 'ms' parameter of the 'key' parameter specifies the new OSCORE o The 'ms' parameter of the 'key' parameter specifies the new OSCORE
Master Secret value. Master Secret value.
o The 'contextId' parameter of the 'key' parameter specifies the new o The 'contextId' parameter of the 'key' parameter specifies the new
Group ID. Group ID.
The Group Manager separately sends a group rekeying message to each The Group Manager separately sends a group rekeying message to each
group member to be rekeyed. Each rekeying message MUST be secured group member to be rekeyed.
with the pairwise secure communication channel between the Group
Manager and the group member used during the joining process. Each rekeying message MUST be secured with the pairwise secure
communication channel between the Group Manager and the group member
used during the joining process. In particular, each rekeying
message can target the 'control_path' URI path defined in
Section 4.1.2.1 of [I-D.ietf-ace-key-groupcomm], if provided by the
intended recipient upon joining the group (see Section 5.2).
It is RECOMMENDED that the Group Manager gets confirmation of
successful distribution from the group members, and admits a maximum
number of individual retransmissions to non-confirming group members.
In case the rekeying terminates and some group members have not
received the new keying material, they will not be able to correctly
process following secured messages exchanged in the group. These
group members will eventually contact the Group Manager, in order to
retrieve the current keying material and its version.
This approach requires group members to act (also) as servers, in This approach requires group members to act (also) as servers, in
order to correctly handle unsolicited group rekeying messages from order to correctly handle unsolicited group rekeying messages from
the Group Manager. In particular, if a group member and the Group the Group Manager. In particular, if a group member and the Group
Manager use OSCORE [RFC8613] to secure their pairwise communications, Manager use OSCORE [RFC8613] to secure their pairwise communications,
the group member MUST create a Replay Window in its own Recipient the group member MUST create a Replay Window in its own Recipient
Context upon establishing the OSCORE Security Context with the Group Context upon establishing the OSCORE Security Context with the Group
Manager, e.g. by means of the OSCORE profile of ACE Manager, e.g. by means of the OSCORE profile of ACE
[I-D.ietf-ace-oscore-profile]. [I-D.ietf-ace-oscore-profile].
Group members and the Group Manager SHOULD additionally support Group members and the Group Manager SHOULD additionally support
alternative rekeying approaches that do not require group members to alternative rekeying approaches that do not require group members to
act (also) as servers. A number of such approaches are defined in act (also) as servers. A number of such approaches are defined in
Section 4.3 of [I-D.ietf-ace-key-groupcomm]. In particular, a group Section 4.3 of [I-D.ietf-ace-key-groupcomm]. In particular, a group
member may subscribe for updates to the group-membership resource of member may subscribe for updates to the group-membership resource of
the group, at the endpoint /group-oscore/GROUPNAME/NODENAME of the the group, at the endpoint /group-oscore/GROUPNAME/nodes/NODENAME of
Group Manager. This can rely on CoAP Observe [RFC7641] or on a full- the Group Manager. This can rely on CoAP Observe [RFC7641] or on a
fledged Pub-Sub model [I-D.ietf-core-coap-pubsub] with the Group full-fledged Pub-Sub model [I-D.ietf-core-coap-pubsub] with the Group
Manager acting as Broker. Manager acting as Broker.
14. Security Considerations 17. Security Considerations
The method described in this document leverages the following Security considerations for this profile are inherited from
management aspects related to OSCORE groups and discussed in the [I-D.ietf-ace-key-groupcomm], the ACE framework for Authentication
sections of [I-D.ietf-core-oscore-groupcomm] referred below. and Authorization [I-D.ietf-ace-oauth-authz], and the specific
transport profile of ACE signalled by the AS, such as
[I-D.ietf-ace-dtls-authorize] and [I-D.ietf-ace-oscore-profile].
o Management of group keying material (see Section 2.1 of The following security considerations also apply for this profile.
17.1. Management of OSCORE Groups
This profile leverages the following management aspects related to
OSCORE groups and discussed in the sections of
[I-D.ietf-core-oscore-groupcomm] referred below.
o Management of group keying material (see Section 2.4 of
[I-D.ietf-core-oscore-groupcomm]). The Group Manager is [I-D.ietf-core-oscore-groupcomm]). The Group Manager is
responsible for the renewal and re-distribution of the keying responsible for the renewal and re-distribution of the keying
material in the groups of its competence (rekeying). According to material in the groups of its competence (rekeying). According to
the specific application requirements, this can include rekeying the specific application requirements, this can include rekeying
the group upon changes in its membership. In particular, renewing the group upon changes in its membership. In particular, renewing
the group keying material is required upon a new node's joining or the group keying material is required upon a new node's joining or
a current node's leaving, in case backward security and forward a current node's leaving, in case backward security and forward
security have to be preserved, respectively. security have to be preserved, respectively.
o Provisioning and retrieval of public keys (see Section 2 of o Provisioning and retrieval of public keys (see Section 2 of
[I-D.ietf-core-oscore-groupcomm]). The Group Manager acts as key [I-D.ietf-core-oscore-groupcomm]). The Group Manager acts as key
repository of public keys of group members, and provides them upon repository of public keys of group members, and provides them upon
request. request.
o Synchronization of sequence numbers (see Section 5.1 of o Synchronization of sequence numbers (see Section 6.1 of
[I-D.ietf-core-oscore-groupcomm]). This concerns how a responder [I-D.ietf-core-oscore-groupcomm]). This concerns how a responder
node that has just joined an OSCORE group can synchronize with the node that has just joined an OSCORE group can synchronize with the
sequence number of requesters in the same group. sequence number of requesters in the same group.
