draft-ietf-ace-oauth-authz-05.txt		draft-ietf-ace-oauth-authz-06.txt
	ACE Working Group L. Seitz		ACE Working Group L. Seitz
	Internet-Draft SICS		Internet-Draft RISE SICS
	Intended status: Standards Track G. Selander		Intended status: Standards Track G. Selander
	Expires: August 7, 2017 Ericsson		Expires: September 14, 2017 Ericsson
	E. Wahlstroem		E. Wahlstroem
			(no affiliation)
	S. Erdtman		S. Erdtman
	Spotify AB		Spotify AB
	H. Tschofenig		H. Tschofenig
	ARM Ltd.		ARM Ltd.
	February 3, 2017		March 13, 2017
	Authentication and Authorization for Constrained Environments (ACE)		Authentication and Authorization for Constrained Environments (ACE)
	draft-ietf-ace-oauth-authz-05		draft-ietf-ace-oauth-authz-06
	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.
	skipping to change at page 1, line 43 ¶		skipping to change at page 1, line 43 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	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 August 7, 2017.		This Internet-Draft will expire on September 14, 2017.
	Copyright Notice		Copyright Notice
	Copyright (c) 2017 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.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 24 ¶		skipping to change at page 2, line 24 ¶
	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 . . . . . . . . . . . . . . . . . . . . . . . . . . 9		3.2. CoAP . . . . . . . . . . . . . . . . . . . . . . . . . . 9
	4. Protocol Interactions . . . . . . . . . . . . . . . . . . . . 9		4. Protocol Interactions . . . . . . . . . . . . . . . . . . . . 9
	5. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 13		5. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 13
	6. The 'Token' Endpoint . . . . . . . . . . . . . . . . . . . . 14		5.1. Authorization Grants . . . . . . . . . . . . . . . . . . 14
	6.1. Client Credentials and Grants . . . . . . . . . . . . . . 15		5.2. Client Credentials . . . . . . . . . . . . . . . . . . . 15
	6.2. Client-to-AS Request . . . . . . . . . . . . . . . . . . 15		5.3. AS Authentication . . . . . . . . . . . . . . . . . . . . 15
	6.3. AS-to-Client Response . . . . . . . . . . . . . . . . . . 18		5.4. The 'Authorize' Endpoint . . . . . . . . . . . . . . . . 15
	6.4. Error Response . . . . . . . . . . . . . . . . . . . . . 20		5.5. The 'Token' Endpoint . . . . . . . . . . . . . . . . . . 16
	6.5. Request and Response Parameters . . . . . . . . . . . . . 20		5.5.1. Client-to-AS Request . . . . . . . . . . . . . . . . 16
	6.5.1. Audience . . . . . . . . . . . . . . . . . . . . . . 20		5.5.2. AS-to-Client Response . . . . . . . . . . . . . . . . 19
	6.5.2. Grant Type . . . . . . . . . . . . . . . . . . . . . 21		5.5.3. Error Response . . . . . . . . . . . . . . . . . . . 21
	6.5.3. Token Type . . . . . . . . . . . . . . . . . . . . . 21		5.5.4. Request and Response Parameters . . . . . . . . . . . 21
	6.5.4. Profile . . . . . . . . . . . . . . . . . . . . . . . 21		5.5.4.1. Audience . . . . . . . . . . . . . . . . . . . . 21
	6.5.5. Confirmation . . . . . . . . . . . . . . . . . . . . 22		5.5.4.2. Grant Type . . . . . . . . . . . . . . . . . . . 22
	6.6. Mapping parameters to CBOR . . . . . . . . . . . . . . . 24		5.5.4.3. Token Type . . . . . . . . . . . . . . . . . . . 22
	7. The 'Introspect' Endpoint . . . . . . . . . . . . . . . . . . 24		5.5.4.4. Profile . . . . . . . . . . . . . . . . . . . . . 22
	7.1. RS-to-AS Request . . . . . . . . . . . . . . . . . . . . 25		5.5.4.5. Confirmation . . . . . . . . . . . . . . . . . . 23
	7.2. AS-to-RS Response . . . . . . . . . . . . . . . . . . . . 25		5.5.5. Mapping parameters to CBOR . . . . . . . . . . . . . 25
	7.3. Error Response . . . . . . . . . . . . . . . . . . . . . 27		5.6. The 'Introspect' Endpoint . . . . . . . . . . . . . . . . 25
	7.4. Client Token . . . . . . . . . . . . . . . . . . . . . . 27		5.6.1. RS-to-AS Request . . . . . . . . . . . . . . . . . . 26
	7.5. Mapping Introspection parameters to CBOR . . . . . . . . 29		5.6.2. AS-to-RS Response . . . . . . . . . . . . . . . . . . 26
	8. The Access Token . . . . . . . . . . . . . . . . . . . . . . 29		5.6.3. Error Response . . . . . . . . . . . . . . . . . . . 28
	8.1. The 'Authorization Information' Endpoint . . . . . . . . 30		5.6.4. Client Token . . . . . . . . . . . . . . . . . . . . 28
	8.2. Token Expiration . . . . . . . . . . . . . . . . . . . . 30		5.6.5. Mapping Introspection parameters to CBOR . . . . . . 30
	9. Security Considerations . . . . . . . . . . . . . . . . . . . 31		5.7. The Access Token . . . . . . . . . . . . . . . . . . . . 30
	10. Privacy Considerations . . . . . . . . . . . . . . . . . . . 33		5.7.1. The 'Authorization Information' Endpoint . . . . . . 31
	11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33		5.7.2. Token Expiration . . . . . . . . . . . . . . . . . . 31
	11.1. OAuth Introspection Response Parameter Registration . . 33		6. Security Considerations . . . . . . . . . . . . . . . . . . . 32
	11.2. OAuth Parameter Registration . . . . . . . . . . . . . . 34		7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 34
	11.3. OAuth Access Token Types . . . . . . . . . . . . . . . . 34		8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34
	11.4. Token Type Mappings . . . . . . . . . . . . . . . . . . 35		8.1. OAuth Introspection Response Parameter Registration . . . 34
	11.4.1. Registration Template . . . . . . . . . . . . . . . 35		8.2. OAuth Parameter Registration . . . . . . . . . . . . . . 35
	11.4.2. Initial Registry Contents . . . . . . . . . . . . . 35		8.3. OAuth Access Token Types . . . . . . . . . . . . . . . . 35
	11.5. CBOR Web Token Claims . . . . . . . . . . . . . . . . . 35		8.4. Token Type Mappings . . . . . . . . . . . . . . . . . . . 36
	11.6. ACE Profile Registry . . . . . . . . . . . . . . . . . . 36		8.4.1. Registration Template . . . . . . . . . . . . . . . . 36
