draft-ietf-ace-oauth-authz-04.txt   draft-ietf-ace-oauth-authz-05.txt 
ACE Working Group L. Seitz ACE Working Group L. Seitz
Internet-Draft SICS Internet-Draft SICS
Intended status: Standards Track G. Selander Intended status: Standards Track G. Selander
Expires: May 4, 2017 Ericsson Expires: August 7, 2017 Ericsson
E. Wahlstroem E. Wahlstroem
S. Erdtman S. Erdtman
Spotify AB Spotify AB
H. Tschofenig H. Tschofenig
ARM Ltd. ARM Ltd.
October 31, 2016 February 3, 2017
Authentication and Authorization for Constrained Environments (ACE) Authentication and Authorization for Constrained Environments (ACE)
draft-ietf-ace-oauth-authz-04 draft-ietf-ace-oauth-authz-05
Abstract Abstract
This specification defines a framework for authentication and This specification defines a framework for authentication and
authorization in Internet of Things (IoT) environments. The authorization in Internet of Things (IoT) environments. The
framework is based on a set of building blocks including OAuth 2.0 framework is based on a set of building blocks including OAuth 2.0
and CoAP, thus making a well-known and widely used authorization and CoAP, thus making a well-known and widely used authorization
solution suitable for IoT devices. Existing specifications are used solution suitable for IoT devices. Existing specifications are used
where possible, but where the constraints of IoT devices require it, where possible, but where the constraints of IoT devices require it,
extensions are added and profiles are defined. extensions are added and profiles are defined.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 4, 2017. This Internet-Draft will expire on August 7, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. OAuth 2.0 . . . . . . . . . . . . . . . . . . . . . . . . 6 3.1. OAuth 2.0 . . . . . . . . . . . . . . . . . . . . . . . . 6
3.2. CoAP . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.2. CoAP . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4. Protocol Interactions . . . . . . . . . . . . . . . . . . . . 9 4. Protocol Interactions . . . . . . . . . . . . . . . . . . . . 9
5. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6. The 'Token' Endpoint . . . . . . . . . . . . . . . . . . . . 14 6. The 'Token' Endpoint . . . . . . . . . . . . . . . . . . . . 14
6.1. Client-to-AS Request . . . . . . . . . . . . . . . . . . 15 6.1. Client Credentials and Grants . . . . . . . . . . . . . . 15
6.2. AS-to-Client Response . . . . . . . . . . . . . . . . . . 17 6.2. Client-to-AS Request . . . . . . . . . . . . . . . . . . 15
6.3. Error Response . . . . . . . . . . . . . . . . . . . . . 19 6.3. AS-to-Client Response . . . . . . . . . . . . . . . . . . 18
6.4. New Request and Response Parameters . . . . . . . . . . . 19 6.4. Error Response . . . . . . . . . . . . . . . . . . . . . 20
6.4.1. Audience . . . . . . . . . . . . . . . . . . . . . . 19 6.5. Request and Response Parameters . . . . . . . . . . . . . 20
6.4.2. Grant Type . . . . . . . . . . . . . . . . . . . . . 19 6.5.1. Audience . . . . . . . . . . . . . . . . . . . . . . 20
6.4.3. Token Type . . . . . . . . . . . . . . . . . . . . . 19 6.5.2. Grant Type . . . . . . . . . . . . . . . . . . . . . 21
6.4.4. Profile . . . . . . . . . . . . . . . . . . . . . . . 20 6.5.3. Token Type . . . . . . . . . . . . . . . . . . . . . 21
6.4.5. Confirmation . . . . . . . . . . . . . . . . . . . . 20 6.5.4. Profile . . . . . . . . . . . . . . . . . . . . . . . 21
6.5. Mapping parameters to CBOR . . . . . . . . . . . . . . . 22 6.5.5. Confirmation . . . . . . . . . . . . . . . . . . . . 22
7. The 'Introspect' Endpoint . . . . . . . . . . . . . . . . . . 23 6.6. Mapping parameters to CBOR . . . . . . . . . . . . . . . 24
7.1. RS-to-AS Request . . . . . . . . . . . . . . . . . . . . 24 7. The 'Introspect' Endpoint . . . . . . . . . . . . . . . . . . 24
7.2. AS-to-RS Response . . . . . . . . . . . . . . . . . . . . 24 7.1. RS-to-AS Request . . . . . . . . . . . . . . . . . . . . 25
7.3. Error Response . . . . . . . . . . . . . . . . . . . . . 25 7.2. AS-to-RS Response . . . . . . . . . . . . . . . . . . . . 25
7.4. Client Token . . . . . . . . . . . . . . . . . . . . . . 26 7.3. Error Response . . . . . . . . . . . . . . . . . . . . . 27
7.5. Mapping Introspection parameters to CBOR . . . . . . . . 28 7.4. Client Token . . . . . . . . . . . . . . . . . . . . . . 27
8. The Access Token . . . . . . . . . . . . . . . . . . . . . . 28 7.5. Mapping Introspection parameters to CBOR . . . . . . . . 29
8.1. The 'Authorization Information' Endpoint . . . . . . . . 29 8. The Access Token . . . . . . . . . . . . . . . . . . . . . . 29
8.2. Token Expiration . . . . . . . . . . . . . . . . . . . . 29 8.1. The 'Authorization Information' Endpoint . . . . . . . . 30
9. Security Considerations . . . . . . . . . . . . . . . . . . . 30 8.2. Token Expiration . . . . . . . . . . . . . . . . . . . . 30
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 31 9. Security Considerations . . . . . . . . . . . . . . . . . . . 31
10.1. OAuth Introspection Response Parameter Registration . . 31 10. Privacy Considerations . . . . . . . . . . . . . . . . . . . 33
10.2. OAuth Parameter Registration . . . . . . . . . . . . . . 32 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33
10.3. OAuth Access Token Types . . . . . . . . . . . . . . . . 32 11.1. OAuth Introspection Response Parameter Registration . . 33
10.4. Token Type Mappings . . . . . . . . . . . . . . . . . . 33 11.2. OAuth Parameter Registration . . . . . . . . . . . . . . 34
10.4.1. Registration Template . . . . . . . . . . . . . . . 33 11.3. OAuth Access Token Types . . . . . . . . . . . . . . . . 34
10.4.2. Initial Registry Contents . . . . . . . . . . . . . 33 11.4. Token Type Mappings . . . . . . . . . . . . . . . . . . 35
10.5. CBOR Web Token Claims . . . . . . . . . . . . . . . . . 33 11.4.1. Registration Template . . . . . . . . . . . . . . . 35
10.6. ACE Profile Registry . . . . . . . . . . . . . . . . . . 34 11.4.2. Initial Registry Contents . . . . . . . . . . . . . 35
10.6.1. Registration Template . . . . . . . . . . . . . . . 34 11.5. CBOR Web Token Claims . . . . . . . . . . . . . . . . . 35
10.7. OAuth Parameter Mappings Registry . . . . . . . . . . . 34 11.6. ACE Profile Registry . . . . . . . . . . . . . . . . . . 36
10.7.1. Registration Template . . . . . . . . . . . . . . . 34 11.6.1. Registration Template . . . . . . . . . . . . . . . 36
10.7.2. Initial Registry Contents . . . . . . . . . . . . . 35 11.7. OAuth Parameter Mappings Registry . . . . . . . . . . . 36
10.8. Introspection Endpoint CBOR Mappings Registry . . . . . 37 11.7.1. Registration Template . . . . . . . . . . . . . . . 36
10.8.1. Registration Template . . . . . . . . . . . . . . . 37 11.7.2. Initial Registry Contents . . . . . . . . . . . . . 37
10.8.2. Initial Registry Contents . . . . . . . . . . . . . 37 11.8. Introspection Endpoint CBOR Mappings Registry . . . . . 39
10.9. CoAP Option Number Registration . . . . . . . . . . . . 39 11.8.1. Registration Template . . . . . . . . . . . . . . . 39
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 40 11.8.2. Initial Registry Contents . . . . . . . . . . . . . 39
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 40 11.9. CoAP Option Number Registration . . . . . . . . . . . . 41
12.1. Normative References . . . . . . . . . . . . . . . . . . 40 11.10. CWT Confirmation Methods Registry . . . . . . . . . . . 42
12.2. Informative References . . . . . . . . . . . . . . . . . 41 11.10.1. Registration Template . . . . . . . . . . . . . . . 42
Appendix A. Design Justification . . . . . . . . . . . . . . . . 43 11.10.2. Initial Registry Contents . . . . . . . . . . . . . 43
Appendix B. Roles and Responsibilites . . . . . . . . . . . . . 45 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 43
Appendix C. Requirements on Profiles . . . . . . . . . . . . . . 47 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 43
Appendix D. Deployment Examples . . . . . . . . . . . . . . . . 47 13.1. Normative References . . . . . . . . . . . . . . . . . . 44
D.1. Local Token Validation . . . . . . . . . . . . . . . . . 48 13.2. Informative References . . . . . . . . . . . . . . . . . 44
D.2. Introspection Aided Token Validation . . . . . . . . . . 51 Appendix A. Design Justification . . . . . . . . . . . . . . . . 46
Appendix E. Document Updates . . . . . . . . . . . . . . . . . . 55 Appendix B. Roles and Responsibilities . . . . . . . . . . . . . 48
E.1. Version -02 to -03 . . . . . . . . . . . . . . . . . . . 55 Appendix C. Requirements on Profiles . . . . . . . . . . . . . . 50
E.2. Version -01 to -02 . . . . . . . . . . . . . . . . . . . 55 Appendix D. Assumptions on AS knowledge about C and RS . . . . . 51
E.3. Version -00 to -01 . . . . . . . . . . . . . . . . . . . 56 Appendix E. Deployment Examples . . . . . . . . . . . . . . . . 51
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 57 E.1. Local Token Validation . . . . . . . . . . . . . . . . . 52
E.2. Introspection Aided Token Validation . . . . . . . . . . 55
Appendix F. Document Updates . . . . . . . . . . . . . . . . . . 59
F.1. Version -04 to -05 . . . . . . . . . . . . . . . . . . . 59
F.2. Version -03 to -04 . . . . . . . . . . . . . . . . . . . 59
F.3. Version -02 to -03 . . . . . . . . . . . . . . . . . . . 60
F.4. Version -01 to -02 . . . . . . . . . . . . . . . . . . . 60
F.5. Version -00 to -01 . . . . . . . . . . . . . . . . . . . 60
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 61
1. Introduction 1. Introduction
Authorization is the process for granting approval to an entity to Authorization is the process for granting approval to an entity to
access a resource [RFC4949]. The authorization task itself can best access a resource [RFC4949]. The authorization task itself can best
be described as granting access to a requesting client, for a be described as granting access to a requesting client, for a
resource hosted on a device, the resource server (RS). This exchange resource hosted on a device, the resource server (RS). This exchange
is mediated by one or multiple authorization servers (AS). Managing is mediated by one or multiple authorization servers (AS). Managing
authorization for a large number of devices and users is a complex authorization for a large number of devices and users is a complex
task. task.
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Implementations may claim conformance with a specific profile, Implementations may claim conformance with a specific profile,
whereby implementations utilizing the same profile interoperate while whereby implementations utilizing the same profile interoperate while
implementations of different profiles are not expected to be implementations of different profiles are not expected to be
interoperable. Some devices, such as mobile phones and tablets, may interoperable. Some devices, such as mobile phones and tablets, may
implement multiple profiles and will therefore be able to interact implement multiple profiles and will therefore be able to interact
with a wider range of low end devices. with a wider range of low end devices.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
document are to be interpreted as described in [RFC2119]. "OPTIONAL" in this document are to be interpreted as described in
[RFC2119].
Certain security-related terms such as "authentication", Certain security-related terms such as "authentication",
"authorization", "confidentiality", "(data) integrity", "message "authorization", "confidentiality", "(data) integrity", "message
authentication code", and "verify" are taken from [RFC4949]. authentication code", and "verify" are taken from [RFC4949].
Since we describe exchanges as RESTful protocol interactions HTTP Since we describe exchanges as RESTful protocol interactions HTTP
[RFC7231] offers useful terminology. [RFC7231] offers useful terminology.
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] and [I-D.ietf-ace-actors], such as client (C), resource [RFC6749] and [I-D.ietf-ace-actors], such as client (C), resource
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A fourth building block is the compact CBOR-based secure message A fourth building block is the compact CBOR-based secure message
format COSE [I-D.ietf-cose-msg], which enables application layer format COSE [I-D.ietf-cose-msg], which enables application layer
security as an alternative or complement to transport layer security security as an alternative or complement to transport layer security
(DTLS [RFC6347] or TLS [RFC5246]). COSE is used to secure self (DTLS [RFC6347] or TLS [RFC5246]). COSE is used to secure self
contained tokens such as proof-of-possession (PoP) tokens, which is contained tokens such as proof-of-possession (PoP) tokens, which is
an extension to the OAuth access tokens, and "client tokens" which an extension to the OAuth access tokens, and "client tokens" which
are defined in this framework (see Section 7.4). The default access are defined in this framework (see Section 7.4). The default access
token format is defined in CBOR web token (CWT) token format is defined in CBOR web token (CWT)
[I-D.ietf-ace-cbor-web-token]. Application layer security for CoAP [I-D.ietf-ace-cbor-web-token]. Application layer security for CoAP
using COSE can be provided with OSCOAP using COSE can be provided with OSCOAP
[I-D.selander-ace-object-security]. [I-D.ietf-core-object-security].
With the building blocks listed above, solutions satisfying various With the building blocks listed above, solutions satisfying various
IoT device and network constraints are possible. A list of IoT device and network constraints are possible. A list of
constraints is described in detail in RFC 7228 [RFC7228] and a constraints is described in detail in RFC 7228 [RFC7228] and a
description of how the building blocks mentioned above relate to the description of how the building blocks mentioned above relate to the
various constraints can be found in Appendix A. various constraints can be found in Appendix A.
Luckily, not every IoT device suffers from all constraints. The ACE Luckily, not every IoT device suffers from all constraints. The ACE
framework nevertheless takes all these aspects into account and framework nevertheless takes all these aspects into account and
allows several different deployment variants to co-exist rather than allows several different deployment variants to co-exist rather than
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Transport layer security for CoAP can be provided by DTLS 1.2 Transport layer security for CoAP can be provided by DTLS 1.2
[RFC6347] or TLS 1.2 [RFC5246]. CoAP defines a number of proxy [RFC6347] or TLS 1.2 [RFC5246]. CoAP defines a number of proxy
operations which requires transport layer security to be terminated operations which requires transport layer security to be terminated
at the proxy. One approach for protecting CoAP communication end-to- at the proxy. One approach for protecting CoAP communication end-to-
end through proxies, and also to support security for CoAP over a end through proxies, and also to support security for CoAP over a
different transport in a uniform way, is to provide security on different transport in a uniform way, is to provide security on
application layer using an object-based security mechanism such as application layer using an object-based security mechanism such as
COSE [I-D.ietf-cose-msg]. COSE [I-D.ietf-cose-msg].
One application of COSE is OSCOAP [I-D.selander-ace-object-security], One application of COSE is OSCOAP [I-D.ietf-core-object-security],
which provides end-to-end confidentiality, integrity and replay which provides end-to-end confidentiality, integrity and replay
protection, and a secure binding between CoAP request and response protection, and a secure binding between CoAP request and response
messages. In OSCOAP, the CoAP messages are wrapped in COSE objects messages. In OSCOAP, the CoAP messages are wrapped in COSE objects
and sent using CoAP. and sent using CoAP.