Before sending the Joining Response, the Group Manager MUST verify Before sending the Joining Response, the Group Manager MUST verify
that the joining node actually owns the associated private key. To that the joining node actually owns the associated private key. To
this end, the Group Manager can rely on the proof-of-possession this end, the Group Manager can rely on the proof-of-possession
challenge-response defined in Section 4. Alternatively, the joining challenge-response defined in Section 5. Alternatively, the joining
node can use its own public key as asymmetric proof-of-possession key node can use its own public key as asymmetric proof-of-possession key
to establish a secure channel with the Group Manager, e.g. as in to establish a secure channel with the Group Manager, e.g. as in
Section 3.2 of [I-D.ietf-ace-dtls-authorize]. However, this requires Section 3.2 of [I-D.ietf-ace-dtls-authorize]. However, this requires
such proof-of-possession key to be compatible with the encoding as such proof-of-possession key to be compatible with the encoding as
well as with the countersignature algorithm and possible associated well as with the countersignature algorithm and possible associated
parameters used in the OSCORE group. parameters used in the OSCORE group.
A node may have joined multiple OSCORE groups under different non- A node may have joined multiple OSCORE groups under different non-
synchronized Group Managers. Therefore, it can happen that those synchronized Group Managers. Therefore, it can happen that those
OSCORE groups have the same Group Identifier (Gid). It follows that, OSCORE groups have the same Group Identifier (Gid). It follows that,
upon receiving a Group OSCORE message addressed to one of those upon receiving a Group OSCORE message addressed to one of those
groups, the node would have multiple Security Contexts matching with groups, the node would have multiple Security Contexts matching with
the Gid in the incoming message. It is up to the application to the Gid in the incoming message. It is up to the application to
decide how to handle such collisions of Group Identifiers, e.g. by decide how to handle such collisions of Group Identifiers, e.g. by
trying to process the incoming message using one Security Context at trying to process the incoming message using one Security Context at
the time until the right one is found. the time until the right one is found.
Further security considerations are inherited from 17.2. Size of Nonces for Signature Challenge
[I-D.ietf-ace-key-groupcomm], the ACE framework for Authentication
and Authorization [I-D.ietf-ace-oauth-authz], and the specific
transport profile of ACE signalled by the AS, such as
[I-D.ietf-ace-dtls-authorize] and [I-D.ietf-ace-oscore-profile].
15. IANA Considerations With reference to the Joining Request message in Section 5.2, the
proof-of-possession signature included in 'client_cred_verify' is
computed over the challenge N_C | N_S, where | denotes concatenation.
For the N_C value, it is RECOMMENDED to use a 8-byte long random
nonce. Furthermore, N_C is always conveyed in the 'cnonce' parameter
of the Joining Request, which is always sent over the secure
communication channel between the joining node and the Group Manager.
As defined in Section 5.2.1, the way the N_S value is computed
depends on the particular interaction between the joining node and
the Group Manager.
o If the Access Token is not explicitly posted to the /authz-info
endpoint of the Group Manager, or if the joining node re-joins
without re-posting the same still valid Access Token, then N_S is
computed as a 32-byte long nonce (see points (2) and (3) of
Section 5.2.1).
o If the Access Token has been explicitly posted to the /authz-info
endpoint of the Group Manager, N_S takes the value conveyed in the
'rsnonce' parameter of the 2.01 response to the Token Post (see
Section 5.1). Similarly, if a Joining Request is not successfully
processed by the Group Manager, the returned error response should
also include the 'rsnonce' parameter specifying a new nonce N_S
(see Section 5.3). In either case, it is RECOMMENDED to use a
8-byte long random nonce as value for N_S.
If we consider both N_C and N_S to be 8-byte long nonces, the
following considerations hold.
o If both N_C and N_S are random nonces, the average collision for
each nonce will happen after 2^32 messages, as per the birthday
paradox and as also discussed in Section 7 of
[I-D.ietf-ace-oscore-profile]. This amounts to considerably more
token provisionings than the expected new joinings of OSCORE
groups under a same Group Manager.
o If N_C and N_S are not generated randomly, e.g. by using a
counter, the joining node and the Group Manager need to guarantee
that reboot and loss of state on either node does not provoke re-
use. If that is not guaranteed, a joining node may repeatedly
post a valid Access Token to the /authz-info endpoint of the Group
Manager, until it gets back an exact, re-used value N_S* to use as
nonce. Then, the joining node can send a Joining Request,
conveying a reused N_C* nonce in 'cnonce' and an old stored
signature in 'client_cred_verify', computed over N_C* | N_S*. By
verifying the signature, the Group Manager would falsely believe
that the joining node possesses its own private key at that point
in time.
o Since N_C is always conveyed in a secured Joining Request, it is
practically infeasible for an on-path attacker to replay Joining
Requests from a joining node to the Group Manager, in order to
cause that joining node to use an arbitrary nonce N_S.
o Section 7 of [I-D.ietf-ace-oscore-profile] as well Appendix B.2 of
[RFC8613] recommend the use of 8-byte random nonces as well.