	11.6.1. Registration Template . . . . . . . . . . . . . . . 36		8.4.2. Initial Registry Contents . . . . . . . . . . . . . . 36
	11.7. OAuth Parameter Mappings Registry . . . . . . . . . . . 36		8.5. CBOR Web Token Claims . . . . . . . . . . . . . . . . . . 36
	11.7.1. Registration Template . . . . . . . . . . . . . . . 36		8.6. ACE Profile Registry . . . . . . . . . . . . . . . . . . 37
	11.7.2. Initial Registry Contents . . . . . . . . . . . . . 37		8.6.1. Registration Template . . . . . . . . . . . . . . . . 37
	11.8. Introspection Endpoint CBOR Mappings Registry . . . . . 39		8.7. OAuth Parameter Mappings Registry . . . . . . . . . . . . 37
	11.8.1. Registration Template . . . . . . . . . . . . . . . 39		8.7.1. Registration Template . . . . . . . . . . . . . . . . 37
	11.8.2. Initial Registry Contents . . . . . . . . . . . . . 39		8.7.2. Initial Registry Contents . . . . . . . . . . . . . . 38
	11.9. CoAP Option Number Registration . . . . . . . . . . . . 41		8.8. Introspection Endpoint CBOR Mappings Registry . . . . . . 40
	11.10. CWT Confirmation Methods Registry . . . . . . . . . . . 42		8.8.1. Registration Template . . . . . . . . . . . . . . . . 40
	11.10.1. Registration Template . . . . . . . . . . . . . . . 42		8.8.2. Initial Registry Contents . . . . . . . . . . . . . . 40
	11.10.2. Initial Registry Contents . . . . . . . . . . . . . 43		8.9. CoAP Option Number Registration . . . . . . . . . . . . . 42
	12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 43		8.10. CWT Confirmation Methods Registry . . . . . . . . . . . . 43
	13. References . . . . . . . . . . . . . . . . . . . . . . . . . 43		8.10.1. Registration Template . . . . . . . . . . . . . . . 43
	13.1. Normative References . . . . . . . . . . . . . . . . . . 44		8.10.2. Initial Registry Contents . . . . . . . . . . . . . 44
	13.2. Informative References . . . . . . . . . . . . . . . . . 44		9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 44
	Appendix A. Design Justification . . . . . . . . . . . . . . . . 46		10. References . . . . . . . . . . . . . . . . . . . . . . . . . 44
	Appendix B. Roles and Responsibilities . . . . . . . . . . . . . 48		10.1. Normative References . . . . . . . . . . . . . . . . . . 45
	Appendix C. Requirements on Profiles . . . . . . . . . . . . . . 50		10.2. Informative References . . . . . . . . . . . . . . . . . 45
	Appendix D. Assumptions on AS knowledge about C and RS . . . . . 51		Appendix A. Design Justification . . . . . . . . . . . . . . . . 47
	Appendix E. Deployment Examples . . . . . . . . . . . . . . . . 51		Appendix B. Roles and Responsibilities . . . . . . . . . . . . . 49
	E.1. Local Token Validation . . . . . . . . . . . . . . . . . 52		Appendix C. Requirements on Profiles . . . . . . . . . . . . . . 51
	E.2. Introspection Aided Token Validation . . . . . . . . . . 55		Appendix D. Assumptions on AS knowledge about C and RS . . . . . 52
	Appendix F. Document Updates . . . . . . . . . . . . . . . . . . 59		Appendix E. Deployment Examples . . . . . . . . . . . . . . . . 52
	F.1. Version -04 to -05 . . . . . . . . . . . . . . . . . . . 59		E.1. Local Token Validation . . . . . . . . . . . . . . . . . 53
	F.2. Version -03 to -04 . . . . . . . . . . . . . . . . . . . 59		E.2. Introspection Aided Token Validation . . . . . . . . . . 56
	F.3. Version -02 to -03 . . . . . . . . . . . . . . . . . . . 60		Appendix F. Document Updates . . . . . . . . . . . . . . . . . . 60
	F.4. Version -01 to -02 . . . . . . . . . . . . . . . . . . . 60		F.1. Version -05 to -06 . . . . . . . . . . . . . . . . . . . 60
	F.5. Version -00 to -01 . . . . . . . . . . . . . . . . . . . 60		F.2. Version -04 to -05 . . . . . . . . . . . . . . . . . . . 60
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 61		F.3. Version -03 to -04 . . . . . . . . . . . . . . . . . . . 61
			F.4. Version -02 to -03 . . . . . . . . . . . . . . . . . . . 61
			F.5. Version -01 to -02 . . . . . . . . . . . . . . . . . . . 61
			F.6. Version -00 to -01 . . . . . . . . . . . . . . . . . . . 62
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 62
	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.
	skipping to change at page 5, line 48 ¶		skipping to change at page 6, line 5 ¶
	designed for small code and message size, which may be used for		designed for small code and message size, which may be used for
	encoding of self contained tokens, and also for encoding CoAP POST		encoding of self contained tokens, and also for encoding CoAP POST
	parameters and CoAP responses.		parameters and CoAP responses.
	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 5.6.4). The default
	token format is defined in CBOR web token (CWT)		access 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.ietf-core-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.
	skipping to change at page 12, line 13 ¶		skipping to change at page 12, line 15 ¶
	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 6.5.		information about these parameters can be found in Section 5.5.4.
	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
	skipping to change at page 12, line 47 ¶		skipping to change at page 12, line 49 ¶
	the AS and compares the claims contained in the access token with		the AS and compares the claims contained in the access token with
	the resource request. If the RS is online, validation can be		the resource request. If the RS is online, validation can be
	handed over to the AS using token introspection (see messages D		handed over to the AS using token introspection (see messages D
	and E) over HTTP or CoAP, in which case the different parts of		and E) over HTTP or CoAP, in which case the different parts of
	step C may be interleaved with introspection.		step C may be interleaved with introspection.
