draft-ietf-ace-oscore-profile-11.txt   draft-ietf-ace-oscore-profile-12.txt 
ACE Working Group F. Palombini ACE Working Group F. Palombini
Internet-Draft Ericsson AB Internet-Draft Ericsson AB
Intended status: Standards Track L. Seitz Intended status: Standards Track L. Seitz
Expires: December 20, 2020 Combitech Expires: March 25, 2021 Combitech
G. Selander G. Selander
Ericsson AB Ericsson AB
M. Gunnarsson M. Gunnarsson
RISE RISE
June 18, 2020 September 21, 2020
OSCORE profile of the Authentication and Authorization for Constrained OSCORE Profile of the Authentication and Authorization for Constrained
Environments Framework Environments Framework
draft-ietf-ace-oscore-profile-11 draft-ietf-ace-oscore-profile-12
Abstract Abstract
This memo specifies a profile for the Authentication and This memo 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, server authentication, (OSCORE) to provide communication security and proof-of-possession
and proof-of-possession for a key owned by the client and bound to an for a key owned by the client and bound to an OAuth 2.0 access token.
OAuth 2.0 access token.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
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This Internet-Draft will expire on December 20, 2020. This Internet-Draft will expire on March 25, 2021.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 20 skipping to change at page 2, line 19
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 4 2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 4
3. Client-AS Communication . . . . . . . . . . . . . . . . . . . 6 3. Client-AS Communication . . . . . . . . . . . . . . . . . . . 6
3.1. C-to-AS: POST to token endpoint . . . . . . . . . . . . . 6 3.1. C-to-AS: POST to token endpoint . . . . . . . . . . . . . 6
3.2. AS-to-C: Access Token . . . . . . . . . . . . . . . . . . 8 3.2. AS-to-C: Access Token . . . . . . . . . . . . . . . . . . 8
3.2.1. OSCORE_Security_Context Object . . . . . . . . . . . 13 3.2.1. The OSCORE_Input_Material . . . . . . . . . . . . . . 13
4. Client-RS Communication . . . . . . . . . . . . . . . . . . . 17 4. Client-RS Communication . . . . . . . . . . . . . . . . . . . 16
4.1. C-to-RS: POST to authz-info endpoint . . . . . . . . . . 18 4.1. C-to-RS: POST to authz-info endpoint . . . . . . . . . . 17
4.1.1. The Nonce 1 Parameter . . . . . . . . . . . . . . . . 19 4.1.1. The Nonce 1 Parameter . . . . . . . . . . . . . . . . 18
4.2. RS-to-C: 2.01 (Created) . . . . . . . . . . . . . . . . . 19 4.2. RS-to-C: 2.01 (Created) . . . . . . . . . . . . . . . . . 18
4.2.1. The Nonce 2 Parameter . . . . . . . . . . . . . . . . 21 4.2.1. The Nonce 2 Parameter . . . . . . . . . . . . . . . . 20
4.3. OSCORE Setup . . . . . . . . . . . . . . . . . . . . . . 21 4.3. OSCORE Setup . . . . . . . . . . . . . . . . . . . . . . 20
4.4. Access rights verification . . . . . . . . . . . . . . . 22 4.4. Access rights verification . . . . . . . . . . . . . . . 22
5. Secure Communication with AS . . . . . . . . . . . . . . . . 22 5. Secure Communication with AS . . . . . . . . . . . . . . . . 22
6. Discarding the Security Context . . . . . . . . . . . . . . . 23 6. Discarding the Security Context . . . . . . . . . . . . . . . 23
7. Security Considerations . . . . . . . . . . . . . . . . . . . 24 7. Security Considerations . . . . . . . . . . . . . . . . . . . 24
8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 25 8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 25
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
9.1. ACE OAuth Profile Registry . . . . . . . . . . . . . . . 25 9.1. ACE Profile Registry . . . . . . . . . . . . . . . . . . 26
9.2. OAuth Parameters Registry . . . . . . . . . . . . . . . . 26 9.2. OAuth Parameters Registry . . . . . . . . . . . . . . . . 26
9.3. OAuth Parameters CBOR Mappings Registry . . . . . . . . . 26 9.3. OAuth Parameters CBOR Mappings Registry . . . . . . . . . 26
9.4. OSCORE Security Context Parameters Registry . . . . . . . 26 9.4. OSCORE Security Context Parameters Registry . . . . . . . 27
9.5. CWT Confirmation Methods Registry . . . . . . . . . . . . 27 9.5. CWT Confirmation Methods Registry . . . . . . . . . . . . 28
9.6. JWT Confirmation Methods Registry . . . . . . . . . . . . 28 9.6. JWT Confirmation Methods Registry . . . . . . . . . . . . 28
9.7. Expert Review Instructions . . . . . . . . . . . . . . . 28 9.7. Expert Review Instructions . . . . . . . . . . . . . . . 28
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 29 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 29
10.1. Normative References . . . . . . . . . . . . . . . . . . 29 10.1. Normative References . . . . . . . . . . . . . . . . . . 29
10.2. Informative References . . . . . . . . . . . . . . . . . 30 10.2. Informative References . . . . . . . . . . . . . . . . . 30
Appendix A. Profile Requirements . . . . . . . . . . . . . . . . 30 Appendix A. Profile Requirements . . . . . . . . . . . . . . . . 31
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 31 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32
1. Introduction 1. Introduction
This memo specifies a profile of the ACE framework This memo specifies a profile of the ACE framework
[I-D.ietf-ace-oauth-authz]. In this profile, a client and a resource [I-D.ietf-ace-oauth-authz]. In this profile, a client and a resource
server use CoAP [RFC7252] to communicate. The client uses an access server use the Constrained Application Protocol (CoAP) [RFC7252] to
token, bound to a key (the proof-of-possession key) to authorize its communicate. The client uses an access token, bound to a symmetric
access to the resource server. Note that this profile uses a key (the proof-of-possession key) to authorize its access to the
symmetric-crypto-based scheme, where the symmetric secret is used as resource server. Note that this profile uses a symmetric-crypto-
input material for keying material derivation. In order to provide based scheme, where the symmetric secret is used as input material
communication security, proof of possession, and server for keying material derivation. In order to provide communication
authentication the client and resource server use Object Security for security and proof of possession, the client and resource server use
Constrained RESTful Environments (OSCORE) [RFC8613]. Note that the Object Security for Constrained RESTful Environments (OSCORE)
proof of possession is not done by a dedicated protocol element, but [RFC8613]. Note that the proof of possession is not done by a
rather occurs implicitly, based on knowledge of the security keying dedicated protocol element, but rather occurs after the first OSCORE
material. exchange.
OSCORE specifies how to use CBOR Object Signing and Encryption (COSE) OSCORE specifies how to use CBOR Object Signing and Encryption (COSE)
[RFC8152] to secure CoAP messages. Note that OSCORE can be used to [RFC8152] to secure CoAP messages. Note that OSCORE can be used to
secure CoAP messages, as well as HTTP and combinations of HTTP and secure CoAP messages, as well as HTTP and combinations of HTTP and
CoAP; a profile of ACE similar to the one described in this document, CoAP; a profile of ACE similar to the one described in this document,
with the difference of using HTTP instead of CoAP as communication with the difference of using HTTP instead of CoAP as communication
protocol, could be specified analogously to this one. protocol, could be specified analogously to this one.
1.1. Terminology 1.1. Terminology
skipping to change at page 3, line 41 skipping to change at page 3, line 40
"authorization", "confidentiality", "(data) integrity", "message "authorization", "confidentiality", "(data) integrity", "message
authentication code", and "verify" are taken from [RFC4949]. authentication code", and "verify" are taken from [RFC4949].
RESTful terminology follows HTTP [RFC7231]. RESTful terminology follows HTTP [RFC7231].
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 Data Definition Language (CDDL) [RFC8610] is used in this Concise Binary Object Representation (CBOR) [I-D.ietf-cbor-7049bis]
specification. and Concise Data Definition Language (CDDL) [RFC8610] are used in
this specification. CDDL predefined type names, especially bstr for
CBOR byte strings and tstr for CBOR text strings, are used
extensively in the document.