4. Protocol Interactions 4. Protocol Interactions
The ACE framework is based on the OAuth 2.0 protocol interactions The ACE framework is based on the OAuth 2.0 protocol interactions
using the /token and /introspect endpoints. A client obtains an using the /token and /introspect endpoints. A client obtains an
access token from an AS using the /token endpoint and subsequently access token from an AS using the /token endpoint and subsequently
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specific credential). specific credential).
Access Token Response (B): Access Token Response (B):
If the AS successfully processes the request from the client, it If the AS successfully processes the request from the client, it
returns an access token. It also returns various parameters, returns an access token. It also returns various parameters,
referred as "RS Information". In addition to the response referred as "RS Information". In addition to the response
parameters defined by OAuth 2.0 and the PoP token extension, parameters defined by OAuth 2.0 and the PoP token extension,
further response parameters, such as information on which profile further response parameters, such as information on which profile
the client should use with the resource server(s). More the client should use with the resource server(s). More
information about these parameters can be found in Section 6.4. information about these parameters can be found in Section 6.5.
Resource Request (C): Resource Request (C):
The client interacts with the RS to request access to the The client interacts with the RS to request access to the
protected resource and provides the access token. The protocol to protected resource and provides the access token. The protocol to
use between the client and the RS is not restricted to CoAP. use between the client and the RS is not restricted to CoAP.
HTTP, HTTP/2, QUIC, MQTT, Bluetooth Low Energy, etc., are also HTTP, HTTP/2, QUIC, MQTT, Bluetooth Low Energy, etc., are also
viable candidates. viable candidates.
Depending on the device limitations and the selected protocol this Depending on the device limitations and the selected protocol this
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or associated information to allow mutual authentication. These or associated information to allow mutual authentication. These
credentials need to be provided to the parties before or during credentials need to be provided to the parties before or during
the authentication protocol is executed, and may be re-used for the authentication protocol is executed, and may be re-used for
subsequent token requests. subsequent token requests.
Proof-of-Possession Proof-of-Possession
The ACE framework by default implements proof-of-possession for The ACE framework by default implements proof-of-possession for
access tokens, i.e. that the token holder can prove being a holder access tokens, i.e. that the token holder can prove being a holder
of the key bound to the token. The binding is provided by the of the key bound to the token. The binding is provided by the
"cnf" claim indicating what key is used for mutual authentication. "cnf" claim indicating what key is used for proof-of-possession.
If clients need to update a token, e.g. to get additional rights, If clients need to update a token, e.g. to get additional rights,
they can request that the AS binds the new access token to the they can request that the AS binds the new access token to the
same credential as the previous token. same key as the previous token.
ACE Profiles ACE Profiles
The client or RS may be limited in the encodings or protocols it The client or RS may be limited in the encodings or protocols it
supports. To support a variety of different deployment settings, supports. To support a variety of different deployment settings,
specific interactions between client and RS are defined in an ACE specific interactions between client and RS are defined in an ACE
profile. In ACE framework the AS is expected to manage the profile. In ACE framework the AS is expected to manage the
matching of compatible profile choices between a client and an RS. matching of compatible profile choices between a client and an RS.
The AS informs the client of the selected profile using the The AS informs the client of the selected profile using the
"profile" parameter in the token request and token response. "profile" parameter in the token response.
OAuth 2.0 requires the use of TLS both to protect the communication OAuth 2.0 requires the use of TLS both to protect the communication
between AS and client when requesting an access token; between client between AS and client when requesting an access token; between client
and RS when accessing a resource and between AS and RS for and RS when accessing a resource and between AS and RS for
introspection. In constrained settings TLS is not always feasible, introspection. In constrained settings TLS is not always feasible,
or desirable. Nevertheless it is REQUIRED that the data exchanged or desirable. Nevertheless it is REQUIRED that the data exchanged
with the AS is encrypted and integrity protected. It is furthermore with the AS is encrypted and integrity protected. It is furthermore
REQUIRED that the AS and the endpoint communicating with it (client REQUIRED that the AS and the endpoint communicating with it (client
or RS) perform mutual authentication. or RS) perform mutual authentication.
Profiles are expected to specify the details of how this is done, Profiles MUST specify how mutual authentication is done, depending
depending e.g. on the communication protocol and the credentials used e.g. on the communication protocol and the credentials used by the
by the client or the RS. client or the RS.
In OAuth 2.0 the communication with the Token and the Introspection In OAuth 2.0 the communication with the Token and the Introspection
endpoints at the AS is assumed to be via HTTP and may use Uri-query endpoints at the AS is assumed to be via HTTP and may use Uri-query
parameters. This framework RECOMMENDS to use CoAP instead and parameters. This framework RECOMMENDS to use CoAP instead and
RECOMMENDS the use of the following alternative instead of Uri-query RECOMMENDS the use of the following alternative instead of Uri-query
parameters: The sender (client or RS) encodes the parameters of its parameters: The sender (client or RS) encodes the parameters of its
request as a CBOR map and submits that map as the payload of the POST request as a CBOR map and submits that map as the payload of the POST
request. The Content-format depends on the security applied to the request. The Content-format depends on the security applied to the
content and must be specified by the corresponding profile. content and MUST be specified by the profile that is used.
The OAuth 2.0 AS uses a JSON structure in the payload of its The OAuth 2.0 AS uses a JSON structure in the payload of its
responses both to client and RS. This framework RECOMMENDS the use responses both to client and RS. This framework RECOMMENDS the use
of CBOR [RFC7049] instead. The requesting device can explicitly of CBOR [RFC7049] instead. The requesting device can explicitly
request this encoding by setting the CoAP Accept option in the request this encoding by setting the CoAP Accept option in the
request to "application/cbor". Depending on the profile, the content request to "application/cbor". Depending on the profile, the content
may arrive in a different format wrapping a CBOR payload. MAY arrive in a different format wrapping a CBOR payload.
6. The 'Token' Endpoint 6. The 'Token' Endpoint
In plain OAuth 2.0 the AS provides the /token endpoint for submitting In plain OAuth 2.0 the AS provides the /token endpoint for submitting
access token requests. This framework extends the functionality of access token requests. This framework extends the functionality of
the /token endpoint, giving the AS the possibility to help client and the /token endpoint, giving the AS the possibility to help client and
RS to establish shared keys or to exchange their public keys. RS to establish shared keys or to exchange their public keys.
Furthermore this framework defines encodings using CoAP and CBOR, Furthermore this framework defines encodings using CoAP and CBOR, in
instead of HTTP and JSON. addition to HTTP and JSON.
Communication between the client and the /token endpoint at the AS Authentication of the requesting client is done using client
MUST be integrity protected and encrypted. Furthermore AS and client credentials as defined by OAuth 2.0. A profile MAY specify new
MUST perform mutual authentication. Profiles of this framework are client credentials types for the authentication of the client.
expected to specify how authentication and communication security is
implemented. Profiles of this framework SHOULD specify how authentication of the
AS is done and how communication security is implemented. If nothing
is specified TLS with server certificate is assumed as defined by
OAuth 2.0.
When requesting a token the client is authenticated with client
credentials and then a grant is presented that gives the client the
right to get a token.
The figures of this section uses CBOR diagnostic notation without the The figures of this section uses CBOR diagnostic notation without the
integer abbreviations for the parameters or their values for better integer abbreviations for the parameters or their values for better
readability. readability.
6.1. Client-to-AS Request 6.1. Client Credentials and Grants
To issue a token the client MUST be authenticated and present a valid
grant for the scopes requested.
The OAuth framework, [RFC6749], defines one client credential type,
client id and client secret. Profiles of this framework MAY extend
with additional client credentials such as DTLS pre-shared keys or
client certificates.
In the OAuth framework five grant types are defined. The grant types
can be split up into three groups, those granted on behalf of the
resource owner (password, authorization code, implicit), those for
the client (client_credentials), and those used to prolong a grant
(refresh token).
profiles MAY define additional grant types if needed, e.g. a proof of
possession refresh token.
6.2. Client-to-AS Request
The client sends a CoAP POST request to the token endpoint at the AS, The client sends a CoAP POST request to the token endpoint at the AS,
the profile is expected to specify the Content-Type and wrapping of the profile MUST specify the Content-Type and wrapping of the
the payload. The content of the request consists of the parameters payload. The content of the request consists of the parameters
specified in section 4 of the OAuth 2.0 specification [RFC6749] specified in section 4 of the OAuth 2.0 specification [RFC6749]
encoded as a CBOR map. encoded as a CBOR map.
In addition to these parameters, this framework defines the following In addition to these parameters, this framework defines the following
parameters for requesting an access token from a /token endpoint: parameters for requesting an access token from a /token endpoint:
aud aud
OPTIONAL. Specifies the audience for which the client is OPTIONAL. Specifies the audience for which the client is
requesting an access token. If this parameter is missing it is requesting an access token. If this parameter is missing it is
assumed that the client and the AS have a pre-established assumed that the client and the AS have a pre-established
skipping to change at page 15, line 31 skipping to change at page 16, line 15
If a client submits a request for an access token without If a client submits a request for an access token without
specifying an "aud" parameter, and the AS does not have a default specifying an "aud" parameter, and the AS does not have a default
"aud" value for this client, then the AS MUST respond with an "aud" value for this client, then the AS MUST respond with an
error message with the CoAP response code 4.00 (Bad Request). error message with the CoAP response code 4.00 (Bad Request).
cnf cnf
OPTIONAL. This field contains information about the key the OPTIONAL. This field contains information about the key the
client would like to bind to the access token for proof-of- client would like to bind to the access token for proof-of-
possession. It is NOT RECOMMENDED that a client submits a possession. It is NOT RECOMMENDED that a client submits a
symmetric key value to the AS using this parameter. See symmetric key value to the AS using this parameter. See
Section 6.4.5 for more details on the formatting of the 'cnf' Section 6.5.5 for more details on the formatting of the 'cnf'
parameter. parameter.
The following examples illustrate different types of requests for The following examples illustrate different types of requests for
proof-of-possession tokens. proof-of-possession tokens.
Figure 2 shows a request for a token with a symmetric proof-of- Figure 2 shows a request for a token with a symmetric proof-of-
possession key. Note that in this example we assume a DTLS-based possession key. Note that in this example we assume a DTLS-based
communication security profile, therefore the Content-Type is communication security profile, therefore the Content-Type is
"application/cbor". "application/cbor". The content is displayed in CBOR diagnostic
notation, without abbreviations for better readability.
Header: POST (Code=0.02) Header: POST (Code=0.02)
Uri-Host: "server.example.com" Uri-Host: "server.example.com"
Uri-Path: "token" Uri-Path: "token"
Content-Type: "application/cbor" Content-Type: "application/cbor"
Payload: Payload:
{ {
"grant_type" : "client_credentials", "grant_type" : "client_credentials",
"aud" : "tempSensor4711", "aud" : "tempSensor4711",
} }
skipping to change at page 16, line 30 skipping to change at page 17, line 12
security-based profile, therefore the Content-Type is "application/ security-based profile, therefore the Content-Type is "application/
cose+cbor". cose+cbor".
Header: POST (Code=0.02) Header: POST (Code=0.02)
Uri-Host: "server.example.com" Uri-Host: "server.example.com"
Uri-Path: "token" Uri-Path: "token"
Content-Type: "application/cose+cbor" Content-Type: "application/cose+cbor"
Payload: Payload:
{ {
"grant_type" : "client_credentials", "grant_type" : "client_credentials",
"client_id" : "myclient",
"client_secret" : "mysecret234",
"cnf" : { "cnf" : {
"COSE_Key" : { "COSE_Key" : {
"kty" : "EC", "kty" : "EC",
"kid" : h'11', "kid" : h'11',
"crv" : "P-256", "crv" : "P-256",
"x" : b64'usWxHK2PmfnHKwXPS54m0kTcGJ90UiglWiGahtagnv8', "x" : b64'usWxHK2PmfnHKwXPS54m0kTcGJ90UiglWiGahtagnv8',
"y" : b64'IBOL+C3BttVivg+lSreASjpkttcsz+1rb7btKLv8EX4' "y" : b64'IBOL+C3BttVivg+lSreASjpkttcsz+1rb7btKLv8EX4'
} }
} }
} }
skipping to change at page 17, line 24 skipping to change at page 18, line 5
"aud" : "valve424", "aud" : "valve424",
"scope" : "read", "scope" : "read",
"cnf" : { "cnf" : {
"kid" : b64'6kg0dXJM13U' "kid" : b64'6kg0dXJM13U'
} }
} }
Figure 4: Example request for an access token bound to a key Figure 4: Example request for an access token bound to a key
reference. reference.
6.2. AS-to-Client Response 6.3. AS-to-Client Response
If the access token request has been successfully verified by the AS If the access token request has been successfully verified by the AS
and the client is authorized to obtain an access token corresponding and the client is authorized to obtain an access token corresponding
to its access token request, the AS sends a response with the CoAP to its access token request, the AS sends a response with the CoAP
response code 2.01 (Created). If client request was invalid, or not response code 2.01 (Created). If client request was invalid, or not
authorized, the AS returns an error response as described in authorized, the AS returns an error response as described in
Section 6.3. Section 6.4.
Note that the AS decides which token type and profile to use when Note that the AS decides which token type and profile to use when
issuing a successful response. It is assumed that the AS has prior issuing a successful response. It is assumed that the AS has prior
knowledge of the capabilities of the client, and the RS. This prior knowledge of the capabilities of the client, and the RS (see
knowledge may, for example, be set by the use of a dynamic client Appendix D. This prior knowledge may, for example, be set by the use
registration protocol exchange [RFC7591]. of a dynamic client registration protocol exchange [RFC7591].
The content of the successful reply MUST be encoded as CBOR map, The content of the successful reply is the RS Information. It MUST
containing parameters as speficied in section 5.1 of [RFC6749]. In be encoded as CBOR map, containing parameters as specified in section
addition to these parameters, the following parameters are also part 5.1 of [RFC6749]. In addition to these parameters, the following
of a successful response: parameters are also part of a successful response:
profile profile
REQUIRED. This indicates the profile that the client MUST use REQUIRED. This indicates the profile that the client MUST use
towards the RS. See Section 6.4.4 for the formatting of this towards the RS. See Section 6.5.4 for the formatting of this
parameter. parameter.
cnf cnf
REQUIRED if the token type is 'pop'. OPTIONAL otherwise. If a REQUIRED if the token type is 'pop'. OPTIONAL otherwise. If a
symmetric proof-of-possession algorithms was selected, this field symmetric proof-of-possession algorithms was selected, this field
contains the proof-of-possession key. If an asymmetric algorithm contains the proof-of-possession key. If an asymmetric algorithm
was selected, this field contains information about the public key was selected, this field contains information about the public key
used by the RS to authenticate. See Section 6.4.5 for the used by the RS to authenticate. See Section 6.5.5 for the
formatting of this parameter. formatting of this parameter.
token_type token_type
OPTIONAL. By default implementations of this framework SHOULD OPTIONAL. By default implementations of this framework SHOULD
assume that the token_type is 'pop'. If a specific use case assume that the token_type is 'pop'. If a specific use case
requires another token_type (e.g. 'Bearer') to be used then this requires another token_type (e.g. 'Bearer') to be used then this
parameter is REQUIRED. parameter is REQUIRED.
