rfc9203.original   rfc9203.txt 
ACE Working Group F. Palombini Internet Engineering Task Force (IETF) F. Palombini
Internet-Draft Ericsson AB Request for Comments: 9203 Ericsson AB
Intended status: Standards Track L. Seitz Category: Standards Track L. Seitz
Expires: 7 November 2021 Combitech ISSN: 2070-1721 Combitech
G. Selander G. Selander
Ericsson AB Ericsson AB
M. Gunnarsson M. Gunnarsson
RISE RISE
6 May 2021 March 2022
OSCORE Profile of the Authentication and Authorization for Constrained The Object Security for Constrained RESTful Environments (OSCORE)
Environments Framework Profile of the Authentication and Authorization for Constrained
draft-ietf-ace-oscore-profile-19 Environments (ACE) Framework
Abstract Abstract
This document specifies a profile for the Authentication and This document specifies a profile for the Authentication and
Authorization for Constrained Environments (ACE) framework. It Authorization for Constrained Environments (ACE) framework. It
utilizes Object Security for Constrained RESTful Environments utilizes Object Security for Constrained RESTful Environments
(OSCORE) to provide communication security and proof-of-possession (OSCORE) to provide communication security and proof-of-possession
for a key owned by the client and bound to an OAuth 2.0 access token. for a key owned by the client and bound to an OAuth 2.0 access token.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on 7 November 2021. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9203.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2022 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 (https://trustee.ietf.org/ Provisions Relating to IETF Documents
license-info) in effect on the date of publication of this document. (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
Please review these documents carefully, as they describe your rights carefully, as they describe your rights and restrictions with respect
and restrictions with respect to this document. Code Components to this document. Code Components extracted from this document must
extracted from this document must include Simplified BSD License text include Revised BSD License text as described in Section 4.e of the
as described in Section 4.e of the Trust Legal Provisions and are Trust Legal Provisions and are provided without warranty as described
provided without warranty as described in the Simplified BSD License. in the Revised BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology
2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 4 2. Protocol Overview
3. Client-AS Communication . . . . . . . . . . . . . . . . . . . 7 3. Client-AS Communication
3.1. C-to-AS: POST to token endpoint . . . . . . . . . . . . . 7 3.1. C-to-AS: POST to Token Endpoint
3.2. AS-to-C: Access Token . . . . . . . . . . . . . . . . . . 9 3.2. AS-to-C: Access Token
3.2.1. The OSCORE_Input_Material . . . . . . . . . . . . . . 13 3.2.1. The OSCORE_Input_Material
4. Client-RS Communication . . . . . . . . . . . . . . . . . . . 16 4. Client-RS Communication
4.1. C-to-RS: POST to authz-info endpoint . . . . . . . . . . 16 4.1. C-to-RS: POST to authz-info Endpoint
4.1.1. The Nonce 1 Parameter . . . . . . . . . . . . . . . . 18 4.1.1. The Nonce 1 Parameter
4.1.2. The ace_client_recipientid Parameter . . . . . . . . 18 4.1.2. The ace_client_recipientid Parameter
4.2. RS-to-C: 2.01 (Created) . . . . . . . . . . . . . . . . . 19 4.2. RS-to-C: 2.01 (Created)
4.2.1. The Nonce 2 Parameter . . . . . . . . . . . . . . . . 20 4.2.1. The Nonce 2 Parameter
4.2.2. The ace_server_recipientid Parameter . . . . . . . . 20 4.2.2. The ace_server_recipientid Parameter
4.3. OSCORE Setup . . . . . . . . . . . . . . . . . . . . . . 20 4.3. OSCORE Setup
4.4. Access rights verification . . . . . . . . . . . . . . . 23 4.4. Access Rights Verification
5. Secure Communication with AS . . . . . . . . . . . . . . . . 23 5. Secure Communication with AS
6. Discarding the Security Context . . . . . . . . . . . . . . . 23 6. Discarding the Security Context
7. Security Considerations . . . . . . . . . . . . . . . . . . . 24 7. Security Considerations
8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 26 8. Privacy Considerations
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26 9. IANA Considerations
9.1. ACE Profile Registry . . . . . . . . . . . . . . . . . . 27 9.1. ACE Profile Registry
9.2. OAuth Parameters Registry . . . . . . . . . . . . . . . . 27 9.2. OAuth Parameters Registry
9.3. OAuth Parameters CBOR Mappings Registry . . . . . . . . . 27 9.3. OAuth Parameters CBOR Mappings Registry
9.4. OSCORE Security Context Parameters Registry . . . . . . . 28 9.4. OSCORE Security Context Parameters Registry
9.5. CWT Confirmation Methods Registry . . . . . . . . . . . . 29 9.5. CWT Confirmation Methods Registry
9.6. JWT Confirmation Methods Registry . . . . . . . . . . . . 29 9.6. JWT Confirmation Methods Registry
9.7. Expert Review Instructions . . . . . . . . . . . . . . . 29 9.7. Expert Review Instructions
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 10. References
10.1. Normative References . . . . . . . . . . . . . . . . . . 30 10.1. Normative References
10.2. Informative References . . . . . . . . . . . . . . . . . 32 10.2. Informative References
Appendix A. Profile Requirements . . . . . . . . . . . . . . . . 33 Appendix A. Profile Requirements
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 34 Acknowledgments
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34 Authors' Addresses
1. Introduction 1. Introduction
This document specifies the "coap_oscore" profile of the ACE This document specifies the "coap_oscore" profile of the ACE
framework [I-D.ietf-ace-oauth-authz]. In this profile, a client and framework [RFC9200]. In this profile, a client (C) and a resource
a resource server use the Constrained Application Protocol (CoAP) server (RS) use the Constrained Application Protocol (CoAP) [RFC7252]
[RFC7252] to communicate. The client uses an access token, bound to to communicate. The client uses an access token, bound to a
a symmetric key (the proof-of-possession key) to authorize its access symmetric key (the proof-of-possession (PoP) key) to authorize its
to the resource server. Note that this profile uses a symmetric- access to the resource server. Note that this profile uses a
crypto-based scheme, where the symmetric secret is used as input symmetric-crypto-based scheme, where the symmetric secret is used as
material for keying material derivation. In order to provide input material for keying material derivation. In order to provide
communication security and proof of possession, the client and communication security and PoP, the client and resource server use
resource server use Object Security for Constrained RESTful Object Security for Constrained RESTful Environments (OSCORE) as
Environments (OSCORE) [RFC8613]. Note that the proof of possession defined in [RFC8613]. Note that the PoP is not achieved through a
is not achieved through a dedicated protocol element, but rather dedicated protocol element but rather occurs after the first message
occurs after the first message exchange using OSCORE. exchange using OSCORE.
OSCORE specifies how to use CBOR Object Signing and Encryption (COSE) OSCORE specifies how to use CBOR Object Signing and Encryption (COSE)
[I-D.ietf-cose-rfc8152bis-struct][I-D.ietf-cose-rfc8152bis-algs] to [RFC9052] [RFC9053] to secure CoAP messages. Note that OSCORE can be
secure CoAP messages. Note that OSCORE can be used to secure CoAP used to secure CoAP messages, as well as HTTP and combinations of
messages, as well as HTTP and combinations of HTTP and CoAP; a HTTP and CoAP; a profile of ACE similar to the one described in this
profile of ACE similar to the one described in this document, with document, with the difference of using HTTP instead of CoAP as the
the difference of using HTTP instead of CoAP as communication communication protocol, could be specified analogously to this one.
protocol, could be specified analogously to this one.
1.1. Terminology 1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
Certain security-related terms such as "authentication", Certain security-related terms such as "authentication",
"authorization", "confidentiality", "(data) integrity", "Message "authorization", "confidentiality", "(data) integrity", "Message
Authentication Code (MAC)", "Hash-based Message Authentication Code Authentication Code (MAC)", "Hash-based Message Authentication Code
(HMAC)", and "verify" are taken from [RFC4949]. (HMAC)", and "verify" are taken from [RFC4949].
RESTful terminology follows HTTP [RFC7231]. RESTful terminology follows HTTP [RFC7231].
Readers are expected to be familiar with the terms and concepts Readers are expected to be familiar with the terms and concepts
defined in OSCORE [RFC8613], such as "Security Context" and defined in OSCORE [RFC8613], such as "Security Context" and
"Recipient ID". "Recipient ID".
Terminology for entities in the architecture is defined in OAuth 2.0 Terminology for entities in the architecture is defined in OAuth 2.0
[RFC6749], such as client (C), resource server (RS), and [RFC6749], such as client (C), resource server (RS), and
authorization server (AS). It is assumed in this document that a authorization server (AS). It is assumed in this document that a
given resource on a specific RS is associated to a unique AS. given resource on a specific RS is associated to a unique AS.
Concise Binary Object Representation (CBOR) [RFC8949] and Concise Concise Binary Object Representation (CBOR) [RFC8949] and Concise
Data Definition Language (CDDL) [RFC8610] are used in this document. Data Definition Language (CDDL) [RFC8610] are used in this document.
CDDL predefined type names, especially bstr for CBOR byte strings and CDDL predefined type names, especially "bstr" for CBOR byte strings
tstr for CBOR text strings, are used extensively in this document. and "tstr" for CBOR text strings, are used extensively in this
document.
Note that the term "endpoint" is used here, as in Note that the term "endpoint" is used as in [RFC9200], following its
[I-D.ietf-ace-oauth-authz], following its OAuth definition, which is OAuth definition, which is to denote resources such as token and
to denote resources such as token and introspect at the AS and authz- introspect at the AS and authz-info at the RS. The CoAP definition,
info at the RS. The CoAP [RFC7252] definition, which is "An entity which is "[a]n entity participating in the CoAP protocol" [RFC7252],
participating in the CoAP protocol" is not used in this document. is not used in this document.
Examples throughout this document are expressed in CBOR diagnostic Examples throughout this document are expressed in CBOR diagnostic
notation without the tag and value abbreviations. notation without the tag and value abbreviations.
2. Protocol Overview 2. Protocol Overview
This section gives an overview of how to use the ACE Framework This section gives an overview of how to use the ACE Framework
[I-D.ietf-ace-oauth-authz] to secure the communication between a [RFC9200] to secure the communication between a client and a resource
client and a resource server using OSCORE [RFC8613]. The parameters server using OSCORE [RFC8613]. The parameters needed by the client
needed by the client to negotiate the use of this profile with the to negotiate the use of this profile with the AS, as well as the
authorization server, as well as the OSCORE setup process, are OSCORE setup process, are described in detail in the following
described in detail in the following sections. sections.
The RS maintains a collection of OSCORE Security Contexts with The RS maintains a collection of OSCORE Security Contexts with
associated authorization information for all the clients that it is associated authorization information for all the clients that it is
communicating with. The authorization information is maintained as communicating with. The authorization information is maintained as
policy that is used as input to processing requests from those policy that is used as input to processing requests from those
clients. clients.
This profile requires a client to retrieve an access token from the This profile requires a client to retrieve an access token from the
AS for the resource it wants to access on an RS, by sending an access AS for the resource it wants to access on an RS, by sending an access
token request to the token endpoint, as specified in section 5.8 of token request to the token endpoint, as specified in Section 5.8 of
[I-D.ietf-ace-oauth-authz]. The access token request and response [RFC9200]. The access token request and response MUST be
MUST be confidentiality-protected and ensure authenticity. This confidentiality protected and ensure authenticity. The use of OSCORE
profile RECOMMENDS the use of OSCORE between client and AS, to reduce between the client and AS is RECOMMENDED in this profile, to reduce
the number of libraries the client has to support, but other the number of libraries the client has to support, but other
protocols fulfilling the security requirements defined in section 5 protocols fulfilling the security requirements defined in Section 5
of [I-D.ietf-ace-oauth-authz] MAY alternatively be used, such as TLS of [RFC9200] MAY alternatively be used, such as TLS [RFC8446] or DTLS
[RFC8446] or DTLS [I-D.ietf-tls-dtls13]. [RFC9147].
Once the client has retrieved the access token, it generates a nonce Once the client has retrieved the access token, it generates a nonce
N1, defined in this document (see Section 4.1.1). The client also N1, as defined in this document (see Section 4.1.1). The client also
generates its own OSCORE Recipient ID ID1 (see Section 3.1 of generates its own OSCORE Recipient ID, ID1 (see Section 3.1 of
[RFC8613]), for use with the keying material associated to the RS. [RFC8613]), for use with the keying material associated to the RS.
The client posts the token, N1 and its Recipient ID to the RS using The client posts the token N1 and its Recipient ID to the RS using
the authz-info endpoint and mechanisms specified in section 5.8 of the authz-info endpoint and mechanisms specified in Section 5.8 of
[I-D.ietf-ace-oauth-authz] and Content-Format = application/ace+cbor. [RFC9200] and Content-Format = application/ace+cbor. When using this
When using this profile, the communication with the authz-info profile, the communication with the authz-info endpoint is not
endpoint is not protected, except for update of access rights. protected, except for the update of access rights.
If the access token is valid, the RS replies to this request with a If the access token is valid, the RS replies to this request with a
2.01 (Created) response with Content-Format = application/ace+cbor, 2.01 (Created) response with Content-Format = application/ace+cbor,
which contains a nonce N2 and its newly generated OSCORE Recipient which contains a nonce N2 and its newly generated OSCORE Recipient
ID, ID2, for use with the keying material associated to the client. ID, ID2, for use with the keying material associated to the client.