Note that the term "endpoint" is used here, as in Note that the term "endpoint" is used here, as in
[I-D.ietf-ace-oauth-authz], following its OAuth definition, which is [I-D.ietf-ace-oauth-authz], following its OAuth definition, which is
to denote resources such as token and introspect at the AS and authz- to denote resources such as token and introspect at the AS and authz-
info at the RS. The CoAP [RFC7252] definition, which is "An entity info at the RS. The CoAP [RFC7252] definition, which is "An entity
participating in the CoAP protocol" is not used in this memo. participating in the CoAP protocol" is not used in this memo.
2. Protocol Overview 2. Protocol Overview
This section gives an overview on 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 [I-D.ietf-ace-oauth-authz] to secure the communication between a
client and a resource server using OSCORE [RFC8613]. The parameters client and a resource server using OSCORE [RFC8613]. The parameters
needed by the client to negotiate the use of this profile with the needed by the client to negotiate the use of this profile with the
authorization server, as well as OSCORE setup process, are described authorization server, as well as the OSCORE setup process, are
in detail in the following sections. described in detail in the following 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's 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 a RS, using the token AS for the resource it wants to access on an RS, by sending an access
endpoint, as specified in section 5.6 of [I-D.ietf-ace-oauth-authz]. token request to the token endpoint, as specified in section 5.6 of
To determine the AS in charge of a resource hosted at the RS, the
client C MAY send an initial Unauthorized Resource Request message to
the RS. The RS then denies the request and sends the address of its
AS back to the client C as specified in section 5.1 of
[I-D.ietf-ace-oauth-authz]. The access token request and response [I-D.ietf-ace-oauth-authz]. The access token request and response
MUST be confidentiality-protected and ensure authenticity. This MUST be confidentiality-protected and ensure authenticity. This
profile RECOMMENDS the use of OSCORE between client and AS, but other profile RECOMMENDS the use of OSCORE between client and AS, but other
protocols (such as TLS or DTLS) can be used as well. protocols (such as TLS or DTLS) can be used as well.
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 and posts both the token and N1 to the RS using the authz-info N1 and posts both the token and N1 to the RS using the authz-info
endpoint and mechanisms specified in section 5.8 of endpoint and mechanisms specified in section 5.8 of
[I-D.ietf-ace-oauth-authz] and Content-Format = application/ace+cbor. [I-D.ietf-ace-oauth-authz] and Content-Format = application/ace+cbor.
Note that, as specified in the ACE framework, the authz-info endpoint When using this profile, the communication with the authz-info
is not a protected resource, so there is no cryptographic protection endpoint is not protected, except for update of access rights.
to this request.
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 in a CBOR map. Moreover, the server which contains a nonce N2 in a CBOR map. Moreover, the server
concatenates the input salt, N1, and N2 to obtain the Master Salt of concatenates the input salt received in the token, N1, and N2 to
the OSCORE Security Context (see section 3 of [RFC8613]). The RS obtain the Master Salt of the OSCORE Security Context (see section 3
then derives the complete Security Context associated with the of [RFC8613]). The RS then derives the complete Security Context
received token from it plus the parameters received in the access associated with the received token from it plus the parameters
token from the AS, following section 3.2 of [RFC8613]. received in the access token from the AS, following section 3.2 of
[RFC8613].
After receiving the nonce N2, the client concatenates the input salt, After receiving the nonce N2, the client concatenates the input salt
N1 and N2 to obtain the Master Salt of the OSCORE Security Context (received from the AS), N1 and N2 to obtain the Master Salt of the
(see section 3 of [RFC8613]). The client then derives the complete OSCORE Security Context (see section 3 of [RFC8613]). The client
Security Context from the nonces plus the parameters received from then derives the complete Security Context from the nonces plus the
the AS. parameters received from the AS.
Finally, the client sends a request protected with OSCORE to the RS. Finally, the client sends a request protected with OSCORE to the RS.
If the request verifies, the server stores the complete Security If the request verifies, 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 expiration. This Security Context is discarded when a until token expiration. This Security Context is discarded when a
token (whether the same or different) is used to successfully derive token (whether the same or different) is used to successfully derive
a new Security Context for that client. a new Security Context for that client.
The use of random nonces during the exchange prevents the reuse of an The use of random nonces during the exchange prevents the reuse of an
AEAD nonces/key pair for two different messages. This situation Authenticated Encryption with Associated Data (AEAD) nonces/key pair
might occur when client and RS derive a new Security Context from an for two different messages. Two-time pad might otherwise occur when
existing (non-expired) access token, as might occur when either party client and RS derive a new Security Context from an existing (non-
has just rebooted. Instead, by using random nonces as part of the expired) access token, as might occur when either party has just
Master Salt, the request to the authz-info endpoint posting the same rebooted. Instead, by using random nonces as part of the Master
token results in a different Security Context, by OSCORE Salt, the request to the authz-info endpoint posting the same token
construction, since even though the Master Secret, Sender ID and results in a different Security Context, by OSCORE construction,
Recipient ID are the same, the Master Salt is different (see since even though the Master Secret, Sender ID and Recipient ID are
Section 3.2.1 of [RFC8613]). Therefore, the main requirement for the the same, the Master Salt is different (see Section 3.2.1 of
nonces is that they have a good amount of randomness. If random [RFC8613]). Therefore, the main requirement for the nonces is that
nonces were not used, a node re-using a non-expired old token would they have a good amount of randomness. If random nonces were not
be susceptible to on-path attackers provoking the creation of OSCORE used, a node re-using a non-expired old token would be susceptible to
messages using old AEAD keys and nonces. on-path attackers provoking the creation of OSCORE messages using old
AEAD keys and nonces.
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 identifier so that the AS can find the correct OSCORE security
material it has previously shared with the Client. This specific material it has previously shared with the Client. This specific
identifier, which [I-D.ietf-ace-oauth-authz] encodes as a bstr, is identifier, which [I-D.ietf-ace-oauth-authz] encodes as a bstr, is
formatted to include two OSCORE identifiers, namely ID context and formatted to include two OSCORE identifiers, namely ID context and
client ID, that are necessary to determine the correct OSCORE client ID, that are necessary to determine the correct OSCORE Input
Security Context. material.
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. Figure 1. The names of messages coincide with those of
[I-D.ietf-ace-oauth-authz] when applicable.
C RS AS C RS AS
| [-- Resource Request --->] | |
| | |
| [<---- AS Request ------] | |
| Creation Hints | |
| | | | | |
| ----- POST /token ----------------------------> | | ----- POST /token ----------------------------> |
| | | | | |
| <---------------------------- Access Token ----- | | <---------------------------- Access Token ----- |
| + Access Information | | + Access Information |
| ---- POST /authz-info ---> | | | ---- POST /authz-info ---> | |
| (access_token, N1) | | | (access_token, N1) | |
| | | | | |
| <--- 2.01 Created (N2) --- | | | <--- 2.01 Created (N2) --- | |
| | | | | |
/Sec Context /Sec Context | /Sec Context /Sec Context |
Derivation/ Derivation/ | derivation/ derivation/ |
| | | | | |
| ---- OSCORE Request -----> | | | ---- OSCORE Request -----> | |
| | | | | |
| /proof-of-possession |
| Sec Context storage/ |
| | |
| <--- OSCORE Response ----- | | | <--- OSCORE Response ----- | |
| | | | | |
/proof-of-possession | |
Sec Context storage/ | |
| | |
| ---- OSCORE Request -----> | | | ---- OSCORE Request -----> | |
| | | | | |
| <--- 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
skipping to change at page 7, line 34 skipping to change at page 7, line 34
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 in its POST request
to the token endpoint a req_cnf object. The req_cnf MUST include a to the token endpoint a req_cnf object. The req_cnf MUST include a
kid field carrying a bstr-wrapped CBOR array object containing the kid field carrying a bstr-wrapped CBOR array object containing the
client's identifier (assigned as discussed in Section 3.2) and the client's identifier (assigned as discussed in Section 3.2) and the
context identifier (if assigned as discussed in Section 3.2). The context identifier (if assigned as discussed in Section 3.2). The
CBOR array is defined in Figure 3, and follows the notation of CBOR array is defined in Figure 3, and follows the notation of
[RFC8610]. These identifiers, together with other information such [RFC8610]. These identifiers, together with other information such
as audience, can be used by the AS to determine the shared secret as audience (see Section 5.6.1 of [I-D.ietf-ace-oauth-authz]), can be
bound to the proof-of-possession token and therefore MUST identify a used by the AS to determine the shared secret bound to the proof-of-
symmetric key that was previously generated by the AS as a shared possession token and therefore MUST identify a symmetric key that was
secret for the communication between the client and the RS. The AS previously generated by the AS as a shared secret for the
MUST verify that the received value identifies a proof-of-possession communication between the client and the RS. The AS MUST verify that
key that has previously been issued to the requesting client. If the received value identifies a proof-of-possession key that has
that is not the case, the Client-to-AS request MUST be declined with previously been issued to the requesting client. If that is not the
the error code 'invalid_request' as defined in Section 5.6.3 of case, the Client-to-AS request MUST be declined with the error code
'invalid_request' as defined in Section 5.6.3 of
[I-D.ietf-ace-oauth-authz]. [I-D.ietf-ace-oauth-authz].