Unlike in those cases, the nonces N_C and N_S considered in this
specification are not used for as sensitive operations as the
derivation of a Security Context, with possible implications in
the security of AEAD ciphers.
18. IANA Considerations
Note to RFC Editor: Please replace all occurrences of "[[This Note to RFC Editor: Please replace all occurrences of "[[This
specification]]" with the RFC number of this specification and delete specification]]" with the RFC number of this specification and delete
this paragraph. this paragraph.
This document has the following actions for IANA. This document has the following actions for IANA.
15.1. ACE Groupcomm Key Registry 18.1. ACE Groupcomm Profile Registry
IANA is asked to register the following entry in the "ACE Groupcomm IANA is asked to register the following entry in the "ACE Groupcomm
Key" Registry defined in Section 8.4 of [I-D.ietf-ace-key-groupcomm]. Profile" Registry defined in Section 9.6 of
[I-D.ietf-ace-key-groupcomm].
o Name: coap_group_oscore_app
o Description: Application profile to provision keying material for
participating in group communication protected with Group OSCORE
as per [I-D.ietf-core-oscore-groupcomm].
o CBOR Value: TBD1
o Reference: [[This specification]] (Section 5.4)
18.2. ACE Groupcomm Key Registry
IANA is asked to register the following entry in the "ACE Groupcomm
Key" Registry defined in Section 9.5 of [I-D.ietf-ace-key-groupcomm].
o Name: Group_OSCORE_Security_Context object o Name: Group_OSCORE_Security_Context object
o Key Type Value: TBD o Key Type Value: TBD2
o Profile: "coap_group_oscore_app", defined in Section 15.3 of this o Profile: "coap_group_oscore_app", defined in Section 18.1 of this
specification. specification.
o Description: A Group_OSCORE_Security_Context object encoded as o Description: A Group_OSCORE_Security_Context object encoded as
described in Section 4.4 of this specification. described in Section 5.4 of this specification.
o Reference: [[This specification]] o Reference: [[This specification]] (Section 5.4)
15.2. OSCORE Security Context Parameters Registry 18.3. OSCORE Security Context Parameters Registry
IANA is asked to register the following entries in the "OSCORE IANA is asked to register the following entries in the "OSCORE
Security Context Parameters" Registry defined in Section 9.2 of Security Context Parameters" Registry defined in Section 9.4 of
[I-D.ietf-ace-oscore-profile]. [I-D.ietf-ace-oscore-profile].
o Name: cs_alg o Name: cs_alg
o CBOR Label: TBD o CBOR Label: TBD3
o CBOR Type: tstr / int o CBOR Type: tstr / int
o Registry: COSE Algorithm Values (ECDSA, EdDSA) o Registry: COSE Algorithm Values (ECDSA, EdDSA)
o Description: OSCORE Counter Signature Algorithm Value o Description: OSCORE Counter Signature Algorithm Value
o Reference: [[This specification]] o Reference: [[This specification]] (Section 5.4)
o Name: cs_params o Name: cs_params
o CBOR Label: TBD o CBOR Label: TBD4
o CBOR Type: map o CBOR Type: map
o Registry: Counter Signatures Parameters o Registry: Counter Signatures Parameters
o Description: OSCORE Counter Signature Algorithm Additional o Description: OSCORE Counter Signature Algorithm Additional
Parameters Parameters
o Reference: [[This specification]] o Reference: [[This specification]] (Section 5.4)
o Name: cs_key_params o Name: cs_key_params
o CBOR Label: TBD o CBOR Label: TBD5
o CBOR Type: map o CBOR Type: map
o Registry: Counter Signatures Key Parameters o Registry: Counter Signatures Key Parameters
o Description: OSCORE Counter Signature Key Additional Parameters o Description: OSCORE Counter Signature Key Additional Parameters
o Reference: [[This specification]] o Reference: [[This specification]] (Section 5.4)
o Name: cs_key_enc o Name: cs_key_enc
o CBOR Label: TBD o CBOR Label: TBD6
o CBOR Type: integer o CBOR Type: integer
o Registry: ACE Public Key Encoding o Registry: ACE Public Key Encoding
o Description: Encoding of Public Keys to be used with the OSCORE o Description: Encoding of Public Keys to be used with the OSCORE
Counter Signature Algorithm Counter Signature Algorithm
o Reference: [[This specification]] o Reference: [[This specification]] (Section 5.4)
15.3. ACE Groupcomm Profile Registry
IANA is asked to register the following entry in the "ACE Groupcomm
Profile" Registry defined in Section 8.5 of
[I-D.ietf-ace-key-groupcomm].