Note that if CBOR Web Tokens [I-D.ietf-ace-cbor-web-token] are used, Note that if CBOR Web Tokens [I-D.ietf-ace-cbor-web-token] are used,
the access token can also contain a 'cnf' claim. This claim is the access token can also contain a 'cnf' claim. This claim is
however consumed by a different party. The access token is created however consumed by a different party. The access token is created
by the AS and processed by the RS (and opaque to the client) whereas by the AS and processed by the RS (and opaque to the client) whereas
the RS Information is created by the AS and processed by the client; the RS Information is created by the AS and processed by the client;
it is never forwarded to the resource server. it is never forwarded to the resource server.
Figure Figure 5 summarizes the parameters that may be part of the RS
Information.
/-------------------+--------------------------\
| Parameter name | Specified in |
|-------------------+--------------------------|
| access_token | RFC 6749 |
| token_type | RFC 6749 |
| expires_in | RFC 6749 |
| refresh_token | RFC 6749 |
| scope | RFC 6749 |
| state | RFC 6749 |
| profile | [[ this specification ]] |
| cnf | [[ this specification ]] |
\-------------------+--------------------------/
Figure 5: RS Information parameters
The following examples illustrate different types of responses for The following examples illustrate different types of responses for
proof-of-possession tokens. proof-of-possession tokens.
Figure 5 shows a response containing a token and a 'cnf' parameter Figure 6 shows a response containing a token and a 'cnf' parameter
with a symmetric proof-of-possession key. Note that we assume a with a symmetric proof-of-possession key. Note that we assume a
DTLS-based communication security profile for this example, therefore DTLS-based communication security profile for this example, therefore
the Content-Type is "application/cbor". the Content-Type is "application/cbor".
Header: Created (Code=2.01) Header: Created (Code=2.01)
Content-Type: "application/cbor" Content-Type: "application/cbor"
Payload: Payload:
{ {
"access_token" : b64'SlAV32hkKG ... "access_token" : b64'SlAV32hkKG ...
(remainder of CWT omitted for brevity; (remainder of CWT omitted for brevity;
skipping to change at page 18, line 46 skipping to change at page 19, line 46
"expires_in" : "3600", "expires_in" : "3600",
"cnf" : { "cnf" : {
"COSE_Key" : { "COSE_Key" : {
"kty" : "Symmetric", "kty" : "Symmetric",
"kid" : b64'39Gqlw', "kid" : b64'39Gqlw',
"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh' "k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'
} }
} }
} }
Figure 5: Example AS response with an access token bound to a Figure 6: Example AS response with an access token bound to a
symmetric key. symmetric key.
6.3. Error Response 6.4. Error Response
The error responses for CoAP-based interactions with the AS are The error responses for CoAP-based interactions with the AS are
equivalent to the ones for HTTP-based interactions as defined in equivalent to the ones for HTTP-based interactions as defined in
section 5.2 of [RFC6749], with the following differences: The section 5.2 of [RFC6749], with the following differences:
Content-Type is specified by the communication security profile used
between client and AS. The raw payload before being processed by the
communication security protocol MUST be encoded as a CBOR map and the
CoAP response code 4.00 (Bad Request) MUST be used unless specified
otherwise.
6.4. New Request and Response Parameters o The Content-Type MUST be specified by the communication security
profile used between client and AS. The raw payload before being
processed by the communication security protocol MUST be encoded
as a CBOR map.
o The CoAP response code 4.00 (Bad Request) MUST be used for all
error responses, except for invalid_client where the CoAP response
code 4.01 (Unauthorized) MAY be used under the same conditions as
specified in section 5.2 of [RFC6749].
o The parameters "error", "error_description" and "error_uri" MAY be
abbreviated using the codes specified in table Figure 13.
o The error codes MAY be abbreviated using the codes specified in
table Figure 7.
/------------------------+----------+--------------\
| error code | CBOR Key | Major Type |
|------------------------+----------+--------------|
| invalid_request | 0 | 0 (uint) |
| invalid_client | 1 | 0 |
| invalid_grant | 2 | 0 |
| unauthorized_client | 3 | 0 |
| unsupported_grant_type | 4 | 0 |
| invalid_scope | 5 | 0 |
\------------------------+----------+--------------/
Figure 7: CBOR abbreviations for common error codes
6.5. Request and Response Parameters
This section provides more detail about the new parameters that can This section provides more detail about the new parameters that can
be used in access token requests and responses, as well as be used in access token requests and responses, as well as
abbreviations for more compact encoding of existing parameters and abbreviations for more compact encoding of existing parameters and
common parameter values. common parameter values.
6.4.1. Audience 6.5.1. Audience
This parameter specifies for which audience the client is requesting This parameter specifies for which audience the client is requesting
a token. It should be encoded as CBOR text string (major type 3). a token. It should be encoded as CBOR text string (major type 3).
The formatting and semantics of these strings are application The formatting and semantics of these strings are application
specific. specific.
6.4.2. Grant Type 6.5.2. Grant Type
The abbreviations in Figure 6 MAY be used in CBOR encodings instead The abbreviations in Figure 8 MAY be used in CBOR encodings instead
of the string values defined in [RFC6749]. of the string values defined in [RFC6749].
/--------------------+----------+--------------\ /--------------------+----------+--------------\
| grant_type | CBOR Key | Major Type | | grant_type | CBOR Key | Major Type |
|--------------------+----------+--------------| |--------------------+----------+--------------|
| password | 0 | 0 (uint) | | password | 0 | 0 (uint) |
| authorization_code | 1 | 0 | | authorization_code | 1 | 0 |
| client_credentials | 2 | 0 | | client_credentials | 2 | 0 |
| refresh_token | 3 | 0 | | refresh_token | 3 | 0 |
\--------------------+----------+--------------/ \--------------------+----------+--------------/
Figure 6: CBOR abbreviations for common grant types Figure 8: CBOR abbreviations for common grant types
6.4.3. Token Type 6.5.3. Token Type
The 'token_type' parameter allows the AS to indicate to the client The toke_type parameter is defined in [RFC6749], allowing the AS to
which type of access token it is receiving (e.g. a bearer token). indicate to the client which type of access token it is receiving
The 'pop' token type MUST be assumed by default if the AS does not (e.g. a bearer token).
provide a different value.
This document registers the new value "pop" for the OAuth Access This document registers the new value "pop" for the OAuth Access
Token Types registry, specifying a Proof-of-Possession token. How Token Types registry, specifying a Proof-of-Possession token. How
the proof-of-possession is performed is specified by the profiles. the proof-of-possession is performed MUST be specified by the
profiles.
The values in the 'token_type' parameter are CBOR text strings (major The values in the 'token_type' parameter MUST be CBOR text strings
type 3). (major type 3).
6.4.4. Profile In this framework token type 'pop' MUST be assumed by default if the
AS does not provide a different value.
Profiles of this framework are expected to define the communication 6.5.4. Profile
protocol and the communication security protocol between the client
and the RS. Furthermore profiles are expected to define proof-of-
possession methods, if they support proof-of-possession tokens.
A profile should specify an identifier that is used to uniquely Profiles of this framework MUST define the communication protocol and
the communication security protocol between the client and the RS.
Furthermore profiles MUST define proof-of-possession methods, if they
support proof-of-possession tokens.
A profile MUST specify an identifier that is used to uniquely
identify itself in the 'profile' parameter. identify itself in the 'profile' parameter.
Profiles MAY define additional parameters for both the token request Profiles MAY define additional parameters for both the token request
and the RS Information in the access token response in order to and the RS Information in the access token response in order to
support negotioation or signalling of profile specific parameters. support negotiation or signalling of profile specific parameters.
6.4.5. Confirmation 6.5.5. Confirmation
The "cnf" parameter identifies or provides the key used for proof-of- The "cnf" parameter identifies or provides the key used for proof-of-
possession or for authenticating the RS depending on the proof-of- possession or for authenticating the RS depending on the proof-of-
possession algorithm and the context cnf is used in. This framework possession algorithm and the context cnf is used in. This framework
extends the definition of 'cnf' from [RFC7800] by adding CBOR/COSE extends the definition of 'cnf' from [RFC7800] by adding CBOR/COSE
encodings and the use of 'cnf' for transporting keys in the RS encodings and the use of 'cnf' for transporting keys in the RS
Information. Information.
The "cnf" parameter is used in the following contexts with the The "cnf" parameter is used in the following contexts with the
following meaning: following meaning:
skipping to change at page 21, line 7 skipping to change at page 22, line 35
o In the introspection response AS -> RS, to indicate the proof-of- o In the introspection response AS -> RS, to indicate the proof-of-
possession key bound to the introspected token. possession key bound to the introspected token.
o In the client token AS -> RS -> C, to indicate the proof-of- o In the client token AS -> RS -> C, to indicate the proof-of-
possession key bound to the access token. possession key bound to the access token.
A CBOR encoded payload MAY contain the 'cnf' parameter with the A CBOR encoded payload MAY contain the 'cnf' parameter with the
following contents: following contents:
COSE_Key In this case the 'cnf' parameter contains the proof-of- COSE_Key In this case the 'cnf' parameter contains the proof-of-
possession key to be used by the client. An example is shown in possession key to be used by the client. An example is shown in
Figure 7. Figure 9.
"cnf" : { "cnf" : {
"COSE_Key" : { "COSE_Key" : {
"kty" : "EC", "kty" : "EC",
"kid" : h'11', "kid" : h'11',
"crv" : "P-256", "crv" : "P-256",
"x" : b64'usWxHK2PmfnHKwXPS54m0kTcGJ90UiglWiGahtagnv8', "x" : b64'usWxHK2PmfnHKwXPS54m0kTcGJ90UiglWiGahtagnv8',
"y" : b64'IBOL+C3BttVivg+lSreASjpkttcsz+1rb7btKLv8EX4' "y" : b64'IBOL+C3BttVivg+lSreASjpkttcsz+1rb7btKLv8EX4'
} }
} }
Figure 7: Confirmation parameter containing a public key Figure 9: Confirmation parameter containing a public key
Note that the COSE_Key structure may contain an "alg" or "key_ops" Note that the COSE_Key structure may contain an "alg" or "key_ops"
parameter. If such parameters are present, a client MUST NOT use parameter. If such parameters are present, a client MUST NOT use
a key that is not compatible with the profile or proof-of- a key that is not compatible with the profile or proof-of-
possession algorithm according to those parameters. possession algorithm according to those parameters.
COSE_Encrypted In this case the 'cnf' parameter contains an COSE_Encrypted In this case the 'cnf' parameter contains an
encrypted symmetric key destined for the client. The client is encrypted symmetric key destined for the client. The client is
assumed to be able to decrypt the cihpertext of this parameter. assumed to be able to decrypt the ciphertext of this parameter.
The parameter is encoded as COSE_Encrypted object wrapping a The parameter is encoded as COSE_Encrypted object wrapping a
COSE_Key object. Figure 8 shows an example of this type of COSE_Key object. Figure 10 shows an example of this type of
encoding. encoding.
"cnf" : { "cnf" : {
"COSE_Encrypted" : { "COSE_Encrypted" : {
993( 993(
[ h'a1010a' # protected header : {"alg" : "AES-CCM-16-64-128"} [ h'a1010a' # protected header : {"alg" : "AES-CCM-16-64-128"}
"iv" : b64'ifUvZaHFgJM7UmGnjA', # unprotected header "iv" : b64'ifUvZaHFgJM7UmGnjA', # unprotected header
b64'WXThuZo6TMCaZZqi6ef/8WHTjOdGk8kNzaIhIQ' # ciphertext b64'WXThuZo6TMCaZZqi6ef/8WHTjOdGk8kNzaIhIQ' # ciphertext
] ]
) )
} }
} }
Figure 8: Confirmation paramter containing an encrypted symmetric key Figure 10: Confirmation parameter containing an encrypted symmetric
key
The ciphertext here could e.g. contain a symmetric key as in The ciphertext here could e.g. contain a symmetric key as in
Figure 9. Figure 11.
{ {
"kty" : "Symmetric", "kty" : "Symmetric",
"kid" : b64'39Gqlw', "kid" : b64'39Gqlw',
"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh' "k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'
} }
Figure 9: Example plaintext of an encrypted cnf parameter Figure 11: Example plaintext of an encrypted cnf parameter
Key Identifier In this case the 'cnf' parameter references a key Key Identifier In this case the 'cnf' parameter references a key
that is assumed to be previously known by the recipient. This that is assumed to be previously known by the recipient. This
allows clients that perform repeated requests for an access token allows clients that perform repeated requests for an access token
for the same audience but e.g. with different scopes to omit key for the same audience but e.g. with different scopes to omit key
transport in the access token, token request and token response. transport in the access token, token request and token response.
Figure 10 shows such an example. Figure 12 shows such an example.
"cnf" : { "cnf" : {
"kid" : b64'39Gqlw' "kid" : b64'39Gqlw'
} }
Figure 10: A Confirmation parameter with just a key identifier Figure 12: A Confirmation parameter with just a key identifier
6.5. Mapping parameters to CBOR This specification establishes the IANA "CWT Confirmation Methods"
registry for these types of confirmation methods in Section 11.10 and
registers the methods defined by this specification. Other
specifications can register other methods used for confirmation. The
registry is meant to be analogous to the "JWT Confirmation Methods"
registry defined by [RFC7800].
6.6. Mapping parameters to CBOR
All OAuth parameters in access token requests and responses are All OAuth parameters in access token requests and responses are
mapped to CBOR types as follows and are given an integer key value to mapped to CBOR types as follows and are given an integer key value to
save space. save space.
/-------------------+----------+-----------------\ /-------------------+----------+-----------------\
| Parameter name | CBOR Key | Major Type | | Parameter name | CBOR Key | Major Type |
|-------------------+----------+-----------------| |-------------------+----------+-----------------|
| aud | 3 | 3 | | aud | 3 | 3 |
| client_id | 8 | 3 (text string) | | client_id | 8 | 3 (text string) |
| client_secret | 9 | 2 (byte string) | | client_secret | 9 | 2 (byte string) |
| response_type | 10 | 3 | | response_type | 10 | 3 |
| redirect_uri | 11 | 3 | | redirect_uri | 11 | 3 |
| scope | 12 | 3 | | scope | 12 | 3 |
| state | 13 | 3 | | state | 13 | 3 |
| code | 14 | 2 | | code | 14 | 2 |
| error_description | 15 | 3 | | error | 15 | 3 |
| error_uri | 16 | 3 | | error_description | 16 | 3 |
| grant_type | 17 | 0 (unit) | | error_uri | 17 | 3 |
| access_token | 18 | 3 | | grant_type | 18 | 0 |
| token_type | 19 | 0 | | access_token | 19 | 3 |
| expires_in | 20 | 0 | | token_type | 20 | 0 |
| username | 21 | 3 | | expires_in | 21 | 0 |
| password | 22 | 3 | | username | 22 | 3 |
| refresh_token | 23 | 3 | | password | 23 | 3 |
| cnf | 24 | 5 (map) | | refresh_token | 24 | 3 |
| profile | 25 | 3 | | cnf | 25 | 5 (map) |
| profile | 26 | 3 |
\-------------------+----------+-----------------/ \-------------------+----------+-----------------/
Figure 11: CBOR mappings used in token requests Figure 13: CBOR mappings used in token requests
7. The 'Introspect' Endpoint 7. The 'Introspect' Endpoint
Token introspection [RFC7662] is used by the RS and potentially the Token introspection [RFC7662] is used by the RS and potentially the
client to query the AS for metadata about a given token e.g. validity client to query the AS for metadata about a given token e.g. validity
or scope. Analogous to the protocol defined in RFC 7662 [RFC7662] or scope. Analogous to the protocol defined in RFC 7662 [RFC7662]
for HTTP and JSON, this section defines adaptations to more for HTTP and JSON, this section defines adaptations to more
constrained environments using CoAP and CBOR. constrained environments using CoAP and CBOR.