kid_arr = [ kid_arr = [
clientId, clientId,
?IdContext ?ContextId
] ]
kid = bstr .cbor kid_arr kid = bstr .cbor kid_arr
Figure 3: CDDL Notation of kid for Update of Access Rights Figure 3: CDDL Notation of kid for Update of Access Rights
An example of such a request, with payload in CBOR diagnostic An example of such a request, with payload in CBOR diagnostic
notation without the tag and value abbreviations is reported in notation without the tag and value abbreviations is reported in
Figure 4 Figure 4
skipping to change at page 9, line 20 skipping to change at page 9, line 20
o a client identifier o a client identifier
Additionally, the AS MAY send the following data, in the same Additionally, the AS MAY send the following data, in the same
response. response.
o a context identifier o a context identifier
o an AEAD algorithm o an AEAD algorithm
o an HKDF algorithm o an HMAC-based key derivation function (HKDF) algorithm
o a salt o a salt
o the OSCORE version number o the OSCORE version number
The OSCORE_Security_Context is a CBOR map object, defined in This data is transported in the the OSCORE_Input_Material. The
Section 3.2.1. This object is transported in the 'cnf' parameter of OSCORE_Input_Material is a CBOR map object, defined in Section 3.2.1.
the access token response as defined in Section 3.2 of This object is transported in the 'cnf' parameter of the access token
[I-D.ietf-ace-oauth-params], as the value of a field named 'osc', response as defined in Section 3.2 of [I-D.ietf-ace-oauth-params], as
registered in Section 9.5 and Section 9.6. The master secret MUST be the value of a field named 'osc', registered in Section 9.5 and
communicated as the 'ms' field in the 'osc' field in the 'cnf' Section 9.6.
parameter of the access token response as defined in Section 3.2 of
[I-D.ietf-ace-oauth-params]. The AEAD algorithm may be included as
the 'alg' parameter in the OSCORE_Security_Context; the HKDF
algorithm may be included as the 'hkdf' parameter of the
OSCORE_Security_Context, a salt may be included as the 'salt'
parameter of the OSCORE_Security_Context, and the OSCORE version
number may be included as the 'version' parameter of the
OSCORE_Security_Context.
The same parameters MUST be included as part of the access token. The AS MUST assign an identifier to the RS (server identifier), and
This profile RECOMMENDS the use of CBOR web token (CWT) as specified to the client (client identifier), and MAY assign an identifier to
in [RFC8392]. If the token is a CWT, the same the context (context identifier). These identifiers are then used as
OSCORE_Security_Context structure defined above MUST be placed in the Sender ID, Recipient ID and ID Context in the OSCORE context as
'osc' field of the 'cnf' claim of this token. The access token MUST described in section 3.1 of [RFC8613]: specifically, the server
be encrypted, since it will be transferred from the client to the RS identifier is used as Sender ID of the node acting as RS in this
over an unprotected channel. profile, and the client identifier is used as Sender ID of the node
acting as ACE client. These parameters are sent as clientId,
serverId and (when assigned) contextId in the OSCORE_Input_Material.
ClientId and serverId MUST be included in the OSCORE_Input_Material,
contextId MUST be included when assigned. The applications need to
consider that these identifiers are sent in the clear and may reveal
information about the endpoints, as mentioned in section 12.8 of
[RFC8613]. The pair (client identifier, context identifier) MUST be
unique in the set of all clients for a single RS.
The AS MUST also assign an identifier to the RS (serverId), and to The master secret MUST be communicated as the 'ms' field in the 'osc'
the client (clientId), and MAY assign an identifier to the context field in the 'cnf' parameter of the access token response. If
(contextId). These identifiers are then used as Sender ID, Recipient included, the AEAD algorithm is sent in the 'alg' parameter in the
ID and ID Context in the OSCORE context as described in section 3.1 OSCORE_Input_Material; the HKDF algorithm in the 'hkdf' parameter of
of [RFC8613]. Applications need to consider that these identifiers the OSCORE_Input_Material; a salt in the 'salt' parameter of the
are sent in the clear and may reveal information about the endpoints, OSCORE_Input_Material; and the OSCORE version in the 'version'
as mentioned in section 12.8 of [RFC8613]. The pair (client parameter of the OSCORE_Input_Material.
identifier, context identifier) MUST be unique in the set of all
clients for a single RS. Moreover, clientId, serverId and (when
assigned) contextId MUST be included in the OSCORE_Security_Context,
as defined in Section 3.2.1.
We assume in this document that a resource is associated to one The same parameters MUST be included in the claims associated with
single AS, which makes it possible for the AS to enforce uniqueness the access token. This profile RECOMMENDS the use of CBOR web token
of identifiers for each client requesting a particular resource to a (CWT) as specified in [RFC8392]. If the token is a CWT, the same
RS. If this is not the case, collisions of identifiers may occur at OSCORE_Input_Material structure defined above MUST be placed in the
the RS, in which case the RS needs to have a mechanism in place to 'osc' field of the 'cnf' claim of this token.
disambiguate identifiers or mitigate the effect of the collisions.
We assume in this document that an RS is associated to one single AS,
which makes it possible for the AS to enforce uniqueness of
identifiers for each client sending requests to an RS. If this is
not the case, collisions of identifiers may occur at the RS, in which
case the RS needs to have a mechanism in place to disambiguate
identifiers or mitigate the effect of the collisions.
Moreover, implementers of this specification need to be aware that if Moreover, implementers of this specification need to be aware that if
other authentication mechanisms are used to set up OSCORE between the other authentication mechanisms are used to set up OSCORE between the
same client and RS, that do not rely on AS assigning identifiers, same client and RS, that do not rely on AS assigning identifiers,
collisions may happen and need to be mitigated. A mitigation example collisions may happen and need to be mitigated. A mitigation example
would be to use distinct namespaces of identifiers for different would be to use distinct namespaces of identifiers for different
authentication mechanisms. authentication mechanisms.
The AS MUST send different OSCORE_Input_Material (and therefore
different access tokens) to different authorized clients, in order
for the RS to differentiate between clients.
Note that in Section 4.3 C sets the Sender ID of its Security Context Note that in Section 4.3 C sets the Sender ID of its Security Context
to the clientId value received and the Recipient ID to the serverId to the clientId value received and the Recipient ID to the serverId
value, and RS does the opposite. value, and RS does the opposite.
Figure 5 shows an example of an AS response, with payload in CBOR Figure 5 shows an example of an AS response, with payload in CBOR
diagnostic notation without the tag and value abbreviations. The diagnostic notation without the tag and value abbreviations. The
access token has been truncated for readability. access token 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'a5037674656d7053656e73 ... "access_token" : h'8343a1010aa2044c53 ...
(remainder of access token (CWT) omitted for brevity)', (remainder of access token (CWT) omitted for brevity)',
"profile" : "coap_oscore", "profile" : "coap_oscore",
"expires_in" : "3600", "expires_in" : "3600",
"cnf" : { "cnf" : {
"osc" : { "osc" : {
"alg" : "AES-CCM-16-64-128", "alg" : "AES-CCM-16-64-128",
"clientId" : h'00', "clientId" : h'00',
"serverId" : h'01', "serverId" : h'01',
"ms" : h'f9af838368e353e78888e1426bd94e6f' "ms" : h'f9af838368e353e78888e1426bd94e6f'
} }
} }
} }
Figure 5: Example AS-to-C Access Token response with OSCORE profile. Figure 5: Example AS-to-C Access Token response with OSCORE profile.