Moreover, the server concatenates the input salt received in the Moreover, the server concatenates the input salt received in the
token, N1, and N2 to obtain the Master Salt of the OSCORE Security token, N1, and N2 to obtain the Master Salt of the OSCORE Security
Context (see section 3 of [RFC8613]). The RS then derives the Context (see Section 3 of [RFC8613]). The RS then derives the
complete Security Context associated with the received token from the complete Security Context associated with the received token from the
Master Salt, the OSCORE Recipient ID generated by the client (set as Master Salt; the OSCORE Recipient ID generated by the client (set as
its OSCORE Sender ID), its own OSCORE Recipient ID, plus the its OSCORE Sender ID); its own OSCORE Recipient ID; plus the
parameters received in the access token from the AS, following parameters received in the access token from the AS, following
section 3.2 of [RFC8613]. Section 3.2 of [RFC8613].
In a similar way, after receiving the nonce N2, the client In a similar way, after receiving the nonce N2, the client
concatenates the input salt, N1 and N2 to obtain the Master Salt of concatenates the input salt N1 and N2 to obtain the Master Salt of
the OSCORE Security Context. The client then derives the complete the OSCORE Security Context. The client then derives the complete
Security Context from the Master Salt, the OSCORE Recipient ID Security Context from the Master Salt; the OSCORE Recipient ID
generated by the RS (set as its OSCORE Sender ID), its own OSCORE generated by the RS (set as its OSCORE Sender ID); its own OSCORE
Recipient ID, plus the parameters received from the AS. Recipient ID; plus the parameters received from the AS.
Finally, the client starts the communication with the RS by sending a Finally, the client starts the communication with the RS by sending a
request protected with OSCORE to the RS. If the request is request protected with OSCORE to the RS. If the request is
successfully verified, the server stores the complete Security successfully verified, the server stores the complete Security
Context state that is ready for use in protecting messages, and uses Context state that is ready for use in protecting messages and uses
it in the response, and in further communications with the client, it in the response, and in further communications with the client,
until token deletion due to, for example, expiration. This Security until token deletion due to, for example, expiration. This Security
Context is discarded when a token (whether the same or a different Context is discarded when a token (whether the same or a different
one) is used to successfully derive a new Security Context for that one) is used to successfully derive a new Security Context for that
client. client.
The use of nonces N1 and N2 during the exchange prevents the reuse of The use of nonces N1 and N2 during the exchange prevents the reuse of
an Authenticated Encryption with Associated Data (AEAD) nonce/key an Authenticated Encryption with Associated Data (AEAD) nonce/key
pair for two different messages. Reuse might otherwise occur when pair for two different messages. Reuse might otherwise occur when
client and RS derive a new Security Context from an existing (non- the client and RS derive a new Security Context from an existing
expired) access token, as might occur when either party has just (non-expired) access token, as might occur when either party has just
rebooted, and might lead to loss of both confidentiality and rebooted, and that might lead to loss of both confidentiality and
integrity. Instead, by using the exchanged nonces N1 and N2 as part integrity. Instead, by using the exchanged nonces N1 and N2 as part
of the Master Salt, the request to the authz-info endpoint posting of the Master Salt, the request to the authz-info endpoint posting
the same token results in a different Security Context, by OSCORE the same token results in a different Security Context, by OSCORE
construction, since even though the Master Secret, Sender ID and construction, since even though the Master Secret, Sender ID, and
Recipient ID are the same, the Master Salt is different (see Recipient ID are the same, the Master Salt is different (see
Section 3.2.1 of [RFC8613]). If the exchanged nonces were reused, a Section 3.2.1 of [RFC8613]). If the exchanged nonces were reused, a
node reusing a non-expired old token would be susceptible to on-path node reusing a non-expired old token would be susceptible to on-path
attackers provoking the creation of an OSCORE message using an old attackers provoking the creation of an OSCORE message using an old
AEAD key and nonce. AEAD key and nonce.
After the whole message exchange has taken place, the client can After the whole message exchange has taken place, the client can
contact the AS to request an update of its access rights, sending a contact the AS to request an update of its access rights, sending a
similar request to the token endpoint that also includes an similar request to the token endpoint that also includes an
identifier so that the AS can find the correct OSCORE security input identifier so that the AS can find the correct OSCORE security input
material it has previously shared with the client. This specific material it has previously shared with the client. This specific
identifier, encoded as a byte string, is assigned by the AS to be identifier, encoded as a byte string, is assigned by the AS to be
unique in the sets of its OSCORE security input materials, and is not unique in the sets of its OSCORE security input materials, and it is
used as input material to derive the full OSCORE Security Context. not used as input material to derive the full OSCORE Security
Context.
An overview of the profile flow for the OSCORE profile is given in An overview of the profile flow for the OSCORE profile is given in
Figure 1. The names of messages coincide with those of Figure 1. The names of messages coincide with those of [RFC9200]
[I-D.ietf-ace-oauth-authz] when applicable. when applicable.
C RS AS C RS AS
| | | | | |
| ----- POST /token ----------------------------> | | ----- POST /token ----------------------------> |
| | | | | |
| <---------------------------- Access Token ----- | | <---------------------------- Access Token ----- |
| + Access Information | | + Access Information |
| ---- POST /authz-info ---> | | | ---- POST /authz-info ---> | |
| (access_token, N1, ID1) | | | (access_token, N1, ID1) | |
| | | | | |
skipping to change at page 7, line 40 skipping to change at line 283
| | | | | |
| <--- OSCORE Response ----- | | | <--- OSCORE Response ----- | |
| | | | | |
| ... | | | ... | |
Figure 1: Protocol Overview Figure 1: Protocol Overview
3. Client-AS Communication 3. Client-AS Communication
The following subsections describe the details of the POST request The following subsections describe the details of the POST request
and response to the token endpoint between client and AS. and response to the token endpoint between the client and AS.
Section 3.2 of [RFC8613] defines how to derive a Security Context Section 3.2 of [RFC8613] defines how to derive a Security Context
based on a shared master secret and a set of other parameters, based on a shared Master Secret and a set of other parameters,
established between client and server, which the client receives from established between the client and server, which the client receives
the AS in this exchange. The proof-of-possession key (pop-key) from the AS in this exchange. The PoP key included in the response
included in the response from the AS MUST be used as master secret in from the AS MUST be used as a Master Secret in OSCORE.
OSCORE.
3.1. C-to-AS: POST to token endpoint 3.1. C-to-AS: POST to Token Endpoint
The client-to-AS request is specified in Section 5.8.1 of The client-to-AS request is specified in Section 5.8.1 of [RFC9200].
[I-D.ietf-ace-oauth-authz].
The client must send this POST request to the token endpoint over a The client must send this POST request to the token endpoint over a
secure channel that guarantees authentication, message integrity and secure channel that guarantees authentication, message integrity, and
confidentiality (see Section 5). confidentiality (see Section 5).
An example of such a request is shown in Figure 2 An example of such a request is shown in Figure 2.
Header: POST (Code=0.02) Header: POST (Code=0.02)
Uri-Host: "as.example.com" Uri-Host: "as.example.com"
Uri-Path: "token" Uri-Path: "token"
Content-Format: "application/ace+cbor" Content-Format: "application/ace+cbor"
Payload: Payload:
{ {
"audience" : "tempSensor4711", "audience" : "tempSensor4711",
"scope" : "read" "scope" : "read"
} }
Figure 2: Example C-to-AS POST /token request for an access token Figure 2: Example C-to-AS POST /token Request for an Access Token
bound to a symmetric key. Bound to a Symmetric Key
If the client wants to update its access rights without changing an If the client wants to update its access rights without changing an
existing OSCORE Security Context, it MUST include in its POST request existing OSCORE Security Context, it MUST include a "req_cnf" object
to the token endpoint a req_cnf object, with the kid field carrying a in its POST request to the token endpoint, with the kid field
CBOR byte string containing the OSCORE Input Material Identifier carrying a CBOR byte string containing the OSCORE Input Material
(assigned as discussed in Section 3.2). This identifier, together identifier (assigned as discussed in Section 3.2). This identifier,
with other information such as audience (see Section 5.8.1 of together with other information such as audience (see Section 5.8.1
[I-D.ietf-ace-oauth-authz]), can be used by the AS to determine the of [RFC9200]), can be used by the AS to determine the shared secret
shared secret bound to the proof-of-possession token and therefore bound to the proof-of-possession token; therefore, it MUST identify a
MUST identify a symmetric key that was previously generated by the AS symmetric key that was previously generated by the AS as a shared
as a shared secret for the communication between the client and the secret for the communication between the client and the RS. The AS
RS. The AS MUST verify that the received value identifies a proof- MUST verify that the received value identifies a proof-of-possession
of-possession key that has previously been issued to the requesting key that has previously been issued to the requesting client. If
client. If that is not the case, the Client-to-AS request MUST be that is not the case, the client-to-AS request MUST be declined with
declined with the error code "invalid_request" as defined in the error code invalid_request as defined in Section 5.8.3 of
Section 5.8.3 of [I-D.ietf-ace-oauth-authz]. [RFC9200].
An example of such a request is shown in Figure 3.
An example of such a request is shown in Figure 3
Header: POST (Code=0.02) Header: POST (Code=0.02)
Uri-Host: "as.example.com" Uri-Host: "as.example.com"
Uri-Path: "token" Uri-Path: "token"
Content-Format: "application/ace+cbor" Content-Format: "application/ace+cbor"
Payload: Payload:
{ {
"audience" : "tempSensor4711", "audience" : "tempSensor4711",
"scope" : "write", "scope" : "write",
"req_cnf" : { "req_cnf" : {
"kid" : h'01' "kid" : h'01'
} }
Figure 3: Example C-to-AS POST /token request for updating rights Figure 3: Example C-to-AS POST /token Request for Updating Rights
to an access token bound to a symmetric key. to an Access Token Bound to a Symmetric Key
3.2. AS-to-C: Access Token 3.2. AS-to-C: Access Token
After verifying the POST request to the token endpoint and that the After verifying the POST request to the token endpoint and that the
client is authorized to obtain an access token corresponding to its client is authorized to obtain an access token corresponding to its
access token request, the AS responds as defined in section 5.8.2 of access token request, the AS responds as defined in Section 5.8.2 of
[I-D.ietf-ace-oauth-authz]. If the client request was invalid, or [RFC9200]. If the client request was invalid, or not authorized, the
not authorized, the AS returns an error response as described in AS returns an error response as described in Section 5.8.3 of
section 5.8.3 of [I-D.ietf-ace-oauth-authz]. [RFC9200].
The AS can signal that the use of OSCORE is REQUIRED for a specific The AS can signal that the use of OSCORE is REQUIRED for a specific
access token by including the "ace_profile" parameter with the value access token by including the ace_profile parameter with the value
"coap_oscore" in the access token response. This means that the "coap_oscore" in the access token response. This means that the
client MUST use OSCORE towards all resource servers for which this client MUST use OSCORE towards all resource servers for which this
access token is valid, and follow Section 4.3 to derive the security access token is valid, and follow Section 4.3 to derive the security
context to run OSCORE. Usually it is assumed that constrained context to run OSCORE. Usually, it is assumed that constrained
devices will be pre-configured with the necessary profile, so that devices will be preconfigured with the necessary profile, so that
this kind of profile signaling can be omitted. this kind of profile signaling can be omitted.
Moreover, the AS MUST send the following data: Moreover, the AS MUST send the following data:
* a master secret * a Master Secret
* an identifier of the OSCORE Input Material * an identifier of the OSCORE Input Material
Additionally, the AS MAY send the following data, in the same Additionally, the AS MAY send the following data, in the same
response. response.
* a context identifier * a context identifier
* an AEAD algorithm * an AEAD algorithm
* an HMAC-based key derivation function (HKDF, [RFC5869]) algorithm,
see section 3.1 of [I-D.ietf-cose-rfc8152bis-algs] * an HMAC-based key derivation function (HKDF) algorithm [RFC5869];
see Section 3.1 of [RFC9053]
* a salt * a salt
* the OSCORE version number * the OSCORE version number
This data is transported in the OSCORE_Input_Material. The This data is transported in the OSCORE_Input_Material. The
OSCORE_Input_Material is a CBOR map object, defined in Section 3.2.1. OSCORE_Input_Material is a CBOR map object, defined in Section 3.2.1.
This object is transported in the "cnf" parameter of the access token This object is transported in the cnf parameter of the access token
response as defined in Section 3.2 of [I-D.ietf-ace-oauth-params], as response, as defined in Section 3.2 of [RFC9201], as the value of a
the value of a field named "osc", registered in Section 9.5 and field named "osc", which is registered in Sections 9.5 and 9.6.
Section 9.6.
The AS MAY assign an identifier to the context (context identifier). The AS MAY assign an identifier to the context (context identifier).
This identifier is used as ID Context in the OSCORE context as This identifier is used as ID Context in the OSCORE context as
described in section 3.1 of [RFC8613]. If assigned, this parameters described in Section 3.1 of [RFC8613]. If assigned, these parameters
MUST be communicated as the "contextId" field in the MUST be communicated as the contextId field in the
OSCORE_Input_Material. The application needs to consider that this OSCORE_Input_Material. The application needs to consider that this
identifier is sent in the clear and may reveal information about the identifier is sent in the clear and may reveal information about the
endpoints, as mentioned in section 12.8 of [RFC8613]. endpoints, as mentioned in Section 12.8 of [RFC8613].