Communication between the RS and the introspection endpoint at the AS Communication between the RS and the introspection endpoint at the AS
MUST be integrity protected and encrypted. Furthermore AS and RS MUST be integrity protected and encrypted. Furthermore AS and RS
MUST perform mutual authentication. Finally the AS SHOULD verify MUST perform mutual authentication. Finally the AS SHOULD verify
that the RS has the right to access introspection information about that the RS has the right to access introspection information about
the provided token. Profiles of this framework are expected to the provided token. Profiles of this framework that support
specify how authentication and communication security is implemented. introspection MUST specify how authentication and communication
security between RS and AS is implemented.
The figures of this section uses CBOR diagnostic notation without the The figures of this section uses CBOR diagnostic notation without the
integer abbreviations for the parameters or their values for better integer abbreviations for the parameters or their values for better
readability. readability.
7.1. RS-to-AS Request 7.1. RS-to-AS Request
The RS sends a CoAP POST request to the introspection endpoint at the The RS sends a CoAP POST request to the introspection endpoint at the
AS, the profile is expected to specify the Content-Type and wrapping AS, the profile MUST specify the Content-Type and wrapping of the
of the payload. The payload MUST be encoded as a CBOR map with a payload. The payload MUST be encoded as a CBOR map with a 'token'
'token' parameter containing the access token along with optional parameter containing the access token along with optional parameters
parameters representing additional context that is known by the RS to representing additional context that is known by the RS to aid the AS
aid the AS in its response. in its response.
The same parameters are required and optional as in section 2.1 of The same parameters are required and optional as in section 2.1 of
RFC 7662 [RFC7662]. RFC 7662 [RFC7662].
For example, Figure 12 shows a RS calling the token introspection For example, Figure 14 shows a RS calling the token introspection
endpoint at the AS to query about an OAuth 2.0 proof-of-possession endpoint at the AS to query about an OAuth 2.0 proof-of-possession
token. Note that we assume a object security-based communication token. Note that we assume a object security-based communication
security profile for this example, therefore the Content-Type is security profile for this example, therefore the Content-Type is
"application/cose+cbor". "application/cose+cbor".
Header: POST (Code=0.02) Header: POST (Code=0.02)
Uri-Host: "server.example.com" Uri-Host: "server.example.com"
Uri-Path: "introspect" Uri-Path: "introspect"
Content-Type: "application/cose+cbor" Content-Type: "application/cose+cbor"
Payload: Payload:
{ {
"token" : b64'7gj0dXJQ43U', "token" : b64'7gj0dXJQ43U',
"token_type_hint" : "pop" "token_type_hint" : "pop"
} }
Figure 12: Example introspection request. Figure 14: Example introspection request.
7.2. AS-to-RS Response 7.2. AS-to-RS Response
If the introspection request is authorized and successfully If the introspection request is authorized and successfully
processed, the AS sends a response with the CoAP response code 2.01 processed, the AS sends a response with the CoAP response code 2.01
(Created). If the introspection request was invalid, not authorized (Created). If the introspection request was invalid, not authorized
or couldn't be processed the AS returns an error response as or couldn't be processed the AS returns an error response as
described in Section 7.3. described in Section 7.3.
In a successful response, the AS encodes the response parameters in a In a successful response, the AS encodes the response parameters in a
CBOR map including with the same required and optional parameters as CBOR map including with the same required and optional parameters as
in section 2.2. of RFC 7662 [RFC7662] with the following additions: in section 2.2. of RFC 7662 [RFC7662] with the following additions:
cnf cnf
OPTIONAL. This field contains information about the proof-of- OPTIONAL. This field contains information about the proof-of-
possession key that binds the client to the access token. See possession key that binds the client to the access token. See
Section 6.4.5 for more details on the formatting of the 'cnf' Section 6.5.5 for more details on the formatting of the 'cnf'
parameter. parameter.
profile profile
OPTIONAL. This indicates the profile that the RS MUST use with OPTIONAL. This indicates the profile that the RS MUST use with
the client. See Section 6.4.4 for more details on the formatting the client. See Section 6.5.4 for more details on the formatting
of this parameter. of this parameter.
client_token client_token
OPTIONAL. This parameter contains information that the RS MUST OPTIONAL. This parameter contains information that the RS MUST
pass on to the client. See Section 7.4 for more details. pass on to the client. See Section 7.4 for more details.
For example, Figure 13 shows an AS response to the introspection For example, Figure 15 shows an AS response to the introspection
request in Figure 12. Note that we assume a DTLS-based communication request in Figure 14. Note that we assume a DTLS-based communication
security profile for this example, therefore the Content-Type is security profile for this example, therefore the Content-Type is
"application/cbor". "application/cbor".
Header: Created Code=2.01) Header: Created Code=2.01)
Content-Type: "application/cbor" Content-Type: "application/cbor"
Payload: Payload:
{ {
"active" : true, "active" : true,
"scope" : "read", "scope" : "read",
"profile" : "coap_dtls", "profile" : "coap_dtls",
skipping to change at page 25, line 37 skipping to change at page 26, line 47
(remainder of client token omitted for brevity)', (remainder of client token omitted for brevity)',
"cnf" : { "cnf" : {
"COSE_Key" : { "COSE_Key" : {
"kty" : "Symmetric", "kty" : "Symmetric",
"kid" : b64'39Gqlw', "kid" : b64'39Gqlw',
"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh' "k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'
} }
} }
} }
Figure 13: Example introspection response. Figure 15: Example introspection response.
7.3. Error Response 7.3. Error Response
The error responses for CoAP-based interactions with the AS are The error responses for CoAP-based interactions with the AS are
equivalent to the ones for HTTP-based interactions as defined in equivalent to the ones for HTTP-based interactions as defined in
section 2.3 of [RFC7662], with the following differences: section 2.3 of [RFC7662], with the following differences:
o If content is sent, the Content-Type MUST be set according to the o If content is sent, the Content-Type MUST be set according to the
specification of the communication security profile, and the specification of the communication security profile, and the
content payload MUST be encoded as a CBOR map. content payload MUST be encoded as a CBOR map.
skipping to change at page 26, line 4 skipping to change at page 27, line 18
equivalent to the ones for HTTP-based interactions as defined in equivalent to the ones for HTTP-based interactions as defined in
section 2.3 of [RFC7662], with the following differences: section 2.3 of [RFC7662], with the following differences:
o If content is sent, the Content-Type MUST be set according to the o If content is sent, the Content-Type MUST be set according to the
specification of the communication security profile, and the specification of the communication security profile, and the
content payload MUST be encoded as a CBOR map. content payload MUST be encoded as a CBOR map.
o If the credentials used by the RS are invalid the AS MUST respond o If the credentials used by the RS are invalid the AS MUST respond
with the CoAP response code 4.01 (Unauthorized) and use the with the CoAP response code 4.01 (Unauthorized) and use the
required and optional parameters from section 5.2 in RFC 6749 required and optional parameters from section 5.2 in RFC 6749
[RFC6749]. [RFC6749].
o If the RS does not have the right to perform this introspection o If the RS does not have the right to perform this introspection
request, the AS MUST respond with the CoAP response code 4.03 request, the AS MUST respond with the CoAP response code 4.03
(Forbidden). In this case no payload is returned. (Forbidden). In this case no payload is returned.
o The parameters "error", "error_description" and "error_uri" MAY be
abbreviated using the codes specified in table Figure 13.
o The error codes MAY be abbreviated using the codes specified in
table Figure 7.
Note that a properly formed and authorized query for an inactive or Note that a properly formed and authorized query for an inactive or
otherwise invalid token does not warrant an error response by this otherwise invalid token does not warrant an error response by this
specification. In these cases, the authorization server MUST instead specification. In these cases, the authorization server MUST instead
respond with an introspection response with the "active" field set to respond with an introspection response with the "active" field set to
"false". "false".
7.4. Client Token 7.4. Client Token
EDITORIAL NOTE: We have tentatively introduced this concept and would EDITORIAL NOTE: We have tentatively introduced this concept and would
skipping to change at page 26, line 33 skipping to change at page 27, line 50
suggests the following approach: The client is pre-configured with a suggests the following approach: The client is pre-configured with a
generic, long-term access token when it is commissioned. When the generic, long-term access token when it is commissioned. When the
client then tries to access a RS it transmits this access token. The client then tries to access a RS it transmits this access token. The
RS then performs token introspection to learn what access this token RS then performs token introspection to learn what access this token
grants. In the introspection response, the AS also relays grants. In the introspection response, the AS also relays
information for the client, such as the proof-of-possession key, information for the client, such as the proof-of-possession key,
through the RS. The RS passes on this Client Token to the client in through the RS. The RS passes on this Client Token to the client in
response to the submission of the token. response to the submission of the token.
The client_token parameter is designed to carry such information, and The client_token parameter is designed to carry such information, and
is intended to be used as described in Figure 14. is intended to be used as described in Figure 16.
Resource Authorization Resource Authorization
Client Server Server Client Server Server
| | | | | |
| | | | | |
C: +--------------->| | C: +--------------->| |
| POST | | | POST | |
| Access Token | | | Access Token | |
| D: +--------------->| | D: +--------------->|
| | Introspection | | | Introspection |
| | Request | | | Request |
| | | | | |
| E: +<---------------+ | E: +<---------------+
| | Introspection | | | Introspection |
| | Response | | | Response |
| | + Client Token | | | + Client Token |
|<---------------+ | |<---------------+ |
| 2.01 Created | | | 2.01 Created | |
| + Client Token | | + Client Token |
Figure 14: Use of the client_token parameter. Figure 16: Use of the client_token parameter.
The client token is a COSE_Encrypted object, containing as payload a The client token is a COSE_Encrypted object, containing as payload a
CBOR map with the following claims: CBOR map with the following claims:
cnf cnf
REQUIRED if the token type is 'pop', OPTIONAL otherwise. Contains REQUIRED if the token type is 'pop', OPTIONAL otherwise. Contains
information about the proof-of-possession key the client is to use information about the proof-of-possession key the client is to use
with its access token. See Section 6.4.5. with its access token. See Section 6.5.5.
token_type token_type
OPTIONAL. See Section 6.4.3. OPTIONAL. See Section 6.5.3.
profile profile
REQUIRED. See Section 6.4.4. REQUIRED. See Section 6.5.4.
rs_cnf rs_cnf
OPTIONAL. Contains information about the key that the RS uses to OPTIONAL. Contains information about the key that the RS uses to
authenticate towards the client. If the key is symmetric then authenticate towards the client. If the key is symmetric then
this claim MUST NOT be part of the Client Token, since this is the this claim MUST NOT be part of the Client Token, since this is the
same key as the one specified through the 'cnf' claim. This claim same key as the one specified through the 'cnf' claim. This claim
uses the same encoding as the 'cnf' parameter. See Section 6.4.4. uses the same encoding as the 'cnf' parameter. See Section 6.5.4.
The AS encrypts this token using a key shared between the AS and the The AS encrypts this token using a key shared between the AS and the
client, so that only the client can decrypt it and access its client, so that only the client can decrypt it and access its
payload. How this key is established is out of scope of this payload. How this key is established is out of scope of this
framework. framework.
7.5. Mapping Introspection parameters to CBOR 7.5. Mapping Introspection parameters to CBOR
The introspection request and response parameters are mapped to CBOR The introspection request and response parameters are mapped to CBOR
types as follows and are given an integer key value to save space. types as follows and are given an integer key value to save space.
skipping to change at page 28, line 22 skipping to change at page 29, line 22
|-----------------+----------+-----------------| |-----------------+----------+-----------------|
| iss | 1 | 3 (text string) | | iss | 1 | 3 (text string) |
| sub | 2 | 3 | | sub | 2 | 3 |
| aud | 3 | 3 | | aud | 3 | 3 |
| exp | 4 | 6 tag value 1 | | exp | 4 | 6 tag value 1 |
| nbf | 5 | 6 tag value 1 | | nbf | 5 | 6 tag value 1 |
| iat | 6 | 6 tag value 1 | | iat | 6 | 6 tag value 1 |
| cti | 7 | 2 (byte string) | | cti | 7 | 2 (byte string) |
| client_id | 8 | 3 | | client_id | 8 | 3 |
| scope | 12 | 3 | | scope | 12 | 3 |
| token_type | 19 | 3 | | token_type | 20 | 3 |
| username | 21 | 3 | | username | 22 | 3 |
| cnf | 24 | 5 (map) | | cnf | 25 | 5 (map) |
| profile | 25 | 0 (uint) | | profile | 26 | 0 (uint) |
| token | 26 | 3 | | token | 27 | 3 |
| token_type_hint | 27 | 3 | | token_type_hint | 28 | 3 |
| active | 28 | 0 | | active | 29 | 0 |
| client_token | 29 | 3 | | client_token | 30 | 3 |
| rs_cnf | 30 | 5 | | rs_cnf | 31 | 5 |
\-----------------+----------+-----------------/ \-----------------+----------+-----------------/
Figure 15: CBOR Mappings to Token Introspection Parameters. Figure 17: CBOR Mappings to Token Introspection Parameters.
8. The Access Token 8. The Access Token
This framework RECOMMENDS the use of CBOR web token (CWT) as This framework RECOMMENDS the use of CBOR web token (CWT) as
specified in [I-D.ietf-ace-cbor-web-token]. specified in [I-D.ietf-ace-cbor-web-token].
In order to facilitate offline processing of access tokens, this In order to facilitate offline processing of access tokens, this
draft specifies the "cnf" and "scope" claims for CBOR web tokens. draft specifies the "cnf" and "scope" claims for CBOR web tokens.
The "scope" claim explicitly encodes the scope of a given access The "scope" claim explicitly encodes the scope of a given access
token. This claim follows the same encoding rules as defined in token. This claim follows the same encoding rules as defined in
section 3.3 of [RFC6749]. The meaning of a specific scope value is section 3.3 of [RFC6749]. The meaning of a specific scope value is
application specific and expected to be known to the RS running that application specific and expected to be known to the RS running that
application. application.
The "cnf" claim follows the same rules as specified for JSON web The "cnf" claim follows the same rules as specified for JSON web
token in RFC7800 [RFC7800], except that it is encoded in CBOR in the token in RFC7800 [RFC7800], except that it is encoded in CBOR in the
same way as specified for the "cnf" parameter in Section 6.4.5. same way as specified for the "cnf" parameter in Section 6.5.5.
8.1. The 'Authorization Information' Endpoint 8.1. The 'Authorization Information' Endpoint
The access token, containing authorization information and The access token, containing authorization information and
information of the key used by the client, needs to be transported to information about the key used by the client, needs to be transported
the RS so that the RS can authenticate and authorize the client to the RS so that the RS can authenticate and authorize the client
request. request.
This section defines a method for transporting the access token to This section defines a method for transporting the access token to
the RS using CoAP. Profiles of this framework MAY define other the RS using CoAP. Profiles of this framework MAY define other
methods for token transport. Implementations conforming to this methods for token transport.
framework MUST implement this method of token transportation.