	Token Introspection Request (D):		Token Introspection Request (D):
	A resource server may be configured to introspect the access token		A resource server may be configured to introspect the access token
	by including it in a request to the /introspect endpoint at that		by including it in a request to the /introspect endpoint at that
	AS. Token introspection over CoAP is defined in Section 7 and for		AS. Token introspection over CoAP is defined in Section 5.6 and
	HTTP in [RFC7662].		for HTTP in [RFC7662].
	Note that token introspection is an optional step and can be		Note that token introspection is an optional step and can be
	omitted if the token is self-contained and the resource server is		omitted if the token is self-contained and the resource server is
	prepared to perform the token validation on its own.		prepared to perform the token validation on its own.
	Token Introspection Response (E):		Token Introspection Response (E):
	The AS validates the token and returns the most recent parameters,		The AS validates the token and returns the most recent parameters,
	such as scope, audience, validity etc. associated with it back to		such as scope, audience, validity etc. associated with it back to
	the RS. The RS then uses the received parameters to process the		the RS. The RS then uses the received parameters to process the
	request to either accept or to deny it. The AS can additionally		request to either accept or to deny it. The AS can additionally
	return information that the RS needs to pass on to the client in		return information that the RS needs to pass on to the client in
	the form of a client token. The latter is used to establish keys		the form of a client token. The latter is used to establish keys
	for mutual authentication between client and RS, when the client		for mutual authentication between client and RS, when the client
	has no direct connectivity to the AS, see Section 7.4 for details.		has no direct connectivity to the AS, see Section 5.6.4 for
			details.
	Protected Resource (F):		Protected Resource (F):
	If the request from the client is authorized, the RS fulfills the		If the request from the client is authorized, the RS fulfills the
	request and returns a response with the appropriate response code.		request and returns a response with the appropriate response code.
	The RS uses the dynamically established keys to protect the		The RS uses the dynamically established keys to protect the
	response, according to used communication security protocol.		response, according to used communication security protocol.
	5. Framework		5. Framework
	skipping to change at page 14, line 37 ¶		skipping to change at page 14, line 41 ¶
	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 profile that is used.		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		5.1. Authorization Grants
	In plain OAuth 2.0 the AS provides the /token endpoint for submitting		To request an access token, the client obtains authorization from the
	access token requests. This framework extends the functionality of		resource owner or uses its client credentials as grant. The
	the /token endpoint, giving the AS the possibility to help client and		authorization is expressed in the form of an authorization grant.
	RS to establish shared keys or to exchange their public keys.
	Furthermore this framework defines encodings using CoAP and CBOR, in
	addition to HTTP and JSON.
	Authentication of the requesting client is done using client		The OAuth framework defines four grant types. The grant types can be
	credentials as defined by OAuth 2.0. A profile MAY specify new		split up into two groups, those granted on behalf of the resource
	client credentials types for the authentication of the client.		owner (password, authorization code, implicit) and those for the
			client (client credentials).
	Profiles of this framework SHOULD specify how authentication of the		The grant type selected depending based on the use case. In cases
	AS is done and how communication security is implemented. If nothing		where the client will act on behalf of the resource owner,
	is specified TLS with server certificate is assumed as defined by		authorization code grant is recommended. If the client should to act
	OAuth 2.0.		on be half of the user but does not have any display or very limited
			interaction possibilities it is recommended to use the device code
			grant defined in [I-D.ietf-oauth-device-flow]. In cases where the
			client will not act on be half of the resource owner, client
			credentials grant is recommended.
	When requesting a token the client is authenticated with client		For details on the different grant types see the OAuth 2.0 framework.
	credentials and then a grant is presented that gives the client the		The OAuth 2.0 framework provides an extension mechanism for defining
	right to get a token.		additional grant types so profiles of this framework MAY define
			additional grant types if needed.
	The figures of this section uses CBOR diagnostic notation without the		5.2. Client Credentials
	integer abbreviations for the parameters or their values for better
	readability.
	6.1. Client Credentials and Grants		Authentication of the client is mandatory independent of the grant
			type when requesting the access token from the token endpoint. In
			the case of client credentials grant type the authentication and
			grant coincides.
	To issue a token the client MUST be authenticated and present a valid		Client registration and provisioning of client credentials to the
	grant for the scopes requested.		client is out of scope for this specification.
	The OAuth framework, [RFC6749], defines one client credential type,		The OAuth framework, [RFC6749], defines one client credential type,
	client id and client secret. Profiles of this framework MAY extend		client id and client secret. Profiles of this framework MAY extend
	with additional client credentials such as DTLS pre-shared keys or		with additional client credentials such as DTLS pre-shared keys or
	client certificates.		client certificates.
	In the OAuth framework five grant types are defined. The grant types		5.3. AS Authentication
	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		Client credential does not by default authenticate the AS that the
	possession refresh token.		client connects to. In classic OAuth the AS is authenticated with a
			TLS server certificate.
	6.2. Client-to-AS Request		Profiles of this framework SHOULD specify how clients authenticate
			the AS and how communication security is implemented, otherwise
			server side TLS certificates as defined by OAuth 2.0 is required.
			5.4. The 'Authorize' Endpoint
			The authorization endpoint is used to interact with the resource
			owner and obtain an authorization grant. It is used for
			authorization code and implicit grant, flows that requires online
			user consent. In the most common implementation a users-agent is
			used and redirected from the client to the AS. The AS shows a
			consent dialog and directs back to the client, with the approved
			grant or an error message.
			The grant types defined in OAuth 2.0, that use the authorization
			endpoint, require the use of a user agent (i.e. a browser). This
			endpoint is therefore out of scope for this specification.
			Implementations should use the definition and recommendations of
			[RFC6749] and [RFC6819].
			If clients involved cannot support HTTP and TLS profiles MAY define
			mappings for the authorization endpoint.
			5.5. The 'Token' Endpoint
			In plain OAuth 2.0 the AS provides the /token endpoint for submitting
			access token requests. This framework extends the functionality of
			the /token endpoint, giving the AS the possibility to help client and
			RS to establish shared keys or to exchange their public keys.
			Furthermore this framework defines encodings using CoAP and CBOR, in
			addition to HTTP and JSON.