The master secret and the identifier of the OSCORE_Input_Material The Master Secret and the identifier of the OSCORE_Input_Material
MUST be communicated as the "ms" and "id" field in the "osc" field in MUST be communicated as the ms and id field in the osc field in the
the "cnf" parameter of the access token response. If included, the cnf parameter of the access token response. If included, the
AEAD algorithm is sent in the "alg" parameter in the following are sent: the AEAD algorithm in the alg parameter in the
OSCORE_Input_Material; the HKDF algorithm in the "hkdf" parameter of OSCORE_Input_Material; the HKDF algorithm in the hkdf parameter of
the OSCORE_Input_Material; a salt in the "salt" parameter of the the OSCORE_Input_Material; a salt in the salt parameter of the
OSCORE_Input_Material; and the OSCORE version in the "version" OSCORE_Input_Material; and the OSCORE version in the version
parameter of the OSCORE_Input_Material. parameter of the OSCORE_Input_Material.
The same parameters MUST be included in the claims associated with The same parameters MUST be included in the claims associated with
the access token. The OSCORE master secret MUST be encrypted by the the access token. The OSCORE Master Secret MUST be encrypted by the
authorization server so that only the resource server can decrypt it authorization server so that only the resource server can decrypt it
(see Section 6.1. of [I-D.ietf-ace-oauth-authz]). This profile (see Section 6.1 of [RFC9200]). The use of a CBOR Web Token (CWT)
RECOMMENDS the use of a CBOR web token (CWT) protected with protected with COSE_Encrypt/COSE_Encrypt0 as specified in [RFC8392]
COSE_Encrypt/COSE_Encrypt0 as specified in [RFC8392]. If the token is RECOMMENDED in this profile. If the token is a CWT, the same
is a CWT, the same OSCORE_Input_Material structure defined above MUST OSCORE_Input_Material structure defined above MUST be placed in the
be placed in the "osc" field of the "cnf" claim of this token. osc field of the cnf claim of this token.
The AS MUST send different OSCORE_Input_Material (and therefore The AS MUST send a different OSCORE_Input_Material (and therefore
different access tokens) to different authorized clients, in order different access tokens) to different authorized clients, in order
for the RS to differentiate between clients. for the RS to differentiate between clients.
Figure 4 shows an example of an AS response. The access token has Figure 4 shows an example of an AS response. The access token has
been truncated for readability. been truncated for readability.
Header: Created (Code=2.01) Header: Created (Code=2.01)
Content-Type: "application/ace+cbor" Content-Type: "application/ace+cbor"
Payload: Payload:
{ {
skipping to change at page 11, line 21 skipping to change at line 439
"ace_profile" : "coap_oscore", "ace_profile" : "coap_oscore",
"expires_in" : "3600", "expires_in" : "3600",
"cnf" : { "cnf" : {
"osc" : { "osc" : {
"id" : h'01', "id" : h'01',
"ms" : h'f9af838368e353e78888e1426bd94e6f' "ms" : h'f9af838368e353e78888e1426bd94e6f'
} }
} }
} }
Figure 4: Example AS-to-C Access Token response with OSCORE profile. Figure 4: Example AS-to-C Access Token Response with an OSCORE
Profile
Figure 5 shows an example CWT Claims Set, including the relevant Figure 5 shows an example CWT Claims Set, including the relevant
OSCORE parameters in the "cnf" claim. OSCORE parameters in the cnf claim.
{ {
"aud" : "tempSensorInLivingRoom", "aud" : "tempSensorInLivingRoom",
"iat" : "1360189224", "iat" : "1360189224",
"exp" : "1360289224", "exp" : "1360289224",
"scope" : "temperature_g firmware_p", "scope" : "temperature_g firmware_p",
"cnf" : { "cnf" : {
"osc" : { "osc" : {
"ms" : h'f9af838368e353e78888e1426bd94e6f', "ms" : h'f9af838368e353e78888e1426bd94e6f',
"id" : h'01' "id" : h'01'
} }
} }
} }
Figure 5: Example CWT Claims Set with OSCORE parameters. Figure 5: Example CWT Claims Set with OSCORE Parameters
The same CWT Claims Set as in Figure 5, using the value abbreviations The same CWT Claims Set as in Figure 5, using the value abbreviations
defined in [I-D.ietf-ace-oauth-authz] and [RFC8747] and encoded in defined in [RFC9200] and [RFC8747] and encoded in CBOR, is shown in
CBOR is shown in Figure 6. The bytes in hexadecimal are reported in Figure 6. The bytes in hexadecimal are reported in the first column,
the first column, while their corresponding CBOR meaning is reported while their corresponding CBOR meaning is reported after the # sign
after the "#" sign on the second column, for easiness of readability. on the second column, for readability.
NOTE TO THE RFC EDITOR: before publishing, it should be checked (and
in case fixed) that the values used below (which are not yet
registered) are the final values registered in IANA.
A5 # map(5) A5 # map(5)
63 # text(3) 63 # text(3)
617564 # "aud" 617564 # "aud"
76 # text(22) 76 # text(22)
74656D7053656E736F72496E4C6976696E67526F6F6D 74656D7053656E736F72496E4C6976696E67526F6F6D
# "tempSensorInLivingRoom" # "tempSensorInLivingRoom"
63 # text(3) 63 # text(3)
696174 # "iat" 696174 # "iat"
6A # text(10) 6A # text(10)
skipping to change at page 12, line 41 skipping to change at line 502
6D73 # "ms" 6D73 # "ms"
50 # bytes(16) 50 # bytes(16)
F9AF838368E353E78888E1426BD94E6F F9AF838368E353E78888E1426BD94E6F
# "\xF9\xAF\x83\x83h\xE3S\xE7 # "\xF9\xAF\x83\x83h\xE3S\xE7
\x88\x88\xE1Bk\xD9No" \x88\x88\xE1Bk\xD9No"
62 # text(2) 62 # text(2)
6964 # "id" 6964 # "id"
41 # bytes(1) 41 # bytes(1)
01 # "\x01" 01 # "\x01"
Figure 6: Example CWT Claims Set with OSCORE parameters, CBOR Figure 6: Example CWT Claims Set with OSCORE Parameters Using
encoded. CBOR Encoding
If the client has requested an update to its access rights using the If the client has requested an update to its access rights using the
same OSCORE Security Context, which is valid and authorized, the AS same OSCORE Security Context, which is valid and authorized, the AS
MUST omit the "cnf" parameter in the response, and MUST carry the MUST omit the cnf parameter in the response and MUST carry the OSCORE
OSCORE Input Material identifier in the "kid" field in the "cnf" Input Material identifier in the kid field in the cnf claim of the
claim of the token. This identifier needs to be included in the token. This identifier needs to be included in the token in order
token in order for the RS to identify the correct OSCORE Input for the RS to identify the correct OSCORE Input Material.
Material.
Figure 7 shows an example of such an AS response The access token has Figure 7 shows an example of such an AS response. The access token
been truncated for readability. has been truncated for readability.
Header: Created (Code=2.01) Header: Created (Code=2.01)
Content-Type: "application/ace+cbor" Content-Type: "application/ace+cbor"
Payload: Payload:
{ {
"access_token" : h'8343a1010aa2044c53 ... "access_token" : h'8343a1010aa2044c53 ...
(remainder of access token (CWT) omitted for brevity)', (remainder of access token (CWT) omitted for brevity)',
"ace_profile" : "coap_oscore", "ace_profile" : "coap_oscore",
"expires_in" : "3600" "expires_in" : "3600"
} }
Figure 7: Example AS-to-C Access Token response with OSCORE Figure 7: Example AS-to-C Access Token Response with an OSCORE
profile, for update of access rights. Profile for the Update of Access Rights
Figure 8 shows an example CWT Claims Set, containing the necessary Figure 8 shows an example CWT Claims Set that contains the necessary
OSCORE parameters in the "cnf" claim for update of access rights. OSCORE parameters in the cnf claim for the update of access rights.
{ {
"aud" : "tempSensorInLivingRoom", "aud" : "tempSensorInLivingRoom",
"iat" : "1360189224", "iat" : "1360189224",
"exp" : "1360289224", "exp" : "1360289224",
"scope" : "temperature_h", "scope" : "temperature_h",
"cnf" : { "cnf" : {
"kid" : h'01' "kid" : h'01'
} }
} }
Figure 8: Example CWT Claims Set with OSCORE parameters for Figure 8: Example CWT Claims Set with OSCORE Parameters for the
update of access rights. Update of Access Rights
3.2.1. The OSCORE_Input_Material 3.2.1. The OSCORE_Input_Material
An OSCORE_Input_Material is an object that represents the input An OSCORE_Input_Material is an object that represents the input
material to derive an OSCORE Security Context, i.e., the local set of material to derive an OSCORE Security Context, i.e., the local set of
information elements necessary to carry out the cryptographic information elements necessary to carry out the cryptographic
operations in OSCORE (Section 3.1 of [RFC8613]). In particular, the operations in OSCORE (Section 3.1 of [RFC8613]). In particular, the
OSCORE_Input_Material is defined to be serialized and transported OSCORE_Input_Material is defined to be serialized and transported
between nodes, as specified by this document, but can also be used by between nodes, as specified by this document, but it can also be used
other specifications if needed. The OSCORE_Input_Material can either by other specifications if needed. The OSCORE_Input_Material can be
be encoded as a JSON object or as a CBOR map. The set of common encoded as either a JSON object or a CBOR map. The set of common
parameters that can appear in an OSCORE_Input_Material can be found parameters that can appear in an OSCORE_Input_Material can be found
in the IANA "OSCORE Security Context Parameters" registry in the IANA "OSCORE Security Context Parameters" registry
(Section 9.4), defined for extensibility, and the initial set of (Section 9.4), defined for extensibility, and the initial set of
parameters defined in this document is specified below. All parameters defined in this document is specified below. All
parameters are optional. Table 1 provides a summary of the parameters are optional. Table 1 provides a summary of the
OSCORE_Input_Material parameters defined in this section. OSCORE_Input_Material parameters defined in this section.
+===========+=======+==========+===================+===============+ +===========+=======+==========+===================+===============+
| name | CBOR | CBOR | registry | description | | name | CBOR | CBOR | registry | description |
| | label | type | | | | | label | type | | |
+===========+=======+==========+===================+===============+ +===========+=======+==========+===================+===============+
| id | 0 | byte | | OSCORE Input | | id | 0 | byte | | OSCORE Input |
| | | string | | Material | | | | string | | Material |
| | | | | Identifier | | | | | | identifier |
+-----------+-------+----------+-------------------+---------------+ +-----------+-------+----------+-------------------+---------------+
| version | 1 | unsigned | | OSCORE | | version | 1 | unsigned | | OSCORE |
| | | integer | | Version | | | | integer | | version |
+-----------+-------+----------+-------------------+---------------+ +-----------+-------+----------+-------------------+---------------+
| ms | 2 | byte | | OSCORE Master | | ms | 2 | byte | | OSCORE Master |
| | | string | | Secret value | | | | string | | Secret value |
+-----------+-------+----------+-------------------+---------------+ +-----------+-------+----------+-------------------+---------------+
| hkdf | 3 | text | [COSE.Algorithms] | OSCORE HKDF | | hkdf | 3 | text | [COSE.Algorithms] | OSCORE HKDF |
| | | string / | Values (HMAC- | value | | | | string / | values (HMAC- | value |
| | | integer | based) | | | | | integer | based) | |
+-----------+-------+----------+-------------------+---------------+ +-----------+-------+----------+-------------------+---------------+
| alg | 4 | text | [COSE.Algorithms] | OSCORE AEAD | | alg | 4 | text | [COSE.Algorithms] | OSCORE AEAD |
| | | string / | Values (AEAD) | Algorithm | | | | string / | values (AEAD) | Algorithm |
| | | integer | | value | | | | integer | | value |
+-----------+-------+----------+-------------------+---------------+ +-----------+-------+----------+-------------------+---------------+
| salt | 5 | byte | | an input to | | salt | 5 | byte | | an input to |
| | | string | | OSCORE Master | | | | string | | OSCORE Master |
| | | | | Salt value | | | | | | Salt value |
+-----------+-------+----------+-------------------+---------------+ +-----------+-------+----------+-------------------+---------------+
| contextId | 6 | byte | | OSCORE ID | | contextId | 6 | byte | | OSCORE ID |
| | | string | | Context value | | | | string | | Context value |
+-----------+-------+----------+-------------------+---------------+ +-----------+-------+----------+-------------------+---------------+
Table 1: OSCORE_Input_Material Parameters Table 1: OSCORE_Input_Material Parameters
id: This parameter identifies the OSCORE_Input_Material and is id: This parameter identifies the OSCORE_Input_Material and is
encoded as a byte string. In JSON, the "id" value is a Base64 encoded as a byte string. In JSON, the "id" value is a
encoded byte string. In CBOR, the "id" type is byte string, and base64-encoded byte string. In CBOR, the "id" type is a byte
has label 0. string, and it has label 0.
version: This parameter identifies the OSCORE Version number, which version: This parameter identifies the OSCORE version number, which
is an unsigned integer. For more information about this field, is an unsigned integer. For more information about this field,
see section 5.4 of [RFC8613]. In JSON, the "version" value is an see Section 5.4 of [RFC8613]. In JSON, the "version" value is an
integer. In CBOR, the "version" type is integer, and has label 1. integer. In CBOR, the "version" type is an integer, and it has
label 1.