The method consists of a /authz-info endpoint, implemented by the RS. The method consists of an /authz-info endpoint, implemented by the
A client using this method MUST make a POST request to /authz-info at RS. A client using this method MUST make a POST request to /authz-
the RS with the access token in the payload. The RS receiving the info at the RS with the access token in the payload. The RS
token MUST verify the validity of the token. If the token is valid, receiving the token MUST verify the validity of the token. If the
the RS MUST respond to the POST request with 2.04 (Changed). token is valid, the RS MUST respond to the POST request with 2.01
(Created). This response MAY contain the identifier of the token
(e.g. the cti for a CWT) as a payload.
If the token is not valid, the RS MUST respond with the CoAP response If the token is not valid, the RS MUST respond with the CoAP response
code 4.01 (Unauthorized). If the token is valid but the audience of code 4.01 (Unauthorized). If the token is valid but the audience of
the token does not match the RS, the RS MUST respond with the CoAP the token does not match the RS, the RS MUST respond with the CoAP
response code 4.03 (Forbidden). response code 4.03 (Forbidden). If the token is valid but is
associated to claims that the RS cannot process (e.g. an unknown
scope) the RS MUST respond with the CoAP response code 4.00 (Bad
Request). In the latter case the RS MAY provide additional
information in the error response, in order to clarify what went
wrong.
The RS MAY make an introspection request to validate the token before The RS MAY make an introspection request to validate the token before
responding to the POST /authz-info request. If the introspection responding to the POST /authz-info request. If the introspection
response contains a client token (Section 7.4) then this token SHALL response contains a client token (Section 7.4) then this token SHALL
be included in the payload of the 2.04 (Changed) response. be included in the payload of the 2.01 (Created) response.
Profiles are expected to specify how the /authz-info endpoint is Profiles MUST specify how the /authz-info endpoint is protected.
protected. Note that since the token contains information that allow Note that since the token contains information that allow the client
the client and the RS to establish a security context in the first and the RS to establish a security context in the first place, mutual
place, mutual authentication may not be possible at this point. authentication may not be possible at this point.
The RS MUST be prepared to store more than one token for each client,
and MUST apply the combined permissions granted by all applicable,
valid tokens to client requests.
8.2. Token Expiration 8.2. Token Expiration
Depending on the capabilities of the RS, there are various ways in Depending on the capabilities of the RS, there are various ways in
which it can verify the validity of a received access token. We list which it can verify the validity of a received access token. We list
the possibilities here including what functionality they require of the possibilities here including what functionality they require of
the RS. the RS.
o The token is a CWT/JWT and includes a 'exp' claim and possibly the o The token is a CWT/JWT and includes a 'exp' claim and possibly the
'nbf' claim. The RS verifies these by comparing them to values 'nbf' claim. The RS verifies these by comparing them to values
skipping to change at page 30, line 20 skipping to change at page 31, line 31
which is a CWT/JWT. The RS keeps track of the most recently which is a CWT/JWT. The RS keeps track of the most recently
received sequence number, and only accepts tokens as valid, that received sequence number, and only accepts tokens as valid, that
are in a certain range around this number. This method does only are in a certain range around this number. This method does only
require the RS to keep track of the sequence number. The method require the RS to keep track of the sequence number. The method
does not provide timely expiration, but it makes sure that older does not provide timely expiration, but it makes sure that older
tokens cease to be valid after a certain number of newer ones got tokens cease to be valid after a certain number of newer ones got
issued. For a constrained RS with no network connectivity and no issued. For a constrained RS with no network connectivity and no
means of reliably measuring time, this is the best that can be means of reliably measuring time, this is the best that can be
achieved. achieved.
If a token, that authorizes a long running request such as e.g. a
CoAP Observe [RFC7641], expires, the RS MUST send an error response
with the response code 4.01 Unauthorized to the client and then
terminate processing the long running request.
9. Security Considerations 9. Security Considerations
The entire document is about security. Security considerations The entire document is about security. Security considerations
applicable to authentication and authorization in RESTful applicable to authentication and authorization in RESTful
environments provided in OAuth 2.0 [RFC6749] apply to this work, as environments provided in OAuth 2.0 [RFC6749] apply to this work, as
well as the security considerations from [I-D.ietf-ace-actors]. well as the security considerations from [I-D.ietf-ace-actors].
Furthermore [RFC6819] provides additional security considerations for Furthermore [RFC6819] provides additional security considerations for
OAuth which apply to IoT deployments as well. OAuth which apply to IoT deployments as well.
A large range of threats can be mitigated by protecting the contents A large range of threats can be mitigated by protecting the contents
skipping to change at page 30, line 45 skipping to change at page 32, line 14
be encrypted by the authorization server with a long-term key shared be encrypted by the authorization server with a long-term key shared
with the resource server. with the resource server.
It is important for the authorization server to include the identity It is important for the authorization server to include the identity
of the intended recipient (the audience), typically a single resource of the intended recipient (the audience), typically a single resource
server (or a list of resource servers), in the token. Using a single server (or a list of resource servers), in the token. Using a single
shared secret with multiple resource servers to simplify key shared secret with multiple resource servers to simplify key
management is NOT RECOMMENDED since the benefit from using the proof- management is NOT RECOMMENDED since the benefit from using the proof-
of-possession concept is significantly reduced. of-possession concept is significantly reduced.
Token replay is also not possible since an eavesdropper will also Token replay is also more difficult since an eavesdropper will have
have to obtain the corresponding private key or shared secret that is to obtain the token and the corresponding private key or shared
bound to the access token. Nevertheless, it is good practice to secret that is bound to the access token. Nevertheless, it is good
limit the lifetime of the access token and therefore the lifetime of practice to limit the lifetime of the access token and therefore the
associated key. lifetime of associated key.
The authorization server MUST offer confidentiality protection for The authorization server MUST offer confidentiality protection for
any interactions with the client. This step is extremely important any interactions with the client. This step is extremely important
since the client will obtain the session key from the authorization since the client will obtain the session key from the authorization
server for use with a specific access token. Not using server for use with a specific access token. Not using
confidentiality protection exposes this secret (and the access token) confidentiality protection exposes this secret (and the access token)
to an eavesdropper thereby making the proof-of-possession security to an eavesdropper thereby completely negating proof-of-possession
model completely insecure. This framework relies on profiles to security. Profiles MUST specify how confidentiality protection is
define how confidentiality protection is provided, and additional provided, and additional protection can be applied by encrypting the
protection can be applied by encrypting the CWT as specified in token, for example encryption of CWTs is specified in section 5.1 of
section 5.1 of [I-D.ietf-ace-cbor-web-token] to provide an additional [I-D.ietf-ace-cbor-web-token].
layer of protection for cases where keying material is conveyed, for
example, to a hardware security module.
Developers MUST ensure that the ephemeral credentials (i.e., the Developers MUST ensure that the ephemeral credentials (i.e., the
private key or the session key) is not leaked to third parties. An private key or the session key) are not leaked to third parties. An
adversary in possession of the ephemeral credentials bound to the adversary in possession of the ephemeral credentials bound to the
access token will be able to impersonate the client. Be aware that access token will be able to impersonate the client. Be aware that
this is a real risk with many constrained environments, since this is a real risk with many constrained environments, since
adversaries can often easily get physical access to the devices. adversaries can often easily get physical access to the devices.
Clients can at any time request a new proof-of-possession capable Clients can at any time request a new proof-of-possession capable
access token. Using a refresh token to regularly request new access access token. Using a refresh token to regularly request new access
tokens that are bound to fresh and unique keys is important if the tokens that are bound to fresh and unique keys is important if the
client has this capability. Keeping the lifetime of the access token client has this capability. Keeping the lifetime of the access token
short allows the authorization server to use shorter key sizes, which short allows the authorization server to use shorter key sizes, which
translate to a performance benefit for the client and for the translate to a performance benefit for the client and for the
resource server. Shorter keys also lead to shorter messages resource server. Shorter keys also lead to shorter messages
(particularly with asymmetric keying material). (particularly with asymmetric keying material).
When authorization servers bind symmetric keys to access tokens then When authorization servers bind symmetric keys to access tokens, they
they SHOULD scope these access tokens to a specific permissions. SHOULD scope these access tokens to a specific permissions.
Furthermore access tokens SHOULD NOT apply to an audience that
comprises more than one RS, since otherwise any RS in the audience
can impersonate the client towards the other members of the audience.
10. IANA Considerations Clients using an asymmetric key pair for proof-of-possession towards
several different RS should be aware that they will need to rotate
that key pair more frequently than if it was only used towards a
single RS.
10. Privacy Considerations
Implementers and users should be aware of the privacy implications of
the different possible deployments of this framework.
The AS is in a very central position can potentially learn sensitive
information about the clients requesting access tokens. If the
client credentials grant is used, the AS can track what kind of
access the client intends to perform. With other grants, the
Resource Owner can bind the grants to anonymous (rotating)
credentials, that do not allow the AS to link different access token
requests by the same client.
If access tokens are only integrity protected and not encrypted, they
may reveal information to attackers listening on the wire, or able to
acquire the access tokens in some other way. In the case of CWTs or
JWTs the token may e.g. reveal the audience, the scope and the
confirmation method used by the client. The latter may reveal the
client's identity.
Clients using asymmetric keys for proof-of-possession should be aware
of the consequences of using the same key pair for proof-of-
possession towards different RS. A set of colluding RS or an
attacker able to obtain the access tokens will be able to link the
requests, or even to determine the client's identity.
11. IANA Considerations
This specification registers new parameters for OAuth and establishes This specification registers new parameters for OAuth and establishes
registries for mappings to CBOR. registries for mappings to CBOR.
10.1. OAuth Introspection Response Parameter Registration 11.1. OAuth Introspection Response Parameter Registration
This specification registers the following parameters in the OAuth This specification registers the following parameters in the OAuth
introspection response parameters introspection response parameters
o Name: "cnf" o Name: "cnf"
o Description: Key to prove the right to use an access token, as o Description: Key to prove the right to use an access token, as
defined in [RFC7800]. defined in [RFC7800].
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Name: "aud" o Name: "aud"
o Description: Reference to intended receiving RS, as defined in PoP o Description: Reference to intended receiving RS, as defined in PoP
token specification. token specification.
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Name: "profile" o Name: "profile"
o Description: The communication and communication security profile o Description: The communication and communication security profile
used between client and RS, as defined in ACE profiles. used between client and RS, as defined in ACE profiles.
o Change Controller: IESG o Change Controller: IESG
skipping to change at page 32, line 27 skipping to change at page 34, line 26
o Description: Information that the RS MUST pass to the client e.g. o Description: Information that the RS MUST pass to the client e.g.
about the proof-of-possession keys. about the proof-of-possession keys.
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Name: "rs_cnf" o Name: "rs_cnf"
o Description: Describes the public key the RS uses to authenticate. o Description: Describes the public key the RS uses to authenticate.
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
10.2. OAuth Parameter Registration 11.2. OAuth Parameter Registration
This specification registers the following parameters in the OAuth This specification registers the following parameters in the OAuth
Parameters Registry Parameters Registry
o Parameter name: "profile" o Parameter name: "profile"
o Parameter usage location: token request, and token response o Parameter usage location: token request, and token response
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Name: "cnf" o Name: "cnf"
o Description: Key to prove the right to use an access token, as o Description: Key to prove the right to use an access token, as
defined in [RFC7800]. defined in [RFC7800].
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
10.3. OAuth Access Token Types 11.3. OAuth Access Token Types
This specification registers the following new token type in the This specification registers the following new token type in the
OAuth Access Token Types Registry OAuth Access Token Types Registry
o Name: "PoP" o Name: "PoP"
o Description: A proof-of-possession token. o Description: A proof-of-possession token.
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
10.4. Token Type Mappings 11.4. Token Type Mappings
A new registry will be requested from IANA, entitled "Token Type A new registry will be requested from IANA, entitled "Token Type
Mappings". The registry is to be created as Expert Review Required. Mappings". The registry is to be created as Expert Review Required.
10.4.1. Registration Template 11.4.1. Registration Template
Token Type: Token Type:
Name of token type as registered in the OAuth token type registry Name of token type as registered in the OAuth token type registry
e.g. "Bearer". e.g. "Bearer".
Mapped value: Mapped value:
Integer representation for the token type value. The key value Integer representation for the token type value. The key value
MUST be an integer in the range of 1 to 65536. MUST be an integer in the range of 1 to 65536.
Change Controller: Change Controller:
For Standards Track RFCs, list the "IESG". For others, give the For Standards Track RFCs, list the "IESG". For others, give the
name of the responsible party. Other details (e.g., postal name of the responsible party. Other details (e.g., postal
address, email address, home page URI) may also be included. address, email address, home page URI) may also be included.
Specification Document(s): Specification Document(s):
Reference to the document or documents that specify the Reference to the document or documents that specify the
parameter,preferably including URIs that can be used to retrieve parameter,preferably including URIs that can be used to retrieve
copies of the documents. An indication of the relevant sections copies of the documents. An indication of the relevant sections
may also be included but is not required. may also be included but is not required.
10.4.2. Initial Registry Contents 11.4.2. Initial Registry Contents
o Parameter name: "Bearer" o Parameter name: "Bearer"
o Mapped value: 1 o Mapped value: 1
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "pop" o Parameter name: "pop"
o Mapped value: 2 o Mapped value: 2
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
10.5. CBOR Web Token Claims 11.5. CBOR Web Token Claims
This specification registers the following new claims in the CBOR Web This specification registers the following new claims in the CBOR Web
Token (CWT) registry: Token (CWT) registry:
o Claim Name: "scope" o Claim Name: "scope"
o Claim Description: The scope of an access token as defined in o Claim Description: The scope of an access token as defined in
[RFC6749]. [RFC6749].
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Claim Name: "cnf" o Claim Name: "cnf"
o Claim Description: The proof-of-possession key of an access token o Claim Description: The proof-of-possession key of an access token
as defined in [RFC7800]. as defined in [RFC7800].
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
10.6. ACE Profile Registry 11.6. ACE Profile Registry
A new registry will be requested from IANA, entitled "ACE Profile A new registry will be requested from IANA, entitled "ACE Profile
Registry". The registry is to be created as Expert Review Required. Registry". The registry is to be created as Expert Review Required.
10.6.1. Registration Template 11.6.1. Registration Template
Profile name: Profile name:
Name of the profile to be included in the profile attribute. Name of the profile to be included in the profile attribute.
Profile description: Profile description:
Text giving an overview of the profile and the context it is Text giving an overview of the profile and the context it is
developed for. developed for.
Profile ID: Profile ID:
Integer value to identify the profile. The value MUST be an Integer value to identify the profile. The value MUST be an
integer in the range of 1 to 65536. integer in the range of 1 to 65536.
Change Controller: Change Controller:
For Standards Track RFCs, list the "IESG". For others, give the For Standards Track RFCs, list the "IESG". For others, give the
name of the responsible party. Other details (e.g., postal name of the responsible party. Other details (e.g., postal
address, email address, home page URI) may also be included. address, email address, home page URI) may also be included.
Specification Document(s): Specification Document(s):
Reference to the document or documents that specify the Reference to the document or documents that specify the
parameter,preferably including URIs that can be used to retrieve parameter,preferably including URIs that can be used to retrieve
copies of the documents. An indication of the relevant sections copies of the documents. An indication of the relevant sections
may also be included but is not required. may also be included but is not required.