			For the AS to be able to issue a token the client MUST be
			authenticated and present a valid grant for the scopes requested.
			The figures of this section uses CBOR diagnostic notation without the
			integer abbreviations for the parameters or their values for better
			readability.
			5.5.1. 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 MUST specify the Content-Type and wrapping of the		the profile MUST specify the Content-Type and wrapping of 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:
	skipping to change at page 16, line 15 ¶		skipping to change at page 17, line 8 ¶
	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 6.5.5 for more details on the formatting of the 'cnf'		Section 5.5.4.5 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". The content is displayed in CBOR diagnostic		"application/cbor". The content is displayed in CBOR diagnostic
	notation, without abbreviations for better readability.		notation, without abbreviations for better readability.
	skipping to change at page 18, line 5 ¶		skipping to change at page 19, 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.
	6.3. AS-to-Client Response		5.5.2. 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 6.4.		Section 5.5.3.
	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 (see		knowledge of the capabilities of the client, and the RS (see
	Appendix D. This prior knowledge may, for example, be set by the use		Appendix D. This prior knowledge may, for example, be set by the use
	of a dynamic client registration protocol exchange [RFC7591].		of a dynamic client registration protocol exchange [RFC7591].
	The content of the successful reply is the RS Information. It MUST		The content of the successful reply is the RS Information. It MUST
	be encoded as CBOR map, containing parameters as specified in section		be encoded as CBOR map, containing parameters as specified in section
	5.1 of [RFC6749]. In addition to these parameters, the following		5.1 of [RFC6749]. In addition to these parameters, the following
	parameters are also part 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 6.5.4 for the formatting of this		towards the RS. See Section 5.5.4.4 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 6.5.5 for the		used by the RS to authenticate. See Section 5.5.4.5 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
	skipping to change at page 20, line 5 ¶		skipping to change at page 21, line 5 ¶
	"kty" : "Symmetric",		"kty" : "Symmetric",
	"kid" : b64'39Gqlw',		"kid" : b64'39Gqlw',
	"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'		"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'
	}		}
	}		}
	}		}
	Figure 6: 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.
	6.4. Error Response		5.5.3. 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 5.2 of [RFC6749], with the following differences:		section 5.2 of [RFC6749], with the following differences:
	o The Content-Type MUST be specified by the communication security		o The Content-Type MUST be specified by the communication security
	profile used between client and AS. The raw payload before being		profile used between client and AS. The raw payload before being
	processed by the communication security protocol MUST be encoded		processed by the communication security protocol MUST be encoded
	as a CBOR map.		as a CBOR map.
	o The CoAP response code 4.00 (Bad Request) MUST be used for all		o The CoAP response code 4.00 (Bad Request) MUST be used for all
	skipping to change at page 20, line 37 ¶		skipping to change at page 21, line 37 ¶
	| invalid_request | 0 | 0 (uint) |		| invalid_request | 0 | 0 (uint) |
	| invalid_client | 1 | 0 |		| invalid_client | 1 | 0 |
	| invalid_grant | 2 | 0 |		| invalid_grant | 2 | 0 |
	| unauthorized_client | 3 | 0 |		| unauthorized_client | 3 | 0 |
	| unsupported_grant_type | 4 | 0 |		| unsupported_grant_type | 4 | 0 |
	| invalid_scope | 5 | 0 |		| invalid_scope | 5 | 0 |
	\------------------------+----------+--------------/		\------------------------+----------+--------------/
	Figure 7: CBOR abbreviations for common error codes		Figure 7: CBOR abbreviations for common error codes
	6.5. Request and Response Parameters		5.5.4. 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.
	6.5.1. Audience		5.5.4.1. 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.
	6.5.2. Grant Type		5.5.4.2. Grant Type
	The abbreviations in Figure 8 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 8: CBOR abbreviations for common grant types		Figure 8: CBOR abbreviations for common grant types
	6.5.3. Token Type		5.5.4.3. Token Type
	The toke_type parameter is defined in [RFC6749], allowing the AS to		The token_type parameter is defined in [RFC6749], allowing the AS to
	indicate to the client which type of access token it is receiving		indicate to the client which type of access token it is receiving
	(e.g. a bearer token).		(e.g. a bearer token).
	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 MUST be specified by the		the proof-of-possession is performed MUST be specified by the
	profiles.		profiles.
	The values in the 'token_type' parameter MUST be CBOR text strings		The values in the 'token_type' parameter MUST be CBOR text strings
	(major type 3).		(major type 3).
	In this framework token type 'pop' MUST be assumed by default if the		In this framework token type 'pop' MUST be assumed by default if the
	AS does not provide a different value.		AS does not provide a different value.
	6.5.4. Profile		5.5.4.4. Profile
	Profiles of this framework MUST define the communication protocol and		Profiles of this framework MUST define the communication protocol and
	the communication security protocol between the client and the RS.		the communication security protocol between the client and the RS.
	Furthermore profiles MUST define proof-of-possession methods, if they		Furthermore profiles MUST define proof-of-possession methods, if they
	support proof-of-possession tokens.		support proof-of-possession tokens.
	A profile MUST specify an identifier that is used to uniquely		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 negotiation or signalling of profile specific parameters.		support negotiation or signalling of profile specific parameters.
	6.5.5. Confirmation		5.5.4.5. 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 23, line 51 ¶		skipping to change at page 24, line 51 ¶
	transport in the access token, token request and token response.		transport in the access token, token request and token response.
	Figure 12 shows such an example.		Figure 12 shows such an example.
	"cnf" : {		"cnf" : {
	"kid" : b64'39Gqlw'		"kid" : b64'39Gqlw'
	}		}
	Figure 12: A Confirmation parameter with just a key identifier		Figure 12: A Confirmation parameter with just a key identifier
	This specification establishes the IANA "CWT Confirmation Methods"		This specification establishes the IANA "CWT Confirmation Methods"
	registry for these types of confirmation methods in Section 11.10 and		registry for these types of confirmation methods in Section 8.10 and
	registers the methods defined by this specification. Other		registers the methods defined by this specification. Other
	specifications can register other methods used for confirmation. The		specifications can register other methods used for confirmation. The
	registry is meant to be analogous to the "JWT Confirmation Methods"		registry is meant to be analogous to the "JWT Confirmation Methods"
	registry defined by [RFC7800].		registry defined by [RFC7800].