o Name: coap_group_oscore_app
o Description: Application profile to provision keying material for
participating in group communication protected with Group OSCORE
as per [I-D.ietf-core-oscore-groupcomm].
o CBOR Value: TBD
o Reference: [[This specification]]
15.4. Sequence Number Synchronization Method Registry 18.4. Sequence Number Synchronization Method Registry
IANA is asked to register the following entries in the "Sequence IANA is asked to register the following entries in the "Sequence
Number Synchronization Method" Registry defined in Section 8.7 of Number Synchronization Method" Registry defined in Section 9.8 of
[I-D.ietf-ace-key-groupcomm]. [I-D.ietf-ace-key-groupcomm].
o Name: Best effort o Name: Best effort
o Value: 1 o Value: 1
o Description: No action is taken. o Description: No action is taken.
o Reference: [I-D.ietf-core-oscore-groupcomm] (Appendix E.1). o Reference: [I-D.ietf-core-oscore-groupcomm] (Appendix E.1)
o Name: Baseline o Name: Baseline
o Value: 2 o Value: 2
o Description: The first received request sets the baseline o Description: The first received request sets the baseline
reference point, and is discarded with no delivery to the reference point, and is discarded with no delivery to the
application. application.
o Reference: [I-D.ietf-core-oscore-groupcomm] (Appendix E.2). o Reference: [I-D.ietf-core-oscore-groupcomm] (Appendix E.2)
o Name: Echo challenge-response o Name: Echo challenge-response
o Value: 3 o Value: 3
o Description: Challenge response using the Echo Option for CoAP o Description: Challenge response using the Echo Option for CoAP
from [I-D.ietf-core-echo-request-tag]. from [I-D.ietf-core-echo-request-tag].
o Reference: [I-D.ietf-core-oscore-groupcomm] (Appendix E.3). o Reference: [I-D.ietf-core-oscore-groupcomm] (Appendix E.3)
15.5. ACE Groupcomm Parameters Registry 18.5. ACE Groupcomm Parameters Registry
IANA is asked to register the following entry in the "ACE Groupcomm IANA is asked to register the following entry in the "ACE Groupcomm
Parameters" Registry defined in Section 8.3 of Parameters" Registry defined in Section 9.4 of
[I-D.ietf-ace-key-groupcomm]. [I-D.ietf-ace-key-groupcomm].
o Name: clientId o Name: clientId
o CBOR Key: TBD o CBOR Key: TBD7
o CBOR Type: Byte string o CBOR Type: Byte string
o Reference: [[This document]] (Section 7). o Reference: [[This specification]] (Section 8)
16. References 18.6. TLS Exporter Label Registry
16.1. Normative References IANA is asked to register the following entry in the "TLS Exporter
Label" Registry defined in Section 6 of [RFC5705] and updated in
Section 12 of [RFC8447].
o Value: EXPORTER-ACE-Sign-Challenge-coap-group-oscore-app
o DTLS-OK: Y
o Recommended: N
o Reference: [[This specification]] (Section 5.2.1)
19. References
19.1. Normative References
[I-D.ietf-ace-cwt-proof-of-possession] [I-D.ietf-ace-cwt-proof-of-possession]
Jones, M., Seitz, L., Selander, G., Erdtman, S., and H. Jones, M., Seitz, L., Selander, G., Erdtman, S., and H.
Tschofenig, "Proof-of-Possession Key Semantics for CBOR Tschofenig, "Proof-of-Possession Key Semantics for CBOR
Web Tokens (CWTs)", draft-ietf-ace-cwt-proof-of- Web Tokens (CWTs)", draft-ietf-ace-cwt-proof-of-
possession-11 (work in progress), October 2019. possession-11 (work in progress), October 2019.
[I-D.ietf-ace-key-groupcomm] [I-D.ietf-ace-key-groupcomm]
Palombini, F. and M. Tiloca, "Key Provisioning for Group Palombini, F. and M. Tiloca, "Key Provisioning for Group
Communication using ACE", draft-ietf-ace-key-groupcomm-04 Communication using ACE", draft-ietf-ace-key-groupcomm-05
(work in progress), January 2020. (work in progress), March 2020.
[I-D.ietf-ace-oauth-authz] [I-D.ietf-ace-oauth-authz]
Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and
H. Tschofenig, "Authentication and Authorization for H. Tschofenig, "Authentication and Authorization for
Constrained Environments (ACE) using the OAuth 2.0 Constrained Environments (ACE) using the OAuth 2.0
Framework (ACE-OAuth)", draft-ietf-ace-oauth-authz-30 Framework (ACE-OAuth)", draft-ietf-ace-oauth-authz-33
(work in progress), January 2020. (work in progress), February 2020.