10.7. OAuth Parameter Mappings Registry 11.7. OAuth Parameter Mappings Registry
A new registry will be requested from IANA, entitled "Token Endpoint A new registry will be requested from IANA, entitled "Token Endpoint
CBOR Mappings Registry". The registry is to be created as Expert CBOR Mappings Registry". The registry is to be created as Expert
Review Required. Review Required.
10.7.1. Registration Template 11.7.1. Registration Template
Parameter name: Parameter name:
OAuth Parameter name, refers to the name in the OAuth parameter OAuth Parameter name, refers to the name in the OAuth parameter
registry e.g. "client_id". registry e.g. "client_id".
CBOR key value: CBOR key value:
Key value for the claim. The key value MUST be an integer in the Key value for the claim. The key value MUST be an integer in the
range of 1 to 65536. range of 1 to 65536.
Change Controller: Change Controller:
For Standards Track RFCs, list the "IESG". For others, give the For Standards Track RFCs, list the "IESG". For others, give the
name of the responsible party. Other details (e.g., postal name of the responsible party. Other details (e.g., postal
address, email address, home page URI) may also be included. address, email address, home page URI) may also be included.
Specification Document(s): Specification Document(s):
Reference to the document or documents that specify the Reference to the document or documents that specify the
parameter,preferably including URIs that can be used to retrieve parameter,preferably including URIs that can be used to retrieve
copies of the documents. An indication of the relevant sections copies of the documents. An indication of the relevant sections
may also be included but is not required. may also be included but is not required.
10.7.2. Initial Registry Contents 11.7.2. Initial Registry Contents
o Parameter name: "aud" o Parameter name: "aud"
o CBOR key value: 3 o CBOR key value: 3
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "client_id" o Parameter name: "client_id"
o CBOR key value: 8 o CBOR key value: 8
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
skipping to change at page 36, line 4 skipping to change at page 38, line 4
o Parameter name: "state" o Parameter name: "state"
o CBOR key value: 13 o CBOR key value: 13
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "code" o Parameter name: "code"
o CBOR key value: 14 o CBOR key value: 14
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "error_description" o Parameter name: "error"
o CBOR key value: 15 o CBOR key value: 15
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "error_uri" o Parameter name: "error_description"
o CBOR key value: 16 o CBOR key value: 16
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "grant_type" o Parameter name: "error_uri"
o CBOR key value: 17 o CBOR key value: 17
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "access_token" o Parameter name: "grant_type"
o CBOR key value: 18 o CBOR key value: 18
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "token_type" o Parameter name: "access_token"
o CBOR key value: 19 o CBOR key value: 19
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "expires_in" o Parameter name: "token_type"
o CBOR key value: 20 o CBOR key value: 20
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "username" o Parameter name: "expires_in"
o CBOR key value: 21 o CBOR key value: 21
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "password" o Parameter name: "username"
o CBOR key value: 22 o CBOR key value: 22
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "refresh_token" o Parameter name: "password"
o CBOR key value: 23 o CBOR key value: 23
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "cnf" o Parameter name: "refresh_token"
o CBOR key value: 24 o CBOR key value: 24
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "profile" o Parameter name: "cnf"
o CBOR key value: 25 o CBOR key value: 25
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
10.8. Introspection Endpoint CBOR Mappings Registry o Parameter name: "profile"
o CBOR key value: 26
o Change Controller: IESG
o Specification Document(s): this document
11.8. Introspection Endpoint CBOR Mappings Registry
A new registry will be requested from IANA, entitled "Introspection A new registry will be requested from IANA, entitled "Introspection
Endpoint CBOR Mappings Registry". The registry is to be created as Endpoint CBOR Mappings Registry". The registry is to be created as
Expert Review Required. Expert Review Required.
10.8.1. Registration Template 11.8.1. Registration Template
Response parameter name: Response parameter name:
Name of the response parameter as defined in the "OAuth Token Name of the response parameter as defined in the "OAuth Token
Introspection Response" registry e.g. "active". Introspection Response" registry e.g. "active".
CBOR key value: CBOR key value:
Key value for the claim. The key value MUST be an integer in the Key value for the claim. The key value MUST be an integer in the
range of 1 to 65536. range of 1 to 65536.
Change Controller: Change Controller:
For Standards Track RFCs, list the "IESG". For others, give the For Standards Track RFCs, list the "IESG". For others, give the
name of the responsible party. Other details (e.g., postal name of the responsible party. Other details (e.g., postal
address, email address, home page URI) may also be included. address, email address, home page URI) may also be included.
Specification Document(s): Specification Document(s):
Reference to the document or documents that specify the Reference to the document or documents that specify the
parameter,preferably including URIs that can be used to retrieve parameter,preferably including URIs that can be used to retrieve
copies of the documents. An indication of the relevant sections copies of the documents. An indication of the relevant sections
may also be included but is not required. may also be included but is not required.
10.8.2. Initial Registry Contents 11.8.2. Initial Registry Contents
o Response parameter name: "iss" o Response parameter name: "iss"
o CBOR key value: 1 o CBOR key value: 1
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Response parameter name: "sub" o Response parameter name: "sub"
o CBOR key value: 2 o CBOR key value: 2
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
skipping to change at page 38, line 35 skipping to change at page 40, line 40
o CBOR key value: 8 o CBOR key value: 8
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Response parameter name: "scope" o Response parameter name: "scope"
o CBOR key value: 12 o CBOR key value: 12
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Response parameter name: "token_type" o Response parameter name: "token_type"
o CBOR key value: 19 o CBOR key value: 20
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Response parameter name: "username" o Response parameter name: "username"
o CBOR key value: 21 o CBOR key value: 22
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "cnf" o Parameter name: "cnf"
o CBOR key value: 24 o CBOR key value: 25
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Parameter name: "profile" o Parameter name: "profile"
o CBOR key value: 25 o CBOR key value: 26
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Response parameter name: "token" o Response parameter name: "token"
o CBOR key value: 26 o CBOR key value: 27
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Response parameter name: "token_type_hint" o Response parameter name: "token_type_hint"
o CBOR key value: 27 o CBOR key value: 28
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Response parameter name: "active" o Response parameter name: "active"
o CBOR key value: 28 o CBOR key value: 29
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Response parameter name: "client_token" o Response parameter name: "client_token"
o CBOR key value: 29 o CBOR key value: 30
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
o Response parameter name: "rs_cnf" o Response parameter name: "rs_cnf"
o CBOR key value: 30 o CBOR key value: 31
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): this document o Specification Document(s): this document
10.9. CoAP Option Number Registration 11.9. CoAP Option Number Registration
This section registers the "Access-Token" CoAP Option Number in the This section registers the "Access-Token" CoAP Option Number in the
"CoRE Parameters" sub-registry "CoAP Option Numbers" in the manner "CoRE Parameters" sub-registry "CoAP Option Numbers" in the manner
described in [RFC7252]. described in [RFC7252].
Name Name
Access-Token Access-Token
Number Number
skipping to change at page 40, line 16 skipping to change at page 42, line 20
Yes Yes
Format Format
Based on the observer the format is perceived differently. Opaque Based on the observer the format is perceived differently. Opaque
data to the client and CWT or reference token to the RS. data to the client and CWT or reference token to the RS.
Length Length
Less then 255 bytes Less then 255 bytes
11. Acknowledgments 11.10. CWT Confirmation Methods Registry
This specification establishes the IANA "CWT Confirmation Methods"
registry for CWT "cnf" member values. The registry records the
confirmation method member and a reference to the specification that
defines it.
11.10.1. Registration Template
Confirmation Method Name:
The name requested (e.g., "kid"). This name is intended to be
human readable and be used for debugging purposes. It is case
sensitive. Names may not match other registered names in a case-
insensitive manner unless the Designated Experts state that there
is a compelling reason to allow an exception.
Confirmation Method Value:
Integer representation for the confirmation method value.
Intended for use to uniquely identify the confirmation method.
The value MUST be an integer in the range of 1 to 65536.
Confirmation Method Description:
Brief description of the confirmation method (e.g. "Key
Identifier").
Change Controller:
For Standards Track RFCs, list the "IESG". For others, give the
name of the responsible party. Other details (e.g., postal
address, email address, home page URI) may also be included.
Specification Document(s):
Reference to the document or documents that specify the parameter,
preferably including URIs that can be used to retrieve copies of
the documents. An indication of the relevant sections may also be
included but is not required.
11.10.2. Initial Registry Contents
o Confirmation Method Name: "COSE_Key"
o Confirmation Method Value: 1
o Confirmation Method Description: A COSE_Key that is either a
public key or a symmetric key.
o Change Controller: IESG
o Specification Document(s): this document
o Confirmation Method Name: "COSE_Encrypted"
o Confirmation Method Value: 2
o Confirmation Method Description: A COSE_Encrypted structure that
wraps a COSE_Key containing a symmetric key.
o Change Controller: IESG
o Specification Document(s): this document
o Confirmation Method Name: "Key Identifier"
o Confirmation Method Value: 3
o Confirmation Method Description: A key identifier.
o Change Controller: IESG
o Specification Document(s): this document
12. Acknowledgments
We would like to thank Eve Maler for her contributions to the use of We would like to thank Eve Maler for her contributions to the use of
OAuth 2.0 and UMA in IoT scenarios, Robert Taylor for his discussion OAuth 2.0 and UMA in IoT scenarios, Robert Taylor for his discussion
input, and Malisa Vucinic for his input on the ACRE proposal input, and Malisa Vucinic for his input on the predecessors of this
[I-D.seitz-ace-core-authz] which was one source of inspiration for proposal. Finally, we would like to thank the ACE working group in
this work. Finally, we would like to thank the ACE working group in
general for their feedback. general for their feedback.
We would like to thank the authors of draft-ietf-oauth-pop-key- We would like to thank the authors of draft-ietf-oauth-pop-key-
distribution, from where we copied large parts of our security distribution, from where we copied large parts of our security
considerations. considerations.
Ludwig Seitz and Goeran Selander worked on this document as part of Ludwig Seitz and Goeran Selander worked on this document as part of
the CelticPlus project CyberWI, with funding from Vinnova. the CelticPlus project CyberWI, with funding from Vinnova.
12. References 13. References
13.1. Normative References
12.1. Normative References
[I-D.ietf-ace-cbor-web-token]
Wahlstroem, E., Jones, M., Tschofenig, H., and S. Erdtman,
"CBOR Web Token (CWT)", draft-ietf-ace-cbor-web-token-01
(work in progress), July 2016.
[I-D.ietf-cose-msg] [I-D.ietf-cose-msg]
Schaad, J., "CBOR Object Signing and Encryption (COSE)", Schaad, J., "CBOR Object Signing and Encryption (COSE)",
draft-ietf-cose-msg-23 (work in progress), October 2016. draft-ietf-cose-msg-24 (work in progress), November 2016.
[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,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer [RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347, Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <http://www.rfc-editor.org/info/rfc6347>. January 2012, <http://www.rfc-editor.org/info/rfc6347>.
skipping to change at page 41, line 23 skipping to change at page 44, line 33
[RFC7662] Richer, J., Ed., "OAuth 2.0 Token Introspection", [RFC7662] Richer, J., Ed., "OAuth 2.0 Token Introspection",
RFC 7662, DOI 10.17487/RFC7662, October 2015, RFC 7662, DOI 10.17487/RFC7662, October 2015,
<http://www.rfc-editor.org/info/rfc7662>. <http://www.rfc-editor.org/info/rfc7662>.
[RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of- [RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of-
Possession Key Semantics for JSON Web Tokens (JWTs)", Possession Key Semantics for JSON Web Tokens (JWTs)",
RFC 7800, DOI 10.17487/RFC7800, April 2016, RFC 7800, DOI 10.17487/RFC7800, April 2016,
<http://www.rfc-editor.org/info/rfc7800>. <http://www.rfc-editor.org/info/rfc7800>.
12.2. Informative References 13.2. Informative References
[I-D.ietf-ace-actors] [I-D.ietf-ace-actors]
Gerdes, S., Seitz, L., Selander, G., and C. Bormann, "An Gerdes, S., Seitz, L., Selander, G., and C. Bormann, "An
architecture for authorization in constrained architecture for authorization in constrained
environments", draft-ietf-ace-actors-04 (work in environments", draft-ietf-ace-actors-04 (work in
progress), September 2016. progress), September 2016.
[I-D.ietf-ace-cbor-web-token]
Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig,
"CBOR Web Token (CWT)", draft-ietf-ace-cbor-web-token-02
(work in progress), January 2017.
[I-D.ietf-core-object-security]
Selander, G., Mattsson, J., Palombini, F., and L. Seitz,
"Object Security of CoAP (OSCOAP)", draft-ietf-core-
object-security-01 (work in progress), December 2016.
[I-D.ietf-oauth-device-flow] [I-D.ietf-oauth-device-flow]
Denniss, W., Myrseth, S., Bradley, J., Jones, M., and H. Denniss, W., Myrseth, S., Bradley, J., Jones, M., and H.
Tschofenig, "OAuth 2.0 Device Flow", draft-ietf-oauth- Tschofenig, "OAuth 2.0 Device Flow", draft-ietf-oauth-
device-flow-03 (work in progress), July 2016. device-flow-03 (work in progress), July 2016.
[I-D.ietf-oauth-native-apps] [I-D.ietf-oauth-native-apps]
Denniss, W. and J. Bradley, "OAuth 2.0 for Native Apps", Denniss, W. and J. Bradley, "OAuth 2.0 for Native Apps",
draft-ietf-oauth-native-apps-05 (work in progress), draft-ietf-oauth-native-apps-07 (work in progress),
October 2016. January 2017.
[I-D.seitz-ace-core-authz]
Seitz, L., Selander, G., and M. Vucinic, "Authorization
for Constrained RESTful Environments", draft-seitz-ace-
core-authz-00 (work in progress), June 2015.
[I-D.selander-ace-object-security]
Selander, G., Mattsson, J., Palombini, F., and L. Seitz,
"Object Security of CoAP (OSCOAP)", draft-selander-ace-
object-security-06 (work in progress), October 2016.
[RFC4949] Shirey, R., "Internet Security Glossary, Version 2", [RFC4949] Shirey, R., "Internet Security Glossary, Version 2",
FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007, FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
<http://www.rfc-editor.org/info/rfc4949>. <http://www.rfc-editor.org/info/rfc4949>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, (TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008, DOI 10.17487/RFC5246, August 2008,
<http://www.rfc-editor.org/info/rfc5246>. <http://www.rfc-editor.org/info/rfc5246>.
skipping to change at page 43, line 10 skipping to change at page 46, line 24
[RFC7521] Campbell, B., Mortimore, C., Jones, M., and Y. Goland, [RFC7521] Campbell, B., Mortimore, C., Jones, M., and Y. Goland,
"Assertion Framework for OAuth 2.0 Client Authentication "Assertion Framework for OAuth 2.0 Client Authentication
and Authorization Grants", RFC 7521, DOI 10.17487/RFC7521, and Authorization Grants", RFC 7521, DOI 10.17487/RFC7521,
May 2015, <http://www.rfc-editor.org/info/rfc7521>. May 2015, <http://www.rfc-editor.org/info/rfc7521>.