	6.6. Mapping parameters to CBOR		5.5.5. 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) |
	skipping to change at page 24, line 42 ¶		skipping to change at page 25, line 42 ¶
	| expires_in | 21 | 0 |		| expires_in | 21 | 0 |
	| username | 22 | 3 |		| username | 22 | 3 |
	| password | 23 | 3 |		| password | 23 | 3 |
	| refresh_token | 24 | 3 |		| refresh_token | 24 | 3 |
	| cnf | 25 | 5 (map) |		| cnf | 25 | 5 (map) |
	| profile | 26 | 3 |		| profile | 26 | 3 |
	\-------------------+----------+-----------------/		\-------------------+----------+-----------------/
	Figure 13: CBOR mappings used in token requests		Figure 13: CBOR mappings used in token requests
	7. The 'Introspect' Endpoint		5.6. 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 that support		the provided token. Profiles of this framework that support
	introspection MUST specify how authentication and communication		introspection MUST specify how authentication and communication
	security between RS and AS is implemented.		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		5.6.1. 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 MUST specify the Content-Type and wrapping of the		AS, the profile MUST specify the Content-Type and wrapping of the
	payload. The payload MUST be encoded as a CBOR map with a 'token'		payload. The payload MUST be encoded as a CBOR map with a 'token'
	parameter containing the access token along with optional parameters		parameter containing the access token along with optional parameters
	representing additional context that is known by the RS to aid the AS		representing additional context that is known by the RS to 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].
	skipping to change at page 25, line 44 ¶		skipping to change at page 26, line 44 ¶
	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 14: Example introspection request.		Figure 14: Example introspection request.
	7.2. AS-to-RS Response		5.6.2. 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 5.6.3.
	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 6.5.5 for more details on the formatting of the 'cnf'		Section 5.5.4.5 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 6.5.4 for more details on the formatting		the client. See Section 5.5.4.4 for more details on the
	of this parameter.		formatting 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 5.6.4 for more details.
	For example, Figure 15 shows an AS response to the introspection		For example, Figure 15 shows an AS response to the introspection
	request in Figure 14. 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:
	{		{
	skipping to change at page 27, line 5 ¶		skipping to change at page 28, line 5 ¶
	"COSE_Key" : {		"COSE_Key" : {
	"kty" : "Symmetric",		"kty" : "Symmetric",
	"kid" : b64'39Gqlw',		"kid" : b64'39Gqlw',
	"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'		"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'
	}		}
	}		}
	}		}
	Figure 15: Example introspection response.		Figure 15: Example introspection response.
	7.3. Error Response		5.6.3. 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.
	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
	skipping to change at page 27, line 32 ¶		skipping to change at page 28, line 32 ¶
	abbreviated using the codes specified in table Figure 13.		abbreviated using the codes specified in table Figure 13.
	o The error codes MAY be abbreviated using the codes specified in		o The error codes MAY be abbreviated using the codes specified in
	table Figure 7.		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		5.6.4. Client Token
	EDITORIAL NOTE: We have tentatively introduced this concept and would		EDITORIAL NOTE: We have tentatively introduced this concept and would
	specifically like feedback whether this is viewed as a useful		specifically like feedback whether this is viewed as a useful
	addition to the framework.		addition to the framework.
	In cases where the client has limited connectivity and needs to get		In cases where the client has limited connectivity and needs to get
	access to a previously unknown resource servers, this framework		access to a previously unknown resource servers, this framework
	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
	skipping to change at page 28, line 32 ¶		skipping to change at page 29, line 32 ¶
	| + Client Token |		| + Client Token |
	Figure 16: 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 6.5.5.		with its access token. See Section 5.5.4.5.
	token_type		token_type
	OPTIONAL. See Section 6.5.3.		OPTIONAL. See Section 5.5.4.3.
	profile		profile
	REQUIRED. See Section 6.5.4.		REQUIRED. See Section 5.5.4.4.
	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 6.5.4.		uses the same encoding as the 'cnf' parameter. See
			Section 5.5.4.4.
	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		5.6.5. 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.
	/-----------------+----------+-----------------\		/-----------------+----------+-----------------\
	| Parameter name | CBOR Key | Major Type |		| Parameter name | CBOR Key | Major Type |
	|-----------------+----------+-----------------|		|-----------------+----------+-----------------|
	| iss | 1 | 3 (text string) |		| iss | 1 | 3 (text string) |
	| sub | 2 | 3 |		| sub | 2 | 3 |
	| aud | 3 | 3 |		| aud | 3 | 3 |
	skipping to change at page 29, line 35 ¶		skipping to change at page 30, line 35 ¶
	| profile | 26 | 0 (uint) |		| profile | 26 | 0 (uint) |
	| token | 27 | 3 |		| token | 27 | 3 |
	| token_type_hint | 28 | 3 |		| token_type_hint | 28 | 3 |
	| active | 29 | 0 |		| active | 29 | 0 |
	| client_token | 30 | 3 |		| client_token | 30 | 3 |
	| rs_cnf | 31 | 5 |		| rs_cnf | 31 | 5 |
	\-----------------+----------+-----------------/		\-----------------+----------+-----------------/
	Figure 17: CBOR Mappings to Token Introspection Parameters.		Figure 17: CBOR Mappings to Token Introspection Parameters.
	8. The Access Token		5.7. 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 6.5.5.		same way as specified for the "cnf" parameter in Section 5.5.4.5.
	8.1. The 'Authorization Information' Endpoint		5.7.1. The 'Authorization Information' Endpoint
	The access token, containing authorization information and		The access token, containing authorization information and
	information about the key used by the client, needs to be transported		information about the key used by the client, needs to be transported
	to 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.		methods for token transport.
	skipping to change at page 30, line 36 ¶		skipping to change at page 31, line 36 ¶
	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). If the token is valid but is		response code 4.03 (Forbidden). If the token is valid but is
	associated to claims that the RS cannot process (e.g. an unknown		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		scope) the RS MUST respond with the CoAP response code 4.00 (Bad
	Request). In the latter case the RS MAY provide additional		Request). In the latter case the RS MAY provide additional
	information in the error response, in order to clarify what went		information in the error response, in order to clarify what went
	wrong.		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 5.6.4) then this token
	be included in the payload of the 2.01 (Created) response.		SHALL be included in the payload of the 2.01 (Created) response.