Figure 6 shows an example CWT, containing the necessary OSCORE Figure 6 shows an example CWT Claims Set, including the relevant
parameters in the 'cnf' claim, in CBOR diagnostic notation without OSCORE parameters in the 'cnf' claim, in CBOR diagnostic notation
tag and value abbreviations. without tag and value abbreviations.
{ {
"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" : {
"alg" : "AES-CCM-16-64-128", "alg" : "AES-CCM-16-64-128",
"clientId" : h'00', "clientId" : h'00',
"serverId" : h'01', "serverId" : h'01',
"ms" : h'f9af838368e353e78888e1426bd94e6f' "ms" : h'f9af838368e353e78888e1426bd94e6f'
} }
} }
Figure 6: Example CWT with OSCORE parameters. Figure 6: Example CWT Claims Set with OSCORE parameters.
The same CWT token as in Figure 6, using the value abbreviations The same CWT Claims Set as in Figure 6, using the value abbreviations
defined in [I-D.ietf-ace-oauth-authz] and [RFC8747] and encoded in defined in [I-D.ietf-ace-oauth-authz] and [RFC8747] and encoded in
CBOR is shown in Figure 7. CBOR is shown in Figure 7. The bytes in hexadecimal are reported in
the first column, while their corresponding CBOR meaning is reported
after the '#' sign on the second column, for easiness of readability.
NOTE TO THE RFC EDITOR: before publishing, it should be checked (and NOTE TO THE RFC EDITOR: before publishing, it should be checked (and
in case fixed) that the values used below (which are not yet in case fixed) that the values used below (which are not yet
registered) are the final values registered in IANA. registered) are the final values registered in IANA.
A5 # map(5) A5 # map(5)
03 # unsigned(3) 03 # unsigned(3)
76 # text(22) 76 # text(22)
74656D7053656E736F72496E4C6976696E67526F6F6D 74656D7053656E736F72496E4C6976696E67526F6F6D
# "tempSensorInLivingRoom" # "tempSensorInLivingRoom"
skipping to change at page 12, line 40 skipping to change at page 12, line 40
636C69656E74 # "client" 636C69656E74 # "client"
03 # unsigned(3) 03 # unsigned(3)
46 # bytes(6) 46 # bytes(6)
736572766572 # "server" 736572766572 # "server"
01 # unsigned(1) 01 # unsigned(1)
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"
Figure 7: Example CWT with OSCORE parameters. Figure 7: Example CWT Claims Set with OSCORE parameters, CBOR
encoded.
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
client identifier and the context identifier (if it was set and client identifier and the context identifier (if it was set and
included in the initial access token response by the AS) in the 'kid' included in the initial access token response by the AS) in the 'kid'
field in the 'cnf' parameter of the token, with the same structure field in the 'cnf' parameter of the token, with the same structure
defined in Figure 3. These identifiers need to be included in the defined in Figure 3. These identifiers need to be included in the
token in order for the RS to identify the previously generated token in order for the RS to identify the previously generated
Security Context. Security Context.
Figure 8 shows an example of such an AS response, with payload in Figure 8 shows an example of such an AS response, with payload in
CBOR diagnostic notation without the tag and value abbreviations. CBOR diagnostic notation without the tag and value abbreviations.
The access token has been truncated for readability. The access token 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'a5037674656d7053656e73 ... "access_token" : h'8343a1010aa2044c53 ...
(remainder of access token (CWT) omitted for brevity)', (remainder of access token (CWT) omitted for brevity)',
"profile" : "coap_oscore", "profile" : "coap_oscore",
"expires_in" : "3600" "expires_in" : "3600"
} }
Figure 8: Example AS-to-C Access Token response with OSCORE profile, Figure 8: Example AS-to-C Access Token response with OSCORE profile,
for update of access rights. for update of access rights.
Figure 9 shows an example CWT, containing the necessary OSCORE Figure 9 shows an example CWT Claims Set, containing the necessary
parameters in the 'cnf' claim for update of access rights, in CBOR OSCORE parameters in the 'cnf' claim for update of access rights, in
diagnostic notation without tag and value abbreviations. CBOR diagnostic notation without tag and value abbreviations.
{ {
"aud" : "tempSensorInLivingRoom", "aud" : "tempSensorInLivingRoom",
"iat" : "1360189224", "iat" : "1360189224",
"exp" : "1360289224", "exp" : "1360289224",
"scope" : "temperature_h", "scope" : "temperature_h",
"cnf" : { "cnf" : {
"kid" : h'43814100' "kid" : h'43814100'
} }
} }
Figure 9: Example CWT with OSCORE parameters for update of access Figure 9: Example CWT Claims Set with OSCORE parameters for update of
rights. access rights.
3.2.1. OSCORE_Security_Context Object 3.2.1. The OSCORE_Input_Material
An OSCORE_Security_Context is an object that represents part or all An OSCORE_Input_Material is an object that represents the input
of an OSCORE Security Context, i.e., the local set of information material to derive an OSCORE Security Context, i.e., the local set of
elements necessary to carry out the cryptographic operations in information elements necessary to carry out the cryptographic
OSCORE (Section 3.1 of [RFC8613]). In particular, the operations in OSCORE (Section 3.1 of [RFC8613]). In particular, the
OSCORE_Security_Context object is defined to be serialized and OSCORE_Input_Material is defined to be serialized and transported
transported between nodes, as specified by this document, but can between nodes, as specified by this document, but can also be used by
also be used by other specifications if needed. The other specifications if needed. The OSCORE_Input_Material can either
OSCORE_Security_Context object can either be encoded as a JSON object be encoded as a JSON object or as a CBOR map. The set of common
or as a CBOR map. The set of common parameters that can appear in an parameters that can appear in an OSCORE_Input_Material can be found
OSCORE_Security_Context object can be found in the IANA "OSCORE in the IANA "OSCORE Security Context Parameters" registry
Security Context Parameters" registry (Section 9.4), defined for (Section 9.4), defined for extensibility, and is specified below.
extensibility, and is specified below. All parameters are optional. All parameters are optional. Table 1 provides a summary of the
Table 1 provides a summary of the OSCORE_Security_Context parameters OSCORE_Input_Material parameters defined in this section.
defined in this section.
+-----------+-------+----------------+--------------+---------------+ +-----------+-------+-------------+-------------------+-------------+
| name | CBOR | CBOR type | registry | description | | name | CBOR | CBOR type | registry | description |
| | label | | | | | | label | | | |
+-----------+-------+----------------+--------------+---------------+ +-----------+-------+-------------+-------------------+-------------+
| version | 0 | int | | OSCORE | | version | 0 | unsigned | | OSCORE |
| | | | | Version | | | | integer | | Version |
| | | | | | | | | | | |
| ms | 1 | bstr | | OSCORE Master | | ms | 1 | byte string | | OSCORE |
| | | | | Secret value | | | | | | Master |
| | | | | | | | | | | Secret |
| clientId | 2 | bstr | | OSCORE Sender | | | | | | value |
| | | | | ID value of | | | | | | |
| | | | | the client, | | clientId | 2 | byte string | | OSCORE |
| | | | | OSCORE | | | | | | Sender ID |
| | | | | Recipient ID | | | | | | value of |
| | | | | value of the | | | | | | the client, |
| | | | | server | | | | | | OSCORE |
| | | | | | | | | | | Recipient |
| serverId | 3 | bstr | | OSCORE Sender | | | | | | ID value of |
| | | | | ID value of | | | | | | the server |
| | | | | the server, | | | | | | |
| | | | | OSCORE | | serverId | 3 | byte string | | OSCORE |
| | | | | Recipient ID | | | | | | Sender ID |
| | | | | value of the | | | | | | value of |
| | | | | client | | | | | | the server, |
| | | | | | | | | | | OSCORE |
| hkdf | 4 | tstr / int | COSE | OSCORE HKDF | | | | | | Recipient |
| | | | Algorithm | value | | | | | | ID value of |
| | | | Values | | | | | | | the client |
| | | | (HMAC-based) | | | | | | | |
| | | | | | | hkdf | 4 | text string | [COSE.Algorithms] | OSCORE HKDF |
| alg | 5 | tstr / int | COSE | OSCORE AEAD | | | | / integer | Values (HMAC- | value |
| | | | Algorithm | Algorithm | | | | | based) | |
| | | | Values | value | | | | | | |
| | | | (AEAD) | | | alg | 5 | text string | [COSE.Algorithms] | OSCORE AEAD |
| | | | | | | | | / integer | Values (AEAD) | Algorithm |
| salt | 6 | bstr | | OSCORE Master | | | | | | value |
| | | | | Salt value | | | | | | |
| | | | | | | salt | 6 | byte string | | an input to |
| contextId | 7 | bstr | | OSCORE ID | | | | | | OSCORE |
| | | | | Context value | | | | | | Master Salt |
+-----------+-------+----------------+--------------+---------------+ | | | | | value |
| | | | | |
| contextId | 7 | byte string | | OSCORE ID |
| | | | | Context |
| | | | | value |
+-----------+-------+-------------+-------------------+-------------+
Table 1: OSCORE_Security_Context Parameters Table 1: OSCORE_Input_Material Parameters
version: This parameter identifies the OSCORE Version number, which version: This parameter identifies the OSCORE Version number, which
is an int. For more information about this field, see section 5.4 is an unsigned integer. For more information about this field,
of [RFC8613]. In JSON, the "version" value is an integer. In see section 5.4 of [RFC8613]. In JSON, the "version" value is an
CBOR, the "version" type is int, and has label 0. integer. In CBOR, the "version" type is int, and has label 0.