ms: This parameter identifies the OSCORE Master Secret value, which ms: This parameter identifies the OSCORE Master Secret value, which
is a byte string. For more information about this field, see is a byte string. For more information about this field, see
section 3.1 of [RFC8613]. In JSON, the "ms" value is a Base64 Section 3.1 of [RFC8613]. In JSON, the "ms" value is a
encoded byte string. In CBOR, the "ms" type is byte string, and base64-encoded byte string. In CBOR, the "ms" type is byte
has label 2. string, and it has label 2.
hkdf: This parameter identifies the OSCORE HKDF Algorithm. For more hkdf: This parameter identifies the OSCORE HKDF Algorithm. For more
information about this field, see section 3.1 of [RFC8613]. The information about this field, see Section 3.1 of [RFC8613]. The
values used MUST be registered in the IANA "COSE Algorithms" values used MUST be registered in the IANA "COSE Algorithms"
registry (see [COSE.Algorithms]) and MUST be HMAC-based HKDF registry (see [COSE.Algorithms]) and MUST be HMAC-based HKDF
algorithms (see section 3.1 of [I-D.ietf-cose-rfc8152bis-algs]). algorithms (see Section 3.1 of [RFC9053]). The value can be
The value can either be the integer or the text string value of either the integer or the text-string value of the HMAC-based HKDF
the HMAC-based HKDF algorithm in the "COSE Algorithms" registry. algorithm in the "COSE Algorithms" registry. In JSON, the "hkdf"
In JSON, the "hkdf" value is a case-sensitive ASCII string or an value is a case-sensitive ASCII string or an integer. In CBOR,
integer. In CBOR, the "hkdf" type is text string or integer, and the "hkdf" type is a text string or integer, and it has label 3.
has label 3.
alg: This parameter identifies the OSCORE AEAD Algorithm. For more alg: This parameter identifies the OSCORE AEAD Algorithm. For more
information about this field, see section 3.1 of [RFC8613] The information about this field, see Section 3.1 of [RFC8613]. The
values used MUST be registered in the IANA "COSE Algorithms" values used MUST be registered in the IANA "COSE Algorithms"
registry (see [COSE.Algorithms]) and MUST be AEAD algorithms. The registry (see [COSE.Algorithms]) and MUST be AEAD algorithms. The
value can either be the integer or the text string value of the value can be either the integer or the text-string value of the
HMAC-based HKDF algorithm in the "COSE Algorithms" registry. In HMAC-based HKDF algorithm in the "COSE Algorithms" registry. In
JSON, the "alg" value is a case-sensitive ASCII string or an JSON, the "alg" value is a case-sensitive ASCII string or an
integer. In CBOR, the "alg" type is text string or integer, and integer. In CBOR, the "alg" type is a text string or integer, and
has label 4. it has label 4.
salt: This parameter identifies an input to the OSCORE Master Salt salt: This parameter identifies an input to the OSCORE Master Salt
value, which is a byte string. For more information about this value, which is a byte string. For more information about this
field, see section 3.1 of [RFC8613]. In JSON, the "salt" value is field, see Section 3.1 of [RFC8613]. In JSON, the "salt" value is
a Base64 encoded byte string. In CBOR, the "salt" type is byte a base64-encoded byte string. In CBOR, the "salt" type is a byte
string, and has label 5. string, and it has label 5.
contextId: This parameter identifies the security context as a byte contextId: This parameter identifies the security context as a byte
string. This identifier is used as OSCORE ID Context. For more string. This identifier is used as OSCORE ID Context. For more
information about this field, see section 3.1 of [RFC8613]. In information about this field, see Section 3.1 of [RFC8613]. In
JSON, the "contextID" value is a Base64 encoded byte string. In JSON, the "contextID" value is a base64-encoded byte string. In
CBOR, the "contextID" type is byte string, and has label 6. CBOR, the "contextID" type is a byte string, and it has label 6.
An example of JSON OSCORE_Input_Material is given in Figure 9. An example of JSON OSCORE_Input_Material is given in Figure 9.
"osc" : { "osc" : {
"alg" : "AES-CCM-16-64-128", "alg" : "AES-CCM-16-64-128",
"id" : b64'AQ==' "id" : b64'AQ=='
"ms" : b64'+a+Dg2jjU+eIiOFCa9lObw' "ms" : b64'+a+Dg2jjU+eIiOFCa9lObw'
} }
Figure 9: Example JSON OSCORE_Input_Material Figure 9: Example JSON OSCORE_Input_Material
skipping to change at page 16, line 21 skipping to change at line 668
? 3 => tstr / int, ; hkdf ? 3 => tstr / int, ; hkdf
? 4 => tstr / int, ; alg ? 4 => tstr / int, ; alg
? 5 => bstr, ; salt ? 5 => bstr, ; salt
? 6 => bstr, ; contextId ? 6 => bstr, ; contextId
* int / tstr => any * int / tstr => any
} }
4. Client-RS Communication 4. Client-RS Communication
The following subsections describe the details of the POST request The following subsections describe the details of the POST request
and response to the authz-info endpoint between client and RS. The and response to the authz-info endpoint between the client and RS.
client generates a nonce N1 and an identifier ID1 unique in the sets The client generates a nonce N1 and an identifier ID1 that is unique
of its own Recipient IDs, and posts them together with the token that in the sets of its own Recipient IDs and posts them together with the
includes the materials (e.g., OSCORE parameters) received from the AS token that includes the materials (e.g., OSCORE parameters) received
to the RS. The RS then generates a nonce N2 and an identifier ID2 from the AS to the RS. The RS then generates a nonce N2 and an
unique in the sets of its own Recipient IDs, and uses Section 3.2 of identifier ID2 that is unique in the sets of its own Recipient IDs
[RFC8613] to derive a security context based on a shared master and uses Section 3.2 of [RFC8613] to derive a security context based
secret, the two exchanged nonces and the two identifiers, established on a shared Master Secret, the two exchanged nonces, and the two
between client and server. The exchanged nonces and identifiers are identifiers, established between the client and server. The
encoded as CBOR byte string if CBOR is used, and as Base64 string if exchanged nonces and identifiers are encoded as a CBOR byte string if
JSON is used. This security context is used to protect all future CBOR is used and as a base64 string if JSON is used. This security
communication between client and RS using OSCORE, as long as the context is used to protect all future communication between the
access token is valid. client and RS using OSCORE, as long as the access token is valid.
Note that the RS and client authenticate each other by generating the Note that the RS and client authenticate each other by generating the
shared OSCORE Security Context using the pop-key as master secret. shared OSCORE Security Context using the PoP key as the Master
An attacker posting a valid token to the RS will not be able to Secret. An attacker posting a valid token to the RS will not be able
generate a valid OSCORE Security Context and thus not be able to to generate a valid OSCORE Security Context and thus will not be able
prove possession of the pop-key. Additionally, the mutual to prove possession of the PoP key. Additionally, the mutual
authentication is only achieved after the client has successfully authentication is only achieved after the client has successfully
verified a response from the RS protected with the generated OSCORE verified a response from the RS protected with the generated OSCORE
Security Context. Security Context.
4.1. C-to-RS: POST to authz-info endpoint 4.1. C-to-RS: POST to authz-info Endpoint
The client MUST generate a nonce value N1 very unlikely to have been The client MUST generate a nonce value N1 that is very unlikely to
previously used with the same input keying material. This profile have been previously used with the same input keying material. The
RECOMMENDS using a 64-bit long random number as the nonce's value. use of a 64-bit long random number as the nonce's value is
The client MUST store the nonce N1 as long as the response from the RECOMMENDED in this profile. The client MUST store the nonce N1 as
RS is not received and the access token related to it is still valid long as the response from the RS is not received and the access token
(to the best of the client's knowledge). related to it is still valid (to the best of the client's knowledge).
The client generates its own Recipient ID, ID1, for the OSCORE The client generates its own Recipient ID, ID1, for the OSCORE
Security Context that it is establishing with the RS. By generating Security Context that it is establishing with the RS. By generating
its own Recipient ID, the client makes sure that it does not collide its own Recipient ID, the client makes sure that it does not collide
with any of its Recipient IDs, nor with any other identifier ID1 if with any of its Recipient IDs, nor with any other identifier ID1 if
the client is executing this exchange with a different RS at the same the client is executing this exchange with a different RS at the same
time. time.
The client MUST use CoAP and the Authorization Information resource The client MUST use CoAP and the authorization information resource
as described in section 5.8.1 of [I-D.ietf-ace-oauth-authz] to as described in Section 5.8.1 of [RFC9200] to transport the token,
transport the token, N1 and ID1 to the RS. N1, and ID1 to the RS.
Note that the use of the payload and the Content-Format is different Note that the use of the payload and the Content-Format is different
from what is described in section 5.8.1 of from what is described in Section 5.8.1 of [RFC9200], which only
[I-D.ietf-ace-oauth-authz], which only transports the token without transports the token without any CBOR wrapping. In this profile, the
any CBOR wrapping. In this profile, the client MUST wrap the token, client MUST wrap the token, N1, and ID1 in a CBOR map. The client
N1 and ID1 in a CBOR map. The client MUST use the Content-Format MUST use the Content-Format "application/ace+cbor" defined in
"application/ace+cbor" defined in section 8.14 of Section 8.14 of [RFC9200]. The client MUST include the access token
[I-D.ietf-ace-oauth-authz]. The client MUST include the access token using the access_token parameter; N1 using the nonce1 parameter
using the "access_token" parameter, N1 using the "nonce1" parameter defined in Section 4.1.1; and ID1 using the ace_client_recipientid
defined in Section 4.1.1, and ID1 using the "ace_client_recipientid"
parameter defined in Section 4.1.2. parameter defined in Section 4.1.2.
The communication with the authz-info endpoint does not have to be The communication with the authz-info endpoint does not have to be
protected, except for the update of access rights case described protected, except for the update of access rights case described
below. below.
Note that a client may be required to re-POST the access token in Note that a client may be required to re-POST the access token in
order to complete a request, since an RS may delete a stored access order to complete a request, since an RS may delete a stored access
token (and associated Security Context) at any time, for example due token (and associated Security Context) at any time, for example, due
to all storage space being consumed. This situation is detected by to all storage space being consumed. This situation is detected by
the client when it receives an AS Request Creation Hints response. the client when it receives an AS Request Creation Hints response.
Reposting the same access token will result in deriving a new OSCORE Reposting the same access token will result in deriving a new OSCORE
Security Context to be used with the RS, as different exchanged Security Context to be used with the RS, as different exchanged
nonces will be used. nonces will be used.
The client may also choose to re-POST the access token in order to The client may also choose to re-POST the access token in order to
update its OSCORE Security Context. In that case, the client and the update its OSCORE Security Context. In that case, the client and the
RS will exchange newly generated nonces, re-negotiate identifiers, RS will exchange newly generated nonces, renegotiate identifiers, and
and derive new keying material. The client and RS might decide to derive new keying material. The client and RS might decide to keep
keep the same identifiers or renew them during the re-negotiation. the same identifiers or renew them during the renegotiation.
Figure 10 shows an example of the request sent from the client to the Figure 10 shows an example of the request sent from the client to the
RS. The access token has been truncated for readability. RS. The access token has been truncated for readability.
Header: POST (Code=0.02) Header: POST (Code=0.02)
Uri-Host: "rs.example.com" Uri-Host: "rs.example.com"
Uri-Path: "authz-info" Uri-Path: "authz-info"
Content-Format: "application/ace+cbor" Content-Format: "application/ace+cbor"
Payload: Payload:
{ {
"access_token": h'8343a1010aa2044c53 ... "access_token": h'8343a1010aa2044c53 ...
(remainder of access token (CWT) omitted for brevity)', (remainder of access token (CWT) omitted for brevity)',
"nonce1": h'018a278f7faab55a', "nonce1": h'018a278f7faab55a',
"ace_client_recipientid" : h'1645' "ace_client_recipientid" : h'1645'
} }
Figure 10: Example C-to-RS POST /authz-info request using CWT Figure 10: Example C-to-RS POST /authz-info Request Using CWT
If the client has already posted a valid token, has already If the client has already posted a valid token, has already
established a security association with the RS, and wants to update established a security association with the RS, and wants to update
its access rights, the client can do so by posting the new token its access rights, the client can do so by posting the new token
(retrieved from the AS and containing the update of access rights) to (retrieved from the AS and containing the update of access rights) to
the /authz-info endpoint. The client MUST protect the request using the /authz-info endpoint. The client MUST protect the request using
the OSCORE Security Context established during the first token the OSCORE Security Context established during the first token
exchange. The client MUST only send the "access_token" field in the exchange. The client MUST only send the access_token field in the
CBOR map in the payload, no nonce or identifier are sent. After CBOR map in the payload; no nonce or identifier is sent. After
proper verification (see Section 4.2), the RS will replace the old proper verification (see Section 4.2), the RS will replace the old
token with the new one, maintaining the same Security Context. token with the new one, maintaining the same Security Context.
4.1.1. The Nonce 1 Parameter 4.1.1. The Nonce 1 Parameter
This parameter MUST be sent from the client to the RS, together with The nonce 1 parameter MUST be sent from the client to the RS,
the access token, if the ace profile used is coap_oscore, and the together with the access token, if the ACE profile used is
message is not an update of access rights, protected with an existing "coap_oscore", and the message is not an update of access rights,
OSCORE Security Context. The parameter is encoded as a byte string protected with an existing OSCORE Security Context. The parameter is
for CBOR-based interactions, and as a string (Base64 encoded binary) encoded as a byte string for CBOR-based interactions and as a string
for JSON-based interactions. This parameter is registered in (base64-encoded binary) for JSON-based interactions. This parameter
Section 9.2. is registered in Section 9.2.