	Profiles MUST specify how the /authz-info endpoint is protected.		Profiles MUST specify how the /authz-info endpoint is protected.
	Note that since the token contains information that allow the client		Note that since the token contains information that allow the client
	and the RS to establish a security context in the first place, mutual		and the RS to establish a security context in the first 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,		The RS MUST be prepared to store more than one token for each client,
	and MUST apply the combined permissions granted by all applicable,		and MUST apply the combined permissions granted by all applicable,
	valid tokens to client requests.		valid tokens to client requests.
	8.2. Token Expiration		5.7.2. 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
	from its internal clock as defined in [RFC7519]. In this case the		from its internal clock as defined in [RFC7519]. In this case the
	RS's internal clock must reflect the current date and time, or at		RS's internal clock must reflect the current date and time, or at
	least be synchronized with the AS's clock. How this clock		least be synchronized with the AS's clock. How this clock
	synchronization would be performed is out of scope for this memo.		synchronization would be performed is out of scope for this memo.
	o The RS verifies the validity of the token by performing an		o The RS verifies the validity of the token by performing an
	introspection request as specified in Section 7. This requires		introspection request as specified in Section 5.6. This requires
	the RS to have a reliable network connection to the AS and to be		the RS to have a reliable network connection to the AS and to be
	able to handle two secure sessions in parallel (C to RS and AS to		able to handle two secure sessions in parallel (C to RS and AS to
	RS).		RS).
	o The RS and the AS both store a sequence number linked to their		o The RS and the AS both store a sequence number linked to their
	common security association. The AS increments this number for		common security association. The AS increments this number for
	each access token it issues and includes it in the access token,		each access token it issues and includes it in the access token,
	which is a CWT/JWT. The RS keeps track of the most recently		which is a CWT. The RS keeps track of the most recently received
	received sequence number, and only accepts tokens as valid, that		sequence number, and only accepts tokens as valid, that are in a
	are in a certain range around this number. This method does only		certain range around this number. This method does only require
	require the RS to keep track of the sequence number. The method		the RS to keep track of the sequence number. The method does not
	does not provide timely expiration, but it makes sure that older		provide timely expiration, but it makes sure that older tokens
	tokens cease to be valid after a certain number of newer ones got		cease to be valid after a certain number of newer ones got issued.
	issued. For a constrained RS with no network connectivity and no		For a constrained RS with no network connectivity and no means of
	means of reliably measuring time, this is the best that can be		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		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		CoAP Observe [RFC7641], expires, the RS MUST send an error response
	with the response code 4.01 Unauthorized to the client and then		with the response code 4.01 Unauthorized to the client and then
	terminate processing the long running request.		terminate processing the long running request.
	9. Security Considerations		6. 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
	of the access token by using a digital signature or a keyed message		of the access token by using a digital signature or a keyed message
	skipping to change at page 33, line 10 ¶		skipping to change at page 34, line 7 ¶
	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		Furthermore access tokens SHOULD NOT apply to an audience that
	comprises more than one RS, since otherwise any RS in the audience		comprises more than one RS, since otherwise any RS in the audience
	can impersonate the client towards the other members of the audience.		can impersonate the client towards the other members of the audience.
	Clients using an asymmetric key pair for proof-of-possession towards		Clients using an asymmetric key pair for proof-of-possession towards
	several different RS should be aware that they will need to rotate		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		that key pair more frequently than if it was only used towards a
	single RS.		single RS.
	10. Privacy Considerations		7. Privacy Considerations
	Implementers and users should be aware of the privacy implications of		Implementers and users should be aware of the privacy implications of
	the different possible deployments of this framework.		the different possible deployments of this framework.
	The AS is in a very central position can potentially learn sensitive		The AS is in a very central position can potentially learn sensitive
	information about the clients requesting access tokens. If the		information about the clients requesting access tokens. If the
	client credentials grant is used, the AS can track what kind of		client credentials grant is used, the AS can track what kind of
	access the client intends to perform. With other grants, the		access the client intends to perform. With other grants, the
	Resource Owner can bind the grants to anonymous (rotating)		Resource Owner can bind the grants to anonymous (rotating)
	credentials, that do not allow the AS to link different access token		credentials, that do not allow the AS to link different access token
	skipping to change at page 33, line 36 ¶		skipping to change at page 34, line 33 ¶
	JWTs the token may e.g. reveal the audience, the scope and the		JWTs the token may e.g. reveal the audience, the scope and the
	confirmation method used by the client. The latter may reveal the		confirmation method used by the client. The latter may reveal the
	client's identity.		client's identity.
	Clients using asymmetric keys for proof-of-possession should be aware		Clients using asymmetric keys for proof-of-possession should be aware
	of the consequences of using the same key pair for proof-of-		of the consequences of using the same key pair for proof-of-
	possession towards different RS. A set of colluding RS or an		possession towards different RS. A set of colluding RS or an
	attacker able to obtain the access tokens will be able to link the		attacker able to obtain the access tokens will be able to link the
	requests, or even to determine the client's identity.		requests, or even to determine the client's identity.
	11. IANA Considerations		8. 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.
	11.1. OAuth Introspection Response Parameter Registration		8.1. 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
	skipping to change at page 34, line 26 ¶		skipping to change at page 35, line 25 ¶
	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
	11.2. OAuth Parameter Registration		8.2. 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
	11.3. OAuth Access Token Types		8.3. 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
	11.4. Token Type Mappings		8.4. 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.
	11.4.1. Registration Template		8.4.1. 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.
	11.4.2. Initial Registry Contents		8.4.2. 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
	11.5. CBOR Web Token Claims		8.5. 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
	11.6. ACE Profile Registry		8.6. 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.
	11.6.1. Registration Template		8.6.1. 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.
	11.7. OAuth Parameter Mappings Registry		8.7. 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.
	11.7.1. Registration Template		8.7.1. 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.
	11.7.2. Initial Registry Contents		8.7.2. 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 39, line 16 ¶		skipping to change at page 40, line 16 ¶
	o Parameter name: "cnf"		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
	o Parameter name: "profile"		o Parameter name: "profile"