[I-D.ietf-ace-oscore-profile] [I-D.ietf-ace-oscore-profile]
Palombini, F., Seitz, L., Selander, G., and M. Gunnarsson, Palombini, F., Seitz, L., Selander, G., and M. Gunnarsson,
"OSCORE profile of the Authentication and Authorization "OSCORE profile of the Authentication and Authorization
for Constrained Environments Framework", draft-ietf-ace- for Constrained Environments Framework", draft-ietf-ace-
oscore-profile-08 (work in progress), July 2019. oscore-profile-10 (work in progress), March 2020.
[I-D.ietf-core-oscore-groupcomm] [I-D.ietf-core-oscore-groupcomm]
Tiloca, M., Selander, G., Palombini, F., and J. Park, Tiloca, M., Selander, G., Palombini, F., and J. Park,
"Group OSCORE - Secure Group Communication for CoAP", "Group OSCORE - Secure Group Communication for CoAP",
draft-ietf-core-oscore-groupcomm-06 (work in progress), draft-ietf-core-oscore-groupcomm-07 (work in progress),
November 2019. March 2020.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC5705] Rescorla, E., "Keying Material Exporters for Transport
Layer Security (TLS)", RFC 5705, DOI 10.17487/RFC5705,
March 2010, <https://www.rfc-editor.org/info/rfc5705>.
[RFC5869] Krawczyk, H. and P. Eronen, "HMAC-based Extract-and-Expand [RFC5869] Krawczyk, H. and P. Eronen, "HMAC-based Extract-and-Expand
Key Derivation Function (HKDF)", RFC 5869, Key Derivation Function (HKDF)", RFC 5869,
DOI 10.17487/RFC5869, May 2010, DOI 10.17487/RFC5869, May 2010,
<https://www.rfc-editor.org/info/rfc5869>. <https://www.rfc-editor.org/info/rfc5869>.
[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained [RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252, Application Protocol (CoAP)", RFC 7252,
DOI 10.17487/RFC7252, June 2014, DOI 10.17487/RFC7252, June 2014,
<https://www.rfc-editor.org/info/rfc7252>. <https://www.rfc-editor.org/info/rfc7252>.
skipping to change at page 26, line 5 skipping to change at page 31, line 13
<https://www.rfc-editor.org/info/rfc8152>. <https://www.rfc-editor.org/info/rfc8152>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>. <https://www.rfc-editor.org/info/rfc8446>.
[RFC8447] Salowey, J. and S. Turner, "IANA Registry Updates for TLS
and DTLS", RFC 8447, DOI 10.17487/RFC8447, August 2018,
<https://www.rfc-editor.org/info/rfc8447>.
[RFC8613] Selander, G., Mattsson, J., Palombini, F., and L. Seitz, [RFC8613] Selander, G., Mattsson, J., Palombini, F., and L. Seitz,
"Object Security for Constrained RESTful Environments "Object Security for Constrained RESTful Environments
(OSCORE)", RFC 8613, DOI 10.17487/RFC8613, July 2019, (OSCORE)", RFC 8613, DOI 10.17487/RFC8613, July 2019,
<https://www.rfc-editor.org/info/rfc8613>. <https://www.rfc-editor.org/info/rfc8613>.
16.2. Informative References 19.2. Informative References
[I-D.dijk-core-groupcomm-bis] [I-D.dijk-core-groupcomm-bis]
Dijk, E., Wang, C., and M. Tiloca, "Group Communication Dijk, E., Wang, C., and M. Tiloca, "Group Communication
for the Constrained Application Protocol (CoAP)", draft- for the Constrained Application Protocol (CoAP)", draft-
dijk-core-groupcomm-bis-02 (work in progress), November dijk-core-groupcomm-bis-03 (work in progress), March
2019. 2020.
[I-D.ietf-ace-dtls-authorize] [I-D.ietf-ace-dtls-authorize]
Gerdes, S., Bergmann, O., Bormann, C., Selander, G., and Gerdes, S., Bergmann, O., Bormann, C., Selander, G., and
L. Seitz, "Datagram Transport Layer Security (DTLS) L. Seitz, "Datagram Transport Layer Security (DTLS)
Profile for Authentication and Authorization for Profile for Authentication and Authorization for
Constrained Environments (ACE)", draft-ietf-ace-dtls- Constrained Environments (ACE)", draft-ietf-ace-dtls-
authorize-09 (work in progress), December 2019. authorize-09 (work in progress), December 2019.
[I-D.ietf-ace-mqtt-tls-profile]
Sengul, C., Kirby, A., and P. Fremantle, "MQTT-TLS profile
of ACE", draft-ietf-ace-mqtt-tls-profile-03 (work in
progress), December 2019.
[I-D.ietf-core-coap-pubsub] [I-D.ietf-core-coap-pubsub]
Koster, M., Keranen, A., and J. Jimenez, "Publish- Koster, M., Keranen, A., and J. Jimenez, "Publish-
Subscribe Broker for the Constrained Application Protocol Subscribe Broker for the Constrained Application Protocol
(CoAP)", draft-ietf-core-coap-pubsub-09 (work in (CoAP)", draft-ietf-core-coap-pubsub-09 (work in
progress), September 2019. progress), September 2019.