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 Base64
encoded byte string. In CBOR, the "ms" type is bstr, and has encoded byte string. In CBOR, the "ms" type is bstr, and has
label 1. label 1.
clientId: This parameter identifies a client identifier as a byte clientId: This parameter identifies a client identifier as a byte
string. This identifier is used as OSCORE Sender ID in the client string. This identifier is used as OSCORE Sender ID in the client
and OSCORE Recipient ID in the server. For more information about and OSCORE Recipient ID in the server. For more information about
skipping to change at page 16, line 30 skipping to change at page 15, line 41
serverId: This parameter identifies a server identifier as a byte serverId: This parameter identifies a server identifier as a byte
string. This identifier is used as OSCORE Sender ID in the server string. This identifier is used as OSCORE Sender ID in the server
and OSCORE Recipient ID in the client. For more information about and OSCORE Recipient ID in the client. For more information about
this field, see section 3.1 of [RFC8613]. In JSON, the "serverId" this field, see section 3.1 of [RFC8613]. In JSON, the "serverId"
value is a Base64 encoded byte string. In CBOR, the "serverId" value is a Base64 encoded byte string. In CBOR, the "serverId"
type is bstr, and has label 3. type is bstr, and has label 3.
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 and MUST be HMAC-based HKDF algorithms. The value can registry (see [COSE.Algorithms]) and MUST be HMAC-based HKDF
either be the integer or the text string value of the HMAC-based algorithms. The value can either be the integer or the text
HKDF algorithm in the "COSE Algorithms" registry. In JSON, the string value of the HMAC-based HKDF algorithm in the "COSE
"hkdf" value is a case-sensitive ASCII string or an integer. In Algorithms" registry. In JSON, the "hkdf" value is a case-
CBOR, the "hkdf" type is tstr or int, and has label 4. sensitive ASCII string or an integer. In CBOR, the "hkdf" type is
tstr or int, and has label 4.
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 and MUST be AEAD algorithms. The value can either be the registry (see [COSE.Algorithms]) and MUST be AEAD algorithms. The
integer or the text string value of the HMAC-based HKDF algorithm value can either be the integer or the text string value of the
in the "COSE Algorithms" registry. In JSON, the "alg" value is a HMAC-based HKDF algorithm in the "COSE Algorithms" registry. In
case-sensitive ASCII string or an integer. In CBOR, the "alg" JSON, the "alg" value is a case-sensitive ASCII string or an
type is tstr or int, and has label 5. integer. In CBOR, the "alg" type is tstr or int, and has label 5.
salt: This parameter identifies the OSCORE Master Salt value, which salt: This parameter identifies an input to the OSCORE Master Salt
is a byte string. For more information about this field, see value, which is a byte string. For more information about this
section 3.1 of [RFC8613]. In JSON, the "salt" value is a Base64 field, see section 3.1 of [RFC8613]. In JSON, the "salt" value is
encoded byte string. In CBOR, the "salt" type is bstr, and has a Base64 encoded byte string. In CBOR, the "salt" type is bstr,
label 6. and has label 6.
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 bstr, and has label 7. CBOR, the "contextID" type is bstr, and has label 7.
An example of JSON OSCORE_Security_Context is given in Figure 10. An example of JSON OSCORE_Input_Material is given in Figure 10.
"osc" : { "osc" : {
"alg" : "AES-CCM-16-64-128", "alg" : "AES-CCM-16-64-128",
"clientId" : b64'AA', "clientId" : b64'AA',
"serverId" : b64'AQ', "serverId" : b64'AQ',
"ms" : b64'+a+Dg2jjU+eIiOFCa9lObw' "ms" : b64'+a+Dg2jjU+eIiOFCa9lObw'
} }
Figure 10: Example JSON OSCORE_Security_Context object Figure 10: Example JSON OSCORE_Input_Material
The CDDL grammar describing the CBOR OSCORE_Security_Context object The CDDL grammar describing the CBOR OSCORE_Input_Material is:
is:
OSCORE_Security_Context = { OSCORE_Input_Material = {
? 0 => int, ; version ? 0 => int, ; version
? 1 => bstr, ; ms ? 1 => bstr, ; ms
? 2 => bstr, ; clientId ? 2 => bstr, ; clientId
? 3 => bstr, ; serverId ? 3 => bstr, ; serverId
? 4 => tstr / int, ; hkdf ? 4 => tstr / int, ; hkdf
? 5 => tstr / int, ; alg ? 5 => tstr / int, ; alg
? 6 => bstr, ; salt ? 6 => bstr, ; salt
? 7 => bstr, ; contextId ? 7 => 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 client and RS. The
client generates a nonce N1, and posts it together with the token client generates a nonce N1, and posts it together with the token
that includes the materials (e.g., OSCORE parameters) received from that includes the materials (e.g., OSCORE parameters) received from
the AS to the RS. The RS then generates a nonce N2, and uses the AS to the RS. The RS then generates a nonce N2, and uses
Section 3.2 of [RFC8613] to derive a security context based on a Section 3.2 of [RFC8613] to derive a security context based on a
shared master secret and the two nonces, established between client shared master secret and the two nonces, established between client
and server. The nonces are encoded as CBOR bstr if CBOR is used, and and server. The nonces are encoded as bstr if CBOR is used, and as
as Base64 string if JSON is used. This security context is used to Base64 string if JSON is used. This security context is used to
protect all future communication between client and RS using OSCORE, protect all future communication between client and RS using OSCORE,
as long as the access token is valid. as long as the access token is valid.
Note that the RS and client authenticates themselves by generating Note that the RS and client authenticates themselves by generating
the shared OSCORE Security Context using the pop-key as master the shared OSCORE Security Context using the pop-key as master
secret. An attacker posting a valid token to the RS will not be able secret. An attacker posting a valid token to the RS will not be able
to generate a valid OSCORE context and thus not be able to prove to generate a valid OSCORE context and thus not be able to prove
possession of the pop-key. possession of the pop-key. Additionally, the mutual authentication
is only achieved after the client has successfully verified the
response from the RS.
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 very unlikely to have been The client MUST generate a nonce value very unlikely to have been
previously used with the same input keying material. This profile previously used with the same input keying material. This profile
RECOMMENDS to use a 64-bit long random number as nonce's value. The RECOMMENDS to use a 64-bit long random number as nonce's value. The
client MUST store the nonce N1 as long as the response from the RS is client MUST store the nonce N1 as long as the response from the RS is
not received and the access token related to it is still valid. The not received and the access token related to it is still valid. The
client MUST use CoAP and the Authorization Information resource as client MUST use CoAP and the Authorization Information resource as
described in section 5.8.1 of [I-D.ietf-ace-oauth-authz] to transport described in section 5.8.1 of [I-D.ietf-ace-oauth-authz] to transport
the token and N1 to the RS. the token and N1 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 described in section 5.8.1 of [I-D.ietf-ace-oauth-authz], from what is described in section 5.8.1 of
which only transports the token without any CBOR wrapping. In this [I-D.ietf-ace-oauth-authz], which only transports the token without
profile, the client MUST wrap the token and N1 in a CBOR map. The any CBOR wrapping. In this profile, the client MUST wrap the token
client MUST use the Content-Format "application/ace+cbor" defined in and N1 in a CBOR map. The client MUST use the Content-Format
section 8.14 of [I-D.ietf-ace-oauth-authz]. The client MUST include "application/ace+cbor" defined in section 8.14 of
the access token using the "access_token" parameter and N1 using the [I-D.ietf-ace-oauth-authz]. The client MUST include the access token
'nonce1' parameter defined in Section 4.1.1. using the "access_token" parameter and N1 using the 'nonce1'
parameter defined in Section 4.1.1.