	o CBOR key value: 26		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
	11.8. Introspection Endpoint CBOR Mappings Registry		8.8. 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.
	11.8.1. Registration Template		8.8.1. 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.
	11.8.2. Initial Registry Contents		8.8.2. 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 41, line 36 ¶		skipping to change at page 42, line 36 ¶
	o Response parameter name: "client_token"		o Response parameter name: "client_token"
	o CBOR key value: 30		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: 31		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
	11.9. CoAP Option Number Registration		8.9. 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 42, line 20 ¶		skipping to change at page 43, 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
	11.10. CWT Confirmation Methods Registry		8.10. CWT Confirmation Methods Registry
	This specification establishes the IANA "CWT Confirmation Methods"		This specification establishes the IANA "CWT Confirmation Methods"
	registry for CWT "cnf" member values. The registry records the		registry for CWT "cnf" member values. The registry records the
	confirmation method member and a reference to the specification that		confirmation method member and a reference to the specification that
	defines it.		defines it.
	11.10.1. Registration Template		8.10.1. Registration Template
	Confirmation Method Name:		Confirmation Method Name:
	The name requested (e.g., "kid"). This name is intended to be		The name requested (e.g., "kid"). This name is intended to be
	human readable and be used for debugging purposes. It is case		human readable and be used for debugging purposes. It is case
	sensitive. Names may not match other registered names in a case-		sensitive. Names may not match other registered names in a case-
	insensitive manner unless the Designated Experts state that there		insensitive manner unless the Designated Experts state that there
	is a compelling reason to allow an exception.		is a compelling reason to allow an exception.
	Confirmation Method Value:		Confirmation Method Value:
	Integer representation for the confirmation method value.		Integer representation for the confirmation method value.
	skipping to change at page 43, line 10 ¶		skipping to change at page 44, line 10 ¶
	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 parameter,		Reference to the document or documents that specify the parameter,
	preferably including URIs that can be used to retrieve copies of		preferably including URIs that can be used to retrieve copies of
	the documents. An indication of the relevant sections may also be		the documents. An indication of the relevant sections may also be
	included but is not required.		included but is not required.
	11.10.2. Initial Registry Contents		8.10.2. Initial Registry Contents
	o Confirmation Method Name: "COSE_Key"		o Confirmation Method Name: "COSE_Key"
	o Confirmation Method Value: 1		o Confirmation Method Value: 1
	o Confirmation Method Description: A COSE_Key that is either a		o Confirmation Method Description: A COSE_Key that is either a
	public key or a symmetric key.		public key or a symmetric key.
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Confirmation Method Name: "COSE_Encrypted"		o Confirmation Method Name: "COSE_Encrypted"
	o Confirmation Method Value: 2		o Confirmation Method Value: 2
	skipping to change at page 43, line 32 ¶		skipping to change at page 44, line 32 ¶
	wraps a COSE_Key containing a symmetric key.		wraps a COSE_Key containing a symmetric key.
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Confirmation Method Name: "Key Identifier"		o Confirmation Method Name: "Key Identifier"
	o Confirmation Method Value: 3		o Confirmation Method Value: 3
	o Confirmation Method Description: A key identifier.		o Confirmation Method Description: A key identifier.
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	12. Acknowledgments		9. 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 predecessors of this		input, and Malisa Vucinic for his input on the predecessors of this
	proposal. Finally, we would like to thank the ACE working group in		proposal. 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.
	13. References		10. References
	13.1. Normative References		10.1. Normative References
	[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-24 (work in progress), November 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>.
	skipping to change at page 44, line 33 ¶		skipping to change at page 45, 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>.
	13.2. Informative References		10.2. 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-05 (work in
	progress), September 2016.		progress), March 2017.
	[I-D.ietf-ace-cbor-web-token]		[I-D.ietf-ace-cbor-web-token]
	Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig,		Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig,
	"CBOR Web Token (CWT)", draft-ietf-ace-cbor-web-token-02		"CBOR Web Token (CWT)", draft-ietf-ace-cbor-web-token-03
	(work in progress), January 2017.		(work in progress), March 2017.
	[I-D.ietf-core-object-security]		[I-D.ietf-core-object-security]
	Selander, G., Mattsson, J., Palombini, F., and L. Seitz,		Selander, G., Mattsson, J., Palombini, F., and L. Seitz,
	"Object Security of CoAP (OSCOAP)", draft-ietf-core-		"Object Security of CoAP (OSCOAP)", draft-ietf-core-
	object-security-01 (work in progress), December 2016.		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., Bradley, J., Jones, M., and H. Tschofenig,
	Tschofenig, "OAuth 2.0 Device Flow", draft-ietf-oauth-		"OAuth 2.0 Device Flow for Browserless and Input
	device-flow-03 (work in progress), July 2016.		Constrained Devices", draft-ietf-oauth-device-flow-04
			(work in progress), February 2017.
	[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-07 (work in progress),		draft-ietf-oauth-native-apps-09 (work in progress), March
	January 2017.		2017.
	[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 50, line 43 ¶		skipping to change at page 51, line 43 ¶
	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.		for the convenience of a profile designer.
	o Optionally Specify the discovery process of how the client finds		o Optionally Specify the discovery process of how the client finds
	the right AS for an RS it wants to send a request to. Section 4		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). Section 5 and Section 6.5.4		(e.g. CoAP). Section 5 and Section 5.5.4.4
	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.
	Section 6.5.4		Section 5.5.4.4
	o Specify how the client and the RS mutually authenticate.		o Specify how the client and the RS mutually authenticate.
	Section 4		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"). Section 4		"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. Section 6.5.3		possession protocol. Section 5.5.4.3
	o Specify a unique profile identifier. Section 6.5.4		o Specify a unique profile identifier. Section 5.5.4.4
	o Optionally specify how the RS talks to the AS for		o Optionally specify how the RS talks to the AS for
	introspection.Section 7		introspection.Section 5.6
	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. Section 6		token. Section 5.5
	o Specify how/if the /authz-info endpoint is protected. Section 8.1		o Specify how/if the /authz-info endpoint is protected.