[I-D.ietf-core-echo-request-tag] [I-D.ietf-core-echo-request-tag]
Amsuess, C., Mattsson, J., and G. Selander, "CoAP: Echo, Amsuess, C., Mattsson, J., and G. Selander, "CoAP: Echo,
Request-Tag, and Token Processing", draft-ietf-core-echo- Request-Tag, and Token Processing", draft-ietf-core-echo-
request-tag-08 (work in progress), November 2019. request-tag-09 (work in progress), March 2020.
[I-D.tiloca-ace-oscore-gm-admin]
Tiloca, M., Hoeglund, R., Stok, P., and F. Palombini,
"Admin Interface for the OSCORE Group Manager", draft-
tiloca-ace-oscore-gm-admin-01 (work in progress), March
2020.
[I-D.tiloca-core-oscore-discovery] [I-D.tiloca-core-oscore-discovery]
Tiloca, M., Amsuess, C., and P. Stok, "Discovery of OSCORE Tiloca, M., Amsuess, C., and P. Stok, "Discovery of OSCORE
Groups with the CoRE Resource Directory", draft-tiloca- Groups with the CoRE Resource Directory", draft-tiloca-
core-oscore-discovery-04 (work in progress), November core-oscore-discovery-05 (work in progress), March
2019. 2020.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer [RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347, Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <https://www.rfc-editor.org/info/rfc6347>. January 2012, <https://www.rfc-editor.org/info/rfc6347>.
[RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", [RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
RFC 6749, DOI 10.17487/RFC6749, October 2012, RFC 6749, DOI 10.17487/RFC6749, October 2012,
<https://www.rfc-editor.org/info/rfc6749>. <https://www.rfc-editor.org/info/rfc6749>.
[RFC7641] Hartke, K., "Observing Resources in the Constrained [RFC7641] Hartke, K., "Observing Resources in the Constrained
Application Protocol (CoAP)", RFC 7641, Application Protocol (CoAP)", RFC 7641,
DOI 10.17487/RFC7641, September 2015, DOI 10.17487/RFC7641, September 2015,
<https://www.rfc-editor.org/info/rfc7641>. <https://www.rfc-editor.org/info/rfc7641>.
Appendix A. Profile Requirements Appendix A. Profile Requirements
This appendix lists the specifications on this application profile of This appendix lists the specifications on this application profile of
ACE, based on the requiremens defined in Appendix A of ACE, based on the requiremens defined in Appendix A of
[I-D.ietf-ace-key-groupcomm]. [I-D.ietf-ace-key-groupcomm].
o REQ1 - Specify the encoding and value of the identifier of group o REQ1 - Specify the encoding and value of the identifier of group,
of 'scope': see Section 3.1. for scope entries of 'scope': see Section 3.1.
o REQ2 - Specify the encoding and value of the identifier of roles o REQ2 - Specify the encoding and value of roles, for scope entries
of 'scope': see Section 3.1. of 'scope': see Section 3.1.
o REQ3 - if used, specify the acceptable values for 'sign_alg': o REQ3 - if used, specify the acceptable values for 'sign_alg':
values from Tables 5 and 6 of [RFC8152]. values from Tables 5 and 6 of [RFC8152].
o REQ4 - If used, specify the acceptable values for o REQ4 - If used, specify the acceptable values for
'sign_parameters': values from the "Counter Signature Parameters" 'sign_parameters': values from the "Counter Signature Parameters"
Registry (see Section 9.1 of [I-D.ietf-core-oscore-groupcomm]). Registry (see Section 11.1 of [I-D.ietf-core-oscore-groupcomm]).
o REQ5 - If used, specify the acceptable values for o REQ5 - If used, specify the acceptable values for
'sign_key_parameters': values from the "Counter Signature Key 'sign_key_parameters': values from the "Counter Signature Key
Parameters" Registry (see Section 9.2 of Parameters" Registry (see Section 11.2 of
[I-D.ietf-core-oscore-groupcomm]). [I-D.ietf-core-oscore-groupcomm]).
o REQ6 - If used, specify the acceptable values for 'pub_key_enc': 1 o REQ6 - If used, specify the acceptable values for 'pub_key_enc': 1
("COSE_Key") from the 'Confirmation Key' column of the "CWT ("COSE_Key") from the 'Confirmation Key' column of the "CWT
Confirmation Method" Registry defined in Confirmation Method" Registry defined in
[I-D.ietf-ace-cwt-proof-of-possession]. Future specifications may [I-D.ietf-ace-cwt-proof-of-possession]. Future specifications may
define additional values for this parameter. define additional values for this parameter.
o REQ7 - Format of the 'key' value: see Section 4.4. o REQ7 - Format of the 'key' value: see Section 5.4.
o REQ8 - Acceptable values of 'gkty': Group_OSCORE_Security_Context o REQ8 - Acceptable values of 'gkty': Group_OSCORE_Security_Context
object (see Section 4.4). object (see Section 5.4).