The authz-info endpoint is not protected, nor are the responses from
this resource.
The access token MUST be encrypted, since it is transferred from the The communication with the authz-info endpoint does not have to be
client to the RS over an unprotected channel. protected, except for the update of access rights case described
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 nonces will be Security Context to be used with the RS, as different nonces will be
used. used.
skipping to change at page 19, line 11 skipping to change at page 18, line 18
RS, with payload in CBOR diagnostic notation without the tag and RS, with payload in CBOR diagnostic notation without the tag and
value abbreviations. The access token has been truncated for value abbreviations. The access token has been truncated for
readability. 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'a5037674656d7053656e73 ... "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'
} }
Figure 11: Example C-to-RS POST /authz-info request using CWT Figure 11: 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
skipping to change at page 19, line 50 skipping to change at page 19, line 10
[I-D.ietf-ace-oauth-authz]: the RS must verify the validity of the [I-D.ietf-ace-oauth-authz]: the RS must verify the validity of the
token. If the token is valid, the RS must respond to the POST token. If the token is valid, the RS must respond to the POST
request with 2.01 (Created). If the token is valid but is associated request with 2.01 (Created). If the token is valid but is associated
to claims that the RS cannot process (e.g., an unknown scope), or if to claims that the RS cannot process (e.g., an unknown scope), or if
any of the expected parameters in the 'osc' is missing (e.g., any of any of the expected parameters in the 'osc' is missing (e.g., any of
the mandatory parameters from the AS), or if any parameters received the mandatory parameters from the AS), or if any parameters received
in the 'osc' is unrecognized, the RS must respond with an error in the 'osc' is unrecognized, the RS must respond with an error
response code equivalent to the CoAP code 4.00 (Bad Request). In the response code equivalent to the CoAP code 4.00 (Bad Request). In the
latter two cases, the RS may provide additional information in the latter two cases, the RS may provide additional information in the
error response, in order to clarify what went wrong. The RS may make error response, in order to clarify what went wrong. The RS may make
an introspection request to validate the token before responding to an introspection request (see Section 5.7.1 of
the POST request to the authz-info endpoint. [I-D.ietf-ace-oauth-authz]) to validate the token before responding
to the POST 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 very unlikely to have
been previously used with the same input keying material, and send it been previously used with the same input keying material, and send it
within the 2.01 (Created) response. The payload of the 2.01 within the 2.01 (Created) response. The payload of the 2.01
(Created) response MUST be a CBOR map containing the 'nonce2' (Created) response MUST be a CBOR map containing the 'nonce2'
parameter defined in Section 4.2.1, set to N2. This profile parameter defined in Section 4.2.1, set to N2. This profile
RECOMMENDS to use a 64-bit long random number as nonce's value. The RECOMMENDS to use a 64-bit long random number as nonce's value. The
RS MUST use the Content-Format "application/ace+cbor" defined in RS MUST use the Content-Format "application/ace+cbor" defined in
section 8.14 of [I-D.ietf-ace-oauth-authz]. section 8.14 of [I-D.ietf-ace-oauth-authz].
skipping to change at page 20, line 37 skipping to change at page 19, line 46
As specified in section 5.8.3 of [I-D.ietf-ace-oauth-authz], the RS As specified in section 5.8.3 of [I-D.ietf-ace-oauth-authz], the RS
must notify the client with an error response with code 4.01 must notify the client with an error response with code 4.01
(Unauthorized) for any long running request before terminating the (Unauthorized) for any long running request before terminating the
session, when the access token expires. session, when the access token expires.
If the RS receives the token in a OSCORE protected message, it means If the RS receives the token in a 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 discard any nonce in the request, if any was sent. The RS MUST MUST discard any nonce in the request, if any was sent. The RS MUST
check that the "kid" of the "cnf" parameter of the new access token check that the "kid" of the "cnf" parameter of the new access token
matches the OSCORE Security Context used to protect the message. If matches the OSCORE Security Context used to protect the message. If
that's the case, the RS MUST discard the old token and associate the that is the case, the RS MUST discard the old token and associate the
new token to the Security Context identified by "kid". The RS MUST new token to the Security Context identified by the "kid" value in
respond with a 2.01 (Created) response protected with the same the "cnf" parameter. The RS MUST respond with a 2.01 (Created)
Security Context, with no payload. If any verification fails, the RS response protected with the same Security Context, with no payload.
MUST respond with a 4.01 (Unauthorized) error response.
If any verification fails, 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 [I-D.ietf-ace-oauth-authz], when
receiving an updated access token with updated authorization receiving an updated access token with updated authorization
information from the client (see Section 3.1), it is recommended that information from the client (see Section 3.1), it is recommended that
the RS overwrites the previous token, that is only the latest the RS overwrites the previous token, that is only the latest
authorization information in the token received by the RS is valid. authorization information in the token received by the RS is valid.
This simplifies for the RS to keep track of authorization information This simplifies the process needed by the RS to keep track of
for a given client. authorization information for a 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 This parameter MUST be sent from the RS to the Client if the ace
profile used is coap_oscore. The parameter is encoded as a byte profile used is coap_oscore. The parameter is encoded as a byte
string for CBOR-based interactions, and as a string (Base64 encoded string for CBOR-based interactions, and as a string (Base64 encoded
binary) for JSON-based interactions. This parameter is registered in binary) for JSON-based interactions. This parameter is registered in
Section 9.2 Section 9.2.
4.3. OSCORE Setup 4.3. OSCORE Setup
Once receiving the 2.01 (Created) response from the RS, following the Once receiving the 2.01 (Created) response from the RS, following the
POST request to authz-info endpoint, the client MUST extract the CBOR POST request to authz-info endpoint, the client MUST extract the bstr
bstr nonce N2 from the 'nonce2' parameter in the CBOR map in the nonce N2 from the 'nonce2' parameter in the CBOR map in the payload
payload of the response. Then, the client MUST set the Master Salt of the response. Then, the client MUST set the Master Salt of the
of the Security Context created to communicate with the RS to 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 | N1 | N2, where | denotes byte string concatenation, where salt salt | N1 | N2, where | denotes byte string concatenation, where salt
was received from the AS in Section 3.2, and where N1 and N2 are the is the CBOR byte string received from the AS in Section 3.2, and
two nonces encoded as CBOR bstr. The client MUST set the Master where N1 and N2 are the two nonces encoded as CBOR byte strings. An
Secret, Sender ID and Recipient ID from the parameters received from example of Master Salt construction using CBOR encoding is given in
the AS in Section 3.2. The client MUST set the AEAD Algorithm, ID Figure 13.
Context, HKDF, and OSCORE Version from the parameters received from
the AS in Section 3.2, if present. In case these parameters are N1, N2 and input salt expressed in CBOR diagnostic notation:
omitted, the default values are used as described in sections 3.2 and nonce1 = h'018a278f7faab55a'
5.4 of [RFC8613]. After that, the client MUST derive the complete nonce2 = h'25a8991cd700ac01'
Security Context following section 3.2.1 of [RFC8613]. From this input salt = h'f9af838368e353e78888e1426bd94e6f'
point on, the client MUST use this Security Context to communicate
with the RS when accessing the resources as specified by the N1, N2 and input salt as CBOR encoded byte strings:
authorization information. nonce1 = 0x48018a278f7faab55a
nonce2 = 0x4825a8991cd700ac01
input salt = 0x50f9af838368e353e78888e1426bd94e6f
Master Salt = 0x50 f9af838368e353e78888e1426bd94e6f 48 018a278f7faab55a 48 25a8991cd700ac01
Figure 13: Example of Master Salt construction using CBOR encoding
If JSON is used instead of CBOR, the Master Salt of the Security
Context is the Base64 encoding of the concatenation of the same
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
bytes. An example of Master Salt construction using Base64 encoding
is given in Figure 14.