4.1.2. The ace_client_recipientid Parameter 4.1.2. The ace_client_recipientid Parameter
This parameter MUST be sent from the client to the RS, together with The ace_client_recipientid parameter MUST be sent from the client to
the access token, if the ace profile used is coap_oscore, and the the RS, together with the access token, if the ACE profile used is
message is not an update of access rights, protected with an existing "coap_oscore", and the message is not an update of access rights,
OSCORE Security Context. The parameter is encoded as a byte string protected with an existing OSCORE Security Context. The parameter is
for CBOR-based interactions, and as a string (Base64 encoded binary) encoded as a byte string for CBOR-based interactions and as a string
for JSON-based interactions. This parameter is registered in (base64-encoded binary) for JSON-based interactions. This parameter
Section 9.2. is registered in Section 9.2.
4.2. RS-to-C: 2.01 (Created) 4.2. RS-to-C: 2.01 (Created)
The RS MUST follow the procedures defined in section 5.8.1 of The RS MUST follow the procedures defined in Section 5.8.1 of
[I-D.ietf-ace-oauth-authz]: the RS must verify the validity of the [RFC9200]: the RS must verify the validity of the token. If the
token. If the token is valid, the RS must respond to the POST token is valid, the RS must respond to the POST request with 2.01
request with 2.01 (Created). If the token is valid but is associated (Created). If the token is valid but is associated to claims that
to claims that the RS cannot process (e.g., an unknown scope), or if the RS cannot process (e.g., an unknown scope), or if any of the
any of the expected parameters is missing (e.g., any of the mandatory expected parameters are missing (e.g., any of the mandatory
parameters from the AS or the identifier "id1"), or if any parameters parameters from the AS or the identifier ID1), or if any parameters
received in the "osc" field is unrecognized, the RS must respond with received in the osc field are unrecognized, the RS must respond with
an error response code equivalent to the CoAP code 4.00 (Bad an error response code equivalent to the CoAP code 4.00 (Bad
Request). In the latter two cases, the RS may provide additional Request). In the latter two cases, the RS may provide additional
information in the error response, in order to clarify what went information in the error response, in order to clarify what went
wrong. The RS may make an introspection request (see Section 5.9.1 wrong. The RS may make an introspection request (see Section 5.9.1
of [I-D.ietf-ace-oauth-authz]) to validate the token before of [RFC9200]) to validate the token before responding to the POST
responding to the POST request to the authz-info endpoint. request to the authz-info endpoint.
Additionally, the RS MUST generate a nonce N2 very unlikely to have Additionally, the RS MUST generate a nonce N2 that is very unlikely
been previously used with the same input keying material, and its own to have been previously used with the same input keying material and
Recipient ID, ID2. The RS makes sure that ID2 does not collide with its own Recipient ID, ID2. The RS makes sure that ID2 does not
any of its Recipient IDs. The RS MUST ensure that ID2 is different collide with any of its Recipient IDs. The RS MUST ensure that ID2
from the value received in the ace_client_recipientid parameter. The is different from the value received in the ace_client_recipientid
RS sends N2 and ID2 within the 2.01 (Created) response. The payload parameter. The RS sends N2 and ID2 within the 2.01 (Created)
of the 2.01 (Created) response MUST be a CBOR map containing the response. The payload of the 2.01 (Created) response MUST be a CBOR
"nonce2" parameter defined in Section 4.2.1, set to N2, and the map containing the nonce2 parameter defined in Section 4.2.1, set to
"ace_server_recipientid" parameter defined in Section 4.2.2, set to N2, and the ace_server_recipientid parameter defined in
ID2. This profile RECOMMENDS using a 64-bit long random number as Section 4.2.2, set to ID2. The use of a 64-bit long random number as
the nonce's value. The RS MUST use the Content-Format "application/ the nonce's value is RECOMMENDED in this profile. The RS MUST use
ace+cbor" defined in section 8.14 of [I-D.ietf-ace-oauth-authz]. the Content-Format "application/ace+cbor" defined in Section 8.14 of
[RFC9200].
Figure 11 shows an example of the response sent from the RS to the Figure 11 shows an example of the response sent from the RS to the
client. client.
Header: Created (Code=2.01) Header: Created (Code=2.01)
Content-Format: "application/ace+cbor" Content-Format: "application/ace+cbor"
Payload: Payload:
{ {
"nonce2": h'25a8991cd700ac01', "nonce2": h'25a8991cd700ac01',
"ace_server_recipientid" : h'0000' "ace_server_recipientid" : h'0000'
} }
Figure 11: Example RS-to-C 2.01 (Created) response Figure 11: Example RS-to-C 2.01 (Created) Response
As specified in section 5.8.3 of [I-D.ietf-ace-oauth-authz], the RS As specified in Section 5.8.3 of [RFC9200], the RS must notify the
must notify the client with an error response with code 4.01 client with an error response with code 4.01 (Unauthorized) for any
(Unauthorized) for any long running request before terminating the long running request before terminating the session, when the access
session, when the access token expires. token expires.
If the RS receives the token in a OSCORE protected message, it means If the RS receives the token in an OSCORE-protected message, it means
that the client is requesting an update of access rights. The RS that the client is requesting an update of access rights. The RS
MUST ignore any nonce and identifiers in the request, if any was MUST ignore any nonce and identifiers in the request, if any were
sent. The RS MUST check that the "kid" of the "cnf" claim of the new sent. The RS MUST check that the "kid" of the cnf claim of the new
access token matches the identifier of the OSCORE Input Material of access token matches the identifier of the OSCORE Input Material of
the context used to protect the message. If that is the case, the RS the context used to protect the message. If that is the case, the RS
MUST overwrite the old token and associate the new token to the MUST overwrite the old token and associate the new token to the
Security Context identified by the "kid" value in the "cnf" claim. Security Context identified by the "kid" value in the cnf claim. The
The RS MUST respond with a 2.01 (Created) response protected with the RS MUST respond with a 2.01 (Created) response protected with the
same Security Context, with no payload. If any verification fails, same Security Context, with no payload. If any verification fails,
the RS MUST respond with a 4.01 (Unauthorized) error response. the RS MUST respond with a 4.01 (Unauthorized) error response.
As specified in section 5.8.1 of [I-D.ietf-ace-oauth-authz], when As specified in Section 5.8.1 of [RFC9200], when receiving an updated
receiving an updated access token with updated authorization access token with updated authorization information from the client
information from the client (see Section 3.1), it is recommended that (see Section 3.1), it is recommended that the RS overwrites the
the RS overwrites the previous token, that is only the latest previous token; that is, only the latest authorization information in
authorization information in the token received by the RS is valid. the token received by the RS is valid. This simplifies the process
This simplifies the process needed by the RS to keep track of needed by the RS to keep track of authorization information for a
authorization information for a given client. given client.
4.2.1. The Nonce 2 Parameter 4.2.1. The Nonce 2 Parameter
This parameter MUST be sent from the RS to the client if the ace The nonce 2 parameter MUST be sent from the RS to the client if the
profile used is coap_oscore, and the message is not a response to an ACE profile used is "coap_oscore" and the message is not a response
update of access rights, protected with an existing OSCORE Security to an update of access rights, protected with an existing OSCORE
Context. The parameter is encoded as a byte string for CBOR-based Security Context. The parameter is encoded as a byte string for
interactions, and as a string (Base64 encoded binary) for JSON-based CBOR-based interactions and as a string (base64-encoded binary) for
interactions. This parameter is registered in Section 9.2 JSON-based interactions. This parameter is registered in Section 9.2
4.2.2. The ace_server_recipientid Parameter 4.2.2. The ace_server_recipientid Parameter
This parameter MUST be sent from the RS to the client if the ace The ace_server_recipientid parameter MUST be sent from the RS to the
profile used is coap_oscore, and the message is not a response to an client if the ACE profile used is "coap_oscore" and the message is
update of access rights, protected with an existing OSCORE Security not a response to an update of access rights, protected with an
Context. The parameter is encoded as a byte string for CBOR-based existing OSCORE Security Context. The parameter is encoded as a byte
interactions, and as a string (Base64 encoded binary) for JSON-based string for CBOR-based interactions and as a string (base64-encoded
interactions. This parameter is registered in Section 9.2 binary) for JSON-based interactions. This parameter is registered in
Section 9.2
4.3. OSCORE Setup 4.3. OSCORE Setup
Once the 2.01 (Created) response is received from the RS, following Once the 2.01 (Created) response is received from the RS, following
the POST request to authz-info endpoint, the client MUST extract the the POST request to authz-info endpoint, the client MUST extract the
bstr nonce N2 from the "nonce2" parameter in the CBOR map in the bstr nonce N2 from the nonce2 parameter in the CBOR map in the
payload of the response. Then, the client MUST set the Master Salt payload of the response. Then, the client MUST set the Master Salt
of the Security Context created to communicate with the RS to the of the Security Context created to communicate with the RS to the
concatenation of salt, N1, and N2, in this order: Master Salt = concatenation of salt, N1, and N2 in this order: Master Salt = salt |
salt | N1 | N2, where | denotes byte string concatenation, where salt N1 | N2, where | denotes byte string concatenation, salt is the CBOR
is the CBOR byte string received from the AS in Section 3.2, and byte string received from the AS in Section 3.2, and N1 and N2 are
where N1 and N2 are the two nonces encoded as CBOR byte strings. An the two nonces encoded as CBOR byte strings. An example of Master
example of Master Salt construction using CBOR encoding is given in Salt construction using CBOR encoding is given in Figure 12.
Figure 12.
N1, N2 and input salt expressed in CBOR diagnostic notation: N1, N2 and input salt expressed in CBOR diagnostic notation:
nonce1 = h'018a278f7faab55a' nonce1 = h'018a278f7faab55a'
nonce2 = h'25a8991cd700ac01' nonce2 = h'25a8991cd700ac01'
input salt = h'f9af838368e353e78888e1426bd94e6f' input salt = h'f9af838368e353e78888e1426bd94e6f'
N1, N2 and input salt as CBOR encoded byte strings: N1, N2 and input salt as CBOR encoded byte strings:
nonce1 = 0x48018a278f7faab55a nonce1 = 0x48018a278f7faab55a
nonce2 = 0x4825a8991cd700ac01 nonce2 = 0x4825a8991cd700ac01
input salt = 0x50f9af838368e353e78888e1426bd94e6f input salt = 0x50f9af838368e353e78888e1426bd94e6f
Master Salt = 0x50 f9af838368e353e78888e1426bd94e6f Master Salt = 0x50 f9af838368e353e78888e1426bd94e6f
48 018a278f7faab55a 48 25a8991cd700ac01 48 018a278f7faab55a 48 25a8991cd700ac01
Figure 12: Example of Master Salt construction using CBOR encoding Figure 12: Example of Master Salt Construction Using CBOR Encoding
If JSON is used instead of CBOR, the Master Salt of the Security If JSON is used instead of CBOR, the Master Salt of the Security
Context is the Base64 encoding of the concatenation of the same Context is the base64 encoding of the concatenation of the same
parameters, each of them prefixed by their size, encoded in 1 byte. parameters, each of them prefixed by their size, encoded in 1 byte.
When using JSON, the nonces and input salt have a maximum size of 255 When using JSON, the nonces and input salt have a maximum size of 255
bytes. An example of Master Salt construction using Base64 encoding bytes. An example of Master Salt construction using base64 encoding
is given in Figure 13. is given in Figure 13.
N1, N2 and input salt values: N1, N2 and input salt values:
nonce1 = 0x018a278f7faab55a (8 bytes) nonce1 = 0x018a278f7faab55a (8 bytes)
nonce2 = 0x25a8991cd700ac01 (8 bytes) nonce2 = 0x25a8991cd700ac01 (8 bytes)
input salt = 0xf9af838368e353e78888e1426bd94e6f (16 bytes) input salt = 0xf9af838368e353e78888e1426bd94e6f (16 bytes)
Input to Base64 encoding: 0x10 f9af838368e353e78888e1426bd94e6f Input to Base64 encoding: 0x10 f9af838368e353e78888e1426bd94e6f
08 018a278f7faab55a 08 25a8991cd700ac01 08 018a278f7faab55a 08 25a8991cd700ac01
Master Salt = b64'EPmvg4No41PniIjhQmvZTm8IAYonj3+qtVoIJaiZHNcArAE=' Master Salt = b64'EPmvg4No41PniIjhQmvZTm8IAYonj3+qtVoIJaiZHNcArAE='
Figure 13: Example of Master Salt construction using Base64 encoding Figure 13: Example of Master Salt Construction Using Base64 Encoding
The client MUST set the Sender ID to the ace_server_recipientid The client MUST set the Sender ID to the ace_server_recipientid
received in Section 4.2, and the Recipient ID to the received in Section 4.2 and set the Recipient ID to the
ace_client_recipientid sent in Section 4.1. The client MUST set the ace_client_recipientid sent in Section 4.1. The client MUST set the
Master Secret from the parameter received from the AS in Section 3.2. Master Secret from the parameter received from the AS in Section 3.2.