[RFC7591] Richer, J., Ed., Jones, M., Bradley, J., Machulak, M., and [RFC7591] Richer, J., Ed., Jones, M., Bradley, J., Machulak, M., and
P. Hunt, "OAuth 2.0 Dynamic Client Registration Protocol", P. Hunt, "OAuth 2.0 Dynamic Client Registration Protocol",
RFC 7591, DOI 10.17487/RFC7591, July 2015, RFC 7591, DOI 10.17487/RFC7591, July 2015,
<http://www.rfc-editor.org/info/rfc7591>. <http://www.rfc-editor.org/info/rfc7591>.
[RFC7641] Hartke, K., "Observing Resources in the Constrained
Application Protocol (CoAP)", RFC 7641,
DOI 10.17487/RFC7641, September 2015,
<http://www.rfc-editor.org/info/rfc7641>.
[RFC7744] Seitz, L., Ed., Gerdes, S., Ed., Selander, G., Mani, M., [RFC7744] Seitz, L., Ed., Gerdes, S., Ed., Selander, G., Mani, M.,
and S. Kumar, "Use Cases for Authentication and and S. Kumar, "Use Cases for Authentication and
Authorization in Constrained Environments", RFC 7744, Authorization in Constrained Environments", RFC 7744,
DOI 10.17487/RFC7744, January 2016, DOI 10.17487/RFC7744, January 2016,
<http://www.rfc-editor.org/info/rfc7744>. <http://www.rfc-editor.org/info/rfc7744>.
[RFC7959] Bormann, C. and Z. Shelby, Ed., "Block-Wise Transfers in [RFC7959] Bormann, C. and Z. Shelby, Ed., "Block-Wise Transfers in
the Constrained Application Protocol (CoAP)", RFC 7959, the Constrained Application Protocol (CoAP)", RFC 7959,
DOI 10.17487/RFC7959, August 2016, DOI 10.17487/RFC7959, August 2016,
<http://www.rfc-editor.org/info/rfc7959>. <http://www.rfc-editor.org/info/rfc7959>.
skipping to change at page 45, line 4 skipping to change at page 48, line 24
security reasons, e.g. to avoid an entry point for Denial-of- security reasons, e.g. to avoid an entry point for Denial-of-
Service attacks. Service attacks.
The communication interactions this framework builds upon (as The communication interactions this framework builds upon (as
shown graphically in Figure 1) may be accomplished using a variety shown graphically in Figure 1) may be accomplished using a variety
of different protocols, and not all parts of the message flow are of different protocols, and not all parts of the message flow are
used in all applications due to the communication constraints. used in all applications due to the communication constraints.
While we envision deployments to make use of CoAP we explicitly While we envision deployments to make use of CoAP we explicitly
want to support HTTP, HTTP/2 or specific protocols, such as want to support HTTP, HTTP/2 or specific protocols, such as
Bluetooth Smart communication, which does not necessarily use IP. Bluetooth Smart communication, which does not necessarily use IP.
The latter raises the need for application layer security over the The latter raises the need for application layer security over the
various interfaces. various interfaces.
Appendix B. Roles and Responsibilites Appendix B. Roles and Responsibilities
Resource Owner Resource Owner
* Make sure that the RS is registered at the AS. This includes * Make sure that the RS is registered at the AS. This includes
making known to the AS which profiles, token_types, scopes, and making known to the AS which profiles, token_types, scopes, and
key types (symmetric/asymmetric) the RS supports. Also making key types (symmetric/asymmetric) the RS supports. Also making
it known to the AS which audience(s) the RS identifies itself it known to the AS which audience(s) the RS identifies itself
with. with.
* Make sure that clients can discover the AS which is in charge * Make sure that clients can discover the AS which is in charge
of the RS. of the RS.
* Make sure that the AS has the necessary, up-to-date, access * If the client-credentials grant is used, make sure that the AS
control policies for the RS. has the necessary, up-to-date, access control policies for the
RS.
Requesting Party Requesting Party
* Make sure that the client is provisioned the necessary * Make sure that the client is provisioned the necessary
credentials to authenticate to the AS. credentials to authenticate to the AS.
* Make sure that the client is configured to follow the security * Make sure that the client is configured to follow the security
requirements of the Requesting Party, when issuing requests requirements of the Requesting Party, when issuing requests
(e.g. minimum communication security requirements, trust (e.g. minimum communication security requirements, trust
anchors). anchors).
* Register the client at the AS. This includes making known to * Register the client at the AS. This includes making known to
the AS which profiles, token_types, and key types (symmetric/ the AS which profiles, token_types, and key types (symmetric/
asymmetric) the client. asymmetric) the client.
Authorization Server Authorization Server
* Register RS and manage corresponding security contexts. * Register RS and manage corresponding security contexts.
* Register clients and including authentication credentials. * Register clients and including authentication credentials.
* Allow Resource Owners to configure and update access control * Allow Resource Owners to configure and update access control
policies related to their registered RS' policies related to their registered RS'
skipping to change at page 45, line 44 skipping to change at page 49, line 19
Authorization Server Authorization Server
* Register RS and manage corresponding security contexts. * Register RS and manage corresponding security contexts.
* Register clients and including authentication credentials. * Register clients and including authentication credentials.
* Allow Resource Owners to configure and update access control * Allow Resource Owners to configure and update access control
policies related to their registered RS' policies related to their registered RS'
* Expose the /token endpoint to allow clients to request tokens. * Expose the /token endpoint to allow clients to request tokens.
* Authenticate clients that wish to request a token. * Authenticate clients that wish to request a token.
* Process a token request against the authorization policies * Process a token request against the authorization policies
configured for the RS. configured for the RS.
* Expose the /introspection endpoint that allows RS's to submit * Optionally: Expose the /introspection endpoint that allows RS's
token introspection requests. to submit token introspection requests.
* Authenticate RS's that wish to get an introspection response. * If providing an introspection endpoint: Authenticate RS's that
* Process token introspection requests. wish to get an introspection response.
* If providing an introspection endpoint: Process token
introspection requests.
* Optionally: Handle token revocation. * Optionally: Handle token revocation.
Client Client
* Discover the AS in charge of the RS that is to be targeted with * Discover the AS in charge of the RS that is to be targeted with
a request. a request.
* Submit the token request (A). * Submit the token request (A).
+ Authenticate towards the AS. + Authenticate towards the AS.
+ Optionally (if not pre-configured): Specify which RS, which + Optionally (if not pre-configured): Specify which RS, which
resource(s), and which action(s) the request(s) will target. resource(s), and which action(s) the request(s) will target.
+ If raw public key (rpk) or certificate is used, make sure + If raw public key (rpk) or certificate is used, make sure
the AS has the right rpk or certificate for this client. the AS has the right rpk or certificate for this client.
* Process the access token and RS Information (B) * Process the access token and RS Information (B)
skipping to change at page 47, line 15 skipping to change at page 50, line 38
+ Check that tokens belonging to the client actually authorize + Check that tokens belonging to the client actually authorize
the requested action. the requested action.
+ Optionally: Check that the matching tokens are still valid, + Optionally: Check that the matching tokens are still valid,
using introspection (if this is possible.) using introspection (if this is possible.)
* Send a response following the agreed upon communication * Send a response following the agreed upon communication
security. security.
Appendix C. Requirements on Profiles Appendix C. Requirements on Profiles
This section lists the requirements on profiles of this framework, This section lists the requirements on profiles of this framework,
for the convenience of a profile designer. All this information is for the convenience of a profile designer.
also given in the appropriate sections of the main document, this is
just meant as a checklist, to make it more easy to spot parts one
might have missed.
o Specify the discovery process of how the client finds the right AS o Optionally Specify the discovery process of how the client finds
for an RS it wants to send a request to. the right AS for an RS it wants to send a request to. Section 4
o Specify the communication protocol the client and RS the must use o Specify the communication protocol the client and RS the must use
(e.g. CoAP). (e.g. CoAP). Section 5 and Section 6.5.4
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 (e.g. OSCOAP or DTLS over CoAP). protect their communication (e.g. OSCOAP or DTLS over CoAP).
This must provide encryption and integrity protection. This must provide encryption and integrity protection.
o Specify how the client and the RS mutually authenticate Section 6.5.4
o Specify how the client and the RS mutually authenticate.
Section 4
o Specify the Content-format of the protocol messages (e.g. o Specify the Content-format of the protocol messages (e.g.
"application/cbor" or "application/cose+cbor"). "application/cbor" or "application/cose+cbor"). Section 4
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. possession protocol. Section 6.5.3
o Specify a unique profile identifier. o Specify a unique profile identifier. Section 6.5.4
o Optionally specify how the RS talks to the AS for introspection. o Optionally specify how the RS talks to the AS for
introspection.Section 7
o Optionally specify how the client talks to the AS for requesting a o Optionally specify how the client talks to the AS for requesting a
token. token. Section 6
o Specify how/if the /authz-info endpoint is protected. o Specify how/if the /authz-info endpoint is protected. Section 8.1
o Optionally define other methods of token transport than the o Optionally define other methods of token transport than the
/authz-info endpoint. /authz-info endpoint. Section 8.1
Appendix D. Deployment Examples Appendix D. Assumptions on AS knowledge about C and RS
This section lists the assumptions on what an AS should know about a
client and a RS in order to be able to respond to requests to the
/token and /introspect endpoints. How this information is
established is out of scope for this document.
o The identifier of the client or RS.
o The profiles that the client or RS supports.
o The scopes that the RS supports.
o The audiences that the RS identifies with.
o The key types (e.g. pre-shared symmetric key, raw public key, key
length, other key parameters) that the client or RS supports.
o The types of access tokens the RS supports (e.g. CWT).
o If the RS supports CWTs, the COSE parameters for the crypto
wrapper (e.g. algorithm, key-wrap algorithm, key-length).
o The expiration time for access tokens issued to this RS (unless
the RS accepts a default time chosen by the AS).
o The symmetric key shared between client or RS and AS (if any).
o The raw public key of the client or RS (if any).
Appendix E. Deployment Examples
There is a large variety of IoT deployments, as is indicated in There is a large variety of IoT deployments, as is indicated in
Appendix A, and this section highlights a few common variants. This Appendix A, and this section highlights a few common variants. This
section is not normative but illustrates how the framework can be section is not normative but illustrates how the framework can be
applied. applied.
For each of the deployment variants there are a number of possible For each of the deployment variants there are a number of possible
security setups between clients, resource servers and authorization security setups between clients, resource servers and authorization
servers. The main focus in the following subsections is on how servers. The main focus in the following subsections is on how
authorization of a client request for a resource hosted by a RS is authorization of a client request for a resource hosted by a RS is
performed. This requires the the security of the requests and performed. This requires the the security of the requests and
responses between the clients and the RS to consider. responses between the clients and the RS to consider.
Note: CBOR diagnostic notation is used for examples of requests and Note: CBOR diagnostic notation is used for examples of requests and
responses. responses.
D.1. Local Token Validation E.1. Local Token Validation
In this scenario we consider the case where the resource server is In this scenario we consider the case where the resource server is
offline, i.e. it is not connected to the AS at the time of the access offline, i.e. it is not connected to the AS at the time of the access
request. This access procedure involves steps A, B, C, and F of request. This access procedure involves steps A, B, C, and F of
Figure 1. Figure 1.
Since the resource server must be able to verify the access token Since the resource server must be able to verify the access token
locally, self-contained access tokens must be used. locally, self-contained access tokens must be used.
This example shows the interactions between a client, the This example shows the interactions between a client, the
authorization server and a temperature sensor acting as a resource authorization server and a temperature sensor acting as a resource
server. Message exchanges A and B are shown in Figure 16. server. Message exchanges A and B are shown in Figure 18.
A: The client first generates a public-private key pair used for A: The client first generates a public-private key pair used for
communication security with the RS. communication security with the RS.
The client sends the POST request to /token at the AS. The The client sends the POST request to /token at the AS. The
security of this request can be transport or application layer, it security of this request can be transport or application layer, it
is up the the comunication security profile to define. In the is up the the communication security profile to define. In the
example trasport layer identification of the AS is done and the example transport layer identification of the AS is done and the
client identifies with client_id and client_secret as in classic client identifies with client_id and client_secret as in classic
OAuth. The request contains the public key of the client and the OAuth. The request contains the public key of the client and the
Audience parameter set to "tempSensorInLivingRoom", a value that Audience parameter set to "tempSensorInLivingRoom", a value that
the temperature sensor identifies itself with. The AS evaluates the temperature sensor identifies itself with. The AS evaluates
the request and authorizes the client to access the resource. the request and authorizes the client to access the resource.
B: The AS responds with a PoP token and RS Information. The PoP B: The AS responds with a PoP token and RS Information. The PoP
token contains the public key of the client, and the RS token contains the public key of the client, and the RS
Information contains the public key of the RS. For communication Information contains the public key of the RS. For communication
security this example uses DTLS RawPublicKey between the client security this example uses DTLS RawPublicKey between the client
and the RS. The issued token will have a short validity time, and the RS. The issued token will have a short validity time,
skipping to change at page 49, line 21 skipping to change at page 53, line 21
A: +-------->| Header: POST (Code=0.02) A: +-------->| Header: POST (Code=0.02)
| POST | Uri-Path:"token" | POST | Uri-Path:"token"
| | Content-Type: application/cbor | | Content-Type: application/cbor
| | Payload: <Request-Payload> | | Payload: <Request-Payload>
| | | |
B: |<--------+ Header: 2.05 Content B: |<--------+ Header: 2.05 Content
| 2.05 | Content-Type: application/cbor | 2.05 | Content-Type: application/cbor
| | Payload: <Response-Payload> | | Payload: <Response-Payload>
| | | |
Figure 16: Token Request and Response Using Client Credentials. Figure 18: Token Request and Response Using Client Credentials.
The information contained in the Request-Payload and the Response- The information contained in the Request-Payload and the Response-
Payload is shown in Figure 17. Note that we assume a DTLS-based Payload is shown in Figure 19. Note that we assume a DTLS-based
communication security profile for this example, therefore the communication security profile for this example, therefore the
Content-Type is "application/cbor". Content-Type is "application/cbor".
Request-Payload : Request-Payload :
{ {
"grant_type" : "client_credentials", "grant_type" : "client_credentials",
"aud" : "tempSensorInLivingRoom", "aud" : "tempSensorInLivingRoom",
"client_id" : "myclient", "client_id" : "myclient",
"client_secret" : "qwerty" "client_secret" : "qwerty"
} }
skipping to change at page 49, line 52 skipping to change at page 53, line 52
"COSE_Key" : { "COSE_Key" : {
"kid" : b64'c29tZSBwdWJsaWMga2V5IGlk', "kid" : b64'c29tZSBwdWJsaWMga2V5IGlk',
"kty" : "EC", "kty" : "EC",
"crv" : "P-256", "crv" : "P-256",
"x" : b64'MKBCTNIcKUSDii11ySs3526iDZ8AiTo7Tu6KPAqv7D4', "x" : b64'MKBCTNIcKUSDii11ySs3526iDZ8AiTo7Tu6KPAqv7D4',
"y" : b64'4Etl6SRW2YiLUrN5vfvVHuhp7x8PxltmWWlbbM4IFyM' "y" : b64'4Etl6SRW2YiLUrN5vfvVHuhp7x8PxltmWWlbbM4IFyM'
} }
} }
} }
Figure 17: Request and Response Payload Details. Figure 19: Request and Response Payload Details.
The content of the access token is shown in Figure 18. The content of the access token is shown in Figure 20.