o REQ9: Specify the format of the identifiers of group members: see o REQ9: Specify the format of the identifiers of group members: see
Section 4.4 and Section 8. Section 5.4 and Section 9.
o REQ10 - Specify the communication protocol that the members of the o REQ10 - Specify the communication protocol that the members of the
group must use: CoAP, possibly over IP multicast. group must use: CoAP, possibly over IP multicast.
o REQ11 - Specify the security protocols that the group members must o REQ11 - Specify the security protocols that the group members must
use to protect their communication: Group OSCORE. use to protect their communication: Group OSCORE.
o REQ12 - Specify and register the application profile identifier: o REQ12 - Specify and register the application profile identifier:
coap_group_oscore_app (see Section 15.3). coap_group_oscore_app (see Section 18.1).
o REQ13 - Specify policies at the KDC to handle member ids that are o REQ13 - Specify policies at the KDC to handle member ids that are
not included in 'get_pub_keys': see Section 8. not included in 'get_pub_keys': see Section 9.
o REQ14 - If used, specify the format and content of o REQ14 - If used, specify the format and content of
'group_policies' and its entries: see Section 4.4, and the three 'group_policies' and its entries: see Section 5.4, and the three
values defined and registered, as content of the entry "Sequence values defined and registered, as content of the entry "Sequence
Number Synchronization Method" (see Section 15.4). Number Synchronization Method" (see Section 18.4).
o REQ15 - Specify the format of newly-generated individual keying o REQ15 - Specify the format of newly-generated individual keying
material for group members, or of the information to derive it, material for group members, or of the information to derive it,
and corresponding CBOR label: see Section 7. and corresponding CBOR label: see Section 8.
o REQ16 - Specify how the communication is secured between the o REQ16 - Specify how the communication is secured between the
Client and KDC: by means of any transport profile of ACE Client and KDC: by means of any transport profile of ACE
[I-D.ietf-ace-oauth-authz] between Client and Group Manager that [I-D.ietf-ace-oauth-authz] between Client and Group Manager that
complies with the requirements in Appendix C of complies with the requirements in Appendix C of
[I-D.ietf-ace-oauth-authz]. [I-D.ietf-ace-oauth-authz].
o REQ17: Specify how the nonce N_S is generated, if the token is not o REQ17: Specify how the nonce N_S is generated, if the token is not
being posted (e.g. if it is used directly to validate TLS being posted (e.g. if it is used directly to validate TLS
instead): see Section 4.2.1. instead): see Section 5.2.1.
o REQ18: Specify if 'mgt_key_material' used, and if yes specify its o REQ18: Specify if 'mgt_key_material' used, and if yes specify its
format and content: not used in this version of the profile. format and content: not used in this version of the profile.
o OPT1 (Optional) - Specify the encoding of public keys, of o OPT1 (Optional) - Specify the encoding of public keys, of
'client_cred', and of 'pub_keys' if COSE_Keys are not used: no. 'client_cred', and of 'pub_keys' if COSE_Keys are not used: no.
o OPT2 (Optional) - Specify the negotiation of parameter values for o OPT2 (Optional) - Specify the negotiation of parameter values for
signature algorithm and signature keys, if 'sign_info' and signature algorithm and signature keys, if 'sign_info' and
'pub_key_enc' are not used: possible early discovery by using the 'pub_key_enc' are not used: possible early discovery by using the
skipping to change at page 29, line 11 skipping to change at page 34, line 16
o OPT3 (Optional) - Specify the encoding of 'pub_keys_repos' if the o OPT3 (Optional) - Specify the encoding of 'pub_keys_repos' if the
default is not used: no. default is not used: no.
o OPT4 (Optional) - Specify policies that instruct clients to retain o OPT4 (Optional) - Specify policies that instruct clients to retain
unsuccessfully decrypted messages and for how long, so that they unsuccessfully decrypted messages and for how long, so that they
can be decrypted after getting updated keying material: no. can be decrypted after getting updated keying material: no.
o OPT5 (Optional) - Specify the behavior of the handler in case of o OPT5 (Optional) - Specify the behavior of the handler in case of
failure to retrieve a public key for the specific node: send a failure to retrieve a public key for the specific node: send a
4.00 Bad Request response to a Joining Request (see Section 4.3). 4.00 Bad Request response to a Joining Request (see Section 5.3).
o OPT6 (Optional) - Specify possible or required payload formats for o OPT6 (Optional) - Specify possible or required payload formats for
specific error cases: send a 4.00 Bad Request response to a specific error cases: send a 4.00 Bad Request response to a
Joining Request (see Section 4.3). Joining Request (see Section 5.3).
o OPT7 (Optional) - Specify CBOR values to use for abbreviating
identifiers of roles in the group or topic (see Section 3.1).
o OPT8 (Optional) - Specify policies for the KDC to perform group
rekeying after receiving a Key Renewal Request: no.