The client MUST set the AEAD Algorithm, ID Context, HKDF, and OSCORE The client MUST set the AEAD algorithm, ID Context, HKDF, and OSCORE
Version from the parameters received from the AS in Section 3.2, if version from the parameters received from the AS in Section 3.2, if
present. In case an optional parameter is omitted, the default value present. In case an optional parameter is omitted, the default value
SHALL be used as described in sections 3.2 and 5.4 of [RFC8613]. SHALL be used as described in Sections 3.2 and 5.4 of [RFC8613].
After that, the client MUST derive the complete Security Context After that, the client MUST derive the complete Security Context
following section 3.2.1 of [RFC8613]. From this point on, the client following Section 3.2.1 of [RFC8613]. From this point on, the client
MUST use this Security Context to communicate with the RS when MUST use this Security Context to communicate with the RS when
accessing the resources as specified by the authorization accessing the resources as specified by the authorization
information. information.
If any of the expected parameters is missing (e.g., any of the If any of the expected parameters are missing (e.g., any of the
mandatory parameters from the AS or the RS), or if mandatory parameters from the AS or the RS), or if
ace_client_recipientid equals ace_server_recipientid (and as a ace_client_recipientid equals ace_server_recipientid (and as a
consequence the Sender and Recipient Keys derived would be equal, see consequence, the Sender and Recipient Keys derived would be equal;
section 3.3 of [RFC8613]), then the client MUST stop the exchange, see Section 3.3 of [RFC8613]), then the client MUST stop the exchange
and MUST NOT derive the Security Context. The client MAY restart the and MUST NOT derive the Security Context. The client MAY restart the
exchange, to get the correct security material. exchange, to get the correct security material.
The client then uses this Security Context to send requests to the RS The client then uses this Security Context to send requests to the RS
using OSCORE. using OSCORE.
After sending the 2.01 (Created) response, the RS MUST set the Master After sending the 2.01 (Created) response, the RS MUST set the Master
Salt of the Security Context created to communicate with the client Salt of the Security Context created to communicate with the client
to the concatenation of salt, N1, and N2, in the same way described to the concatenation of salt, N1, and N2 in the same way described
above. An example of Master Salt construction using CBOR encoding is above. An example of Master Salt construction using CBOR encoding is
given in Figure 12 and using Base64 encoding is given in Figure 13. given in Figure 12 and using base64 encoding is given in Figure 13.
The RS MUST set the Sender ID from the ace_client_recipientid The RS MUST set the Sender ID from the ace_client_recipientid
received in Section 4.1, and the Recipient ID from the received in Section 4.1 and set the Recipient ID from the
ace_server_recipientid sent in Section 4.2. The RS MUST set the ace_server_recipientid sent in Section 4.2. The RS MUST set the
Master Secret from the parameter received from the AS and forwarded Master Secret from the parameter received from the AS and forwarded
by the client in the access token in Section 4.1 after validation of by the client in the access token in Section 4.1 after validation of
the token as specified in Section 4.2. The RS MUST set the AEAD the token as specified in Section 4.2. The RS MUST set the AEAD
Algorithm, ID Context, HKDF, and OSCORE Version from the parameters algorithm, ID Context, HKDF, and OSCORE version from the parameters
received from the AS and forwarded by the client in the access token received from the AS and forwarded by the client in the access token
in Section 4.1 after validation of the token as specified in in Section 4.1 after validation of the token as specified in
Section 4.2, if present. In case an optional parameter is omitted, Section 4.2, if present. In case an optional parameter is omitted,
the default value SHALL be used as described in sections 3.2 and 5.4 the default value SHALL be used as described in Sections 3.2 and 5.4
of [RFC8613]. After that, the RS MUST derive the complete Security of [RFC8613]. After that, the RS MUST derive the complete Security
Context following section 3.2.1 of [RFC8613], and MUST associate this Context following Section 3.2.1 of [RFC8613] and MUST associate this
Security Context with the authorization information from the access Security Context with the authorization information from the access
token. token.
The RS then uses this Security Context to verify requests and send The RS then uses this Security Context to verify requests and send
responses to the client using OSCORE. If OSCORE verification fails, responses to the client using OSCORE. If OSCORE verification fails,
error responses are used, as specified in section 8 of [RFC8613]. error responses are used, as specified in Section 8 of [RFC8613].
Additionally, if OSCORE verification succeeds, the verification of Additionally, if OSCORE verification succeeds, the verification of
access rights is performed as described in section Section 4.4. The access rights is performed as described in Section 4.4. The RS MUST
RS MUST NOT use the Security Context after the related token has NOT use the Security Context after the related token has expired and
expired, and MUST respond with a unprotected 4.01 (Unauthorized) MUST respond with an unprotected 4.01 (Unauthorized) error message to
error message to requests received that correspond to a Security requests received that correspond to a Security Context with an
Context with an expired token. expired token.
Note that the ID Context can be assigned by the AS, communicated and Note that the ID Context can be assigned by the AS, communicated and
set in both the RS and client after the exchange specified in this set in both the RS and client after the exchange specified in this
profile is executed. Subsequently, client and RS can update their ID profile is executed. Subsequently, the client and RS can update
Context by running a mechanism such as the one defined in their ID Context by running a mechanism such as the one defined in
Appendix B.2 of [RFC8613] if they both support it and are configured Appendix B.2 of [RFC8613] if they both support it and are configured
to do so. In that case, the ID Context in the OSCORE Security to do so. In that case, the ID Context in the OSCORE Security
Context will not match the "contextId" parameter of the corresponding Context will not match the contextId parameter of the corresponding
OSCORE_Input_Material. Running Appendix B.2 results in the keying OSCORE_Input_Material. Running Appendix B.2 results in the keying
material in the Security Contexts of client and RS being updated; material being updated in the Security Contexts of the client and RS;
this same result can also be achieved by the client reposting the this same result can also be achieved by the client reposting the
access token to the unprotected /authz-info endpoint at the RS, as access token to the unprotected /authz-info endpoint at the RS, as
described in Section 4.1, but without updating the ID Context. described in Section 4.1, but without updating the ID Context.
4.4. Access rights verification 4.4. Access Rights Verification
The RS MUST follow the procedures defined in section 5.8.2 of The RS MUST follow the procedures defined in Section 5.8.2 of
[I-D.ietf-ace-oauth-authz]: if an RS receives an OSCORE-protected [RFC9200]: if an RS receives an OSCORE-protected request from a
request from a client, then the RS processes it according to client, then the RS processes it according to [RFC8613]. If OSCORE
[RFC8613]. If OSCORE verification succeeds, and the target resource verification succeeds, and the target resource requires
requires authorization, the RS retrieves the authorization authorization, the RS retrieves the authorization information using
information using the access token associated to the Security the access token associated to the Security Context. The RS then
Context. The RS then must verify that the authorization information must verify that the authorization information covers the resource
covers the resource and the action requested. and the action requested.
5. Secure Communication with AS 5. Secure Communication with AS
As specified in the ACE framework (section 5.9 of As specified in the ACE framework (Section 5.9 of [RFC9200]), the
[I-D.ietf-ace-oauth-authz]), the requesting entity (RS and/or client) requesting entity (RS and/or client) and the AS communicates via the
and the AS communicates via the introspection or token endpoint. The introspection or token endpoint. The use of CoAP and OSCORE
use of CoAP and OSCORE ([RFC8613]) for this communication is [RFC8613] for this communication is RECOMMENDED in this profile;
RECOMMENDED in this profile; other protocols fulfilling the security other protocols fulfilling the security requirements defined in
requirements defined in section 5 of [I-D.ietf-ace-oauth-authz] (such Section 5 of [RFC9200] (such as HTTP and DTLS or TLS) MAY be used
as HTTP and DTLS or TLS) MAY be used instead. instead.
If OSCORE is used, the requesting entity and the AS are expected to If OSCORE is used, the requesting entity and the AS are expected to
have pre-established security contexts in place. How these security have preestablished security contexts in place. How these security
contexts are established is out of scope for this profile. contexts are established is out of scope for this profile.
Furthermore the requesting entity and the AS communicate through the Furthermore, the requesting entity and the AS communicate through the
introspection endpoint as specified in section 5.9 of introspection endpoint as specified in Section 5.9 of [RFC9200] and
[I-D.ietf-ace-oauth-authz] and through the token endpoint as through the token endpoint as specified in Section 5.8 of [RFC9200].
specified in section 5.8 of [I-D.ietf-ace-oauth-authz].
6. Discarding the Security Context 6. Discarding the Security Context
There are a number of scenarios where a client or RS needs to discard There are a number of scenarios where a client or RS needs to discard
the OSCORE security context, and acquire a new one. the OSCORE security context and acquire a new one.
The client MUST discard the current Security Context associated with The client MUST discard the current Security Context associated with
an RS when any of the following occurs: an RS when any of the following occurs:
* the Sequence Number space ends. * the sequence number space ends.
* the access token associated with the context becomes invalid due * the access token associated with the context becomes invalid due
to, for example, expiration. to, for example, expiration.
* the client receives a number of 4.01 Unauthorized responses to * the client receives a number of 4.01 Unauthorized responses to
OSCORE requests using the same Security Context. The exact number OSCORE requests using the same Security Context. The exact number
needs to be specified by the application. needs to be specified by the application.
* the client receives a new nonce in the 2.01 (Created) response * the client receives a new nonce in the 2.01 (Created) response
(see Section 4.2) to a POST request to the authz-info endpoint, (see Section 4.2) to a POST request to the authz-info endpoint,
when re-posting a (non-expired) token associated to the existing when reposting a (non-expired) token associated to the existing
context. context.
The RS MUST discard the current Security Context associated with a The RS MUST discard the current Security Context associated with a
client when any of the following occurs: client when any of the following occurs:
* the Sequence Number space ends. * the sequence number space ends.
* the access token associated with the context expires. * the access token associated with the context expires.
* the client has successfully replaced the current security context * the client has successfully replaced the current security context
with a newer one by posting an access token to the unprotected with a newer one by posting an access token to the unprotected
/authz-info endpoint at the RS, e.g., by re-posting the same /authz-info endpoint at the RS, e.g., by reposting the same token,
token, as specified in Section 4.1. as specified in Section 4.1.
Whenever one more access token is successfully posted to the RS, and Whenever one more access token is successfully posted to the RS, and
a new Security Context is derived between the client and RS, messages a new Security Context is derived between the client and RS, messages
in transit that were protected with the previous Security Context in transit that were protected with the previous Security Context
might not pass verification, as the old context is discarded. That might not pass verification, as the old context is discarded. That
means that messages sent shortly before the client posts one more means that messages sent shortly before the client posts one more
access token to the RS might not successfully reach the destination. access tokens to the RS might not successfully reach the destination.
Analogously, implementations may want to cancel CoAP observations at Analogously, implementations may want to cancel CoAP observations at
the RS registered before the Security Context is replaced, or the RS registered before the Security Context is replaced, or
conversely they will need to implement a mechanism to ensure that conversely, they will need to implement a mechanism to ensure that
those observations are to be protected with the newly derived those observations are to be protected with the newly derived
Security Context. Security Context.
7. Security Considerations 7. Security Considerations
This document specifies a profile for the Authentication and This document specifies a profile for the ACE framework [RFC9200].
Authorization for Constrained Environments (ACE) framework Thus, the general security considerations from the framework also
[I-D.ietf-ace-oauth-authz]. Thus the general security considerations apply to this profile.
from the framework also apply to this profile.
Furthermore the general security considerations of OSCORE [RFC8613] Furthermore, the general security considerations of OSCORE [RFC8613]
also apply to this specific use of the OSCORE protocol. also apply to this specific use of the OSCORE protocol.
As previously stated, the proof-of-possession in this profile is As previously stated, the proof of possession in this profile is
performed by both parties verifying that they have established the performed by both parties verifying that they have established the
same Security Context, as specified in Section 4.3, which means that same Security Context, as specified in Section 4.3, which means that
both the OSCORE request and the OSCORE response passes verification. both the OSCORE request and the OSCORE response passes verification.
RS authentication requires both that the client trusts the AS and RS authentication requires both that the client trusts the AS and
that the OSCORE response from the RS passes verification. that the OSCORE response from the RS passes verification.
OSCORE is designed to secure point-to-point communication, providing OSCORE is designed to secure point-to-point communication, providing
a secure binding between the request and the response(s). Thus the a secure binding between the request and the response(s). Thus, the
basic OSCORE protocol is not intended for use in point-to-multipoint basic OSCORE protocol is not intended for use in point-to-multipoint
communication (e.g., multicast, publish-subscribe). Implementers of communication (e.g., multicast, publish-subscribe). Implementers of
this profile should make sure that their use case corresponds to the this profile should make sure that their use case corresponds to the
expected use of OSCORE, to prevent weakening the security assurances expected use of OSCORE, to prevent weakening the security assurances
provided by OSCORE. provided by OSCORE.