			Section 5.7.1
	o Optionally define other methods of token transport than the		o Optionally define other methods of token transport than the
	/authz-info endpoint. Section 8.1		/authz-info endpoint. Section 5.7.1
	Appendix D. Assumptions on AS knowledge about C and RS		Appendix D. Assumptions on AS knowledge about C and RS
	This section lists the assumptions on what an AS should know about a		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		client and a RS in order to be able to respond to requests to the
	/token and /introspect endpoints. How this information is		/token and /introspect endpoints. How this information is
	established is out of scope for this document.		established is out of scope for this document.
	o The identifier of the client or RS.		o The identifier of the client or RS.
	o The profiles that the client or RS supports.		o The profiles that the client or RS supports.
	skipping to change at page 59, line 30 ¶		skipping to change at page 60, line 30 ¶
	| | 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 27: Resource request and response protected by OSCOAP		Figure 27: Resource request and response protected by OSCOAP
	Appendix F. Document Updates		Appendix F. Document Updates
	F.1. Version -04 to -05		F.1. Version -05 to -06
			o Moved sections that define the ACE framework into a subsection of
			the framework Section 5.
			o Split section on client credentials and grant into two separate
			sections, Section 5.1, and Section 5.2.
			o Added Section 5.3 on AS authentication.
			o Added Section 5.4 on the Authorize endpoint.
			F.2. Version -04 to -05
	o Added RFC 2119 language to the specification of the required		o Added RFC 2119 language to the specification of the required
	behavior of profile specifications.		behavior of profile specifications.
	o Added section 6.1 on the relation to the OAuth2 grant types.		o Added Section 5.2 on the relation to the OAuth2 grant types.
	o Added CBOR abbreviations for error and the error codes defined in		o Added CBOR abbreviations for error and the error codes defined in
	OAuth2.		OAuth2.
	o Added clarification about token expiration and long-running		o Added clarification about token expiration and long-running
	requests in section 8.2.		requests in Section 5.7.2
	o Added security considerations about tokens with symmetric pop keys		o Added security considerations about tokens with symmetric pop keys
	valid for more than one RS.		valid for more than one RS.
	o Added privacy considerations section.		o Added privacy considerations section.
	o Added IANA registry mapping the confirmation types from RFC 7800		o Added IANA registry mapping the confirmation types from RFC 7800
	to equivalent COSE types.		to equivalent COSE types.
	o Added appendix D, describing assumptions about what the AS knows		o Added appendix D, describing assumptions about what the AS knows
	about the client and the RS.		about the client and the RS.
	F.2. Version -03 to -04		F.3. Version -03 to -04
	o Added a description of the terms "framework" and "profiles" as		o Added a description of the terms "framework" and "profiles" as
	used in this document.		used in this document.
	o Clarified protection of access tokens in section 3.1.		o Clarified protection of access tokens in section 3.1.
	o Clarified uses of the 'cnf' parameter in section 6.4.5.		o Clarified uses of the 'cnf' parameter in section 6.4.5.
	o Clarified intended use of Client Token in section 7.4.		o Clarified intended use of Client Token in section 7.4.
	F.3. Version -02 to -03		F.4. 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.
	F.4. Version -01 to -02		F.5. 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 possession.		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.
	F.5. Version -00 to -01		F.6. 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
	skipping to change at page 61, line 4 ¶		skipping to change at page 62, line 17 ¶
	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
	token.		token.
	* Require that the messages between AS and client are secured,		* Require that the messages between AS and client are secured,
	either with (D)TLS or with COSE_Encrypted wrappers.		either with (D)TLS or with COSE_Encrypted wrappers.
	* Removed dependency on OSCoAP and added generic text about		* Removed dependency on OSCOAP and added generic text about
	object security instead.		object security instead.
	* Defined the "rpk" parameter in the client information to		* Defined the "rpk" parameter in the client information to
	transmit the raw public key of the RS from AS to client.		transmit the raw public key of the RS from AS to client.
	* (D)TLS MUST use the PoP key in the handshake (either as PSK or		* (D)TLS MUST use the PoP key in the handshake (either as PSK or
	as client RPK with client authentication).		as client RPK with client authentication).
	* Defined the use of x5c, x5t and x5tS256 parameters when a		* Defined the use of x5c, x5t and x5tS256 parameters when a
	client certificate is used for proof of possession.		client certificate is used for proof of possession.
	* Defined "tktn" parameter for signaling for how to transfer the		* Defined "tktn" parameter for signaling for how to transfer the
	access token.		access token.
	o Added 5.2. the CoAP Access-Token option for transferring access		o Added 5.2. the CoAP Access-Token option for transferring access
	skipping to change at page 61, line 29 ¶		skipping to change at page 62, line 41 ¶
	o 5.3.2. Defined success and error responses from the RS when		o 5.3.2. Defined success and error responses from the RS when
	receiving an access token.		receiving an access token.
	o 5.6.:Added section giving guidance on how to handle token		o 5.6.:Added section giving guidance on how to handle token
	expiration in the absence of reliable time.		expiration in the absence of reliable time.
	o Appendix B Added list of roles and responsibilities for C, AS and		o Appendix B Added list of roles and responsibilities for C, AS and
	RS.		RS.
	Authors' Addresses		Authors' Addresses
	Ludwig Seitz		Ludwig Seitz
	SICS		RISE SICS
	Scheelevaegen 17		Scheelevaegen 17
	Lund 223 70		Lund 223 70
	SWEDEN		SWEDEN
	Email: ludwig@sics.se		Email: ludwig@ri.se
	Goeran Selander		Goeran Selander
	Ericsson		Ericsson
	Faroegatan 6		Faroegatan 6
	Kista 164 80		Kista 164 80
	SWEDEN		SWEDEN
	Email: goran.selander@ericsson.com		Email: goran.selander@ericsson.com
	Erik Wahlstroem		Erik Wahlstroem
			(no affiliation)
	Sweden		Sweden
	Email: erik@wahlstromtekniska.se		Email: erik@wahlstromtekniska.se
	Samuel Erdtman		Samuel Erdtman
	Spotify AB		Spotify AB
	Birger Jarlsgatan 61, 4tr		Birger Jarlsgatan 61, 4tr
	Stockholm 113 56		Stockholm 113 56
	Sweden		Sweden
	Email: erdtman@spotify.com		Email: erdtman@spotify.com
	Hannes Tschofenig		Hannes Tschofenig
	ARM Ltd.		ARM Ltd.
End of changes. 108 change blocks.
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