Appendix B. Document Updates Appendix B. Document Updates
RFC EDITOR: PLEASE REMOVE THIS SECTION. RFC EDITOR: PLEASE REMOVE THIS SECTION.
B.1. Version -03 to -04 B.1. Version -04 to -05
o Nonce N_S also in error responses to the Joining Requests.
o Supporting single Access Token for multiple groups/topics.
o Supporting legal requesters/responders using the 'peer_roles'
parameter.
o Registered and used dedicated label for TLS Exporter.
o Added method for uploading a new public key to the Group Manager.
o Added resource and method for retrieving the current group status.
o Fixed inconsistency in retrieving group keying material only.
o Clarified retrieval of keying material for monitor-only members.
o Clarification on incrementing version number when rekeying the
group.
o Clarification on what is re-distributed with the group rekeying.
o Security considerations on the size of the nonces used for the
signature challenge.
o Added CBOR values to abbreviate role identifiers in the group.
B.2. Version -03 to -04
o New abstract. o New abstract.
o Moved general content to draft-ietf-ace-key-groupcomm o Moved general content to draft-ietf-ace-key-groupcomm
o Terminology: node name; node resource. o Terminology: node name; node resource.
o Creation and pointing at node resource. o Creation and pointing at node resource.
o Updated Group Manager API (REST methods and offered services). o Updated Group Manager API (REST methods and offered services).
skipping to change at page 29, line 43 skipping to change at page 35, line 37
o Size of challenges 'cnonce' and 'rsnonce'. o Size of challenges 'cnonce' and 'rsnonce'.
o Value of 'rsnonce' for reused or non-traditionally-posted tokens. o Value of 'rsnonce' for reused or non-traditionally-posted tokens.
o Removed reference to RFC 7390. o Removed reference to RFC 7390.
o New requirements from draft-ietf-ace-key-groupcomm o New requirements from draft-ietf-ace-key-groupcomm
o Editorial improvements. o Editorial improvements.
B.2. Version -02 to -03 B.3. Version -02 to -03
o New sections, aligned with the interface of ace-key-groupcomm . o New sections, aligned with the interface of ace-key-groupcomm .
o Exchange of information on the countersignature algorithm and o Exchange of information on the countersignature algorithm and
related parameters, during the Token POST (Section 4.1). related parameters, during the Token POST (Section 4.1).
o Nonce 'rsnonce' from the Group Manager to the Client o Nonce 'rsnonce' from the Group Manager to the Client
(Section 4.1). (Section 4.1).
o Client PoP signature in the Key Distribution Request upon joining o Client PoP signature in the Key Distribution Request upon joining
skipping to change at page 30, line 18 skipping to change at page 36, line 12
o Local actions on the Group Manager, upon a new node's joining o Local actions on the Group Manager, upon a new node's joining
(Section 4.2). (Section 4.2).
o Local actions on the Group Manager, upon a node's leaving o Local actions on the Group Manager, upon a node's leaving
(Section 12). (Section 12).
o IANA registration in ACE Groupcomm Parameters Registry. o IANA registration in ACE Groupcomm Parameters Registry.
o More fulfilled profile requirements (Appendix A). o More fulfilled profile requirements (Appendix A).
B.3. Version -01 to -02 B.4. Version -01 to -02
o Editorial fixes. o Editorial fixes.
o Changed: "listener" to "responder"; "pure listener" to "monitor". o Changed: "listener" to "responder"; "pure listener" to "monitor".
o Changed profile name to "coap_group_oscore_app", to reflect it is o Changed profile name to "coap_group_oscore_app", to reflect it is
an application profile. an application profile.
o Added the 'type' parameter for all requests to a Join Resource. o Added the 'type' parameter for all requests to a Join Resource.
skipping to change at page 31, line 8 skipping to change at page 37, line 5
o Extended security considerations: proof-of-possession of signature o Extended security considerations: proof-of-possession of signature
keys; collision of OSCORE Group Identifiers (Section 8). keys; collision of OSCORE Group Identifiers (Section 8).
o Registered three entries in the IANA Registry "Sequence Number o Registered three entries in the IANA Registry "Sequence Number
Synchronization Method Registry" (Section 9). Synchronization Method Registry" (Section 9).
o Registered one public key encoding in the "ACE Public Key o Registered one public key encoding in the "ACE Public Key
Encoding" IANA Registry (Section 9). Encoding" IANA Registry (Section 9).
B.4. Version -00 to -01 B.5. Version -00 to -01
o Changed name of 'req_aud' to 'audience' in the Authorization o Changed name of 'req_aud' to 'audience' in the Authorization
Request (Section 3.1). Request (Section 3.1).
o Added negotiation of countersignature algorithm/parameters between o Added negotiation of countersignature algorithm/parameters between
Client and Group Manager (Section 4). Client and Group Manager (Section 4).
o Updated format of the Key Distribution Response as a whole o Updated format of the Key Distribution Response as a whole
(Section 4.3). (Section 4.3).
 End of changes. 146 change blocks. 
273 lines changed or deleted 572 lines changed or added

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