N1, N2 and input salt values:
nonce1 = 0x018a278f7faab55a (8 bytes)
nonce2 = 0x25a8991cd700ac01 (8 bytes)
input salt = 0xf9af838368e353e78888e1426bd94e6f (16 bytes)
Input to Base64 encoding: 0x10 f9af838368e353e78888e1426bd94e6f 08 018a278f7faab55a 08 25a8991cd700ac01
Master Salt = b64'EPmvg4No41PniIjhQmvZTm8IAYonj3+qtVoIJaiZHNcArAE='
Figure 14: Example of Master Salt construction using Base64 encoding
The client MUST set the Master Secret, Sender ID and Recipient ID
from the parameters received from the AS in Section 3.2. 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 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]. After that,
the client MUST derive the complete Security Context following
section 3.2.1 of [RFC8613]. From this point on, the client MUST use
this Security Context to communicate with the RS when accessing the
resources as specified by the authorization information.
If any of the expected parameters is missing (e.g., any of the If any of the expected parameters is missing (e.g., any of the
mandatory parameters from the AS, the client MUST stop the exchange, mandatory parameters from the AS, 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 RS The client then uses this Security Context to send requests to 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 this order: Master Salt to the concatenation of salt, N1, and N2, in the same way described
= salt | N1 | N2, where | denotes byte string concatenation, where above. An example of Master Salt construction using CBOR encoding is
salt was received from the AS in Section 4.2, and where N1 and N2 are given in Figure 13 and using Base64 encoding is given in Figure 14.
the two nonces encoded as CBOR bstr. The RS MUST set the Master The RS MUST set the Master Secret, Sender ID and Recipient ID from
Secret, Sender ID and Recipient ID from the parameters, received from the parameters, 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 Section 4.2. The RS MUST set the AEAD Algorithm, ID
Context, HKDF, and OSCORE Version from the parameters received from
the AS and forwarded by the client in the access token in Section 4.1 the AS and forwarded by the client in the access token in Section 4.1
after validation of the token as specified in Section 4.2. The RS after validation of the token as specified in Section 4.2, if
MUST set the AEAD Algorithm, ID Context, HKDF, and OSCORE Version present. In case an optional parameter is omitted, the default value
from the parameters received from the AS and forwarded by the client SHALL be used as described in sections 3.2 and 5.4 of [RFC8613].
in the access token in Section 4.1 after validation of the token as After that, the RS MUST derive the complete Security Context
specified in Section 4.2, if present. In case these parameters are following section 3.2.1 of [RFC8613], and MUST associate this
omitted, the default values are used as described in sections 3.2 and Security Context with the authorization information from the access
5.4 of [RFC8613]. After that, the RS MUST derive the complete token.
Security Context following section 3.2.1 of [RFC8613], and MUST
associate this Security Context with the authorization information
from the access 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 C using OSCORE. If OSCORE verification fails, error responses to C using OSCORE. If OSCORE verification fails, error
responses are used, as specified in section 8 of [RFC8613]. 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 Section 4.4. The
RS MUST NOT use the Security Context after the related token has RS MUST NOT use the Security Context after the related token has
expired, and MUST respond with a unprotected 4.01 (Unauthorized) expired, and MUST respond with a unprotected 4.01 (Unauthorized)
error message to requests received that correspond to a Security error message to requests received that correspond to a Security
Context with an expired token. Context with an expired token.
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
profile is executed. Subsequently, client and RS can update their ID
Context by running a mechanism such as the one defined in
Appendix B.2 of [RFC8613] if they support it. In that case, the ID
Context in the OSCORE Security Context will not match the "contextId"
parameter of the corresponding OSCORE_Input_Material. That is fine,
as long as the nodes store and use the "contextId" value to identify
the correct OSCORE_Input_Material at the AS.
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 [I-D.ietf-ace-oauth-authz]: if an RS receives an OSCORE-protected
request from a client, then the RS processes it according to request from a client, then the RS processes it according to
[RFC8613]. If OSCORE verification succeeds, and the target resource [RFC8613]. If OSCORE verification succeeds, and the target resource
requires authorization, the RS retrieves the authorization requires authorization, the RS retrieves the authorization
information using the access token associated to the Security information using the access token associated to the Security
Context. The RS then must verify that the authorization information Context. The RS then must verify that the authorization information
covers the resource and the action requested. covers the resource and the action requested.
The response code must be 4.01 (Unauthorized) in case the client has
a valid token associated with that Security Context, but the Security
Context has not been used before, as the proof-of-possession in this
profile is performed by both parties verifying that they have
established the same Security Context.
5. Secure Communication with AS 5. Secure Communication with AS
As specified in the ACE framework (section 5.7 of As specified in the ACE framework (section 5.7 of
[I-D.ietf-ace-oauth-authz]), the requesting entity (RS and/or client) [I-D.ietf-ace-oauth-authz]), the requesting entity (RS and/or client)
and the AS communicates via the introspection or token endpoint. The and the AS communicates via the introspection or token endpoint. The
use of CoAP and OSCORE ([RFC8613]) for this communication is use of CoAP and OSCORE ([RFC8613]) for this communication is
RECOMMENDED in this profile, other protocols (such as HTTP and DTLS RECOMMENDED in this profile, other protocols (such as HTTP and DTLS
or TLS) MAY be used instead. or TLS) MAY be used 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
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7. Security Considerations 7. Security Considerations
This document specifies a profile for the Authentication and This document specifies a profile for the Authentication and
Authorization for Constrained Environments (ACE) framework Authorization for Constrained Environments (ACE) framework
[I-D.ietf-ace-oauth-authz]. Thus the general security considerations [I-D.ietf-ace-oauth-authz]. Thus the general security considerations
from the framework also 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
performed by both parties verifying that they have established the
same Security Context, as specified in Section 4.3, which means that
both the OSCORE request and OSCORE pass verification. RS
authentication requires both that the client trusts the AS and that
the OSCORE response from the RS pass 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 usecase corresponds to the this profile should make sure that their usecase 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 in the exchange guarantees uniqueness of AEAD Since the use of nonces in the exchange guarantees uniqueness of AEAD
keys and nonces, it is REQUIRED that nonces are not reused with the keys and nonces, it is REQUIRED that nonces are not reused with the
skipping to change at page 24, line 43 skipping to change at page 25, line 4
of state on either node does not provoke re-use. If that is not of state on either node does not provoke re-use. If that is not
guaranteed, nodes are susceptible to re-use of AEAD (nonces, keys) guaranteed, nodes are susceptible to re-use of AEAD (nonces, keys)
pairs, especially since an on-path attacker can cause the client to pairs, especially since an on-path attacker can cause the client to
use an arbitrary nonce for Security Context establishment by use an arbitrary nonce for Security Context establishment by
replaying client-to-server messages. replaying client-to-server messages.
This profile recommends that the RS maintains a single access token This profile recommends that the RS maintains a single access token
for a client. The use of multiple access tokens for a single client for a client. The use of multiple access tokens for a single client
increases the strain on the resource server as it must consider every increases the strain on the resource server as it must consider every
access token and calculate the actual permissions of the client. access token and calculate the actual permissions of the client.
Also, tokens indicating different or disjoint permissions from each Also, tokens indicating different or disjoint permissions from each
other may lead the server to enforce wrong permissions. If one of other may lead the server to enforce wrong permissions. If one of
the access tokens expires earlier than others, the resulting the access tokens expires earlier than others, the resulting
permissions may offer insufficient protection. Developers should permissions may offer insufficient protection. Developers should
avoid using multiple access tokens for a client. avoid using multiple access tokens for a client.
If a single OSCORE_Input_Material is used with multiple RSs, the RSs
can impersonate C to one of the other RS, and impersonate another RS
to the client. If a master secret is used with several clients, the
Cs can impersonate RS to one of the other C. 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 RSs can impersonate AS
to one of the other RS. If the token key is used for any other
communication between the RSs and AS, the RSs can 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 Authentication and
Authorization for Constrained Environments (ACE) framework Authorization for Constrained Environments (ACE) framework
[I-D.ietf-ace-oauth-authz]. Thus the general privacy considerations [I-D.ietf-ace-oauth-authz]. Thus the general privacy considerations
from the framework also 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, thus 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.