Since the use of nonces N1 and N2 during the exchange guarantees Since the use of nonces N1 and N2 during the exchange guarantees
uniqueness of AEAD keys and nonces, it is REQUIRED that the exchanged uniqueness of AEAD keys and nonces, it is REQUIRED that the exchanged
nonces are not reused with the same input keying material even in nonces are not reused with the same input keying material even in
case of re-boots. This document RECOMMENDS the exchange of 64 bit case of reboots. The exchange of 64-bit random nonces is RECOMMENDED
random nonces. Considering the birthday paradox, the average in this document. Considering the birthday paradox, the average
collision for each nonce will happen after 2^32 messages, which is collision for each nonce will happen after 2^32 messages, which is
considerably more token provisioned than would be expected for considerably more token provisionings than would be expected for
intended applications. If applications use something else, such as a intended applications. If applications use something else, such as a
counter, they need to guarantee that reboot and loss of state on counter, they need to guarantee that reboot and loss of state on
either node does not provoke reuse. If that is not guaranteed, nodes either node does not provoke reuse. If that is not guaranteed, nodes
are susceptible to reuse of AEAD (nonce, key) pairs, especially since are susceptible to reuse of AEAD (nonce, key) pairs, especially since
an on-path attacker can cause the use of a previously exchanged an on-path attacker can cause the use of a previously exchanged
client nonce N1 for Security Context establishment by replaying the client nonce N1 for Security Context establishment by replaying the
corresponding client-to-server message. corresponding client-to-server message.
This profile RECOMMENDS that the RS maintains a single access token In this profile, it is RECOMMENDED that the RS maintains a single
for each client. The use of multiple access tokens for a single access token for each client. The use of multiple access tokens for
client increases the strain on the resource server as it must a single client increases the strain on the resource server as it
consider every access token and calculate the actual permissions of must consider every access token and calculate the actual permissions
the client. Also, tokens indicating different or disjoint of the client. Also, tokens indicating different or disjoint
permissions from each other may lead the server to enforce wrong permissions from each other may lead the server to enforce wrong
permissions. If one of the access tokens expires earlier than permissions. If one of the access tokens expires earlier than
others, the resulting permissions may offer insufficient protection. others, the resulting permissions may offer insufficient protection.
Developers SHOULD avoid using multiple access tokens for a same Developers SHOULD avoid using multiple access tokens for the same
client. client.
If a single OSCORE Input Material is used with multiple RSs, the RSs If a single OSCORE Input Material is used with multiple RSs, the RSs
can impersonate the client to one of the other RS, and impersonate can impersonate the client to one of the other RSs and impersonate
another RS to the client. If a master secret is used with several another RS to the client. If a Master Secret is used with several
clients, the clients can impersonate RS to one of the other clients. clients, the clients can impersonate RS to one of the other clients.
Similarly, if symmetric keys are used to integrity protect the token
Similarly if symmetric keys are used to integrity protect the token
between AS and RS and the token can be used with multiple RSs, the between AS and RS and the token can be used with multiple RSs, the
RSs can impersonate AS to one of the other RS. If the token key is RSs can impersonate AS to one of the other RSs. If the token key is
used for any other communication between the RSs and AS, the RSs can used for any other communication between the RSs and AS, the RSs can
impersonate each other to the AS. impersonate each other to the AS.
8. Privacy Considerations 8. Privacy Considerations
This document specifies a profile for the Authentication and This document specifies a profile for the ACE framework [RFC9200].
Authorization for Constrained Environments (ACE) framework Thus, the general privacy considerations from the framework also
[I-D.ietf-ace-oauth-authz]. Thus the general privacy considerations apply to this profile.
from the framework also apply to this profile.
As this document uses OSCORE, thus the privacy considerations from As this document uses OSCORE, the privacy considerations from
[RFC8613] apply here as well. [RFC8613] apply here as well.
An unprotected response to an unauthorized request may disclose An unprotected response to an unauthorized request may disclose
information about the resource server and/or its existing information about the resource server and/or its existing
relationship with the client. It is advisable to include as little relationship with the client. It is advisable to include as little
information as possible in an unencrypted response. When an OSCORE information as possible in an unencrypted response. When an OSCORE
Security Context already exists between the client and the resource Security Context already exists between the client and the resource
server, more detailed information may be included. server, more detailed information may be included.
The token is sent in the clear to the authz-info endpoint, so if a The token is sent in the clear to the authz-info endpoint, so if a
client uses the same single token from multiple locations with client uses the same single token from multiple locations with
multiple Resource Servers, it can risk being tracked by the token's multiple resource servers, it can risk being tracked by the token's
value even when the access token is encrypted. value even when the access token is encrypted.
The nonces exchanged in the request and response to the authz-info The nonces exchanged in the request and response to the authz-info
endpoint are also sent in the clear, so using random nonces is best endpoint are also sent in the clear, so using random nonces is best
for privacy (as opposed to, e.g., a counter, that might leak some for privacy (as opposed to, e.g., a counter, which might leak some
information about the client). information about the client).
The identifiers used in OSCORE, negotiated between client and RS are The identifiers used in OSCORE, negotiated between the client and RS,
privacy sensitive (see Section 12.8 of [RFC8613]), and could reveal are privacy sensitive (see Section 12.8 of [RFC8613]) and could
information about the client, or may be used for correlating requests reveal information about the client, or they may be used for
from one client. correlating requests from one client.
Note that some information might still leak after OSCORE is Note that some information might still leak after OSCORE is
established, due to observable message sizes, the source, and the established, due to observable message sizes, the source, and the
destination addresses. destination addresses.
9. IANA Considerations 9. IANA Considerations
Note to RFC Editor: Please replace all occurrences of "[[this
document]]" with the RFC number of this document. Please add a
reference to the IANA ACE Profile registry in the nextt subsection
once it has been created by IANA, and then delete this paragraph.
9.1. ACE Profile Registry 9.1. ACE Profile Registry
The following registration is done for the ACE Profile Registry The following registration has been made in the "ACE Profiles"
following the procedure specified in section 8.8 of registry following the procedure specified in Section 8.8 of
[I-D.ietf-ace-oauth-authz]: [RFC9200]:
* Name: coap_oscore Name: coap_oscore
* Description: Profile for using OSCORE to secure communication Description: Profile for using OSCORE to secure communication
between constrained nodes using the Authentication and between constrained nodes using the Authentication and
Authorization for Constrained Environments framework. Authorization for Constrained Environments framework.
* CBOR Value: TBD (value between 1 and 255) CBOR Value: 2
* Reference: [[this document]] Reference: RFC 9203
9.2. OAuth Parameters Registry 9.2. OAuth Parameters Registry
The following registrations are done for the OAuth Parameters The following registrations have been made in the "OAuth Parameters"
Registry [IANA.OAuthParameters] following the procedure specified in registry [IANA.OAuthParameters] following the procedure specified in
section 11.2 of [RFC6749]: Section 11.2 of [RFC6749]:
* Parameter name: nonce1 Parameter name: nonce1
* Parameter usage location: client-rs request Parameter usage location: client-rs request
* Change Controller: IESG Change Controller: IETF
* Specification Document(s): [[this document]] Specification Document(s): RFC 9203
* Parameter name: nonce2 Parameter name: nonce2
* Parameter usage location: rs-client response Parameter usage location: rs-client response
* Change Controller: IESG Change Controller: IETF
* Specification Document(s): [[this document]] Specification Document(s): RFC 9203
* Parameter name: ace_client_recipientid Parameter name: ace_client_recipientid
* Parameter usage location: client-rs request Parameter usage location: client-rs request
* Change Controller: IESG Change Controller: IETF
* Specification Document(s): [[this document]] Specification Document(s): RFC 9203
* Parameter name: ace_server_recipientid Parameter name: ace_server_recipientid
* Parameter usage location: rs-client response Parameter usage location: rs-client response
* Change Controller: IESG Change Controller: IETF
* Specification Document(s): [[this document]] Specification Document(s): RFC 9203
9.3. OAuth Parameters CBOR Mappings Registry 9.3. OAuth Parameters CBOR Mappings Registry
The following registrations are done for the OAuth Parameters CBOR The following registrations have been made in the "OAuth Parameters
Mappings Registry following the procedure specified in section 8.10 CBOR Mappings" registry following the procedure specified in
of [I-D.ietf-ace-oauth-authz]: Section 8.10 of [RFC9200]:
* Name: nonce1 Name: nonce1
* CBOR Key: TBD1 CBOR Key: 40
* Value Type: bstr Value Type: bstr
* Reference: [[this document]] Reference: RFC 9203
Original Specification: RFC 9203
* Name: nonce2 Name: nonce2
* CBOR Key: TBD2 CBOR Key: 42
* Value Type: bstr Value Type: bstr
* Reference: [[this document]] Reference: RFC 9203
Original Specification: RFC 9203
* Name: ace_client_recipientid Name: ace_client_recipientid
* CBOR Key: TBD3 CBOR Key: 43
* Value Type: bstr Value Type: bstr
* Reference: [[this document]] Reference: RFC 9203
Original Specification: RFC 9203
* Name: ace_server_recipientid Name: ace_server_recipientid
* CBOR Key: TBD4 CBOR Key: 44
* Value Type: bstr Value Type: bstr
* Reference: [[this document]] Reference: RFC 9203
Original Specification: RFC 9203
9.4. OSCORE Security Context Parameters Registry 9.4. OSCORE Security Context Parameters Registry
It is requested that IANA create a new registry entitled "OSCORE IANA has created a new registry entitled "OSCORE Security Context
Security Context Parameters" registry. The registry is to be created Parameters". The registration procedure is Expert Review [RFC8126].
as Expert Review Required. Guidelines for the experts is provided Guidelines for the experts are provided in Section 9.7. It should be
Section 9.7. It should be noted that in addition to the expert noted that in addition to the Expert Review, some portions of the
review, some portions of the registry require a specification, registry require a specification, potentially on the Standards Track,
potentially on standards track, be supplied as well. be supplied as well.
The columns of the registry are: The columns of the registry are:
name The JSON name requested (e.g., "ms"). Because a core goal of Name: The JSON name requested (e.g., "ms"). Because a core goal of
this document is for the resulting representations to be compact, this document is for the resulting representations to be compact,
it is RECOMMENDED that the name be short. This name is case it is RECOMMENDED that the name be short. This name is case
sensitive. Names may not match other registered names in a case- sensitive. Names may not match other registered names in a case-
insensitive manner unless the Designated Experts determine that insensitive manner unless the designated experts determine that
there is a compelling reason to allow an exception. The name is there is a compelling reason to allow an exception. The name is
not used in the CBOR encoding. not used in the CBOR encoding.
CBOR label The value to be used to identify this algorithm. Map key
labels MUST be unique. The label can be a positive integer, a CBOR Label: The value to be used to identify this algorithm. Map
negative integer or a string. Integer values between -256 and 255 key labels MUST be unique. The label can be a positive integer, a
and strings of length 1 are designated as Standards Track Document negative integer, or a string. Integer values between -256 and
required. Integer values from -65536 to -257 and from 256 to 255 and strings of length 1 are designated as Standards Track
65535 and strings of length 2 are designated as Specification document required. Integer values from -65536 to -257 and from
Required. Integer values greater than 65535 and strings of length 256 to 65535 and strings of length 2 are designated as
greater than 2 are designated as expert review. Integer values Specification Required. Integer values greater than 65535 and
less than -65536 are marked as private use. strings of length greater than 2 are designated as Expert Review.
CBOR Type This field contains the CBOR type for the field. Integer values less than -65536 are marked as Private Use.
registry This field denotes the registry that values may come from,
CBOR Type: This field contains the CBOR type for the field.
Registry: This field denotes the registry that values may come from,
if one exists. if one exists.
description This field contains a brief description for the field.
specification This contains a pointer to the public specification Description: This field contains a brief description for the field.
for the field if one exists
This registry will be initially populated by the values in Table 1. Reference: This contains a pointer to the public specification for
The specification column for all of these entries will be this the field, if one exists.
document and [RFC8613].
This registry has been initially populated by the values in Table 1.
The Reference column for all of these entries is this document and
[RFC8613].
9.5. CWT Confirmation Methods Registry 9.5. CWT Confirmation Methods Registry
The following registration is done for the CWT Confirmation Methods The following registration has been made in the "CWT Confirmation
Registry [IANA.CWTConfirmationMethods] following the procedure Methods" registry [IANA.CWTConfirmationMethods] following the
specified in section 7.2.1 of [RFC8747]: procedure specified in Section 7.2.1 of [RFC8747]:
* Confirmation Method Name: "osc" Confirmation Method Name: "osc"
* Confirmation Method Description: OSCORE_Input_Material carrying Confirmation Method Description: OSCORE_Input_Material carrying the
the parameters for using OSCORE per-message security with implicit parameters for using OSCORE per-message security with implicit key
key confirmation confirmation
* Confirmation Key: TBD (value between 4 and 255) JWT Confirmation Method Name: osc
* Confirmation Value Type(s): map Confirmation Key: 4
* Change Controller: IESG Confirmation Value Type(s): map
* Specification Document(s): Section 3.2.1 of [[this document]] Change Controller: IETF
Specification Document(s): Section 3.2.1 of RFC 9203
9.6. JWT Confirmation Methods Registry 9.6. JWT Confirmation Methods Registry
The following registration is done for the JWT Confirmation Methods The following registration has been made in the "JWT Confirmation
Registry [IANA.JWTConfirmationMethods] following the procedure Methods" registry [IANA.JWTConfirmationMethods] following the
specified in section 6.2.1 of [RFC7800]: procedure specified in Section 6.2.1 of [RFC7800]:
* Confirmation Method Value: "osc" Confirmation Method Value: "osc"
* Confirmation Method Description: OSCORE_Input_Material carrying Confirmation Method Description: OSCORE_Input_Material carrying the
the parameters for using OSCORE per-message security with implicit parameters for using OSCORE per-message security with implicit key
key confirmation confirmation
* Change Controller: IESG Change Controller: IETF
* Specification Document(s): Section 3.2.1 of [[this document]] Specification Document(s): Section 3.2.1 of RFC 9203
9.7. Expert Review Instructions 9.7. Expert Review Instructions
The IANA registry established in this document is defined to use the The IANA registry established in this document is defined to use the
Expert Review registration policy. This section gives some general Expert Review registration policy. This section gives some general
guidelines for what the experts should be looking for, but they are guidelines for what the experts should be looking for, but they are
being designated as experts for a reason so they should be given being designated as experts for a reason, so they should be given
substantial latitude. substantial latitude.