{ {
"aud" : "tempSensorInLivingRoom", "aud" : "tempSensorInLivingRoom",
"iat" : "1360189224", "iat" : "1360189224",
"exp" : "1360289224", "exp" : "1360289224",
"scope" : "temperature_g firmware_p", "scope" : "temperature_g firmware_p",
"cnf" : { "cnf" : {
"jwk" : { "jwk" : {
"kid" : b64'1Bg8vub9tLe1gHMzV76e8', "kid" : b64'1Bg8vub9tLe1gHMzV76e8',
"kty" : "EC", "kty" : "EC",
"crv" : "P-256", "crv" : "P-256",
"x" : b64'f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU', "x" : b64'f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU',
"y" : b64'x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0' "y" : b64'x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0'
} }
} }
} }
Figure 18: Access Token including Public Key of the Client. Figure 20: Access Token including Public Key of the Client.
Messages C and F are shown in Figure 19 - Figure 20. Messages C and F are shown in Figure 21 - Figure 22.
C: The client then sends the PoP token to the /authz-info endpoint C: The client then sends the PoP token to the /authz-info endpoint
at the RS. This is a plain CoAP request, i.e. no transport or at the RS. This is a plain CoAP request, i.e. no transport or
application layer security between client and RS, since the token application layer security between client and RS, since the token
is integrity protected between AS and RS. The RS verifies that is integrity protected between AS and RS. The RS verifies that
the PoP token was created by a known and trusted AS, is valid, and the PoP token was created by a known and trusted AS, is valid, and
responds to the client. The RS caches the security context responds to the client. The RS caches the security context
together with authorization information about this client together with authorization information about this client
contained in the PoP token. contained in the PoP token.
skipping to change at page 50, line 47 skipping to change at page 54, line 47
Client Server Client Server
| | | |
C: +-------->| Header: POST (Code=0.02) C: +-------->| Header: POST (Code=0.02)
| POST | Uri-Path:"authz-info" | POST | Uri-Path:"authz-info"
| | Payload: SlAV32hkKG ... | | Payload: SlAV32hkKG ...
| | | |
|<--------+ Header: 2.04 Changed |<--------+ Header: 2.04 Changed
| 2.04 | | 2.04 |
| | | |
Figure 19: Access Token provisioning to RS Figure 21: Access Token provisioning to RS
The client and the RS runs the DTLS handshake using the raw public The client and the RS runs the DTLS handshake using the raw public
keys established in step B and C. keys established in step B and C.
The client sends the CoAP request GET to /temperature on RS over The client sends the CoAP request GET to /temperature on RS over
DTLS. The RS verifies that the request is authorized, based on DTLS. The RS verifies that the request is authorized, based on
previously established security context. previously established security context.
F: The RS responds with a resource representation over DTLS. F: The RS responds with a resource representation over DTLS.
Resource Resource
Client Server Client Server
skipping to change at page 51, line 25 skipping to change at page 55, line 25
| | | |
+-------->| Header: GET (Code=0.01) +-------->| Header: GET (Code=0.01)
| GET | Uri-Path: "temperature" | GET | Uri-Path: "temperature"
| | | |
| | | |
| | | |
F: |<--------+ Header: 2.05 Content F: |<--------+ Header: 2.05 Content
| 2.05 | Payload: <sensor value> | 2.05 | Payload: <sensor value>
| | | |
Figure 20: Resource Request and Response protected by DTLS. Figure 22: Resource Request and Response protected by DTLS.
D.2. Introspection Aided Token Validation E.2. Introspection Aided Token Validation
In this deployment scenario we assume that a client is not able to In this deployment scenario we assume that a client is not able to
access the AS at the time of the access request. Since the RS is, access the AS at the time of the access request. Since the RS is,
however, connected to the back-end infrastructure it can make use of however, connected to the back-end infrastructure it can make use of
token introspection. This access procedure involves steps A-F of token introspection. This access procedure involves steps A-F of
Figure 1, but assumes steps A and B have been carried out during a Figure 1, but assumes steps A and B have been carried out during a
phase when the client had connectivity to AS. phase when the client had connectivity to AS.
Since the client is assumed to be offline, at least for a certain Since the client is assumed to be offline, at least for a certain
period of time, a pre-provisioned access token has to be long-lived. period of time, a pre-provisioned access token has to be long-lived.
The resource server may use its online connectivity to validate the The resource server may use its online connectivity to validate the
access token with the authorization server, which is shown in the access token with the authorization server, which is shown in the
example below. example below.
In the example interactions between an offline client (key fob), a RS In the example interactions between an offline client (key fob), a RS
(online lock), and an AS is shown. We assume that there is a (online lock), and an AS is shown. We assume that there is a
provisioning step where the client has access to the AS. This provisioning step where the client has access to the AS. This
corresponds to message exchanges A and B which are shown in corresponds to message exchanges A and B which are shown in
Figure 21. Figure 23.
Authorization consent from the resource owner can be pre-configured, Authorization consent from the resource owner can be pre-configured,
but it can also be provided via an interactive flow with the resource but it can also be provided via an interactive flow with the resource
owner. An example of this for the key fob case could be that the owner. An example of this for the key fob case could be that the
resource owner has a connected car, he buys a generic key that he resource owner has a connected car, he buys a generic key that he
wants to use with the car. To authorize the key fob he connects it wants to use with the car. To authorize the key fob he connects it
to his computer that then provides the UI for the device. After that to his computer that then provides the UI for the device. After that
OAuth 2.0 implicit flow can used to authorize the key for his car at OAuth 2.0 implicit flow can used to authorize the key for his car at
the the car manufacturers AS. the the car manufacturers AS.
skipping to change at page 52, line 42 skipping to change at page 56, line 42
A: +-------->| Header: POST (Code=0.02) A: +-------->| Header: POST (Code=0.02)
| POST | Uri-Path:"token" | POST | Uri-Path:"token"
| | Content-Type: application/cbor | | Content-Type: application/cbor
| | Payload: <Request-Payload> | | Payload: <Request-Payload>
| | | |
B: |<--------+ Header: 2.05 Content B: |<--------+ Header: 2.05 Content
| | Content-Type: application/cbor | | Content-Type: application/cbor
| 2.05 | Payload: <Response-Payload> | 2.05 | Payload: <Response-Payload>
| | | |
Figure 21: Token Request and Response using Client Credentials. Figure 23: Token Request and Response using Client Credentials.
The information contained in the Request-Payload and the Response- The information contained in the Request-Payload and the Response-
Payload is shown in Figure 22. Payload is shown in Figure 24.
Request-Payload: Request-Payload:
{ {
"grant_type" : "client_credentials", "grant_type" : "client_credentials",
"aud" : "lockOfDoor4711", "aud" : "lockOfDoor4711",
"client_id" : "keyfob", "client_id" : "keyfob",
"client_secret" : "qwerty" "client_secret" : "qwerty"
} }
Response-Payload: Response-Payload:
skipping to change at page 53, line 28 skipping to change at page 57, line 28
"cnf" : { "cnf" : {
"COSE_Key" : { "COSE_Key" : {
"kid" : b64'c29tZSBwdWJsaWMga2V5IGlk', "kid" : b64'c29tZSBwdWJsaWMga2V5IGlk',
"kty" : "oct", "kty" : "oct",
"alg" : "HS256", "alg" : "HS256",
"k": b64'ZoRSOrFzN_FzUA5XKMYoVHyzff5oRJxl-IXRtztJ6uE' "k": b64'ZoRSOrFzN_FzUA5XKMYoVHyzff5oRJxl-IXRtztJ6uE'
} }
} }
} }
Figure 22: Request and Response Payload for C offline Figure 24: Request and Response Payload for C offline
The access token in this case is just an opaque string referencing The access token in this case is just an opaque string referencing
the authorization information at the AS. the authorization information at the AS.
C: Next, the client POSTs the access token to the /authz-info C: Next, the client POSTs the access token to the /authz-info
endpoint in the RS. This is a plain CoAP request, i.e. no DTLS endpoint in the RS. This is a plain CoAP request, i.e. no DTLS
between client and RS. Since the token is an opaque string, the between client and RS. Since the token is an opaque string, the
RS cannot verify it on its own, and thus defers to respond the RS cannot verify it on its own, and thus defers to respond the
client with a status code until after step E. client with a status code until after step E.
D: The RS forwards the token to the /introspect endpoint on the D: The RS forwards the token to the /introspect endpoint on the
skipping to change at page 54, line 30 skipping to change at page 58, line 30
| | | | | |
| E: |<---------+ Header: 2.05 Content | E: |<---------+ Header: 2.05 Content
| | 2.05 | Content-Type: "application/cbor" | | 2.05 | Content-Type: "application/cbor"
| | | Payload: <Response-Payload> | | | Payload: <Response-Payload>
| | | | | |
| | | |
|<--------+ Header: 2.01 Created |<--------+ Header: 2.01 Created
| 2.01 | | 2.01 |
| | | |
Figure 23: Token Introspection for C offline Figure 25: Token Introspection for C offline
The information contained in the Request-Payload and the Response- The information contained in the Request-Payload and the Response-
Payload is shown in Figure 24. Payload is shown in Figure 26.
Request-Payload: Request-Payload:
{ {
"token" : b64'SlAV32hkKG...', "token" : b64'SlAV32hkKG...',
"client_id" : "FrontDoor", "client_id" : "FrontDoor",
"client_secret" : "ytrewq" "client_secret" : "ytrewq"
} }
Response-Payload: Response-Payload:
{ {
"active" : true, "active" : true,
"aud" : "lockOfDoor4711", "aud" : "lockOfDoor4711",
"scope" : "open, close", "scope" : "open, close",
"iat" : 1311280970, "iat" : 1311280970,
"cnf" : { "cnf" : {
"kid" : b64'JDLUhTMjU2IiwiY3R5Ijoi ...' "kid" : b64'JDLUhTMjU2IiwiY3R5Ijoi ...'
} }
} }
Figure 24: Request and Response Payload for Introspection Figure 26: Request and Response Payload for Introspection
The client uses the symmetric PoP key to establish a DTLS The client uses the symmetric PoP key to establish a DTLS
PreSharedKey secure connection to the RS. The CoAP request PUT is PreSharedKey secure connection to the RS. The CoAP request PUT is
sent to the uri-path /state on RS changing state of the door to sent to the uri-path /state on RS changing state of the door to
locked. locked.
F: The RS responds with a appropriate over the secure DTLS F: The RS responds with a appropriate over the secure DTLS
channel. channel.
Resource Resource
Client Server Client Server
skipping to change at page 55, line 26 skipping to change at page 59, line 26
| | using Pre Shared Key | | using Pre Shared Key
| | | |
+-------->| Header: PUT (Code=0.03) +-------->| Header: PUT (Code=0.03)
| PUT | Uri-Path: "state" | PUT | Uri-Path: "state"
| | Payload: <new state for the lock> | | Payload: <new state for the lock>
| | | |
F: |<--------+ Header: 2.04 Changed F: |<--------+ Header: 2.04 Changed
| 2.04 | Payload: <new state for the lock> | 2.04 | Payload: <new state for the lock>
| | | |
Figure 25: Resource request and response protected by OSCOAP Figure 27: Resource request and response protected by OSCOAP
Appendix E. Document Updates Appendix F. Document Updates
E.1. Version -02 to -03 F.1. Version -04 to -05
o Added RFC 2119 language to the specification of the required
behavior of profile specifications.
o Added section 6.1 on the relation to the OAuth2 grant types.
o Added CBOR abbreviations for error and the error codes defined in
OAuth2.
o Added clarification about token expiration and long-running
requests in section 8.2.
o Added security considerations about tokens with symmetric pop keys
valid for more than one RS.
o Added privacy considerations section.
o Added IANA registry mapping the confirmation types from RFC 7800
to equivalent COSE types.
o Added appendix D, describing assumptions about what the AS knows
about the client and the RS.
F.2. Version -03 to -04
o Added a description of the terms "framework" and "profiles" as
used in this document.
o Clarified protection of access tokens in section 3.1.
o Clarified uses of the 'cnf' parameter in section 6.4.5.
o Clarified intended use of Client Token in section 7.4.
F.3. Version -02 to -03
o Removed references to draft-ietf-oauth-pop-key-distribution since o Removed references to draft-ietf-oauth-pop-key-distribution since
the status of this draft is unclear. the status of this draft is unclear.
o Copied and adapted security considerations from draft-ietf-oauth- o Copied and adapted security considerations from draft-ietf-oauth-
pop-key-distribution. pop-key-distribution.
o Renamed "client information" to "RS information" since it is o Renamed "client information" to "RS information" since it is
information about the RS. information about the RS.
o Clarified the requirements on profiles of this framework. o Clarified the requirements on profiles of this framework.
o Clarified the token endpoint protocol and removed negotiation of o Clarified the token endpoint protocol and removed negotiation of
'profile' and 'alg' (section 6). 'profile' and 'alg' (section 6).
o Renumbered the abbreviations for claims and parameters to get a o Renumbered the abbreviations for claims and parameters to get a
consistent numbering across different endpoints. consistent numbering across different endpoints.
o Clarified the introspection endpoint. o Clarified the introspection endpoint.
o Renamed token, introspection and authz-info to 'endpoint' instead o Renamed token, introspection and authz-info to 'endpoint' instead
of 'resource' to mirror the OAuth 2.0 terminology. of 'resource' to mirror the OAuth 2.0 terminology.
o Updated the examples in the appendices. o Updated the examples in the appendices.
E.2. Version -01 to -02 F.4. Version -01 to -02
o Restructured to remove communication security parts. These shall o Restructured to remove communication security parts. These shall
now be defined in profiles. now be defined in profiles.
o Restructured section 5 to create new sections on the OAuth o Restructured section 5 to create new sections on the OAuth
endpoints /token, /introspect and /authz-info. endpoints /token, /introspect and /authz-info.
o Pulled in material from draft-ietf-oauth-pop-key-distribution in o Pulled in material from draft-ietf-oauth-pop-key-distribution in
order to define proof-of-possession key distribution. order to define proof-of-possession key distribution.
o Introduced the 'cnf' parameter as defined in RFC7800 to reference o Introduced the 'cnf' parameter as defined in RFC7800 to reference
or transport keys used for proof of posession. or transport keys used for proof of possession.
o Introduced the 'client-token' to transport client information from o Introduced the 'client-token' to transport client information from
the AS to the client via the RS in conjunction with introspection. the AS to the client via the RS in conjunction with introspection.
o Expanded the IANA section to define parameters for token request, o Expanded the IANA section to define parameters for token request,
introspection and CWT claims. introspection and CWT claims.
o Moved deployment scenarios to the appendix as examples. o Moved deployment scenarios to the appendix as examples.
E.3. Version -00 to -01 F.5. Version -00 to -01
o Changed 5.1. from "Communication Security Protocol" to "Client o Changed 5.1. from "Communication Security Protocol" to "Client
Information". Information".
o Major rewrite of 5.1 to clarify the information exchanged between o Major rewrite of 5.1 to clarify the information exchanged between
C and AS in the PoP token request profile for IoT. C and AS in the PoP token request profile for IoT.
* Allow the client to indicate preferences for the communication * Allow the client to indicate preferences for the communication
security protocol. security protocol.
* Defined the term "Client Information" for the additional * Defined the term "Client Information" for the additional
information returned to the client in addition to the access information returned to the client in addition to the access
 End of changes. 180 change blocks. 
330 lines changed or deleted 585 lines changed or added

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