Although encrypted, the token is sent in the clear to the authz-info The token is sent in the clear to the authz-info endpoint, so if a
endpoint, so if a client uses the same single token from multiple client uses the same single token from multiple locations with
locations with multiple Resource Servers, it can risk being tracked multiple Resource Servers, it can risk being tracked by the token's
by the token's value. 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, that might leak some
information about the client). information about the client).
The AS is the party tasked of assigning the identifiers used in The AS is the party tasked with assigning the identifiers used in
OSCORE, which are privacy sensitive (see Section 12.8 of [RFC8613]), OSCORE, which are privacy sensitive (see Section 12.8 of [RFC8613]),
and which could reveal information about the client, or may be used and which could reveal information about the client, or may be used
for correlating requests from one client. for 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 Note to RFC Editor: Please replace all occurrences of "[[this
specification]]" with the RFC number of this specification and delete specification]]" with the RFC number of this specification and delete
this paragraph. this paragraph.
9.1. ACE OAuth Profile Registry 9.1. ACE Profile Registry
The following registration is done for the ACE OAuth Profile Registry The following registration is done for the ACE Profile Registry
following the procedure specified in section 8.7 of following the procedure specified in section 8.8 of
[I-D.ietf-ace-oauth-authz]: [I-D.ietf-ace-oauth-authz]:
o Profile name: coap_oscore o Name: coap_oscore
o Profile Description: Profile for using OSCORE to secure o Description: Profile for using OSCORE to secure communication
communication between constrained nodes using the Authentication between constrained nodes using the Authentication and
and Authorization for Constrained Environments framework. Authorization for Constrained Environments framework.
o Profile ID: TBD (value between 1 and 255) o CBOR Value: TBD (value between 1 and 255)
o Change Controller: IESG o Reference: [[this specification]]
o Specification Document(s): [[this specification]]
9.2. OAuth Parameters Registry 9.2. OAuth Parameters Registry
The following registrations are done for the OAuth Parameters The following registrations are done for the OAuth Parameters
Registry following the procedure specified in section 11.2 of Registry following the procedure specified in section 11.2 of
[RFC6749]: [RFC6749]:
o Parameter name: nonce1 o Parameter name: nonce1
o Parameter usage location: token request o Parameter usage location: client-rs request
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): [[this specification]] o Specification Document(s): [[this specification]]
o Parameter name: nonce2 o Parameter name: nonce2
o Parameter usage location: token response o Parameter usage location: rs-client response
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): [[this specification]] o Specification Document(s): [[this specification]]
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 are done for the OAuth Parameters CBOR
Mappings Registry following the procedure specified in section 8.9 of Mappings Registry following the procedure specified in section 8.10
[I-D.ietf-ace-oauth-authz]: of [I-D.ietf-ace-oauth-authz]:
o Name: nonce1 o Name: nonce1
o CBOR Key: TBD1 o CBOR Key: TBD1
o Value Type: bstr o Value Type: bstr
o Reference: [[this specification]] o Reference: [[this specification]]
o Name: nonce2 o Name: nonce2
o CBOR Key: TBD2 o CBOR Key: TBD2
o Value Type: IESG o Value Type: bstr
o Reference: [[this specification]] o Reference: [[this specification]]
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 It is requested that IANA create a new registry entitled "OSCORE
Security Context Parameters" registry. The registry is to be created Security Context Parameters" registry. The registry is to be created
as Expert Review Required. Guidelines for the experts is provided as Expert Review Required. Guidelines for the experts is provided
Section 9.7. It should be noted that in addition to the expert Section 9.7. It should be noted that in addition to the expert
review, some portions of the registry require a specification, review, some portions of the registry require a specification,
potentially on standards track, be supplied as well. potentially on standards track, be supplied as well.
skipping to change at page 27, line 41 skipping to change at page 28, line 12
The specification column for all of these entries will be this The specification column for all of these entries will be this
document and [RFC8613]. 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 is done for the CWT Confirmation Methods
Registry following the procedure specified in section 7.2.1 of Registry following the procedure specified in section 7.2.1 of
[RFC8747]: [RFC8747]:
o Confirmation Method Name: "osc" o Confirmation Method Name: "osc"
o Confirmation Method Description: OSCORE_Security_Context carrying o Confirmation Method Description: OSCORE_Input_Material carrying
the parameters for using OSCORE per-message security with implicit the parameters for using OSCORE per-message security with implicit
key confirmation key confirmation
o Confirmation Key: TBD (value between 4 and 255) o Confirmation Key: TBD (value between 4 and 255)
o Confirmation Value Type(s): map o Confirmation Value Type(s): map
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): Section 3.2.1 of [[this specification]] o Specification Document(s): Section 3.2.1 of [[this specification]]
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 is done for the JWT Confirmation Methods
Registry following the procedure specified in section 6.2.1 of Registry following the procedure specified in section 6.2.1 of
[RFC7800]: [RFC7800]:
o Confirmation Method Value: "osc" o Confirmation Method Value: "osc"
o Confirmation Method Description: OSCORE_Security_Context carrying o Confirmation Method Description: OSCORE_Input_Material carrying
the parameters for using OSCORE per-message security with implicit the parameters for using OSCORE per-message security with implicit
key confirmation key confirmation
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): Section 3.2.1 of [[this specification]] o Specification Document(s): Section 3.2.1 of [[this specification]]
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
skipping to change at page 29, line 9 skipping to change at page 29, line 23
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]
IANA, "COSE Algorithms",
<https://www.iana.org/assignments/cose/
cose.xhtml#algorithms>.
[I-D.ietf-ace-oauth-authz] [I-D.ietf-ace-oauth-authz]
Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and
H. Tschofenig, "Authentication and Authorization for H. Tschofenig, "Authentication and Authorization for
Constrained Environments (ACE) using the OAuth 2.0 Constrained Environments (ACE) using the OAuth 2.0
Framework (ACE-OAuth)", draft-ietf-ace-oauth-authz-33 Framework (ACE-OAuth)", draft-ietf-ace-oauth-authz-35
(work in progress), February 2020. (work in progress), June 2020.
[I-D.ietf-ace-oauth-params] [I-D.ietf-ace-oauth-params]
Seitz, L., "Additional OAuth Parameters for Authorization Seitz, L., "Additional OAuth Parameters for Authorization
in Constrained Environments (ACE)", draft-ietf-ace-oauth- in Constrained Environments (ACE)", draft-ietf-ace-oauth-
params-13 (work in progress), April 2020. params-13 (work in progress), April 2020.
[I-D.ietf-cbor-7049bis]
Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", draft-ietf-cbor-7049bis-14 (work
in progress), June 2020.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained [RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252, Application Protocol (CoAP)", RFC 7252,
DOI 10.17487/RFC7252, June 2014, DOI 10.17487/RFC7252, June 2014,
<https://www.rfc-editor.org/info/rfc7252>. <https://www.rfc-editor.org/info/rfc7252>.
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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
o Optionally specify new grant types: Not specified o Optionally specify new grant types: Not specified
o Optionally define the use of client certificates as client o Optionally define the use of client certificates as client
credential type: Not specified credential type: Not specified
o Specify the communication protocol the client and RS the must use: o Specify the communication protocol the client and RS the must use:
CoAP CoAP
o Specify the security protocol the client and RS must use to o Specify the security protocol the client and RS must use to
protect their communication: OSCORE protect their communication: OSCORE
o Specify how the client and the RS mutually authenticate: o 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
client has verified an OSCORE response using this security
context.
o Specify the proof-of-possession protocol(s) and how to select one, o 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; pre-established symmetric
keys keys
o Specify a unique ace_profile identifier: coap_oscore o Specify a unique ace_profile identifier: coap_oscore
o If introspection is supported: Specify the communication and o 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)
o Specify the communication and security protocol for interactions o 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)
o Specify how/if the authz-info endpoint is protected, including how o Specify how/if the authz-info endpoint is protected, including how
error responses are protected: Not protected. error responses are protected: Not protected.
o Optionally define other methods of token transport than the authz- o Optionally define other methods of token transport than the authz-
info endpoint: Not defined info endpoint: Not defined
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