Expert reviewers should take into consideration the following points: Expert reviewers should take into consideration the following points:
* Point squatting should be discouraged. Reviewers are encouraged * Point squatting should be discouraged. Reviewers are encouraged
to get sufficient information for registration requests to ensure to get sufficient information for registration requests to ensure
that the usage is not going to duplicate one that is already that the usage is not going to duplicate one that is already
registered and that the point is likely to be used in deployments. registered and that the point is likely to be used in deployments.
The zones tagged as private use are intended for testing purposes The zones tagged as Private Use are intended for testing purposes
and closed environments. Code points in other ranges should not and closed environments. Code points in other ranges should not
be assigned for testing. be assigned for testing.
* Specifications are required for the standards track range of point * Specifications are required for the Standards Track range of point
assignment. Specifications should exist for specification assignment. Specifications should exist for specification
required ranges, but early assignment before a specification is required ranges, but early assignment before a specification is
available is considered to be permissible. Specifications are available is considered to be permissible. Specifications are
needed for the first-come, first-serve range if they are expected needed for the First Come First Served range if they are expected
to be used outside of closed environments in an interoperable way. to be used outside of closed environments in an interoperable way.
When specifications are not provided, the description provided When specifications are not provided, the description provided
needs to have sufficient information to identify what the point is needs to have sufficient information to identify what the point is
being used for. being used for.
* Experts should take into account the expected usage of fields when * Experts should take into account the expected usage of fields when
approving point assignment. The fact that there is a range for approving point assignment. The fact that there is a range for
standards track documents does not mean that a standards track Standards Track documents does not mean that a Standards Track
document cannot have points assigned outside of that range. The document cannot have points assigned outside of that range. The
length of the encoded value should be weighed against how many length of the encoded value should be weighed against how many
code points of that length are left, the size of device it will be code points of that length are left, the size of device it will be
used on, and the number of code points left that encode to that used on, and the number of code points left that encode to that
size. size.
10. References 10. References
10.1. Normative References 10.1. Normative References
[COSE.Algorithms] [COSE.Algorithms]
IANA, "COSE Algorithms", IANA, "COSE Algorithms",
<https://www.iana.org/assignments/cose/ <https://www.iana.org/assignments/cose>.
cose.xhtml#algorithms>.
[I-D.ietf-ace-oauth-authz]
Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and
H. Tschofenig, "Authentication and Authorization for
Constrained Environments (ACE) using the OAuth 2.0
Framework (ACE-OAuth)", Work in Progress, Internet-Draft,
draft-ietf-ace-oauth-authz-40, 26 April 2021,
<https://www.ietf.org/archive/id/draft-ietf-ace-oauth-
authz-40.txt>.
[I-D.ietf-ace-oauth-params]
Seitz, L., "Additional OAuth Parameters for Authorization
in Constrained Environments (ACE)", Work in Progress,
Internet-Draft, draft-ietf-ace-oauth-params-14, 25 March
2021, <https://www.ietf.org/archive/id/draft-ietf-ace-
oauth-params-14.txt>.
[I-D.ietf-cose-rfc8152bis-algs]
Schaad, J., "CBOR Object Signing and Encryption (COSE):
Initial Algorithms", Work in Progress, Internet-Draft,
draft-ietf-cose-rfc8152bis-algs-12, 24 September 2020,
<https://www.ietf.org/archive/id/draft-ietf-cose-
rfc8152bis-algs-12.txt>.
[I-D.ietf-cose-rfc8152bis-struct]
Schaad, J., "CBOR Object Signing and Encryption (COSE):
Structures and Process", Work in Progress, Internet-Draft,
draft-ietf-cose-rfc8152bis-struct-15, 1 February 2021,
<https://www.ietf.org/archive/id/draft-ietf-cose-
rfc8152bis-struct-15.txt>.
[IANA.CWTConfirmationMethods] [IANA.CWTConfirmationMethods]
IANA, "CWT Confirmation Methods", IANA, "CWT Confirmation Methods",
<https://www.iana.org/assignments/cwt/ <https://www.iana.org/assignments/cwt>.
cwt.xhtml#confirmation-methods>.
[IANA.JWTConfirmationMethods] [IANA.JWTConfirmationMethods]
IANA, "JWT Confirmation Methods", IANA, "JWT Confirmation Methods",
<https://www.iana.org/assignments/jwt/ <https://www.iana.org/assignments/jwt>.
jwt.xhtml#confirmation-methods>.
[IANA.OAuthParameters] [IANA.OAuthParameters]
IANA, "OAuth Parameters", IANA, "OAuth Parameters",
<https://www.iana.org/assignments/oauth-parameters/oauth- <https://www.iana.org/assignments/oauth-parameters>.
parameters.xhtml#parameters>.
[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>.
[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>.
skipping to change at page 32, line 25 skipping to change at line 1398
[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>.
[RFC8949] Bormann, C. and P. Hoffman, "Concise Binary Object [RFC8949] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", STD 94, RFC 8949, Representation (CBOR)", STD 94, RFC 8949,
DOI 10.17487/RFC8949, December 2020, DOI 10.17487/RFC8949, December 2020,
<https://www.rfc-editor.org/info/rfc8949>. <https://www.rfc-editor.org/info/rfc8949>.
10.2. Informative References [RFC9052] Schaad, J., "CBOR Object Signing and Encryption (COSE):
Structures and Process", RFC 9052, DOI 10.17487/RFC9052,
March 2022, <https://www.rfc-editor.org/info/rfc9052>.
[I-D.ietf-tls-dtls13] [RFC9053] Schaad, J., "CBOR Object Signing and Encryption (COSE):
Rescorla, E., Tschofenig, H., and N. Modadugu, "The Initial Algorithms", RFC 9053, DOI 10.17487/RFC9053, March
Datagram Transport Layer Security (DTLS) Protocol Version 2022, <https://www.rfc-editor.org/info/rfc9053>.
1.3", Work in Progress, Internet-Draft, draft-ietf-tls-
dtls13-43, 30 April 2021, <https://www.ietf.org/internet- [RFC9200] Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and
drafts/draft-ietf-tls-dtls13-43.txt>. H. Tschofenig, "Authentication and Authorization for
Constrained Environments (ACE) Using the OAuth 2.0
Framework (ACE-OAuth)", RFC 9200, DOI 10.17487/RFC9200,
September 2021, <https://www.rfc-editor.org/info/rfc9200>.
[RFC9201] Seitz, L., "Additional OAuth Parameters for Authentication
and Authorization for Constrained Environments (ACE)",
RFC 9201, DOI 10.17487/RFC9201, September 2021,
<https://www.rfc-editor.org/info/rfc9201>.
10.2. Informative References
[RFC4949] Shirey, R., "Internet Security Glossary, Version 2", [RFC4949] Shirey, R., "Internet Security Glossary, Version 2",
FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007, FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
<https://www.rfc-editor.org/info/rfc4949>. <https://www.rfc-editor.org/info/rfc4949>.
[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>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer [RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231, Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014, DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/info/rfc7231>. <https://www.rfc-editor.org/info/rfc7231>.
[RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of- [RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of-
Possession Key Semantics for JSON Web Tokens (JWTs)", Possession Key Semantics for JSON Web Tokens (JWTs)",
RFC 7800, DOI 10.17487/RFC7800, April 2016, RFC 7800, DOI 10.17487/RFC7800, April 2016,
<https://www.rfc-editor.org/info/rfc7800>. <https://www.rfc-editor.org/info/rfc7800>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[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>.
[RFC8747] Jones, M., Seitz, L., Selander, G., Erdtman, S., and H. [RFC8747] 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)", RFC 8747, DOI 10.17487/RFC8747, March Web Tokens (CWTs)", RFC 8747, DOI 10.17487/RFC8747, March
2020, <https://www.rfc-editor.org/info/rfc8747>. 2020, <https://www.rfc-editor.org/info/rfc8747>.
[RFC9147] Rescorla, E., Tschofenig, H., and N. Modadugu, "The
Datagram Transport Layer Security (DTLS) Protocol Version
1.3", RFC 9147, DOI 10.17487/RFC9147, March 2022,
<https://www.rfc-editor.org/info/rfc9147>.
Appendix A. Profile Requirements Appendix A. Profile Requirements
This section lists the specifications on this profile based on the This section lists the specifications of this profile based on the
requirements on the framework, as requested in Appendix C of requirements of the framework, as requested in Appendix C of
[I-D.ietf-ace-oauth-authz]. [RFC9200].
* Optionally define new methods for the client to discover the * Optionally, define new methods for the client to discover the
necessary permissions and AS for accessing a resource, different necessary permissions and AS for accessing a resource, different
from the one proposed in: Not specified from the one proposed in: Not specified
* Optionally specify new grant types: Not specified * Optionally, specify new grant types: Not specified
* Optionally define the use of client certificates as client * Optionally, define the use of client certificates as client
credential type: Not specified credential type: Not specified
* Specify the communication protocol the client and RS the must use: * Specify the communication protocol the client and RS must use:
CoAP CoAP
* Specify the security protocol the client and RS must use to * Specify the security protocol the client and RS must use to
protect their communication: OSCORE protect their communication: OSCORE
* Specify how the client and the RS mutually authenticate: * Specify how the client and the RS mutually authenticate:
Implicitly by possession of a common OSCORE security context. Implicitly by possession of a common OSCORE security context.
Note that the mutual authentication is not completed before the Note that the mutual authentication is not completed before the
client has verified an OSCORE response using this security client has verified an OSCORE response using this security
context. context.
* Specify the proof-of-possession protocol(s) and how to select one, * Specify the proof-of-possession protocol(s) and how to select one,
if several are available. Also specify which key types (e.g., if several are available. Also specify which key types (e.g.,
symmetric/asymmetric) are supported by a specific proof-of- symmetric/asymmetric) are supported by a specific proof-of-
possession protocol: OSCORE algorithms; pre-established symmetric possession protocol: OSCORE algorithms; preestablished symmetric
keys keys
* Specify a unique ace_profile identifier: coap_oscore * Specify a unique ace_profile identifier: coap_oscore
* If introspection is supported: Specify the communication and * If introspection is supported, specify the communication and
security protocol for introspection: HTTP/CoAP (+ TLS/DTLS/OSCORE) security protocol for introspection: HTTP/CoAP (+ TLS/DTLS/OSCORE)
* Specify the communication and security protocol for interactions * Specify the communication and security protocol for interactions
between client and AS: HTTP/CoAP (+ TLS/DTLS/OSCORE) between client and AS: HTTP/CoAP (+ TLS/DTLS/OSCORE)
* Specify how/if the authz-info endpoint is protected, including how * Specify if/how the authz-info endpoint is protected, including how
error responses are protected: Not protected. error responses are protected: Not protected
* Optionally define other methods of token transport than the authz- * Optionally, define methods of token transport other than the
info endpoint: Not defined authz-info endpoint: Not defined
Acknowledgments Acknowledgments
The authors wish to thank Jim Schaad and Marco Tiloca for the The authors wish to thank Jim Schaad and Marco Tiloca for the
substantial input to this document, as well as Elwyn Davies, Linda substantial input to this document, as well as Elwyn Davies, Linda
Dunbar, Roman Danyliw, Martin Duke, Lars Eggert, Murray Kucherawy, Dunbar, Roman Danyliw, Martin Duke, Lars Eggert, Murray Kucherawy,
and Zaheduzzaman Sarker for their reviews and feedback. Special and Zaheduzzaman Sarker for their reviews and feedback. Special
thanks to the responsible area director Benjamin Kaduk for his thanks to the responsible area director Benjamin Kaduk for his
extensive review and contributed text. Ludwig Seitz worked on this extensive review and contributed text. Ludwig Seitz worked on this
document as part of the CelticNext projects CyberWI, and CRITISEC document as part of the CelticNext projects CyberWI and CRITISEC with
with funding from Vinnova. The work on this document has been partly funding from Vinnova. The work on this document has been partly
supported also by the H2020 project SIFIS-Home (Grant agreement supported also by the H2020 project SIFIS-Home (Grant agreement
952652). 952652).
Authors' Addresses Authors' Addresses
Francesca Palombini Francesca Palombini
Ericsson AB Ericsson AB
Email: francesca.palombini@ericsson.com Email: francesca.palombini@ericsson.com
Ludwig Seitz Ludwig Seitz
Combitech Combitech
Djaeknegatan 31 Djäknegatan 31
SE-211 35 Malmoe SE-211 35 Malmö
Sweden Sweden
Email: ludwig.seitz@combitech.com Email: ludwig.seitz@combitech.com
Göran Selander Göran Selander
Ericsson AB Ericsson AB
Email: goran.selander@ericsson.com Email: goran.selander@ericsson.com
Martin Gunnarsson Martin Gunnarsson
RISE RISE
Scheelevagen 17 Scheelevagen 17
SE-22370 Lund SE-22370 Lund
Sweden Sweden
Email: martin.gunnarsson@ri.se Email: martin.gunnarsson@ri.se
 End of changes. 202 change blocks. 
616 lines changed or deleted 592 lines changed or added

This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/